Synthesis and Crystal Structures of Rhomb-Shaped Dimeric Pd(II) Complexes with Arylethynyl-Substituted 2,2 ′ -Bipyridine through CH · · · π Interactions in the Crystalline States

: Two molecular structures of a complex C 26 H 16 Cl 2 N 2 Pd ( 1 ) with a benzene hemisolvate ( 1 • 0.5C 6 H 6 ) and a complex C 34 H 20 Cl 2 N 2 Pd ( 2 ) revealed similar conformations: one side of the arylethynyl group is flat to the bipyridine plane while the other side of the arylethynyl group is highly twisted to the plane because rhomb-like dimer fragments are formed between respective two complexes through CH · · · π interactions. The Hirshfeld surface analysis indicates that the most important contributions for the crystal packing of 1 are from H · · · H (33.6%), C · · · H/H · · · C (28.3%), Cl · · · H/H · · · Cl (17.8%), and C · · · C (10.6%) interactions and those of 2 are from H · · · H (36.5%), C · · · H/H · · · C (26.0%), Cl · · · H/H · · · Cl (15.7%), and C · · · C (12.3%) interactions, indicating the remarkable CH · · · π and electron distribution of molecules by Cl ions. The benzene solvate molecule of 1 • 0.5C 6 H 6 performs to fill the internal space instead of the naphthyl group. Detailed crystallographic and DFT studies were performed to understand the molecular structures and the corresponding supramolecular associations.

The complexation and molecular recognition events of such bipyridine derivatives fascinate us while also promoting the understanding of the driving forces of aggregation and the corresponding weak interactions by crystallographic studies.In such molecular recognition strategies, it is necessary to have a flexible molecular design that allows the molecule itself to undergo thermodynamic stabilization due to intermolecular interactions.One effective method to achieve this goal is the incorporation of ethynyl linkers between aromatic rings, which generally permits rotation without steric hindrance, making it challenging to control the intramolecular stereo-conformation between the phenyl groups and the bipyridine moiety of L 1 .Such free rotation within the molecule has the potential to hinder photo activities and host functions in both solution and solid states but can also lead to interesting packing structures influenced by intermolecular interactions and external stimuli from a crystallographic perspective [17,20,21].
In this subject, we synthesized and found the molecular structure of [PdCl 2 (L n )] (1), as shown in Scheme 1, in which one phenyl group is flat with respect to a plane of the bipyridine moiety and the other phenyl group is highly twisted, and each phenyl group forms a rhomb-like arrangement by two compounds through intermolecular CH• • • π interactions [22,23] in the single crystal of 1•0.5C 6 H 6 .Thus, we synthesized a naphthalene derivative, 4,4 ′ -di(naphthalen-1-ylethynyl)-2,2 ′ -bipyridine (L 2 ), and the crystal of the corresponding Pd complex, [PdCl 2 (L 2 )] (2), to confirm that the similar arrangement is a common stabilized structure of the motifs in crystal.In this report, we describe the syntheses and the detailed crystal structures of 1•0.5C 6 H 6 and 2 (Scheme 1), which were crystallized in a benzene-acetone solution to give pale yellow crystals and orange crystals, respectively.In a benzene-dimethylsulfoxide (dmso) solution, the same crystals were obtained.investigation of 4,4′-di(phenylethynyl)-2,2′-bipyridine (L 1 ), which forms a 1:1 cocrystal with 4,4′-bis(pentafluorophenylethynyl)-2,2′-bipyridine to give alternately stacking materials [17] through π-hole⋯π interactions [18,19].The complexation and molecular recognition events of such bipyridine derivatives fascinate us while also promoting the understanding of the driving forces of aggregation and the corresponding weak interactions by crystallographic studies.In such molecular recognition strategies, it is necessary to have a flexible molecular design that allows the molecule itself to undergo thermodynamic stabilization due to intermolecular interactions.One effective method to achieve this goal is the incorporation of ethynyl linkers between aromatic rings, which generally permits rotation without steric hindrance, making it challenging to control the intramolecular stereo-conformation between the phenyl groups and the bipyridine moiety of L 1 .Such free rotation within the molecule has the potential to hinder photo activities and host functions in both solution and solid states but can also lead to interesting packing structures influenced by intermolecular interactions and external stimuli from a crystallographic perspective [17,20,21].
In this subject, we synthesized and found the molecular structure of [PdCl2(L n )] (1), as shown in Scheme 1, in which one phenyl group is flat with respect to a plane of the bipyridine moiety and the other phenyl group is highly twisted, and each phenyl group forms a rhomb-like arrangement by two compounds through intermolecular CH⋯π interactions [22,23] in the single crystal of 1•0.5C6H6.Thus, we synthesized a naphthalene derivative, 4,4′-di(naphthalen-1-ylethynyl)-2,2′-bipyridine (L 2 ), and the crystal of the corresponding Pd complex, [PdCl2(L 2 )] (2), to confirm that the similar arrangement is a common stabilized structure of the motifs in crystal.In this report, we describe the syntheses and the detailed crystal structures of 1•0.5C6H6 and 2 (Scheme 1), which were crystallized in a benzene-acetone solution to give pale yellow crystals and orange crystals, respectively.In a benzene-dimethylsulfoxide (dmso) solution, the same crystals were obtained.Scheme 1.Molecular structures of 1 and 2.

