Copper(II) Perfluorinated Carboxylate Complexes with Small Aliphatic Amines as Universal Precursors for Nanomaterial Fabrication

Copper(II) carboxylate compounds with ethylamine and isopropylamine of the general formula [Cu2(RNH2)2(µ-O2CRf)4], where R = Et, iPr, and Rf = CnF2n+1, n = 1–6, were characterised in the condensed and gas phases by electron impact mass spectrometry (EI MS), IR spectroscopy, and thermal analysis. A mass spectra analysis confirmed the presence of metallated species in the gas phase. Among the observed fragments, the pseudomolecular ions [Cu2(RNH2)2(µ-O2CRf)3]+ were found, which suggests the dimeric structure of the studied complexes with axially N-coordinated ethyl- or isopropylamine molecules and bridging perfluorinated carboxylates. TGA studies demonstrated that copper transfer to the gas phase occurs even under atmospheric pressure. The temperature range of the [Cu2(RNH2)2(µ-O2CRf)4] and other copper carriers detection, observed in variable temperature infrared spectra, depends on the type of amine. The possible mechanisms of the decomposition of the tested compounds are proposed. The copper films were produced without additional reducing agents despite using Cu(II) CVD precursors in the chemical vapor deposition experiments. The layers of the gel-like complexes were fabricated in both spin- and dip-coating experiments, resulting in copper or copper oxide materials when heated. Dinuclear copper(II) carboxylate complexes with ethyl- and isopropylamine [Cu2(RNH2)2(µ-O2CRf)4] can be applied for the formation of metal or metal oxide materials, also in the nanoscale, by vapour and ‘wet’ deposition methods.


Introduction
Nowadays, copper compounds are applied as antifungal and antibacterial coatings, catalysts, or in the assembly of chemical and electrochemical sensors. [1]. Additionally, organic-inorganic hybrid compounds containing copper-bis(triazole) complexes and Keggin-type polyoxometalates (POMs) showed electrocatalytic activities towards the reduction of nitrites [2]. Copper-halide compounds may be employed as new light-emitting materials [3] and in photovoltaic application [4].
The spin coating was a multistage process, the spin speed was varied from 600 to 3000 rpm, and the process time was changed over the range 4-60 s. The SC (spin-coated) materials were obtained in four stages program. Each program consisted of three steps with variable spin speed and one drying stage (3000 rpm, 1 min). The solution introduction on the substrate and all deposition procedures for each layer were repeated twice.
The dip-coating parameters were the following: the withdraw rate 20-80 mm/min, the immersion rate 60-80 mm/min, the immersion time 5, 10, or 120 s, and the coating count 5-80.
The films obtained by both techniques were characterised and next heated in a tube furnace PRW 55 Czylok equipped with a quartz reactor with steel gas heads. The process was carried out under a nitrogen atmosphere (1 cm 3 /min) at 673 K for 3 h. Then deposits were cooled down under nitrogen for 3 h. The heating temperature of the films was selected based on the thermal analysis results.
The results of elementary analyses and spectroscopic data are given below: Data for copper complexes (2) and (3) have been published previously [11,12].
The obtained compounds (1-10) were blue, gel-like solids, stable without moisture access for months.
Assuming the C 4v microsymmetry of the Cu(II) coordination sphere [9] spectra in the metal-ligand vibrations region (600-100 cm −1 ) can be described in the following manner: the bands detected over the range 419-429 cm −1 can be assigned to Cu-N stretching vibrations and these observed over 375-395 cm −1 and 331-360 cm −1 -to asymmetric and symmetric CuO 4 stretching vibrations, respectively [28].

Mass Spectra Analysis
Mass spectra (EI MS) of the studied compounds were measured between 303 and 623 K (Figures S11-S20) and applied for the molecular mass determination and structural characteristics. Additionally, metallated fragments in the gas phase can be identified, and a preliminary usefulness evaluation of usefulness by vapour deposition techniques can also be considered.

Results of Thermal Analysis
The thermal analysis of the complexes (1-4) and (7)(8)(9)(10) indicates that the slow weight loss occurs from the beginning of heating of the complex (Figures S21 and S23-S28). A complicated process is observed at higher temperatures. Analysis of the DTA curve for these compounds indicates the endothermic effects connected with thermal decomposition.
The temperature of the decomposition process onset changed over the range 388-410 K and 308-355 K for complexes containing ethyl or isopropyl group, respectively. The temperature of the final product formation varied from 505 K to 532 K (1), (3), (4), and 478 K to 548 K (7-10). The lowest T m (466 K and 463-464 K) was observed for the compound (3), (9), and (10) containing chain R f = C 3 F 7 , C 4 F 9 and the highest value (486 K and 474 K) for (1) and (7) including group CF 3 . The mass of the residues after the thermal analysis for compounds (1) and (7) reveals that the decomposition product of the compounds with EtNH 2 is metallic copper, while for compounds with i PrNH 2, it is copper(II) oxide ( Table 4). The formation of these substances is also confirmed by the color of the residue, red-orange and black, respectively. In the case of the complexes (3), (4), (8), and (9), the mass of the final decomposition products was lower than the value calculated for pure copper or copper(II) oxide (Table 4), which suggests that the copper transfer to the gas phase occurred under the atmospheric pressure, which seemed promising for the CVD and FEBID application. The higher residue mass with regard to its theoretical value for the compound (10) (R f = C 6 F 13 ) may indicate carbon contamination during thermal decomposition. In the case of [Cu 2 (EtNH 2 ) 2 (µ-O 2 CR f ) 4 ] complexes, the onset temperatures achieved higher values than those for the tert-butylamine analogues. However, for the [Cu 2 ( i PrNH 2 ) 2 (µ-O 2 CR f ) 4 ] complexes, the initial temperatures of the decomposition process were similar to the temperatures observed for the compounds containing the tert-butylamine group. On the contrary, the observed final decomposition temperatures were lower for the compounds containing ethylamine and also the isopropylamine group. It means that the thermal decomposition ranges for the [Cu 2 (RNH 2 ) 2 (µ-O 2 CR f ) 4 ] complexes discussed here are narrower than those for previously described [Cu 2 ( t BuNH 2 ) 2 (µ-O 2 CR f ) 4 ] compounds. Interestingly, in the case of complexes with t BuNH 2 , [Cu 2 ( t BuNH 2 ) 2 (µ-O 2 CCF 3 ) 4 ] was the most volatile, while for i PrNH 2 and EtNH 2, it was observed that compounds with trifluoroacetate have the lowest volatility [9].
