cis,cis,cis-Di-chlorido-bis-(N4,N4-di-methyl-pyridin-4-amine-κN1)bis-(dimethyl sulfoxide-κS)ruthenium(II).

The structure of the title compound, [RuCl2(C7H10N2)2(C2H6OS)2], has monoclinic (P21/n) symmetry. The Ru-N distances of the coordination compound are influenced by the trans chloride or di-methyl-sulfoxide-κS ligands. The mol-ecular structure exhibits disorder for two of the terminal methyl groups of a dimethyl sulfoxide ligand.

trans-Di-chlorido-tetra-kis-(4-meth-oxy-pyridine-κN)ruthenium(II).

The structure of the title complex, [RuCl2(C6H6NO)4], exhibits point group symmetry . The structure exhibits disorder around a axis. The 4-meth-oxy-pyridine ligands have a propeller-like arrangement around the RuII atom at 52.0 (3)° from the RuN4 plane.

trans-Dichloridotetra-pyrazine-ruthenium(II) dichloro-methane disolvate.

In the title compound, [RuCl(2)(C(4)H(4)N(2))(4)]·2CH(2)Cl(2), the Ru(II) atom occupies a position of 222 symmetry and the C atom of the solvent mol-ecule occupies a site with twofold symmetry. The Ru(II) atom has a slightly distorted octa-hedral geometry. The pyrazine rings are propeller-like and rotated 45.1 (1)° from the RuN(4) plane. In the crystal, the complex and solvent mol-ecules are bridged by weak C-H⋯N hydrogen bonds along the c axis. Weak inter-molecular C-H⋯Cl contacts link the complexes in the ab plane, forming a network.

1,1'-Methyl-enebis(4,4'-bipyridin-1-ium) dibromide.

The asymmetric unit of the title salt, C21H18N4 2+·2Br-, comprises half of the mol-ecule and a bromide ion. The chevron-shaped cations stack as columns in the [001] direction with suitable inter-molecular distance for π-π inter-actions. These cationic columns are further stabilized by inter-columnar C-H⋯N hydrogen bonding with the bromide ions distributed between them.

1,1'-Methyl-enebis{4-[(E)-2-(pyridin-4-yl)ethen-yl]pyridinium} dibromide dihydrate.

The chevron-shaped cations of the title hydrated salt, C25H22N4 2+·2Br-·2H2O, are arranged in back-to-back alternating directions to form a zigzag ribbon propagating along the [010] direction. Inter-molecular inter-actions comprising these ribbons are π-π inter-actions between the pyridinium and adjacent pyridyl rings, as well as O-H⋯O hydrogen bonding between water molecules and two adjacent pyridyl N atoms. Half of the cation is generated by the mirror plane. The water O atoms, the central C atom and one Br atom are located on this mirror plane while the other Br atom is on a twofold screw axis.

1-(2-Methyl-phen-yl)-4,4'-bipyridin-1-ium tetra-fluorido-borate.

Crystals of the title compound, C17H15N2 +·BF4 -, were unexpectedly grown from crystallization attempts of [Pt(4,4'-bpy)4](BF4)2 [Smith et al. (2019 ▸). Comments Inorg. Chem. 39, 188-215] using toluene and aceto-nitrile. The tetra-fluoro-borate anion and the central pyridinium ring of the cation are disordered, with atomic site occupancies close to ½. The tolyl group of the cation has a 75.31 (11)° twist relative to the unsubstituted pyridyl group. This rotation allows for a centrosymmetric dimer of cations with weak hydrogen bonding between the pyridyl nitro-gen atom and a methyl H atom on the neighbouring cation.

trans-Bis(4-amino-pyridine-κN)bis-(quin-ox-aline-2,3-di-thiol-ato-κ2 S,S')platinum(IV) dimethyl sulfoxide monosolvate.

In the structure of the title solvated complex, [Pt(C8H4N2S2)2(C5H6N2)2]·C2H6OS or trans-[Pt(4-ap)2(qdt)2]·dmso (4-ap = 4-amino-pyridyl, C5H6N2; qdt = quinoxaline-2,3-di-thiol-ate, C8H4N2S2; dmso = dimethyl sulfoxide, C2H6OS) the centrosymmetric complex exhibits Pt-S distances in agreement with other PtIV-S bond lengths found in platinum(IV) di-thiol-ene complexes. The qdt ligands have inter-molecular inter-actions with an amine hydrogen atom on a 4-ap ligand (hydrogen bonding) and have sandwich π-π inter-actions with a neighboring qdt ligand.

