Ni Distance Research Articles

Unusual Ni⋯Ni interaction in Ni(ii) complexes as potential inhibitors for the development of new anti-SARS-CoV-2 Omicron drugs.

Two nickel(ii) coordination complexes [Ni(L)]2(1) and [Ni(L)]n(2) of a tetradentate Schiff base ligand (H2L) derived from 2-hydroxy-1-naphthaldehyde with ethylenediamine were synthesized, designed, and characterized via spectroscopic and single crystal XRD analyses. Both nickel(ii) complexes exhibited unusual Ni⋯Ni interactions and were fully characterized via single-crystal X-ray crystallography. Nickel(ii) complexes [Ni(L)]2(1) and [Ni(L)]n(2) crystallize in monoclinic and triclinic crystal systems with P21/c and P1̄ space groups, respectively, and revealed square planar geometry around each Ni(ii) ion. The structure of both the complexes have established the existence of a new kind of metal system containing nickel(ii)-nickel(ii) interactions with a square planar-like geometry about the nickel(ii) atoms. Both square planar Ni(ii) complexes were often stacked with relatively short Ni⋯Ni distances. The non-bonded Ni-Ni distance (Ni⋯Ni separation) seems to be 3.356 Å and 3.214 Å from the nickel atoms of [Ni(L)]2(1) and [Ni(L)]n(2), respectively. These distances are shorter than the sum of their van der Waals radii (4.80 Å) but longer than the sum of their covalent radii (2.50 Å), indicating that there is a Ni⋯Ni interaction but not a Ni-Ni bond. The discrete molecules are π-stacked and connected via weak intermolecular interactions (C-H⋯O and C-H⋯N). Cyclic voltammetry measurements were obtained for both the complexes, and their pharmacokinetic and chemoinformatics properties were also explored. Detailed structural analysis and non-covalent supramolecular interactions were investigated using single-crystal structure analysis and computational approaches. Both the unique structures show good inhibition performance for the Omicron spike proteins of the SARS CoV-2 virus. To gain insights into potential SARS-CoV-2 Omicron drugs and find inhibitors against the Omicron variants of SARS-CoV-2, we examined the molecular docking of the nickel(ii) complexes [Ni(L)]2(1) and [Ni(L)]n(2) with the SARS-CoV-2 Omicron spike protein (PDB ID: 7WK2 and 7WVO). A strong binding was predicted between Ni(ii) coordination complexes [Ni(L)]2(1) and [Ni(L)]n(2) with the SARS-CoV-2 Omicron variant receptor protein through the negative value of binding affinity. Molecular docking of Nil(ii) complexes [Ni(L)]2(1) and [Ni(L)]n(2) with a DNA duplex (PDB ID: 7D3T) and RNA (PDB ID: 7TDC) binding protein was also studied. Overall, this study suggests that Ni(ii) complexes can be considered as drug candidates against the Omicron variants of SARS-CoV-2.

Three-Electron Nickel(I)/Nickel(0) Half-Bond.

An (N-heterocyclic carbene)nickel(I) cation precursor reacts with the corresponding nickel(0) complex to form a dinickel(I,0) monocation. The Ni···Ni distance in this cation is 0.93 Å shorter than in the analogous dinickel(0) complex. Although the solid-state structure shows equivalent Ni centers, density functional theory calculations indicate significant electronic localization. Reactions with CO and NO form mononuclear carbonyl and nitrosyl complexes. Oxidative addition of an aryl bromide results in C-arylation of the carbene ligands.