Due to the complexity of the process of thermal decomposition of the compounds, we decided to investigate it in more detail for the complex (1) by examining gas phase composition during thermal analysis by infrared spectroscopy (TGA/IR). The spectra analysis showed the characteristic absorption bands for coordinated ethylamine (νCH = 2990 cm −1 , δNH 2 = 1524 cm −1 ) and carboxylate ligands (ν as COO = 1701 cm −1 , ν s COO = 1440 cm −1 ). These results suggested that from 413 to 436 K, the complex (1) undergoes evaporation. The 2361 cm −1 band, characteristics of CO 2 [34], was detected over the whole studied temperature range (413-501 K), but between 446 and 478 K, its intensity decreased rapidly ( Figure S22). The bands typical for fluorinated species (νCF = 1199 cm −1 , 1156 cm −1 ) were observed throughout the temperature range. The typical bands for H 2 O (νOH = 4000-3500 cm −1 , δOH = 1800-1300 cm −1 ) [35] were registered over the 446-501 K. The free amine [36] was detected over 413-478 K. The observed organic molecule bands indicate the partial compound decomposition in the gas phase ( Figure 3). studied temperature range (413-501 K), but between 446 and 478 K, its intensity decreased rapidly ( Figure S22). The bands typical for fluorinated species (νCF = 1199 cm −1 , 1156 cm −1 ) were observed throughout the temperature range. The typical bands for H2O (νOH = 4000-3500 cm −1 , δOH = 1800-1300 cm −1 ) [35] were registered over the 446-501 K. The free amine [36] was detected over 413-478 K. The observed organic molecule bands indicate the partial compound decomposition in the gas phase ( Figure 3). The TGA/IR results confirm that the thermal decomposition of the compound (1) is a complicated process. Additionally, it has been shown that the complex (1) enters the gas phase in the initial heating phase in a narrow temperature range and is accompanied by its decomposition.

Temperature Variable Infrared Spectroscopy
The The TGA/IR results confirm that the thermal decomposition of the compound (1) is a complicated process. Additionally, it has been shown that the complex (1) enters the gas phase in the initial heating phase in a narrow temperature range and is accompanied by its decomposition.
In the case of the [Cu 2 (EtNH 2 ) 2 (µ-O 2 CCF 3 ) 4 ] (1) four bands (1801 cm −1 , 1759 cm −1 , 1709 cm −1 , and 1682 cm −1 ) within the range characteristic of C=O stretching vibrations were observed in the temperature between 433 and 533 K. The first is typical of gas-phase ethyl trifluoroacetate, which seems to be the decomposition product [37] The carboxylic acid formation was also considered, but in the spectrum of CF 3 COOH acid in the gas phase, the band νC=O band appears at 1826 cm −1 and 1788 cm −1 for the monomeric and the dimeric form, respectively [38][39][40]. Due to the existence of a band coordination shift relative to ν as COO for the free carboxylic acid, other bands in this area can be attributed to asymmetric vibrations of the coordinated COO group ( Figure 4). Therefore, the lowest band (1682 cm −1 ) can be assigned to the ν as COO vibrations in the copper carboxylate [Cu 2 (µ-O 2 CCF 3 ) 4 ], as evidenced by the gas-phase spectrum measured for copper(II) pentafluoropropionate ( Figure S29). In the solid-phase spectra, the v as COO band are shifted towards higher values for the amine-containing compounds when compared to the copper carboxylate (1647 cm −1 → 1672 cm −1 ; Figure S30 and Figure 5). Taking this fact into account, the band at 1709 cm −1 can be assigned to the vibration of ν as COO in the molecule of the complex (1) in the gas phase, which means shifting up 37 cm −1 with regard to the compound (1) in the solid phase ( Figure 5). The coordinated ethylamine vibrations bands were also identified at 2995 cm −1 (νCH 3 ), 3168 cm −1 (νNH 2 ), and 1532 cm −1 (δNH 2 ), which additionally confirmed the evaporation of the complex during heating. Interestingly, no bands characteristic of free ethylamine in the gas phase were observed in the spectra (3345 cm −1 ,1620 cm −1 [41]). The occurrence of the v as COO at 1759 cm −1 (shift towards higher values) indicates a change in the coordination mode from bidentate to unidentate [42] Combining this fact with the presence of the vNH 2 at 3486 cm −1 , the formation of the transitional copper(II) carboxylate complex with coordinated amido group (NH 2 − ) in the gas phase, in which the coordination center is reduced to Cu(I) and a hydrazine-bridged complex is generated, has been proposed ( Figure 6). A similar chemical reaction was observed for the nickel complexes. [43] The strongest registered signals came from the νCF stretching vibrations over the 1152-1203 cm −1 range.
