Heteroleptic LaIII Anilate/Dicarboxylate Based Neutral 3D-Coordination Polymers

Three new 3D metal–organic frameworks of lanthanum based on mixed anionic ligands, [(La2(pQ)2(BDC)4)·4DMF]n, [(La2(pQ)2(DHBDC)4)·4DMF]n, [(La2(CA)2(BDC)4)·4DMF]n (pQ—dianion of 2,5-dihydroxy-3,6-di-tert-butyl-para-quinone, CA—dianion of chloranilic acid, BDC-1,4-benzenedicarboxylate, DHBDC-2,5-dihydroxy-1,4-benzenedicarboxylate and DMF-N,N′-dimethylformamide), were synthesized using solvothermal methodology. Coordination polymers demonstrate the rare xah or 4,6T187 topology of a 3D framework. The homoleptic 2D-coordination polymer [(La2(pQ)3)·4DMF]n was obtained as a by-product in the course of synthetic procedure optimization. The thermal stability, spectral characteristics and porosity of coordination polymers were investigated.

The most used types of ligands for MOFs' construction are various di-, tri-, and tetracarboxylic acids [13]. Their use allows a variety of structures of different dimensions to be obtained, from linear to 3D frames. Among the unique modern trends is the combination of various anionic bridges to obtain heteroleptic polymeric systems. The combination of two or more types of ligands in one link leads to the manifestation of the unusual properties of MOFs and CPs [1,2,4,7]. For example, Fedin and coworkers [1,2] have shown that zinc complexes' design based on dicarboxylic acids and diatomic alcohols allows the synthesis of functional coordination polymers with outstanding characteristics, excellent adsorption selectivity of benzene over cyclohexane, for example.

Results and Discussion
Compounds 1-3 were synthesized by a solvothermal technique in DMF (Scheme 1).
The first examples of heteroleptic NIR-Emitting Yb III /anilate-based coordination polymer nanosheets were prepared recently using terephthalic dicarboxylate coligands [7]. These 2D nanosheets are ideal objects for performing advanced photophysical studies by an innovative multiprobe approach. The research of perturbations of photoluminescence induced by different solvents, both aromatic and aliphatic, bearing electron-withdrawing and electro-donating groups, has demonstrated high-sensitivity to nitrobenzene [7].

Results and Discussion
Compounds 1-3 were synthesized by a solvothermal technique in DMF (Scheme 1). The synthetic procedure involves consecutive two-stage heating of the reaction mixture at 80 and 130 °C. This ensures a high yield of violet crystals of heteroleptic reaction Scheme 1. Synthetic scheme for the preparation of coordination polymers 1-3.
The synthetic procedure involves consecutive two-stage heating of the reaction mixture at 80 and 130 • C. This ensures a high yield of violet crystals of heteroleptic reaction products. The reaction under conditions of single-stage heating of the components in a DMF solution is accompanied by the formation of crystalline colorless lanthanum carboxylates and red homoleptic anilate derivatives as by-products. Additionally, an increase in the carboxylate ligand's content in the initial reaction mixture contributes to an increase in the yield of the target product. Therefore, for polymers 1 and 2, the optimal ratio is H 2 pQ:H 2 bdc (H 2 dhbdc) = 1:4. For the chloranilic acid derivative 3, the ratio is H 2 CA:H 2 bdc = 1:3. It should be noted that the optimal ratio of reagents differs from the stoichiometric one. This is obviously due to the different rates of formation and crystallization of homoleptic polymers. Additionally, the anilate ligands have a stronger affinity toward the La(III) ion than the carboxylate one. This assertion was forecasted by the authors of [7]. The interaction Yb(III)/anilate/dicarboxylate with stoichiometric (2:1:1) ratio in the reaction produces coordination polymers with the 2:2.5:0.5 or 2:2:1 formula ratios [7]. A significant increase in the content of dicarboxylic acid in the reaction mixture makes it possible to obtain a polymer with a component ratio of La(III)/anilate/dicarboxylate-2:2:4, which dramatically affects the resulting CPs' structures. In contrast to [7], it is possible to obtain three-dimensional structures instead of layered ones.