Homogeneous {Ti2Ni} Heterotrinuclear Catalyst for Ethylene Polymerization and Copolymerization

We synthesized and spectroscopically characterized a new heterotrimetallic {Ti2Ni} ethylene (co)polymerization precatalyst containing one (α-diimine)NiBr2 and two (phenoxy-imine)TiCl4 scaffolds. Its calculated structure was investigated at the DFT B3LYP/LACVP** level. Our calculations showed that the titanium(IV) centers were in a slightly distorted trigonal bipyramidal environment, and the average Ti···Ni distance was 8.76 Å. The precatalyst was used for synthesizing polyethylene and ethylene copolymers. The results of GPC analyses showed that the obtained polyethylenes had the desired bimodal molecular weight distributions. The FTIR spectra revealed that polydispersity decreased as the vinyl end-group content increased. These results suggested that high mechanical resistance can increase the mechanical energy needed for processing the material. All 13C NMR signals were assigned to short-chain branches with specific spatial arrangements along the polymer backbone. The chain walking mechanism of branch formation controls the spacing and conformational arrangements between these short chains.

Synthesis, characterization, X-ray crystal structure and Hirshfeld surface analysis of Ni(II) complex of 1,2-bis(pyridin-2-ylmethylene)hydrazine

We report the synthesis, characterization, X-ray crystal structure and Hirshfeld surface analysis of Ni(II) perchlorate complex (1, Ni2L3·4ClO4·2CH3CN) of 1,2-bis(pyridin-2-ylmethylene)hydrazine (L) ligand. The X-ray crystallographic study of complex 1 reveals that in the presence of Ni(II) ions,the ligand L forms a dimeric triple helix with a Ni(II)-Ni(II) distance of 3.794 Å. Crystal data for C40H36Cl4N14Ni2O16: Monoclinic, space group P21/c (no. 14), a = 20.7558(19) Å, b = 13.1937(12) Å, c = 20.0181(18) Å, β = 96.9510(10)°, V = 5441.6(9) Å3, Z = 4, T = 293.15 K, μ(MoKα) = 0.965 mm-1, Dcalc = 1.498 g/cm3, 38075 reflections measured (1.976° ≤ 2Θ ≤ 43.728°), 6557 unique (Rint = 0.0695, Rsigma = 0.0466) which were used in all calculations. The final R1 was 0.0518 (I > 2σ(I)) and wR2 was 0.1270 (all data). The Hirshfeld surface analysis of complex 1 shows that C···H, H···H, N···H and O···H interactions of 10.9, 26.4, 6.7, and 33.4%; respectively, which exposed that the main intermolecular interactions were H···H intermolecular interactions.

Unsaturated Ni/V centers and short Ni·V/Ni distances in nickel vanadate for high-performance zinc-ion battery

Ni0.22V2O5(H2O)0.94 (NiVO) nanobelts were synthesized via a facile one-step hydrothermal method, which exhibited a 3D framework built by [Ni(H2O)6]2+ pillars connecting 2D V-O-V layers. Upon subsequent annealing, Ni0.22V2O5 (o-NiVO) nanobelts with a large d spacing of 9.2 Å were obtained. 3D rotation electron diffraction (cRED), Rietveld refinement and spherical aberration-corrected TEM reveal that o-NiVO displays a novel 3D framework. Annealing led to atom arrangement and partial Ni2+ ions entered into 2D V-O-V layer of o-NiVO with unsaturated Ni/V centers and short Ni ··· V (2.463 Å)/Ni ···Ni distances (2.401 Å), which can facilitate the electron transfer from O → Ni and improve the electron conductivity with a low Zn2+ migration barrier (0.64 eV) in o-NiVO, as evidenced by DFT calculations. Therefore, o-NiVO can deliver a high initial capacity of 445 mAh g−1 at 0.1 A g−1 with good rate capability and fast Zn2+ diffusion kinetics. Meanwhile, o-NiVO also possesses excellent long-term durability with capacity retention of 99.8 % over 1500 discharge/charge cycles. The fully discharged o-NiVO nanobelts was characterized by cRED, which disclosed the structural integrity of o-NiVO during the discharge process. A series of ex situ characterizations of the o-NiVO electrode reveal a co(de)intercalation mechanism of Zn2+/H+ along with partial phase transformation of o-NiVO → Zn3(OH)2V2O7(H2O)2.