Synthesis and Crystallization
Preparation of L 2 .This was prepared by the general procedure of the Sonogashira coupling reaction [17,26,27].Excess amounts of triethylamine (10 mL) were added into the Scheme 1.Molecular structures of 1 and 2.

Crystal Structure Determination
The single crystal X-ray structures were determined by a Bruker SMART APEX CCD diffractometer (Bruker Japan, Yokohama, Japan) with a graphite monochrometer and MoKα radiation (λ = 0.71073 Å) generated at 50 kV and 30 mA.Crystals 1•0.5C 6 H 6 and 2 were coated by paratone-N oil and measured at 100 and 120 K, respectively.SHELXT program was used for solving the structures [28].Refinement and further calculations were carried out using SHELXL 2016 [29].The crystal data and structure refinement of 1•0.5C 6 H 6 and 2 are summarized in Table 1.All H atoms were placed in geometrically idealized positions and refined as riding, with aromatic C-H = 0.95 Å and U iso (H) = 1.2 U eq (C).These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html (accessed on 19 February 2024).

Results and Discussion
3.1.Preparations of 1 and 2 4,4 ′ -Di(naphthalen-1-ylethynyl)-2,2 ′ -bipyridine (L 2 ) was prepared by Sonogashira coupling reaction [17] to yield a pale yellow powder in 83%.Complexations of 1 and 2 were examined in a one-step reaction with the corresponding ligand and [PdCl 2 (dmso) 2 ] in several solvents.The yellow and orange precipitates of 1 and 2, respectively, of low solubility products quickly grew in the solution as a single product.The single crystals of 1•0.5C 6 H 6 and 2 were obtained from a benzene-acetone solution suitable for single-crystal X-ray crystallographic studies.

Crystal Structure and Intermolecular Interactions of 1•0.5C 6 H 6
The ORTEP views of 1•0.5C 6 H 6 and 2 are shown in Figure 1a and Figure 3a, respectively, with the numbering schemes.In the crystal of 1•0.5C 6 H 6 , the asymmetric unit contains a whole complex and one half of benzene (Figure 1).The complex comprises one Pd 2+ ion, two Cl ions, and one ligand (L 1 ) to give a mononuclear complex.The solvate benzene comprises C27-C28-C29-C27 i -C28 i -C29 i [symmetry code: (i) −x, −y + 1, −z

Preparations of 1 and 2
4,4′-Di(naphthalen-1-ylethynyl)-2,2′-bipyridine (L 2 ) was prepared by Sonogashira coupling reaction [17] to yield a pale yellow powder in 83%.Complexations of 1 and 2 were examined in a one-step reaction with the corresponding ligand and [PdCl2(dmso)2] in several solvents.The yellow and orange precipitates of 1 and 2, respectively, of low solubility products quickly grew in the solution as a single product.The single crystals of 1•0.5C6H6 and 2 were obtained from a benzene-acetone solution suitable for single-crystal X-ray crystallographic studies.