Tridentate N(2)S ligand from 2,2'-dithiodibenzaldehyde and N,N-dimethylethylenediamine: Synthesis, structure, and characterization of a Ni(II) complex with relevance to Ni Superoxide Dismutase.

Nickel Superoxide Dismutase (NiSOD) and the A-cluster of Carbon Monoxide Dehydrogenase/Acetyl Coenzyme A Synthase (CODH/ACS) both feature active sites with Ni coordinated by thiolate and amide donors. It is likely that the particular set of donors is important in tuning the redox potential of the Ni center(s). We report herein an expansion of our efforts involving the use of 2,2'-dithiodibenzaldehyde (DTDB) as a synthon for metal-thiolate complexes to reactions with Ni complexes of N,N-dimethylethylenediamine (dmen). In the presence of coordinating counterions, these reactions result in monomeric square-planar complexes of the tridentate N(2)S donor ligand derived from the Schiff-base condensation of dmen and DTDB. In the absence of a coordinating counterion, we have isolated a Ni(II) complex with an asymmetric N(2)S(2) donor set involving one amine and one imine N donor in addition to two thiolate donors. This latter complex is discussed with respect to its relevance to the active site of NiSOD.

Chlorido(4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine)-platinum(II) tetra-fluorido-borate.

In the title compound, [PtCl(C(27)H(35)N(3))]BF(4), the Pt(II) atom is in a pseudo-square-planar coordination, which is typical of Pt-terpyridine complexes. The Pt-Cl bond distance is 2.2998 (7) Å. The Pt-N distance of the N atom on the central pyridine is 1.931 (2) Å, while the peripheral N atoms have Pt-N distances of 2.018 (2) and 2.022 (2) Å. The cations pack as dimers in a head-to-tail orientation with an inter-molecular Pt⋯Pt distance of 3.5214 (2) Šand Pt⋯N distances of 3.527 (2), 3.873 (2) and 4.532 (2) Å. In the crystal, cations and anions are linked by weak C-H⋯F hydrogen-bonding inter-actions.

Chlorido(4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine)-platinum(II) chloride toluene monosolvate.

In the title compound, [PtCl(C(27)H(35)N(3))]Cl·C(7)H(8), the Pt(II) atom is coordinated in a pseudo-square-planar fashion by the N atoms of a 4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine (tbtrpy) ligand and a Cl atom. The Pt-N distance of the N atom on the central pyridine is 1.941 (4) Å, while the peripheral N atoms have Pt-N distances of 2.015 (4) and 2.013 (4) Å. The Pt-Cl bond distance is 2.3070 (10) Å. The cations pack as dimers in a head-to-tail orientation with an inter-molecular Pt⋯Pt distance of 3.2774 (3) Šand Pt⋯N distances of 3.599 (4), 3.791 (4) and 4.115 (4) Å. The solvent mol-ecule is disordered and occupies two positions with a ratio of 0.553 (6):0.447 (6).

Poly[[[µ-trans-1,2-bis-(pyridin-4-yl)ethene-κ2 N:N']-µ-iodido-copper(I)]-trans-1,2-bis-(pyridin-4-yl)ethene (1/0.25)].

The title compound, {[CuI(bpe)]·0.25(bpe)} n , was synthesized similarly to (CuI)2(bpe) [Neal et al. (2019 ▸). IUCrData, 4, x190122] with red crystals grown from aceto-nitrile solutions of CuI and the bpe ligand [bpe = 1,2-bis-(pyridin-4-yl)ethene, C12H10N2]. The structure of the title compound is a type 1 complex in the Graham nomenclature [Graham et al. (2000 ▸). Inorg. Chem. 39, 5121-5132], having rhombic dimers of Cu2I2 that are bridged by two bpe ligands, to form oligomeric ribbons arranged as stairsteps. The step height is 2.8072 (11) Å, which is the Cu-Ii distance of the dimer [symmetry code (i): 1 - x, 2 - y, 1 - z]. The resulting polymer displays a two-dimensional honeycomb framework along the (01) plane, and disordered free bpe mol-ecules fill the voids in the crystal.

trans-Diamminebis(1,2-di-cyano-ethene-1,2-di-thiol-ato)platinum(IV).