Two nickel (II) complexes with side chain isomeric ligands: L-leucine and L-isoleucine to study non-covalent interactions and metal-ligand bonding

Two new Ni(II) complexes with isomeric α-amino acid ligands were prepared and studied from Synchrotron X-ray powder diffraction data. In Complex I, trans-diaqua-(L-leucinate- κ2 N,O) nickel(II), the two L-leucinate ligands display symmetrical (κ2 N,O) bites, with Ni···Ni distances of 4.842(2) Å. In complex II, cis-diaqua-(L-isoleucinate- κ2 N,O) nickel(II), the L-isoleucinate ligands adopt (κ2 N,O) crossbites to the metal center. A redistribution of the hydrophobic and bulkier ethyl groups occurs that balances the H···H interactions in the L-isoleucinate's tails and increments Ni···Ni distances to 5.822(5) Å. In complex I, Hirshfeld surfaces show that two C—H···O hydrogen bonds act as stacking forces during molecular aggregation. The electron localization analysis (ELF), quantum theory of atoms in molecules (QTAIM), and natural bond orbital (NBO) results suggest that all the coordination sphere's bonds have weak covalent character. In hydrogen bond formation, the more polarized Ni—N coordination bond makes the N a stronger H-donor than related O—H donors from coordination water molecules. Net electron transfer from the N(2s,2p) and O(2s,2p) orbitals to the 4s and 4p Ni orbitals, with net atomic charges over the Ni atom being less than the expected +2 value by more than 54%, confirm the weak covalent character of these bond.

Syntheses, structures and magnetic properties of two CoII/NiII isostructural coordination polymers based on an asymmetric semirigid tricarboxylate ligand.

Two new isostructural complexes, namely, poly[aqua[μ3-2-(4-carboxyphenoxy)terephthalato-κ3O1:O4:O4'](1,10-phenanthroline-κ2N,N')cobalt(II)], [Co(C15H8O7)(C12H8N2)(H2O)]n or [Co(μ3-Hcpota)(phen)(H2O)]n, I, and poly[aqua[μ3-2-(4-carboxyphenoxy)terephthalato-κ3O1:O4:O4'](1,10-phenanthroline-κ2N,N')nickel(II)], [Ni(C15H8O7)(C12H8N2)(H2O)]n or [Ni(μ3-Hcpota)(phen)(H2O)]n, II, have been synthesized by solvothermal reactions. Complexes I and II were fully characterized by IR spectroscopy, elemental analyses, thermogravimetric analyses, and powder and single-crystal X-ray diffraction. They both present two-dimensional structures based on [M2(μ-COO)2]2+ (M= CoII or NiII) dinuclear metal units with a fes topology and a vertex symbol (4·82). Interestingly, the positions of the two dimeric metal motifs and the two partially deprotonated Hcpota2- ligands reproduce regular flying butterfly arrangements flipped upside down and sharing wings in the ab plane. Magnetic studies indicate antiferromagnetic interactions (J= -5.21 cm-1 for I and -11.53 cm-1 for II) in the dimeric units, with Co...Co and Ni...Ni distances of 4.397 (1) and 4.358 (1) Å, respectively, that are related to double syn-anti carboxylate bridges.

Synthesis of a Nickel(I) alkoxide and related cation equivalents

An (N-heterocyclic carbene)nickel(I) hexamethyldisilazide deprotonates neopentanol (NpOH) to form the corresponding nickel(I) neopentoxide, which crystallizes as an alkoxide-bridged dimer. Reaction of the dimer with one equivalent of tert-butyldimethylsilyl trifluoromethanesulfonate gives an alkoxide-bridged dinickel(I) complex bridged by the CF3SO3 (OTf) anion. In both [LNiONp]2 and [(LNi)2(μ-ONp)(μ-OTf)], Ni•••Ni distances are consistent with the absence of metal–metal bonding, and Evans NMR data are consistent with the S = 1 spin state. Treatment of the dimer with two equivalents of silyl triflate results instead in complete abstraction of alkoxide. Addition of diethyl ether forms the monomeric d9 complex LNi(OEt2)OTf.