Crystal Structure and Intermolecular Interactions of 1•0.5C6H6
The ORTEP views of 1•0.5C6H6 and 2 are shown in Figures 1a and 3a, respectively, with the numbering schemes.In the crystal of 1•0.5C6H6, the asymmetric unit contains a whole complex and one half of benzene (Figure 1).The complex comprises one Pd 2+ ion, two Cl ions, and one ligand (L 1 ) to give a mononuclear complex.The solvate benzene comprises C27-C28-C29-C27 i -C28 i -C29 i A benzene molecule, ring-E, is located in a rhomb-like dimer framework, which is formed by the surrounded four phenylethynyl groups of the complex and complex i , as shown in Figure 1b.Two complexes are stabilized by CH⋯π interactions and the intermolecular distance of C26-H26⋯Cg<ring-B i > is short (2.75 Å for H26⋯Cg<ring-B i > and 3.591(3) Å for C26⋯Cg<ring-B i >).No remarkable π⋯π and CH⋯π interactions were observed between the benzene molecule and the frameworks.A benzene molecule, ring-E, is located in a rhomb-like dimer framework, which is formed by the surrounded four phenylethynyl groups of the complex and complex i , as shown in Figure 1b.The packing structures of 1•0.5C 6 H 6 are shown in Figures 1b and 2. The two complexes form a dimer with the inversion center between the two complexes; e.g., the complex [symmetry code: x, y, z] closely interacts with the adjacent complex ii [symmetry code: (ii) −x + 1, −y + 1, −z + 1] with the π• • • π stacking between the two bipyridine moieties (Figure 2a).The ring-A (N1−C1-C2-C3-C4-C5) of the bipyridine closely interacts with the ring-C ii (N2 ii -C14 ii -C15 ii -C16 ii -C17 ii -C18 ii ) of the adjacent complex ii ; the distance of The packing structures of 1•0.5C6H6 are shown in Figures 1b and 2. The two complexes form a dimer with the inversion center between the two complexes; e.g., the complex [symmetry code: x, z] closely interacts with the adjacent complex ii [symmetry code: (ii) −x + 1, −y + 1, −z + 1] with the π⋯π stacking between the two bipyridine moieties (Figure 2a).The ring-A (N1−C1-C2-C3-C4-C5) of the bipyridine closely interacts with the ring-C ii (N2 ii -C14 ii -C15 ii -C16 ii -C17 ii -C18 ii ) of the adjacent complex ii ; the distance of Cg<ring-A>•••Cg<ring-C ii > is 3.4638 ( 16) Å, where Cg<ring-A> and Cg<ring-C ii > are the centroids of the rings-A and C ii , respectively, of the bipyridine moieties.The corresponding shortest perpendicular distance from the ring centroid to the adjacent plane is 3.2614(8) Å.According to the π⋯π stacking, the intermolecular distance between Pd1 and Pd1 ii is 6.609( 2