The La(III) CP (4)  products. The reaction under conditions of single-stage heating of the components in a DMF solution is accompanied by the formation of crystalline colorless lanthanum carboxylates and red homoleptic anilate derivatives as by-products. Additionally, an increase in the carboxylate ligand's content in the initial reaction mixture contributes to an increase in the yield of the target product. Therefore, for polymers 1 and 2, the optimal ratio is H2pQ:H2bdc (H2dhbdc) = 1:4. For the chloranilic acid derivative 3, the ratio is H2CA:H2bdc = 1:3. It should be noted that the optimal ratio of reagents differs from the stoichiometric one. This is obviously due to the different rates of formation and crystallization of homoleptic polymers. Additionally, the anilate ligands have a stronger affinity toward the La(III) ion than the carboxylate one. This assertion was forecasted by the authors of [7]. The interaction Yb(III)/anilate/dicarboxylate with stoichiometric (2:1:1) ratio in the reaction produces coordination polymers with the 2:2.5:0.5 or 2:2:1 formula ratios [7]. A significant increase in the content of dicarboxylic acid in the reaction mixture makes it possible to obtain a polymer with a component ratio of La(III)/anilate/dicarboxylate-2:2:4, which dramatically affects the resulting CPs' structures. In contrast to [7], it is possible to obtain three-dimensional structures instead of layered ones. The La(III) CP (4) bearing pQ 2− and DMF ligands only was prepared by the test synthesis excluding the dicarboxylate component (Scheme 2). The SC XRD studies of 1-3 compounds were performed, revealing a series of new MOFs with similar structural compositions. MOFs 1 and 2 crystallize in the triclinic P-1 space group, while 3 crystallizes in the monoclinic P21/n. MOFs 1 and 2 display a rarely xah [37] topology of the 3D framework. The topology of the underlying network of 3 is 4,6T187 in the standard representation of the valence-bonded MOFs.
The simplest unit of 1-3 comprises two La(III) centers (Figures 1 and 2). They are bridged by four carboxylate ligands forming the Chinese-lantern structure. Each La(III) center coordinates five oxygen atoms from four BDC 2− (1, 3) or DHBDC 2− (2) anions, two oxygen atoms from pQ 2− (1, 2) or CA 2− (3) anions, and two oxygen atoms of two DMF coordination molecules ( Figure 3). Thus, the formal coordination number of La 3+ in 1-3 is nine. The La…La distances in these dimeric units are 4.1978  The SC XRD studies of 1-3 compounds were performed, revealing a series of new MOFs with similar structural compositions. MOFs 1 and 2 crystallize in the triclinic P-1 space group, while 3 crystallizes in the monoclinic P2 1 /n. MOFs 1 and 2 display a rarely xah [37] topology of the 3D framework. The topology of the underlying network of 3 is 4,6T187 in the standard representation of the valence-bonded MOFs.
The simplest unit of 1-3 comprises two La(III) centers (Figures 1 and 2). They are bridged by four carboxylate ligands forming the Chinese-lantern structure. Each La(III) center coordinates five oxygen atoms from four BDC 2− (1, 3) or DHBDC 2− (2) anions, two oxygen atoms from pQ 2− (1, 2) or CA 2− (3) anions, and two oxygen atoms of two DMF coordination molecules (      Systematic analysis of the coordination geometries around the La(III) centers using SHAPE 2.1 software [38,39] reveals that the nine coordinated [40] lanthanide centers of complexes 1-3 adopt different geometries. The coordination polyhedron of lanthanum ion in compound 1 is best described as a spherical capped square antiprism (CSAPR-9, minimum CShM value is 1.383) (Figure 4a  A large excess of dicarboxylic acid contributes to the formation of layers constructed from carboxylate lanterns ( Figures 5-7). The latter form two-dimensional grids with fourmembered cells. The structures of polymers 1 and 2 are close to each other. The carboxylate layers in them are almost flat. In derivative 3, a zigzag formation of the layers is observed, which leads to its thickening. The layers in 1-3 are cross-linked into a threedimensional structure through anilate ligands. This mechanism of a three-dimensional framework formation explains the difference between the here presented results and those obtained in the preparation of heteroleptic ytterbium complexes [7]. In the case of an excess of the anilic acid, a typical for such complexes (6,3)-2D topology of six-membered rings with hexagonal cavities is formed on the first stage, and dicarboxylate ligands Systematic analysis of the coordination geometries around the La(III) centers using SHAPE 2.1 software [38,39] reveals that the nine coordinated [40] lanthanide centers of complexes 1-3 adopt different geometries. The coordination polyhedron of lanthanum ion in compound 1 is best described as a spherical capped square antiprism (CSAPR-9, minimum CShM value is 1.383) (  Systematic analysis of the coordination geometries around the La(III) centers using SHAPE 2.1 software [38,39] reveals that the nine coordinated [40] lanthanide centers of complexes 1-3 adopt different geometries. The coordination polyhedron of lanthanum ion in compound 1 is best described as a spherical capped square antiprism (CSAPR-9, minimum CShM value is 1.383) (  A large excess of dicarboxylic acid contributes to the formation of layers constructed from carboxylate lanterns ( Figures 5-7). The latter form two-dimensional grids with fourmembered cells. The structures of polymers 1 and 2 are close to each other. The carboxylate layers in them are almost flat. In derivative 3, a zigzag formation of the layers is observed, which leads to its thickening. The layers in 1-3 are cross-linked into a threedimensional structure through anilate ligands. This mechanism of a three-dimensional framework formation explains the difference between the here presented results and those obtained in the preparation of heteroleptic ytterbium complexes [7]. In the case of an excess of the anilic acid, a typical for such complexes (6,3)-2D topology of six-membered rings with hexagonal cavities is formed on the first stage, and dicarboxylate ligands A large excess of dicarboxylic acid contributes to the formation of layers constructed from carboxylate lanterns (Figures 5-7). The latter form two-dimensional grids with fourmembered cells. The structures of polymers 1 and 2 are close to each other. The carboxylate layers in them are almost flat. In derivative 3, a zigzag formation of the layers is observed, which leads to its thickening. The layers in 1-3 are cross-linked into a three-dimensional structure through anilate ligands. This mechanism of a three-dimensional framework formation explains the difference between the here presented results and those obtained in the preparation of heteroleptic ytterbium complexes [7]. In the case of an excess of the anilic acid, a typical for such complexes (6,3)-2D topology of six-membered rings with hexagonal cavities is formed on the first stage, and dicarboxylate ligands replace some anilate ligands in this lattice. Thus, the predominance of anilic over dicarboxylate ligands in the reaction mixture forms a two-dimensional coordination polymer structure. At the same time, the inverse ratio of the reagents leads to a 3D framework. replace some anilate ligands in this lattice. Thus, the predominance of anilic over dicarboxylate ligands in the reaction mixture forms a two-dimensional coordination polymer structure. At the same time, the inverse ratio of the reagents leads to a 3D framework.    (001)  replace some anilate ligands in this lattice. Thus, the predominance of anilic over dicarboxylate ligands in the reaction mixture forms a two-dimensional coordination polymer structure. At the same time, the inverse ratio of the reagents leads to a 3D framework.   The dianionic form of anilate ligands can bind to metals either as a bridging (bis)bidentate ligand, which has a dianion-like structure (Scheme 3, type I and II), or as a terminal bidentate ligand with an ortho-quinoid structure (type III) [41,42]. The dianions of 2,5dihydroxy-3,6-di-tert-butyl-para-quinone in 1-2 and chloranilic acid in 3 consist of two delocalized π-electron systems connected by single C-C bonds (1.552 (3)  The dianionic form of anilate ligands can bind to metals either as a bridging (bis)bidentate ligand, which has a dianion-like structure (Scheme 3, type I and II), or as a terminal bidentate ligand with an ortho-quinoid structure (type III) [41,42]. The dianions of 2,5dihydroxy-3,6-di-tert-butyl-para-quinone in 1-2 and chloranilic acid in 3 consist of two delocalized π-electron systems connected by single C-C bonds (1.552 (3) (Figure 3a,b). For all four dicarboxylate ligands in 3, the μ2-κ 1 : κ 2 coordination mode for one C(O)O-group and coordination by μ2-κ 1 : κ 1type for another one were observed (type c in Scheme 4, Figure 3c). The La-Odicarb bond distances in 1-3 are in the range of 2.466(3)-2.849(2) Å, which are similar to those of other related La(III) compounds with dicarboxylate ligands [43,44]. Selected bond lengths are presented in Table 1.  