Combined experimental and computational approach to the structure of a new nickel(II) complex with tridentate Schiff base ligand

A combined experimental and theoretical study on a new complex [NiL(NCS)], derived from the Schiff base ligand HL, (E)-2-methoxy-6-(((pyridin-2-ylmethyl)imino)methyl)phenol is described herein. X-ray structure reveals that metal center of the complex has a square planar environment with a N3O donor set from the ligand and terminal thiocyanate anion. In the solid state, π—π stacking interactions lead to a one-dimensional arrangement with alternating short and long Ni…Ni distances. The different isomeric forms of the ligand can provide alternative molecular structures for the nickel(II) complex. Density functional theory calculations at B3LYP/6-311+G(d,p) level were performed to elucidate the structure and stability of the possible isomeric forms of the complex.

Template‐Directed Synthesis of Two Dinuclear Ni(II) Complexes together with Their Interconversion, Crystal Structures and DNA‐Binding Studies

AbstractDinuclear Ni(II) macrocyclic complex A ([Ni2L1OAc]ClO4⋅CH3OH⋅H2O) and dinuclear Ni(II) acyclic complex B ([Ni2L2](ClO4)2) were synthesized by condensation between H2L (3,3′‐(ethane‐1,2‐diylbis(benzylazanediyl))bis(methylene)bis(2‐hydroxy‐5‐methyl‐benzaldehyde)) and different molar equivalent 1,3‐propanediamine in the presence of Ni(II) ions. The structures of complexes were characterized by IR spectroscopy, elemental analysis, electrospray mass spectra and X‐ray single crystal diffraction. In complex A, the Ni(II)‐Ni(II) distance was 2.9413(7) Å, bridged by two phenolic oxygens and an acetate anion, while in complex B, it was 3.0540(1) Å, only bridged by two phenolic oxygens. The calf thymus DNA (CT‐DNA) binding ability was studied through spectroscopic and electrochemical methods, the corresponding binding constant for complexes A and B were 6.45×104 M−1 and 8.65×104 M−1, respectively. The MS revealed that B can transform to A by adding more H2L, and A cannot transform to B in the presence of excess 1,3‐propanediamine.

Distance Effect of Ni-Pt Dual Sites for Active Hydrogen Transfer in Tandem Reaction

SummaryUnveiling the distance effect between different sites in multifunctional catalysts remains a major challenge. Herein, we investigate the distance effect by constructing a dual-site distance-controlled tandem catalyst with a five-layered TiO2/Pt/TiO2/Ni/TiO2 tubular nanostructure by template-assisted atomic layer deposition. In this catalyst, the Ni and Pt sites are separated by a porous TiO2 interlayer, and the distance between them can be precisely controlled on the subnanometer scale by altering the thickness of the interlayer, while the inner and outer porous TiO2 layers are designed for structural stability. The catalyst exhibits superior performance for the tandem hydrazine hydrate decomposition to hydrogen and subsequent nitrobenzene hydrogenation when the Ni and Pt site distance is on the subnanometer level. The performance increases with the decrease of the distance and is better than the catalyst without the TiO2 interlayer. Isotopic and kinetic experiments reveal that the distance effect controls the transfer of active hydrogen, which is the rate-determining step of the tandem reaction in a water solvent. Reduced Ti species with oxygen vacancies on the TiO2 interlayer provide the active sites for hydrogen transfer with -Ti-OH surface intermediates via the continuous chemisorption/desorption of water. A smaller distance induces the generation of more active sites for hydrogen transfer and thus higher efficiency in the synergy of Ni and Pt sites. Our work provides new insight for the distance effect of different active sites and the mechanism of intermediate transfer in tandem reactions.