In the next step, at the temperature of 553 K, the band at 3035 cm −1 from the νCH 3 stretching vibrations and at 1154 cm −1 from the νCF stretching vibrations were registered. Ethyl trifluoroacetate was still observed in the gas phase. Moreover, the identified bands at 2345 cm −1 and 2172 cm −1 can be assigned to the CO 2 and CO molecules, respectively. A band characteristic of aliphatic fluorinated compounds (1029 cm −1 ) was also detected. The above data analysis leads to a conclusion that the [Cu 2 (EtNH 2 ) 2 (µ-O 2 CCF 3 ) 4 ] complex (1) exists from 473 K to 533 K in the gas phase. Over this temperature, the compound (1) disappeared, and the decomposition products mixture was formed.
stretching vibrations and at 1154 cm from the νCF stretching vibrations were registered. Ethyl trifluoroacetate was still observed in the gas phase. Moreover, the identified bands at 2345 cm −1 and 2172 cm −1 can be assigned to the CO2 and CO molecules, respectively. A band characteristic of aliphatic fluorinated compounds (1029 cm −1 ) was also detected. The above data analysis leads to a conclusion that the [Cu2(EtNH2)2(µ-O2CCF3)4] complex (1) exists from 473 K to 533 K in the gas phase. Over this temperature, the compound (1) disappeared, and the decomposition products mixture was formed.  Similar products in the gas phase were observed in the VT IR spectra for compounds (2), (4), (7), and (8). Bands characteristic of the studied complexes were noted for each of them, and they are also shifted towards higher values in relation to the signals in the solid phase ( Figures S31−S36). In conclusion, the compounds with ethylamine evaporate in the temperature range 433−533 K but those with isopropylamine in the range 473−613 K (Table  5). Similar products in the gas phase were observed in the VT IR spectra for compounds (2), (4), (7), and (8). Bands characteristic of the studied complexes were noted for each of them, and they are also shifted towards higher values in relation to the signals in the solid phase ( Figures S31-S36). In conclusion, the compounds with ethylamine evaporate in the temperature range 433-533 K but those with isopropylamine in the range 473-613 K ( Table 5). Table 5. Temperature ranges of occurrence of decomposition products in the gas phase for compounds (1), (2), (4), (7), and (8).

The Product in the Gas
The presence of carboxylic acid was identified for compounds (2) and (7) in the gas phase. In the case of the complex (2), relatively intense signals characteristic of water contamination in the gas phase were also observed in the spectra. Its presence may explain the formation of acid during decomposition. For the compound (7), the bands for water are not visible. The low intensity of the ν as COO band for the acid testifies to its little concentration in the gas phase. Therefore, the water content in the gas phase may be so low that it is invisible in the spectra but sufficient to form an acid. In addition, for the complex (2), the formation of CO 2 was detected at the temperature of 413 K before the appearance of metal carriers in the gas phase. In the case of the compound (4), the bands characteristic of copper carboxylates with a coordinated amide (NH 2 − ) group were not registered. The possible mechanisms of the decomposition of the tested compounds are shown in Figure 6.  (7), the bands for water are not visible. The low intensity of the νasCOO band for the acid testifies to its little concentration in the gas phase. Therefore, the water content in the gas phase may be so low that it is invisible in the spectra but sufficient to form an acid. In addition, for the complex (2), the formation of CO2 was detected at the temperature of 413 K before the appearance of metal carriers in the gas phase. In the case of the compound (4), the bands characteristic of copper carboxylates with a coordinated amide (NH2 − ) group were not registered. The possible mechanisms of the decomposition of the tested compounds are shown in Figure 6. The intensity of bands registered above 3000 cm −1 in the VT IR spectra of the compounds (1), (2), (4), (7), and (8) was lower than that in the solid phase, which confirms that in the gas phase, the number of hydrogen bonds decreased, as expected. Comparing all the [Cu2(RNH2)2(µ-O2CRf)4] complexes (R = Et, i Pr, t Bu), the earlier described compound [Cu2( t BuNH2)2(µ-O2CC2F5)4] with tert-butylamine [9,10] has the lowest evaporation temperature (413 K). On the other hand, the gas-phase complex occurs in the widest temperature range, in the case of [Cu2( i PrNH2)2(µ-O2CC2F5)4] (8). The intensity of bands registered above 3000 cm −1 in the VT IR spectra of the compounds (1), (2), (4), (7), and (8) was lower than that in the solid phase, which confirms that in the gas phase, the number of hydrogen bonds decreased, as expected. Comparing all the [Cu 2 (RNH 2 ) 2 (µ-O 2 CR f ) 4 ] complexes (R = Et, i Pr, t Bu), the earlier described compound [Cu 2 ( t BuNH 2 ) 2 (µ-O 2 CC 2 F 5 ) 4 ] with tert-butylamine [9,10] has the lowest evaporation temperature (413 K). On the other hand, the gas-phase complex occurs in the widest temperature range, in the case of [Cu 2 ( i PrNH 2 ) 2 (µ-O 2 CC 2 F 5 ) 4 ] (8).