The dianionic form of anilate ligands can bind to metals either as a bridging (bis)bidentate ligand, which has a dianion-like structure (Scheme 3, type I and II), or as a terminal bidentate ligand with an ortho-quinoid structure (type III) [41,42]. The dianions of 2,5dihydroxy-3,6-di-tert-butyl-para-quinone in 1-2 and chloranilic acid in 3 consist of two delocalized π-electron systems connected by single C-C bonds (1.552 (3)   Ligands BDC 2− in 1 and 3 or DHBDC 2-in 2 adopted bridging mode, linking four La 3+ ions. The types of bridging are shown in Scheme 4. In compounds 1 and 2, two out of four dicarboxylate ligands act as a linker with each C(O)O-group coordinated by μ2-κ 1 : κ 1 -type (type a in Scheme 4), while in the other two ligands, the functional groups have the μ2-κ 1 : κ 2 coordination mode (type b in Scheme 4) (Figure 3a,b). For all four dicarboxylate ligands in 3, the μ2-κ 1 : κ 2 coordination mode for one C(O)O-group and coordination by μ2-κ 1 : κ 1type for another one were observed (type c in Scheme 4, Figure 3c). The La-Odicarb bond distances in 1-3 are in the range of 2.466(3)-2.849(2) Å, which are similar to those of other related La(III) compounds with dicarboxylate ligands [43,44]. Selected bond lengths are presented in Table 1. Ligands BDC 2− in 1 and 3 or DHBDC 2in 2 adopted bridging mode, linking four La 3+ ions. The types of bridging are shown in Scheme 4. In compounds 1 and 2, two out of four dicarboxylate ligands act as a linker with each C(O)O-group coordinated by µ 2 -κ 1 : κ 1 -type (type a in Scheme 4), while in the other two ligands, the functional groups have the µ 2 -κ 1 : κ 2 coordination mode (type b in Scheme 4) (Figure 3a,b). For all four dicarboxylate ligands in 3, the µ 2 -κ 1 : κ 2 coordination mode for one C(O)O-group and coordination by µ 2 -κ 1 : κ 1 -type for another one were observed (type c in Scheme 4, Figure 3c). The La-O dicarb bond distances in 1-3 are in the range of 2.466(3)-2.849(2) Å, which are similar to those of other related La(III) compounds with dicarboxylate ligands [43,44]. Selected bond lengths are presented in Table 1. The dianionic form of anilate ligands can bind to metals either as a bridging (bis)bidentate ligand, which has a dianion-like structure (Scheme 3, type I and II), or as a terminal bidentate ligand with an ortho-quinoid structure (type III) [41,42]. The dianions of 2,5dihydroxy-3,6-di-tert-butyl-para-quinone in 1-2 and chloranilic acid in 3 consist of two delocalized π-electron systems connected by single C-C bonds (1.552 (3)   Ligands BDC 2− in 1 and 3 or DHBDC 2-in 2 adopted bridging mode, linking four La 3+ ions. The types of bridging are shown in Scheme 4. In compounds 1 and 2, two out of four dicarboxylate ligands act as a linker with each C(O)O-group coordinated by μ2-κ 1 : κ 1 -type (type a in Scheme 4), while in the other two ligands, the functional groups have the μ2-κ 1 : κ 2 coordination mode (type b in Scheme 4) (Figure 3a,b). For all four dicarboxylate ligands in 3, the μ2-κ 1 : κ 2 coordination mode for one C(O)O-group and coordination by μ2-κ 1 : κ 1type for another one were observed (type c in Scheme 4, Figure 3c). The La-Odicarb bond distances in 1-3 are in the range of 2.466(3)-2.849(2) Å, which are similar to those of other related La(III) compounds with dicarboxylate ligands [43,44]. Selected bond lengths are presented in Table 1.   (2) La (1) (A) −x + 3, −y, −z + 2; (B) −x + 5/2, y + 1/2, −z + 3/2; (C) x + 1/2, −y−1/2, z + 1/2; (D) −x + 2, −y, −z + 2; (E) x + 1/2, −y −1/2, z + 1/2 4: According to X-ray structural analysis, compounds 2 and 3 contain free accessible voids filled with solvent molecules. The volume of these voids for compound 2 was estimated at 13.8% of unit cell volume (Figure 7a). The voids volume in 3 is about 15.6% (Figure 7b) [45]. Visually, compounds 2 and 3 lost crystallinity within a day, which is associated with the removal of guest DMF molecules from the pores of compounds. The data of elemental and thermogravimetric analyses confirm the absence of guest DMF molecules in the dried samples of 2 and 3.