Synthesis, structure, spectra, magnetism, non-linear optical properties and DFT calculations of a bis(dithiolene)nickel(III) anion salt with substituted isoquinolinium

Self-assemble of the bis(maleonitriledithiolate)nickel(III) anion ([Ni(mnt)2]−) and 4-cyanobenzyl isoquinolinium cation ([4CNBzIQl]+) results into a new molecular solid, [4CNBzIQl][Ni(mnt)2](1). Single crystal X-ray diffraction revealed that contains segregated columns of anions and cations and the Ni(III) ions form a 1 D zigzag alternating chain through Ni···S and π···π interactions between anions. Powder XRD diffraction study confirms the crystalline nature of the title material. The UV-Vis spectral analysis was used to determine the band gap energy, and the nonlinear optical (NLO) effect of the compound was predicted using DFT. Upon the temperature is lowered, the non-uniform chain has been compressed with the change of Ni···Ni distance, and a spin gap transition around 128 K.

Binuclear Nickel(II) Complex Containing 6-Methyl-2,2'-bipyridine and Chloride Ligands: Synthesis, Characterization, Thermal Analyses, and Crystal Structure Determination

A new binuclear complex of [{NiCl(6-mbipy)}2(μ-Cl)2] (1) was prepared from the reaction of NiCl2.6H2O and 6-methyl-2,2'-bipyridine (6-mbipy) in a mixture of methanol and acetonitrile. Suitable crystals of 1 for X-ray diffraction measurement were obtained by slow evaporation of the resulted green solution at room temperature. Complex 1 was characterized by spectral methods (IR, UV–Vis, and luminescence), elemental analysis (CHN), and single-crystal X-ray diffraction. The structure of 1 is centrosymmetric binuclear complex and each Ni(II) cation is five-coordinated in a slightly distorted square-pyramidal configuration. In this binuclear complex, the Ni…Ni distance is 3.533(1)A. Furthermore, the luminescence emission of the title complex was blue-shifted and is stronger than that of free 6-methyl-2,2'-bipyridine ligand. Thermal stabilities of this complex was also studied by thermogravimetric analysis.

Impact of gamma-ray irradiation on some aryl-amide-bridged Schiff-base complexes: spectral, TGA, XRD, and antioxidant properties

Some aryl amide Schiff base Co(II), Ni(II) and Cu(II) distance between Cu(II) and complexes (1–7) have been obtained and identified by various analytical and spectroscopic tools. To through a light on the probability of structure changes with γ-irradiation, powder samples of complexes 1, 3, 5 and 6 were irradiated with 60Co γ-rays at dose of 100 kGy (hereafter referred to as 1F, 3F, 5F and 6F). Spectral, molar conductance, magnetic susceptibility, thermal, X-ray diffraction and antioxidant activity for the irradiated complexes were gained using similar methods used for the non-irradiated complexes. The data revealed that the irradiated complexes were not seriously affected by the utilized γ-irradiation dose.

EXAFS studies of enhancement of L21-B2 chemical disorder induced by ball milling in martensitic Ni50Mn36Sn14 pseudo-Heusler alloy