Crystal Structure and Intermolecular Interactions of 2
Crystal 2 has a whole complex in the asymmetric unit, as shown in Figure 3.The geometry around the metal center in 2 is also square planar.The bond distances of Pd1-N1, Pd1-N2, Pd1-Cl1, and Pd1-Cl2 are 2.033(2), 2.029(2), 2.2799(9), and 2.2885(9) Å, respectively.The molecular structures of the two complexes in crystals 1•0.5C6H6 and 2 are almost the same.Two pyridine planes (rings-A and C) are highly flat by Pd coordination, and the torsion angle of N1-C5-C18-N2 is 3.7(3)°.The naphthalene group (C8-C9-C10-C11-C12-C13-C14-C15-C16-C17, ring-B) is situated on the same plane as Pd coordination with the dihedral angle between rings-A and B of 1.96°.The other naphthalene group (C25-C26-C27-C28-C29-C30-C31-C32-C33-C34, ring-D) is almost perpendicular to the coordination plane with the dihedral angle between rings-C and D of 85.76°, which is larger than that of 1 (60.66°).The packing structure of 2 is shown in Figures 3b and 4. The naphthalene groups (rings-B and D) of the complex [x, y, z] closely interact with rings-D vi and B vi , respectively, of the complex vi [symmetry code: (vi) −x + 2, −y + 1, −z + 1], forming a rhomb-like dimer fragment through intermolecular CH⋯π interactions (Figure 3b).Between the naphthalene groups, one six-membered ring, C25 vi -C26 vi -C27 vi -C28 vi -C34 vi -C33 vi (ring-Da vi ), is only involved in the interaction, and the intermolecular distance of C12-H12⋯Cg<ring-Da vi > is also short (2.80 Å for H12⋯Cg<ring-Da vi > and 3.656(4) Å for C12⋯Cg<ring-Da vi >).The intermolecular distance of H12 and the whole naphthalene ring-D vi is 3.34 Å.The naphthalene ring-B further interacts with the bipyridine moiety of the adjacent complex vii [symmetry code: (vii) −x + 1, −y, −z +1] with the π-π stacking (Figure 4a).The ring-Bb (C12-C13-C14-C15-C16-C17) of the naphthalene closely interacts with the five-membered coordination ring-E vii (Pd1 vii -N1 vii -C5 vii -C18 vii -N2 vii ), and the distance of Cg<ring-Bb>•••Cg<ring-E vii > is 3.517(2) Å.The corresponding shortest perpendicular distance from the ring centroid to the adjacent plane is 3.342(1) Å.The distance of rings-Bb and A vii is also short (Cg<ring-Bb>•••Cg<ring-A vii > is 3.631(2) Å).This π⋯π stacking is observed between the ring-A of bipyridine and ring-Bb vii of the naphthalene group.It is pointed out that the weak CH⋯Cl interaction is shown between C26 viii -H26 viii in the naphthalene ring-D viii [symmetry code: (viii) x − 1, y − 1, z] and the Cl − ion in the complex (2.88 Å for H26 viii ⋯Cl1).In Figure 4b The packing structure of 2 is shown in Figures 3b and 4 showing the no interaction between the metal ions.Thus, the orange color of crystal 2 is estimated due to the expanded π-conjugated system of the naphthalene rings and not metal• • • metal interactions.The twist differences between the two arylethynyl groups are induced by the rhomb-like structure for both 1 and 2, which will give the common prospects for the stabilizing structure in similar compounds.While compound 1 encapsulated the benzene molecule, no solvated crystal was obtained for 2. The results indicate that the large naphthalene groups behave Crystals 2024, 14, 255 7 of 11 like guests instead of solvate benzenes in the space.Typically, from void space calculations using CCDC Mercury, the space calculated for the crystal 1•0.5C 6 H 6 , excluding benzene, was 12.5%, with a volume per unit lattice of about 294 Å 3 (Van der Waals radius set to a minimum value of 1.2 Å).The volume of benzene per molecule was about 150 Å 3 , with two molecules closely packed in the unit lattice.The volume of naphthalene is about 200 Å 3 , and changing from a phenyl group to a naphthyl group occupies about 50 Å 3 of new space, which corresponds to 4/3 of a benzene molecule when the two complexes forming the rhombic structure are changed to four naphthyl substituents.
Pd1⋯Pd1 iv and Pd1⋯Pd1 x [symmetry code: (x) x + 1, y, z], showing the no interaction between the metal ions.Thus, the orange color of crystal 2 is estimated due to the expanded π-conjugated system of the naphthalene rings and not metal⋯metal interactions.The twist differences between the two arylethynyl groups are induced by the rhomb-like structure for both 1 and 2, which will give the common prospects for the stabilizing structure in similar compounds.While compound 1 encapsulated the benzene molecule, no solvated crystal was obtained for 2. The results indicate that the large naphthalene groups behave like guests instead of solvate benzenes in the space.Typically, from void space calculations using CCDC Mercury, the space calculated for the crystal 1•0.5C6H6, excluding benzene, was 12.5%, with a volume per unit lattice of about 294 Å 3 (Van der Waals radius set to a minimum value of 1.2 Å).The volume of benzene per molecule was about 150 Å 3 , with two molecules closely packed in the unit lattice.The volume of naphthalene is about 200 Å 3 , and changing from a phenyl group to a naphthyl group occupies about 50 Å 3 of new space, which corresponds to 4/3 of a benzene molecule when the two complexes forming the rhombic structure are changed to four naphthyl substituents.