Metal-organic coordination polymer 4 crystallizes in the triclinic P-1 space group. The topology of the underlying net of 4 is hcb and typical for this type of compound [7,21,22,33]. The simplest unit of [(La 2 (pQ) 3 )·4DMF] n comprises two La(III) cations, three pQ 2− dianions and four coordinated N,N -dimethylformamide ligands (Figure 8). The atom La(III) is 8-coordinated with a distorted triangular dodecahedron geometry (TDD-8, minimum CShM value is 1.148) (Figure 8). The metal-organic coordination polymer 4 has a similar structure to the recently published derivatives [Ln 2 (pQ) 3 ·4DMAA] n (Ln = La, Pr, Nd, DMAA = N,N -dimethylacetamide) [29]. The main difference is the type of anilate ligands binding to lanthanide ions (Scheme 3). For complexes with dimethylacetamide, two of the three ligands are characterized by type I coordination, and the third one has p-quinoid type II coordination mode. In contrast, all three dianions of 2,5-dihydroxy-3,6-di-tertbutyl-para-quinone in 4 are coordinated by type I and characterized by two delocalized π-electron systems (C-O 1.28(2)-1.32(2) Å) connected by single C-C bonds (1.54(2)-1.551(5) Å). Selected bond lengths in coordination polymer 4 are presented in Table 1.  Thermal stability of obtained compounds 1-3 was examined by TGA and DTA (Figure 9). Compounds 1-3 started to decompose above 150 °C and showed a slight mass decrease upon heating to 260 °C due to a continuous loss of DMF molecules. The observed mass loss was 10%, 10%, and 8% for 1, 2, and 3, respectively, which corresponds to 1.5 DMF molecules. Up to 150 °C, no weight loss was observed on the TGA curve, which indicates the absence of occluded solvent and guest DMF molecules in the samples. According to DTA data, heating above 270 °C leads to several different processes, which lead to the decomposition of the framework of compounds 1-3. Compound 4 demonstrates thermal stability up to 170 °C. The sample starts to decompose above 170 °C and shows a steady mass decrease upon heating to 250 °C due to a continuous loss of coordination solvent molecules. The observed mass loss equal to 11% corresponds to two DMF molecules in counting on the simplest unit of [(La2(pQ)3)•4DMF]. Decomposition of the frame- Thermal stability of obtained compounds 1-3 was examined by TGA and DTA (Figure 9). Compounds 1-3 started to decompose above 150 • C and showed a slight mass decrease upon heating to 260 • C due to a continuous loss of DMF molecules. The observed mass loss was 10%, 10%, and 8% for 1, 2, and 3, respectively, which corresponds to 1.5 DMF molecules. Up to 150 • C, no weight loss was observed on the TGA curve, which indicates the absence of occluded solvent and guest DMF molecules in the samples. According to DTA data, heating above 270 • C leads to several different processes, which lead to the decomposition of the framework of compounds 1-3. Compound 4 demonstrates thermal stability up to 170 • C. The sample starts to decompose above 170 • C and shows a steady mass decrease upon heating to 250 • C due to a continuous loss of coordination solvent molecules. The observed mass loss equal to 11% corresponds to two DMF molecules in counting on the simplest unit of [(La 2 (pQ) 3 )·4DMF]. Decomposition of the framework occurred at 298 • C. TG curves for 4 are presented in Figure S2 (ESI).