Chemical disorders in L21-B2-type structure, naturally occurred in 57Fe-doped Ni50Mn36Sn14 pseudo-Heusler alloy or enhanced in milled material, were systematically investigated using local probe methods: 57Fe Mössbauer spectroscopy (MS) and extended X-ray absorption fine structure (EXAFS). 57Fe Mössbauer studies show two Fe configurations: paramagnetic (singlet) and ferromagnetic (magnetic distribution) with approximately a 1:1 ratio. Fe atoms in singlet configuration are replacing Ni or Sn sites, where a near zero or magnetically frustrated state occurs. The magnetic distribution component is due to Fe magnetically coupled to Mn atoms. The singlet fraction is 100% after 220 s of milling. Low temperature thermal annealing easily recovers the original magnetic component and its initial ratio. Ni and Mn K-edges EXAFS spectra suggest that the milled material still displays the long range crystalline ordering, but with an enhancement of the local disorder due to Mn atoms occupying Sn sites and Mn-distance changes (D-sites of the L21 structure: Mn–Sn). While Mn–Mn distances seem to reduce slightly from 2.91 Å to 2.89 Å after the milling, the chemical disorder parameter (σ2) enhanced 29%. No change in Mn–Ni distances was observed; a condition necessary for observation of structural transition inside of crystalline grain. The structural transition properties change due to the increase of σ2-parameters of Mn–Ni (enhanced to 38%) and Mn–Sn (increased to 29%). EXAFS spectra of annealed sample indicate an improvement of the D-site symmetry, which is confirmed by a distance value of 2.92 Å for the Mn–Mn and Mn–Sn in the L21 structure as well as a large reduction (between 40% and 80%) of the σ2 parameter value. The chemical order improvement of the L21-structure favors Mn–Mn ferromagnetic order, indirectly measured by 57Fe MS that probed a magnetic hyperfine field component.

Conformational Effects of [Ni2 (μ-ArS)2 ] Cores on Their Electrocatalytic Activity.

Two nickel complexes supported by tridentate NS2 ligands, [Ni2 (κ-N,S,S,S'-NPh {CH2 (MeC6 H2 R')S}2 )2 ] (1; R'=3,5-(CF3 )2 C6 H3 ) and [Ni2 (κ-N,S,S,S'-NiBu {CH2 C6 H4 S}2 )2 ] (2), were prepared as bioinspired models of the active site of [NiFe] hydrogenases. The solid-state structure of 1 reveals that the [Ni2 (μ-ArS)2 ] core is bent, with the planes of the nickel centers at a hinge angle of 81.3(5)°, whereas 2 shows a coplanar arrangement between both nickel(II) ions in the dimeric structure. Complex 1 electrocatalyzes proton reduction from CF3 COOH at -1.93 (overpotential of 1.04 V, with icat /ip ≈21.8) and -1.47 V (overpotential of 580 mV, with icat /ip ≈5.9) versus the ferrocene/ferrocenium redox couple. The electrochemical behavior of 1 relative to that of 2 may be related to the bent [Ni2 (μ-ArS)2 ] core, which allows proximity of the two Ni⋅⋅⋅Ni centers at 2.730(8) Å; thus possibly favoring H+ reduction. In contrast, the planar [Ni2 (μ-ArS)2 ] core of 2 results in a Ni⋅⋅⋅Ni distance of 3.364(4) Å and is unstable in the presence of acid.

Synthesis of heterobinuclear Cu(Ⅱ)-Ni(Ⅱ) complex: Structure, CT-DNA interaction, hydrolytic function and antibacterial studies

A new benzyls pendant-armed macrobicyclic heterbinuclear Cu(Ⅱ)-Ni(Ⅱ) complex has been obtained by template-directed synthesis and characterized by elemental analysis, IR spectra, electrospray mass spectra, and single crystal X-ray diffraction. The complex was bridged by two phenolic oxygens and an acetate radical, with the Cu(Ⅱ)-Ni(Ⅱ) distance of 2.9292(8) Å. The hydrolytic function, CT-DNA binding and antibacterial properties were also studied. The initial rate values for the hydrolysis of 4-nitophenylphosphate to 4-nitrophenolate by the Cu(Ⅱ)-Ni(Ⅱ) complex was 1.33 × 10−5 s−1, and 104 times faster than that the spontaneous hydrolysis of the phosphate monoester. The complex shows a better binding property to CT-DNA and the intrinsic binding constant is 1.29 × 105 M−1. The Stern-Volmer constant is 1.25 × 105 M−1. The viscosity increased obviously with the increase of complex concentration, the results showed that the complex bind to DNA through intercalation mode, which was in accordance with the absorption and emission spectral studies. The antibacterial activities against E.coli was also investigated using the Gentamycinas reference system.