Hirshfeld Surface Analysis of the Structures
To understand the detailed intermolecular interactions, the HS analysis [30,31] of each complex was carried out using Crystal Explorer 17.5 [32].The results of 1 mapped with dnorm (the distance between the surface and external atoms) are shown in Figure 5.The red sports are short intermolecular distances of the molecules, indicating two important results: (1) the remarkable interactions, e.g., CH⋯π, π⋯π and Cl⋯H, are observed between the complexes and (2) no remarkable interactions are observed between the benzene molecule.The most important contributions for the crystal packing are from H⋯H

Hirshfeld Surface Analysis of the Structures
To understand the detailed intermolecular interactions, the HS analysis [30,31] of each complex was carried out using Crystal Explorer 17.5 [32] weak H⋯H (58.0%),H⋯C (10.0%),H⋯Cl (10.0%).Very similar contributions are observed for 2 (Figures 7 and 8), and the most important contributions for the crystal packing of 2 are from H⋯H (36.5%),C⋯H/H⋯C (26.0%),Cl⋯H/H⋯Cl (15.7%), and C⋯C (12.3%) interactions.These slightly different contributions are estimated that the phenyl group has expanded to the naphthyl group.Thus, the crystallographic studies of 1•0.5C6H6 and 2 prove common structures and the corresponding intermolecular interactions.

Density Functional Theory Calculations of the Structures
DFT calculations were performed using the crystal structures of 1 and 2 to understand the quantitative value of the surface potential and the corresponding intermolecular interactions.The electrostatic potentials of each metal complex ranged from −303.75 to +206.48 kJ mol −1 for 1 and −302.92 to +204.25 kJ mol −1 for 2, as shown in Figure 9a,b, respectively, showing almost the same values.The highest electrostatic potential, of which the electron-poor region is shown as blue, is on the top edge of the bipyridine protons, H4 and H15 for 1 (H4 and H19 for 2), and the other protons of bipyridine and phenyl moieties.The electron-poor protons have a good possibility of forming the Intermolecular interaction with the guest, and the benzene molecule is inserted for 1 but self-association for 2. The lowest electrostatic potential, as shown in red, is Cl1 and Cl2 of the coordinated anions.The lowest electrostatic potentials of the aromatic center of each complex were approximately −26 and −41 kJ mol −1 for phenyl and naphthyl groups, respectively, which interact with the next complex to form the rhombic structure.The potential energies of the