Thermal stability of obtained compounds 1-3 was examined by TGA and DTA (Figure 9). Compounds 1-3 started to decompose above 150 °C and showed a slight mass decrease upon heating to 260 °C due to a continuous loss of DMF molecules. The observed mass loss was 10%, 10%, and 8% for 1, 2, and 3, respectively, which corresponds to 1.5 DMF molecules. Up to 150 °C, no weight loss was observed on the TGA curve, which indicates the absence of occluded solvent and guest DMF molecules in the samples. According to DTA data, heating above 270 °C leads to several different processes, which lead to the decomposition of the framework of compounds 1-3. Compound 4 demonstrates thermal stability up to 170 °C. The sample starts to decompose above 170 °C and shows a steady mass decrease upon heating to 250 °C due to a continuous loss of coordination solvent molecules. The observed mass loss equal to 11% corresponds to two DMF molecules in counting on the simplest unit of [(La2(pQ)3)•4DMF]. Decomposition of the framework occurred at 298 °C. TG curves for 4 are presented in Figure S2 (ESI). The porous structure of compounds 1-3 was investigated using the example of compound 1, because this compound retains its crystallinity over a prolonged time period. An analysis of the porous structure was performed by a carbon dioxide adsorption technique at 195 K. Initially, the compound 1 was activated in a dynamic vacuum using the standard "outgas" option of the equipment at 453 K for 2 or 6 h. Measured adsorption isotherms of The porous structure of compounds 1-3 was investigated using the example of compound 1, because this compound retains its crystallinity over a prolonged time period. An analysis of the porous structure was performed by a carbon dioxide adsorption technique at 195 K. Initially, the compound 1 was activated in a dynamic vacuum using the standard "outgas" option of the equipment at 453 K for 2 or 6 h. Measured adsorption isotherms of 1 are represented in Figure 10. Compound 1 has low porosity, pore volume and specific surface area. Longer activation leads to a decrease in the adsorption capacity, as evidenced by a drop in the adsorbed volume of CO 2 . Evidently, this is due to the destruction of the 3D structure when the molecules of the coordinated DMF are eliminated. This is also indicated by a significant deterioration of the powder diffractogram after the completion of the sorption-desorption cycle. Calculated parameters of the porous structure are shown in Table 2. Pore size distributions were calculated using the DFT approach, which shows good agreement between the measured and calculated isotherms and is presented in ESI. Isotherms are typical for microporous materials with slit pores, which was also proven by DFT PSD calculations. 1 are represented in Figure 10. Compound 1 has low porosity, pore volume and specific surface area. Longer activation leads to a decrease in the adsorption capacity, as evidenced by a drop in the adsorbed volume of CO2. Evidently, this is due to the destruction of the 3D structure when the molecules of the coordinated DMF are eliminated. This is also indicated by a significant deterioration of the powder diffractogram after the completion of the sorption-desorption cycle. Calculated parameters of the porous structure are shown in Table 2. Pore size distributions were calculated using the DFT approach, which shows good agreement between the measured and calculated isotherms and is presented in ESI. Isotherms are typical for microporous materials with slit pores, which was also proven by DFT PSD calculations.

Reagents and Methods
All reactants were purchased from Sigma Aldrich. 2,5-dihydroxy-3,6-di-tert-butyl-pbenzoquinone was synthesized according to the previously reported procedure [46]. All synthetic manipulations were performed under Schlenk line conditions. Solvents were purified by standard methods [47]. Elemental analyses were performed with an Elementar Vario El cube instrument. Electronic absorption (UV-vis) spectra in the range 200-900 nm of nujol mulls were recorded on a Carl Zeiss Jena Specord M400 spectrophotometer. IRspectra of the studied compounds were recorded on a FSM1201 Fourier-IR spectrometer in a nujol using KBr plates in the range 4000-400 cm −1 . TGA of compound 1-3 was measured on a Shimadzu DTG-60H synchronous thermal analyzer instrument from 30 to 600 • C using an Al pan and heated at a rate of 5 • C/min under an air atmosphere. TGA of compound 4 was measured on a Mettler Toledo TGA/DSC3+ instrument from 30 to 500 • C using an PCA pan and heated at a rate of 5 • C/min under a nitrogen atmosphere.
The X-ray data for 1-4 were collected with Bruker D8 Quest (1-3) and Rigaku OD Xcalibur (4) diffractometers (Mo Kα -radiation, ω-scans technique, λ = 0.71073Å, T = 100 K) using APEX3 [48] and CrysAlis Pro [49] software packages. The structures were solved via an intrinsic phasing algorithm and refined by full-matrix least squares against F 2 using SHELX [50,51]. SADABS [52] and scaling algorithms implemented in CrysAlis Pro were used to perform absorption corrections. All non-hydrogen atoms in 1-4 were found from Fourier syntheses of electron density and refined anisotropically. All hydrogen atoms were placed in calculated positions and refined isotropically in the "riding" model with U(H) iso = 1.2U eq of their parent atoms (U(H) iso = 1.5U eq for methyl groups). The crystal data and structure refinement details for compounds 1-4 are presented in Table 3.