CVD Experiments
The above-mentioned studies in the gas phase indicated that from among the obtained complexes, [Cu 2 (EtNH 2 ) 2 (µ-O 2 CCF 3 ) 4 ] (1), [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 2 F 5 ) 4 ] (2), [Cu 2 ( i PrNH 2 ) 2 (µ-O 2 CCF 3 ) 4 ] (7), [Cu 2 ( i PrNH 2 ) 2 (µ-O 2 CC 2 F 5 ) 4 ] (8), and [Cu 2 ( i PrNH 2 ) 2 (µ-O 2 CC 3 F 7 ) 4 ] (9) revealed the best properties for the purposes of Chemical Vapor Deposition precursors formation. These are derivatives of the carboxylate ligands with shorter carbon chains (number of carbon atoms in the chain n = 1-3). For all the selected compounds ((1), (2), (7), (8), and (9)), deposits were obtained by the CVD method. The vaporisation temperatures T V were 453 K (7) and 473 K (1, 2, 8, and 9), whereas the deposition temperatures T D values were from 573 K to 713 K ( Table 6). The surface morphology of the formed deposits from the complex [Cu 2 (EtNH 2 ) 2 (µ-O 2 CCF 3 ) 4 ] (1) is differentiated due to the size, shape, and density of the objects (Figure 7) and depends on the length of the transport pathway in the CVD reactor. On the first covered silicone substrate (Figure 7a), sparsely distributed nanowires with the length of 300 nm to 800 nm in length and around 50 nm to 90 nm in diameter were observed. Instead, the surface of the sample (Figure 7b) is covered by a heterogeneous and rough deposit layer on which a few nanoparticles of 80 nm in diameter were visible. The surface of the next deposit (Figure 7c) is most different from the other two because it is covered by grains with of 40 nm to 70 nm in diameter that overlap in some areas.  The surface morphology of the formed deposits from the complex [Cu2(EtNH2)2(µ-O2CCF3)4] (1) is differentiated due to the size, shape, and density of the objects (Figure 7) and depends on the length of the transport pathway in the CVD reactor. On the first covered silicone substrate (Figure 7a), sparsely distributed nanowires with the length of 300 nm to 800 nm in length and around 50 nm to 90 nm in diameter were observed. Instead, the surface of the sample (Figure 7b) is covered by a heterogeneous and rough deposit layer on which a few nanoparticles of 80 nm in diameter were visible. The surface of the next deposit (Figure 7c) is most different from the other two because it is covered by grains with of 40 nm to 70 nm in diameter that overlap in some areas.   (Figure 8b) is composed of densely packed grains with a size of 60-150 nm in size, which begin to interconnect with each other. The deposit (Figure 8c) shows that the grains virtually completely coalesce with the formation of a continuous layer. Considering data for the morphology of the obtained materials, it was found that the grains merged more and more intensively with the extension of the transport way. In order to check the effect of an amine on the type of deposits formed in the CVD process, complexes containing i PrNH2 in the axial position were also used. The surface morphology of the obtained materials (a, b, c) ( Figure 9) for the complex [Cu2( i PrNH2)2(µ-O2CCF3)4] (7) is heterogeneous. The Si(111) substrate (a) is covered by a rugged film on which oblong elements are visible. The deposit (b) consists of clusters of elements forming a rough surface. A similar situation is observed for the cover (c) but, this surface is even less homogeneous, and the areas with holes are visible. As for the complex (2), in the case of the deposits obtained for the complex [Cu2( i PrNH2)2(µ-O2CC2F5)4] (8) (Figure 10), the influence of the precursor transport way on the surface morphology and the formation of nanowires was observed. However, when the compound (8) was used, the obtained nanorods were overgrown with dropletshaped grains with a size of 80−200 nm in size (Figure 10a,b). The size of the nanorods (a) was 50−150 nm in diameter and about 900 nm in length, but the structures (b) were 20−50 nm in diameter and 500−900 nm in length. In the formed deposit (c), the packed grains with in size of 140−300 nm and nanorods in diameter of 30−70 nm and about 300−600 nm in length were grown. In order to check the effect of an amine on the type of deposits formed in the CVD process, complexes containing i PrNH2 in the axial position were also used. The surface morphology of the obtained materials (a, b, c) ( Figure 9) for the complex [Cu2( i PrNH2)2(µ-O2CCF3)4] (7) is heterogeneous. The Si(111) substrate (a) is covered by a rugged film on which oblong elements are visible. The deposit (b) consists of clusters of elements forming a rough surface. A similar situation is observed for the cover (c) but, this surface is even less homogeneous, and the areas with holes are visible. As for the complex (2), in the case of the deposits obtained for the complex [Cu2( i PrNH2)2(µ-O2CC2F5)4] (8) (Figure 10), the influence of the precursor transport way on the surface morphology and the formation of nanowires was observed. However, when the compound (8) was used, the obtained nanorods were overgrown with dropletshaped grains with a size of 80−200 nm in size (Figure 10a,b). The size of the nanorods (a) was 50−150 nm in diameter and about 900 nm in length, but the structures (b) were 20−50 nm in diameter and 500−900 nm in length. In the formed deposit (c), the packed grains with in size of 140−300 nm and nanorods in diameter of 30−70 nm and about 300−600 nm in length were grown. As for the complex (2), in the case of the deposits obtained for the complex [Cu 2 ( i PrNH 2 ) 2 (µ-O 2 CC 2 F 5 ) 4 ] (8) (Figure 10), the influence of the precursor transport way on the surface morphology and the formation of nanowires was observed. However, when the compound (8) was used, the obtained nanorods were overgrown with droplet-shaped grains with a size of 80-200 nm in size (Figure 10a,b). The size of the nanorods (a) was 50-150 nm in diameter and about 900 nm in length, but the structures (b) were 20-50 nm in diameter and 500-900 nm in length. In the formed deposit (c), the packed grains with in size of 140-300 nm and nanorods in diameter of 30-70 nm and about 300-600 nm in length were grown. Morphology of the compound [Cu2( i PrNH2)2(µ-O2CC3F7)4] (9) deposits ( Figure 11) is also heterogeneous. On the surface (a), rods of about 1 µm and single grains are visible. The substrate (b) is covered by grains differing in shape (100-180 nm) and round, smaller elements (approx. 