Density Functional Theory Calculations of the Structures
DFT calculations were performed using the crystal structures of 1 and 2 to understand the quantitative value of the surface potential and the corresponding intermolecular interactions.The electrostatic potentials of each metal complex ranged from −303.75 to +206.48 kJ mol −1 for 1 and −302.92 to +204.25 kJ mol −1 for 2, as shown in Figure 9a,b, respectively, showing almost the same values.The highest electrostatic potential, of which the electron-poor region is shown as blue, is on the top edge of the bipyridine protons, H4 and H15 for 1 (H4 and H19 for 2), and the other protons of bipyridine and phenyl moieties.The electron-poor protons have a good possibility of forming the Intermolecular interaction with the guest, and the benzene molecule is inserted for 1 but self-association for 2. The lowest electrostatic potential, as shown in red, is Cl1 and Cl2 of the coordinated anions.The lowest electrostatic potentials of the aromatic center of each complex were approximately −26 and −41 kJ mol −1 for phenyl and naphthyl groups, respectively, which interact with the next complex to form the rhombic structure.The potential energies of the Pd center in each complex are approximately −74 and −87 kJ mol −1 , which was in good agreement with similar complexes with nucleophilic characteristics.Since there is no extreme value around the Pd atom, it is assumed that the electrostatic potential near the palladium atom is largely contributed by the coordinated bipyridine and chlorine moieties.Pd center in each complex are approximately −74 and −87 kJ mol −1 , which was in good agreement with similar complexes with nucleophilic characteristics.Since there is no extreme value around the Pd atom, it is assumed that the electrostatic potential near the palladium atom is largely contributed by the coordinated bipyridine and chlorine moieties.

Conclusions
In conclusion, we prepared palladium complexes with a new naphthalene derivative, 4,4′-di(naphthalen-1-ylethynyl)-2,2′-bipyridine (L 2 ), to compare with the corresponding phenyl derivative (L 1 ).We prepared the Pd complexes 1 and 2, and the single crystals of 1•0.5C6H6 and 2 were obtained from a benzene-acetone and/or benzene-dmso solution, which was investigated by single crystallographic and DFT studies.For complex 1, the benzene solvent was useful for crystal growth, and sufficiently large crystals for crystallographic studies were obtained.Both structures show the rhomb-shaped dimer through

Conclusions
In conclusion, we prepared palladium complexes with a new naphthalene derivative, 4,4 ′ -di(naphthalen-1-ylethynyl)-2,2 ′ -bipyridine (L 2 ), to compare with the corresponding phenyl derivative (L 1 ).We prepared the Pd complexes 1 and 2, and the single crystals of 1•0.5C 6 H 6 and 2 were obtained from a benzene-acetone and/or benzene-dmso solution, which was investigated by single crystallographic and DFT studies.For complex 1, the benzene solvent was useful for crystal growth, and sufficiently large crystals for crystallographic studies were obtained.Both structures show the rhomb-shaped dimer through the CH• • • π interactions between the complexes, indicating that the central cavity prefers to recognize the aromatic moieties by surrounding the organic wall of the complex.It was found that the rhomb shape within this crystal was prioritized in the crystal states, while palladium preferred the charge repulsion of each other over the metallophilic interaction.Crystals containing solvated aromatic compounds have the potential to be developed into molecular recognition materials that dynamically and selectively incorporate further aromatic compounds.

11 C
g <ring-A>•••C g <ring-C ii > is 3.4638 (16) Å, where C g <ring-A> and C g <ring-C ii > are the centroids of the rings-A and C ii , respectively, of the bipyridine moieties.The corresponding shortest perpendicular distance from the ring centroid to the adjacent plane is 3.2614(8) Å.According to the π• • • π stacking, the intermolecular distance between Pd1 and Pd1 ii is 6.609(2) Å.A twisted phenyl ring-D iii [symmetry code: (iii) x, −y + 0.5, z − 0.5] further interacts with the bipyridine moieties of the dimer and the shortest distance of C g <Pd1-N1-C5-C14-N2>•••C g <ring-D iii > is 3.4684(17) Å (Figure 2b), giving the twisted conformation of the ring-D.The phenyl ring-D iii further interacted with the adjusted phenyl ring-B iv [symmetry code: (iv) x, y − 1, z] through π-π interaction, and the C g <ring-D iii >•••C g <ring-B iv > is 3.6678(18) Å.For the opposite side of ring-B iv , CH• • • π interaction is observed with H22 of the ring-D v [symmetry code: (v) −x, −y, −z + 1].

Figure 4 .
Figure 4.The crystal packing of 2, viewed along the (a) b and (b) a axes.