Synthesis, crystallographic structure, Hirshfeld surface analysis and DFT calculations of two salen-type halogenated Schiff-base Ni(II) complexes

A detailed description of the crystal structure, Hirshfeld surface analysis and DFT calculations of two new salen-type halogenated Schiff-base Ni(II) complexes are reported. The crystallographic analysis indicates that halogen-atom play a key role in the formation and adjusting of self-assembled supramolecular dimer structures. Hirshfeld surface analysis also show that CH…X interactions are predominated the overall crystal packing. In order to gain a deep insight into the electronic features of the complex, density functional theory (DFT) was used for calculate HOMO and LUMO energies and molecular electrostatic potential of the title compounds. In addition, the variable temperature magnetic susceptibility measurements indicate that, probability due to a closer Ni…Ni distance, title compound exhibit weak ferromagnetic interactions at lower temperature.

Pentanuclear Heterometallic String Complexes with High‐Bond‐order Units [Ni23+−Mo24+−Ni2+(bna)4X2]3+ (X = Cl, NCS)

Our quest for ligands toward the synthesis of functional metal string complexes started from α‐pyridylamido anions. With the modulation of naphthyridylamido anions, the ligands carry less negative charge to be balanced and, thus, to some extent, can tune the oxidation state of the metal centers and the strength of metal–metal interactions. For example, the formation of Ni23+, a mixed‐valence moiety, has been demonstrated. In this paper, high‐bond‐order units of M2 (Mo2 or Ru2) and Ni23+ are introduced and supported by four equatorial ligands of the bisnaphthyridylamido anion (bna−). The resulting compounds are [Ni2Mo2Ni(bna)4Cl2](PF6)3 (1), [Ni2Mo2Ni(bna)4(NCS)2](PF6)3 (2), and [Ni2Ru2Ni(bna)4Cl2](ClO4)3 (3). X‐ray crystallography reveal quadruply bonded characteristics with Mo–Mo distances of 2.133(2) and 2.109(2) Å for 1 and 2, respectively. The Ni2 moieties have a short Ni–Ni distance of 2.331(5) for 1 and 2.334(4) Å for 2, suggesting the formation of mixed‐valence Ni23+ units. It appears that there are no significant metal–metal interactions between Mo2 and its neighboring Ni centers. Characterization using magnetism, voltammetry, electronic absorption, and single‐molecule conductance, however, shows significant influence of Mo2 on the properties of the metal string complexes.

Reluctant cocrystal growth of fullerenes with nickel dithiolene complexes

Attempts to form covalent CS bonds between fullerenes and dithiolene complexes, Ni(S2C2R2)2, lead only to the formation of the cocrystals C60·Ni(S2C2Ph2)2·0.5C7H8 and 2C70·2Ni(S2C2Ph2)2·C7H8. Both cocrystals contained pairs of Ni(S2C2Ph2)2 molecules that make offset face-to-face contact with Ni⋯Ni distances of 3.8793(5) Å in the C60 crystal and 3.7529(9) and 3.7983(9) Å in the C70 crystal. The fullerenes are nestled near the NiS4 portion of the Ni(S2C2Ph2)2 molecules. In 2C70·2Ni(S2C2Ph2)2·C7H8 there are two distinctly different interactions between the fullerene and the nickel complex. In one C70·Ni(S2C2Ph2)2 pair, the long axis of the fullerene is nearly parallel to the long axis of the nickel complex, while in the other pair, the long axis of the C70 cage is oriented nearly perpendicular to the long axis of the nickel complex. Thus, the immediate intimate contact between molecules such as fullerenes and flat molecules like Ni(S2C2Ph2)2 is not fixed, but can be altered by other aspects of crystal packing. The structure of a new solvated form of Ni(S2C2Ph2)2, Ni(S2C2Ph2)2·2C6H6, is also reported.