50nm in diameter) between which single rods are visible. In comparison, surface (c) is uniformly coated by small and round grains (30-80 nm). The EDX spectra (Figure 12) confirm the presence of copper in the obtained deposits. For the majority of materials, signals from oxygen, nitrogen, carbon, and fluorine, of which the precursor was composed of which, were not observed in the spectra. A slight peak corresponding to oxygen was recorded for the cover obtained from the complex (7). It may be due to the formation of small amounts of copper oxide. In all the cases, the evaporation temperatures were similar as opposed to the deposition temperatures. In the case of the precursors (2) and (8), the copper signal in the spectrum is the most intense because the resulting covers contain a densely packed material. This result may due to the better transport of the metal carriers in the gas phase and the higher decomposition temperature used.   The EDX spectra (Figure 12) confirm the presence of copper in the obtained deposits. For the majority of materials, signals from oxygen, nitrogen, carbon, and fluorine, of which the precursor was composed of which, were not observed in the spectra. A slight peak corresponding to oxygen was recorded for the cover obtained from the complex (7). It may be due to the formation of small amounts of copper oxide. In all the cases, the evaporation temperatures were similar as opposed to the deposition temperatures. In the case of the precursors (2) and (8), the copper signal in the spectrum is the most intense because the resulting covers contain a densely packed material. This result may due to the better transport of the metal carriers in the gas phase and the higher decomposition temperature used. The EDX spectra (Figure 12) confirm the presence of copper in the obtained deposits. For the majority of materials, signals from oxygen, nitrogen, carbon, and fluorine, of which the precursor was composed of which, were not observed in the spectra. A slight peak corresponding to oxygen was recorded for the cover obtained from the complex (7). It may be due to the formation of small amounts of copper oxide. In all the cases, the evaporation temperatures were similar as opposed to the deposition temperatures. In the case of the precursors (2) and (8), the copper signal in the spectrum is the most intense because the resulting covers contain a densely packed material. This result may due to the better transport of the metal carriers in the gas phase and the higher decomposition temperature used.

Spin-and Dip-Coating Deposition
Since the first preliminary attempts to deposit nanomaterials using the ethylamine derivative in the CVD method failed, dip-and spin-coating methods were used to prepare thin layers of the gel-like copper complexes on a silicon substrate. The thus fabricated materials were then heated to decompose the compounds to produce thin copper oxide or copper layers.

Spin-Coated Materials
In the case of the [Cu2(EtNH2)2(µ-O2CC3F7)4] complex (3) deposited on the Si substrate (at 1100 rpm, 30 s), the copper compound covered the surface evenly-in the dots shape ( Figure 13). The phase AFM images show homogeneity of the covers (Figure 14a). One area of the complex layer was observed. The height (thickness) of the layers ranged from 2.5 to 25 nm. After annealing, the dots become flatter and more extensive. The roughness parameters achieved Ra = 2.46 nm, Rq = 2.14 nm before heating, and Ra = 8.76 nm, Rq = 27.50

Spin-and Dip-Coating Deposition
Since the first preliminary attempts to deposit nanomaterials using the ethylamine derivative in the CVD method failed, dip-and spin-coating methods were used to prepare thin layers of the gel-like copper complexes on a silicon substrate. The thus fabricated materials were then heated to decompose the compounds to produce thin copper oxide or copper layers.

Spin-Coated Materials
In the case of the [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 3 F 7 ) 4 ] complex (3) deposited on the Si substrate (at 1100 rpm, 30 s), the copper compound covered the surface evenly-in the dots shape ( Figure 13). The phase AFM images show homogeneity of the covers (Figure 14a). One area of the complex layer was observed. The height (thickness) of the layers ranged from 2.5 to 25 nm.

Spin-and Dip-Coating Deposition
Since the first preliminary attempts to deposit nanomaterials using the ethylamine derivative in the CVD method failed, dip-and spin-coating methods were used to prepare thin layers of the gel-like copper complexes on a silicon substrate. The thus fabricated materials were then heated to decompose the compounds to produce thin copper oxide or copper layers.

Spin-Coated Materials
In the case of the [Cu2(EtNH2)2(µ-O2CC3F7)4] complex (3) deposited on the Si substrate (at 1100 rpm, 30 s), the copper compound covered the surface evenly-in the dots shape ( Figure 13). The phase AFM images show homogeneity of the covers (Figure 14a). One area of the complex layer was observed. The height (thickness) of the layers ranged from 2.5 to 25 nm. After annealing, the dots become flatter and more extensive. The roughness parameters achieved Ra = 2.46 nm, Rq = 2.14 nm before heating, and Ra = 8.76 nm, Rq = 27.50 After annealing, the dots become flatter and more extensive. The roughness parameters achieved R a = 2.46 nm, R q = 2.14 nm before heating, and R a = 8.76 nm, R q = 27.50 nm after heating, which points to the roughness increasing after the complex thermal decomposition Figure 14b.  The application of the [Cu2(EtNH2)2(µ-O2CC2F5)4] complex (2) on Si(111) in the multistage spin coating process gave the formation of a new type of layers type, in which small islands of the compound occasionally appeared. The size of these islands did not exceed 1 µm. Depending on the spin coating conditions, the films with different arrangements were obtained. The complex formed grains of regular size and covered the surface evenly without empty spaces. The layer was smooth with Ra = 1.78 nm, Rq = 2.37 nm, and 15 nm thick. Similar to how it was observed for the [Cu2(EtNH2)2(µ-O2CC3F7)4] (3) materials, SEM analysis indicated the presence of the small crystallites in the complex surface.