Figure 4 .
Figure 4.The crystal packing of 2, viewed along the (a) b and (b) a axes.
. The results of 1 mapped with d norm (the distance between the surface and external atoms) are shown in Figure 5.The red sports are short intermolecular distances of the molecules, indicating two important results: (1) the remarkable interactions, e.g., CH• • • π, π• • • π and Cl• • • H, are observed between the complexes and (2) no remarkable interactions are observed between the benzene molecule.The most important contributions for the crystal packing are from H•• • H (33.6%), C• • • H/H• • • C (28.3%), Cl• • • H/H• • • Cl (17.8%), and C• • • C (10.6%) interactions, and the values with the corresponding fingerprint plots are summarized in Figure 6.The C atoms of the phenyl ring-B contact with the H atom adjacent to the complex, but that of ring-A shows C• • • C interaction with the benzene molecule.The close contact from the C atom of benzene molecule (21.6%) shows only the CH• • • π interaction [C(inside)•••H(outside) 21.5%] without any π• • • π stacking [C(inside)•••C(outside) 0.1%] and that from the H atom shows weak H• • • H (58.0%), H• • • C (10.0%), H• • • Cl (10.0%).Very similar contributions are observed for 2 (Figures 7 and 8), and the most important contributions for the crystal packing of 2 are from H• • • H (36.5%), C• • • H/H• • • C (26.0%), Cl• • • H/H• • • Cl (15.7%), and C• • • C (12.3%) interactions.These slightly different contributions are estimated that the phenyl group has expanded to the naphthyl group.Thus, the crystallographic studies of 1•0.5C 6 H 6 and 2 prove common structures and the corresponding intermolecular interactions.

Figure 5 .
Figure 5. HS of the complex 1•0.5C6H6 mapped with dnorm and the intermolecular interactions of the surrounding molecules: (a) and (b) show the front and back structures, respectively.

Figure 6 .
Figure 6.HS of 1 mapped with de and the fingerprint plots for the contributions of the remarkable intermolecular interactions of 1 in the crystal of 1•0.5C6H6.

Figure 5 .
Figure 5. HS of the complex 1•0.5C 6 H 6 mapped with d norm and the intermolecular interactions of the surrounding molecules: (a) and (b) show the front and back structures, respectively.

Figure 5 .
Figure 5. HS of the complex 1•0.5C6H6 mapped with dnorm and the intermolecular interactions of the surrounding molecules: (a) and (b) show the front and back structures, respectively.

Figure 6 .
Figure 6.HS of 1 mapped with de and the fingerprint plots for the contributions of the remarkable intermolecular interactions of 1 in the crystal of 1•0.5C6H6.

Figure 6 . 11 Figure 7 .
Figure 6.HS of 1 mapped with d e and the fingerprint plots for the contributions of the remarkable intermolecular interactions of 1 in the crystal of 1•0.5C 6 H 6 .Crystals 2024, 14, x FOR PEER REVIEW 9 of 11

Figure 7 .
Figure 7. HS of the complex 2 mapped with d e and the intermolecular interactions of the surrounding molecules.

Figure 7 .
Figure 7. HS of the complex 2 mapped with de and the intermolecular interactions of the surrounding molecules.

Figure 8 .
Figure 8. HS of 2 mapped with de and the fingerprint plots for the contributions of the remarkable intermolecular interactions of 2.

Figure 8 .
Figure 8. HS of 2 mapped with d e and the fingerprint plots for the contributions of the remarkable intermolecular interactions of 2.

Figure 9 .
Figure 9.The energy potential maps of (a) 1 and (b) 2 from the crystal structures: the color of the potential is shown between −200 kJ mol −1 (red) and +200 kJ mol −1 (blue).

Figure 9 .
Figure 9.The energy potential maps of (a) 1 and (b) 2 from the crystal structures: the color of the potential is shown between −200 kJ mol −1 (red) and +200 kJ mol −1 (blue).

Table 1 .
Crystal data and structure refinement for 1