One solvate DMF molecule in the asymmetric unit of 2 was modelled by SQUEEZE/ Platon [53]. Coordination polymer 4 was refined as 2-component non-merohedral twin with a domain ratio 0.65/0.35.
The crystallographic data and structure refinement details are shown in Table S1. CCDC 2,074,328 (1), 2,074,329 (2), 2,074,330 (3) and 2,074,331 (4) contain the supplementary crystallographic data for this paper. These data are provided free of charge by The Cambridge Crystallographic Data Centre: ccdc.cam.ac.uk/structures. An analysis of the porous structure was performed by a carbon dioxide adsorption technique using Quantochrome's Autosorb iQ at 195 K. Cryostat CryoCooler was used to adjust temperature with 0.05 K accuracy. Carbon dioxide adsorption−desorption isotherms were measured within the range of relative pressures from 10 to 3 till 0.995. The specific surface area was calculated from the data obtained on the basis of the conventional BET, Langmuir and DFT models. Pore size distributions were calculated using the DFT method. The database of the National Institute of Standards and Technology available at http: //webbook.nist.gov/chemistry/fluid/ (accessed on 23 April 2021) was used as a source of p−V−T relations at experimental pressures and temperatures.
X-ray powder diffraction measurements were performed on a Shimadzu LabX XRD-6100 X-ray Powder Diffractometer. Storage of crystalline compounds after their separation from the mother liquors led to a partial loss of solvate DMF molecules, which led to the destruction of the crystals studied by X-ray diffraction and the formation of a new crystalline phase. Apparently, the formation of this new phase is reflected in the appearance of extra peaks in the powder diffractogram.  4 )·4DMF]n (2). A mixture of LaCl 3 ·7H 2 O (0.04 mmol), H 2 DHBDC (0.12 mmol) and H 2 pQ (0.04 mmol) in a mole ratio of 1: 3: 1 in DMF (2 mL) was heated sequentially at 80 • C for 24 h and 130 • C for 48 h in a sealed glass ampule. The obtained purple crystals were separated by the filtration, washed with DMF (2 × 2 mL), and dried on air. Yield was 81% based on LaCl 3 ·7H 2 O. Visually, the compound lost its crystallinity within 1 day. According to the data of X-ray structural analysis, compound 2 contains 2 DMF molecules per simplest unit. According to elemental analysis, after the loss of crystallinity, the compound does not contain guest solvent. Elemental analysis calculated for [C 24

Synthesis of 3
[(La 2 (CA) 2 (BDC) 4 )·4DMF]n (3). A mixture of LaCl 3 ·7H2O (0.04 mmol), H 2 BDC (0.12 mmol) and H 2 CA (0.04 mmol) in a mole ratio of 1:3:1 in DMF (2 mL) was heated sequentially at 80 • C for 24 h and 130 • C for 48 h in a sealed glass ampule. The obtained purple crystals were separated by the filtration, washed with DMF (2 × 2 mL) and dried on air. Yield was 81% based on LaCl 3 ·7H 2 O. Visually, the compound lost its crystallinity within 1 day. According to the data of X-ray structural analysis, compound 3 contains 0.6 DMF molecules per simplest unit. According to elemental analysis, after the loss of crystallinity, the compound does not contain guest solvent. Elemental analysis calculated for [C 34

Conclusions
In summary, we reported the first examples of lanthanide heteroleptic anilate/ dicarboxylate three-dimensional metal-organic frameworks constructed from mixed dianionic ligands. The synthesis was carried out under conditions of an excess of dicarboxylic acid. This led to the assembly of two-dimensional layers formed by binuclear lanthanum carboxylate lanterns, spliced into three-dimensional structures by anilate crosslinks. The synthesized structures have low porosity and are thermally stable up to a temperature of 150 • C. We believe that the synthetic approach developed in this work will be particularly useful and can be used for the purposeful construction of functional MOFs based on the entire range of lanthanides.
Supplementary Materials: The following are available online, Figure S1: Pore size distribution curves for compounds 1; Figure S2: Pore size distribution curves for TG curve for 4; Figure S3: PXRD patterns for 1-4; Figure S4: The molecular structure of the binuclear unit in 2. Shape analysis for 1-3, Shape analysis for 4.