After heating, the size of the grains increased, and sometimes the empty spaces appeared; the cracks were also noted resulting in inhomogeneous cover ( Figure 15). This fact influenced the surface roughness, and the parameters Ra and Rq increased significantly, achieving 15.1 nm and 18.7 nm, respectively. Generally, the roughness of the obtained layers increased after annealing (Figure 16). Additionally, after heating the layers, the defects (spaces between compounds structures) increased twice from about 60 nm to 120 nm. As a consequence, the discontinuity of the films was observed. Different film thicknesses can be explained by the above-mentioned spin coating process as a result of which defects upon heating can be produced. Unequal evaporation of the in situ formed reaction products leads to partially cracked films of copper compounds films. A similar phenomenon was observed in the case of other copper and silver complexes [44]. The application of the [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 2 F 5 ) 4 ] complex (2) on Si(111) in the multistage spin coating process gave the formation of a new type of layers type, in which small islands of the compound occasionally appeared. The size of these islands did not exceed 1 µm. Depending on the spin coating conditions, the films with different arrangements were obtained. The complex formed grains of regular size and covered the surface evenly without empty spaces. The layer was smooth with R a = 1.78 nm, R q = 2.37 nm, and 15 nm thick. Similar to how it was observed for the [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 3 F 7 ) 4 ] (3) materials, SEM analysis indicated the presence of the small crystallites in the complex surface.
After heating, the size of the grains increased, and sometimes the empty spaces appeared; the cracks were also noted resulting in inhomogeneous cover ( Figure 15). This fact influenced the surface roughness, and the parameters R a and R q increased significantly, achieving 15.1 nm and 18.7 nm, respectively. Generally, the roughness of the obtained layers increased after annealing (Figure 16). Additionally, after heating the layers, the defects (spaces between compounds structures) increased twice from about 60 nm to 120 nm. As a consequence, the discontinuity of the films was observed. Different film thicknesses can be explained by the above-mentioned spin coating process as a result of which defects upon heating can be produced. Unequal evaporation of the in situ formed reaction products leads to partially cracked films of copper compounds films. A similar phenomenon was observed in the case of other copper and silver complexes [44].     4 ]/Si (2) material (1100 rpm 30 s), and the following amount of copper: 0.78 wt.% before and 1.05 wt.% after heating were found. Moreover, the punctual copper quantity was much higher and achieved 20.4 wt.%. This situation results from the heating and an irregularly arrangement of a compound on the substrate surface (the presence of local islands of compounds). After heating, only Cu and O elements were detected as the result of the copper complex thermal decomposition. The lack of fluorine and nitrogen signals indicated the most probable formation of CuO as the final product. According to our expectations, the relative concentration of copper in the layers increased after heating. The above discussion suggests that the quality of the layer (uniformity, roughness) can be optimised by the spin speed and deposition time variation.

Dip-Coated Materials
Dip coating was the second method used to obtain thin layers of both complexes (2) and (3). Considering the essential factors affecting the formation and quality of the fabricated covers, the effect of the following parameters was taken into account: the number of coating counts (varied from 5 to 30), immersion rate (from 20 to 80 mm/min), and the immersion time (over 5−120 s). Selected from among twenty-one, the four different sets of process parameters, for which the deposition effects were most promising, were chosen ( Table 7). The influence of coating counts on the properties of the [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 2 F 5 ) 4 ] (2) layers were studied as well. Again, the complex layers were heated to obtain copper oxide or thin copper materials. AFM results showed evenly distributed copper complexes on the silicon surface and layers without discontinuities. The phase AFM images exhibited only one area of the complex layers (Figures 17 and 18).
The covers of [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 3 F 7 ) 4 ] (3) obtained at the immersion time 30 s exhibited tight surface; in some places, depressions and ridges appeared (R a = 2.90 nm, R q = 3.98 nm) ( Figures S37, S38 and Figure 17). These layers are slightly rougher than the deposits obtained in the spin coating process (R a = 2.46 nm, R q = 2.14 nm). Reducing the immersion time to 20 s led to a more covered surface-the weight percent of silicon equals 10, which suggests a relatively good deposition of the copper complex on the surface. The best dip-coating parameters were immersion rate 10, immersion speed 80 mm/min, immersion time 20 s (Figures S15 and S39). The EDX analysis confirmed the presence of the complex by the percentage of copper 9.93 wt.%, oxygen 3. The [Cu2(EtNH2)2(µ-O2CC2F5)4] (2) complex forming materials obtained by deposition on Si(111) exhibited a thin, regular structure at the following roughness parameters as follows: Ra = 0.34-0.40 nm, Rq = 0.45-0.50 nm. In some cases, small, single crystallites appeared. These layers are smoother than those fabricated by the spin-coating method (Ra = 1.78 nm, Rq = 2.37 nm for SC). The phase AFM images show homogeneity of the covers (Figure 18). One area of the complex layer was observed. The height of the layer was equal to 68 nm. Additionally, the AFM analysis pointed out a difference in the materials depending on the coating counts (5 or 10). In both cases, the layers are smooth, but increasing the coating count leads to the layers in which the singular, randomly distributed crystallites appear. For all the dip-coated materials, the roughness of the layers increased after heating. The enhancement of the roughness is a consequence of the solvent lose and decomposition of the copper complex. Other authors observed the same effect in the case of silver and copper complexes [13,14,45]. After heating, the layers' shape, structure, and composition were changed significantly. In the [Cu2(EtNH2)2(µ-O2CC3F7)4] (3)/Si materials, the grains of sizes from 5 to 500 nm, formed irregular aggregates. The regular grains were evenly dispersed on the silicon surface ( Figures S40A and 19-21). The [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 2 F 5 ) 4 ] (2) complex forming materials obtained by deposition on Si(111) exhibited a thin, regular structure at the following roughness parameters as follows: R a = 0.34-0.40 nm, R q = 0.45-0.50 nm. In some cases, small, single crystallites appeared. These layers are smoother than those fabricated by the spin-coating method (R a = 1.78 nm, R q = 2.37 nm for SC). The phase AFM images show homogeneity of the covers ( Figure 18). One area of the complex layer was observed. The height of the layer was equal to 68 nm. Additionally, the AFM analysis pointed out a difference in the materials depending on the coating counts (5 or 10). In both cases, the layers are smooth, but increasing the coating count leads to the layers in which the singular, randomly distributed crystallites appear. The [Cu2(EtNH2)2(µ-O2CC2F5)4] (2) complex forming materials obtained by deposition on Si(111) exhibited a thin, regular structure at the following roughness parameters as follows: Ra = 0.34-0.40 nm, Rq = 0.45-0.50 nm. In some cases, small, single crystallites appeared. These layers are smoother than those fabricated by the spin-coating method (Ra = 1.78 nm, Rq = 2.37 nm for SC). The phase AFM images show homogeneity of the covers (Figure 18). One area of the complex layer was observed. The height of the layer was equal to 68 nm. Additionally, the AFM analysis pointed out a difference in the materials depending on the coating counts (5 or 10). In both cases, the layers are smooth, but increasing the coating count leads to the layers in which the singular, randomly distributed crystallites appear. For all the dip-coated materials, the roughness of the layers increased after heating. The enhancement of the roughness is a consequence of the solvent lose and decomposition of the copper complex. Other authors observed the same effect in the case of silver and copper complexes [13,14,45]. After heating, the layers' shape, structure, and composition were changed significantly. In the [Cu2(EtNH2)2(µ-O2CC3F7)4] (3)/Si materials, the grains of sizes from 5 to 500 nm, formed irregular aggregates. The regular grains were evenly dispersed on the silicon surface ( Figures S40A and 19-21). For all the dip-coated materials, the roughness of the layers increased after heating. The enhancement of the roughness is a consequence of the solvent lose and decomposition of the copper complex. Other authors observed the same effect in the case of silver and copper complexes [13,14,45]. After heating, the layers' shape, structure, and composition were changed significantly. In the [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 3 F 7 ) 4 ] (3)/Si materials, the grains of sizes from 5 to 500 nm, formed irregular aggregates. The regular grains were evenly dispersed on the silicon surface ( Figures S40A and 19-21).  Surprisingly, the relative copper content decreased several times in some cases (e.g., from 9.93 to 5.64 wt.%). The layers were smooth with Ra = 3.53 nm, Rq = 4.31 nm before heating and rough Ra = 33.4 nm, Rq = 42.3 nm after heating ( Figure 21).
Similar results were observed in the case of nickel and cobalt films, which were achieved by a dip-coating process using acetolhydrazone (ALH) as a dissolving and reducing agent [46]. When the copper acetate and diethanoldiamine as solvent were used and the produced films were then heated, thin, homogenous, and smooth layers without cracks were obtained [25]. The films consisted of grains of sizes dependent on heating temperature. The roughness of these films was relatively low and ranged from 50 to 100 nm.  Surprisingly, the relative copper content decreased several times in some cases (e.g., from 9.93 to 5.64 wt.%). The layers were smooth with Ra = 3.53 nm, Rq = 4.31 nm before heating and rough Ra = 33.4 nm, Rq = 42.3 nm after heating ( Figure 21).
Similar results were observed in the case of nickel and cobalt films, which were achieved by a dip-coating process using acetolhydrazone (ALH) as a dissolving and reducing agent [46]. When the copper acetate and diethanoldiamine as solvent were used and the produced films were then heated, thin, homogenous, and smooth layers without cracks were obtained [25]. The films consisted of grains of sizes dependent on heating temperature. The roughness of these films was relatively low and ranged from 50 to 100 nm. Surprisingly, the relative copper content decreased several times in some cases (e.g., from 9.93 to 5.64 wt.%). The layers were smooth with R a = 3.53 nm, R q = 4.31 nm before heating and rough R a = 33.4 nm, R q = 42.3 nm after heating ( Figure 21).
Similar results were observed in the case of nickel and cobalt films, which were achieved by a dip-coating process using acetolhydrazone (ALH) as a dissolving and reducing agent [46]. When the copper acetate and diethanoldiamine as solvent were used and the produced films were then heated, thin, homogenous, and smooth layers without cracks were obtained [25]. The films consisted of grains of sizes dependent on heating temperature. The roughness of these films was relatively low and ranged from 50 to 100 nm. Additionally, for [Cu2(EtNH2)2(µ-O2CC3F7)4] (3)/Si covers after heating, TEM analysis was performed ( Figure 22). TEM results confirmed the presence of copper (96.51 atomic %) and a small amount of oxygen in the layer, suggesting the metallic copper materials as the final product of thermal treatment. The diffraction analysis pointed to the d h k l = 2/5 nm = 0.4 nm and confirmed the copper grains formation as the final heating product [47]. The materials were formed by spherical structures of around 50 nm in size and were also grouped, creating agglomerates.  Additionally, for [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 3 F 7 ) 4 ] (3)/Si covers after heating, TEM analysis was performed ( Figure 22). TEM results confirmed the presence of copper (96.51 atomic %) and a small amount of oxygen in the layer, suggesting the metallic copper materials as the final product of thermal treatment. The diffraction analysis pointed to the d h k l = 2/5 nm = 0.4 nm and confirmed the copper grains formation as the final heating product [47]. The materials were formed by spherical structures of around 50 nm in size and were also grouped, creating agglomerates. Additionally, for [Cu2(EtNH2)2(µ-O2CC3F7)4] (3)/Si covers after heating, TEM analysis was performed ( Figure 22). TEM results confirmed the presence of copper (96.51 atomic %) and a small amount of oxygen in the layer, suggesting the metallic copper materials as the final product of thermal treatment. The diffraction analysis pointed to the d h k l = 2/5 nm = 0.4 nm and confirmed the copper grains formation as the final heating product [47]. The materials were formed by spherical structures of around 50 nm in size and were also grouped, creating agglomerates.  Moreover, for [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 2 F 5 ) 4 ] (2)/Si, the regular spherical shapes of 7-420 nm in dimension were observed ( Figure S40B and Figure 23). These grains were regularly disposed on the silicon surface. These structures are unusual regarding materials obtained by the dip-coating method. Moreover, for [Cu2(EtNH2)2(µ-O2CC2F5)4] (2)/Si, the regular spherical shapes of 7-420 nm in dimension were observed ( Figures S40B, 23 and 24). These grains were regularly disposed on the silicon surface. These structures are unusual regarding materials obtained by the dip-coating method. The EDX results indicated the presence of copper and oxygen suggesting copper oxide to be the thermal decomposition product. Carbon as an impurity was detected as well (a few weight percent). Grains were evenly spread on the silicon surface. Therefore, a tight, rough surface of materials without cracks was observed (Figures 24 and 25). The surface roughness increased from several to tens of nanometres (Ra over the range 14.0-33.0 nm, Rq = 21.5-42.0 nm). The height of the layer is about 0.5 µm. The increase in the surface's roughness was observed for materials resulting from applying both, the spinand dip-coating methods.  The EDX results indicated the presence of copper and oxygen suggesting copper oxide to be the thermal decomposition product. Carbon as an impurity was detected as well (a few weight percent). Grains were evenly spread on the silicon surface. Therefore, a tight, rough surface of materials without cracks was observed (Figures 24 and 25). The surface roughness increased from several to tens of nanometres (R a over the range 14.0-33.0 nm, R q = 21.5-42.0 nm). The height of the layer is about 0.5 µm. The increase in the surface's roughness was observed for materials resulting from applying both, the spin-and dip-coating methods. Moreover, for [Cu2(EtNH2)2(µ-O2CC2F5)4] (2)/Si, the regular spherical shapes of 7-420 nm in dimension were observed ( Figures S40B, 23 and 24). These grains were regularly disposed on the silicon surface. These structures are unusual regarding materials obtained by the dip-coating method. The EDX results indicated the presence of copper and oxygen suggesting copper oxide to be the thermal decomposition product. Carbon as an impurity was detected as well (a few weight percent). Grains were evenly spread on the silicon surface. Therefore, a tight, rough surface of materials without cracks was observed (Figures 24 and 25). The surface roughness increased from several to tens of nanometres (Ra over the range 14.0-33.0 nm, Rq = 21.5-42.0 nm). The height of the layer is about 0.5 µm. The increase in the surface's roughness was observed for materials resulting from applying both, the spinand dip-coating methods.  The comparison of the layers obtained by two different wet methods, i.e., dip-and spin-coating indicates that the better results-thin, smooth materials without cracks with high copper content-were obtained by the dip-coating technique (immersion rate: 10 or 5, immersion speed 80 mm/min, immersion time 20 s). Moreover, the best conditions for the spin-coating process were 1000 rpm and of 30s coating time. Better results were obtained for the [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 3 F 7 ) 4 ] (3) complex.
After heating, all the surfaces prepared by the spin-coating method change colour and roughness (from several to tens of nanometres). Additionally, the presence of cracks was noted. However, the films obtained by the dip-coating technique keep the tight structure, changing their colour and roughness (from several to tens of nanometres). This latter method can be an alternative to the CVD technique.  the temperature determination for the spin-and dip-coating materials heating was also proven.   Figure S31 Temperature variable infrared spectra VT IR of vapors formed during the [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 2 F 5 ) 4 ] complex (2) heating; Figure S32 The spectra comparison for the [Cu 2 (EtNH 2 ) 2 (µO 2 CC 2 F 5 ) 4 ] complex (2) in the solid state (orange line) and in the gas phase at 473 K (blue line); Figure S33 Temperature variable infrared spectra VT IR of vapors formed during the [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 4 F 9 ) 4 ] complex (4) heating; Figure S34 The spectra comparison for the [Cu 2 (EtNH 2 ) 2 (µO 2 CC 4 F 9 ) 4 ] complex (4) a) in the solid state (red line) and in the gas phase at 493 K (black line) b) at temperature 493 K and 533 K; Figure S35 Temperature vari-