The title compound, [Pt(C4N2S2)2(NH3)2], represents an octa-hedral platinum(IV) complex with two trans-ammine and two mnt (mnt = 1,2-di-cyano-ethene-1,2-di-thiol-ato) ligands. The Pt-N and Pt-S distances are consistent with those in other platinum(IV) complexes. As a result of a slight canting of the coordination of the mnt ligand to the platinum(IV) atom, the nitrile nitro-gen atoms are positioned suitably to hydrogen-bond with adjacent ammines.

Tetra-pyrazine-platinum(II) bis-(tetra-fluoro-borate) acetonitrile hemisolvate.

The improved synthesis and characterization of tetra-pyrazine-platinum(II) bis-(tetra-fluoro-borate) acetonitrile hemisolvate, [Pt(C(4)H(4)N(2))(4)](BF(4))(2)·0.5CH(3)CN, is reported. The unit cell contains a half equivalent of an acetonitrile solvent mol-ecule per tetra-pyrazine-platinum(II) ion. The coordination geometry of the Pt(II) ion is almost square-planar, with the Pt atom residing on an inversion center. The BF(4) (-) counter-anion, located at a general position, has an idealized tetra-hedral geometry and an acetonitrile solvent mol-ecule, the methyl group of which is disordered over two equal positions, sits on a twofold rotation axis.

Crystal structure of bis-(aceto-nitrile-κN)(4,4'-di-tert-butyl-2,2'-bi-pyridine-κ2N,N')platinum(II) bis-(tetra-fluorido-borate) packing as head-to-head dimers.

The crystal structure of a platinum(II) supra-molecular building block, [Pt(dbbpy)(NCCH3)2](BF4)2 (dbbpy = 4,4'-di-tert-butyl-2,2'-bi-pyridine, C18H24N2) is an example of a rare head-to-head dimer, even with the bulky tert-butyl groups of the bi-pyridine. This packing motif still enables significant π-π inter-actions between two pyridyl groups, and may result from the close proximity of the tetra-fluorido-borate ions to the platinum(II) complexes, resulting in intra-molecular H⋯F distances between 2.156 and 2.573 Å.

Incorporation of thiolate donation using 2,2'-dithiodibenzaldehyde: complexes of a pentadentate N2S3 ligand with relevance to the active site of Co nitrile hydratase.

The use of 2,2'-dithiodibenzaldehyde (DTDB) as a reactant for incorporating thiolate donors into the coordination sphere of a transition metal complex without the need for protecting groups is expanded to include the synthesis of complexes with pentadentate ligands. The ligand N,N'-bis(thiosalicylideneimine)-2,2'-thiobis(ethylamine) (tsaltp) is synthesized at a cobalt center by the reaction of DTDB with a Co complex of thiobis(ethylamine). The resulting Co complexes are thus coordinated by the N(2)S(3) pentadentate ligand through two imine N atoms, two thiolate S atoms, and one thioether S atom. A dimeric, bis-thiolate-bridged complex (1) is isolated and converted to a monomeric CN adduct (2) by treatment with KCN. The N(2)S(3) coordination environment provided by the tsaltp ligand is similar to that provided by the protein donors at the active site of the nitrile hydratase enzymes, with 2 being the first octahedral Co complex reported with such a coordination sphere.

A series of complexes of the phosphorus-based TTF ligand o-P2 with the metal ions Fe(II), Co(II), Ni(II), Pd(II), Pt(II), and Ag(I).

Reactions of 3,4-dimethyl-3',4'-bis(diphenylphosphino)tetrathiafulvalene, o-P2, with [BF(4)](-) salts of Fe(ii), Co(ii), Ni(II), Pd(II), and Pt(II) yield complexes of general formula [M(o-P2)(2)][BF(4)](2). Similar reactions between o-P2 and AgSbF(6) or AgPF(6) produced the salts [Ag(o-P2)(2)][X] where X = [SbF(6)](-) or [PF(6)](-). The resulting compounds were fully characterized by (1)H and (31)P{(1)H} NMR, infrared and electronic absorption spectroscopies, cyclic voltammetry, FAB-MS and single-crystal X-ray diffraction. The paramagnetic Co(II) compound exhibits an S = 3/2 state with large spin-orbit coupling contribution at higher temperatures and an effective S' = 1/2 state below 20 K. Electrochemical studies of the compounds indicate that the two functionalized TTF ligands are not in electronic communication and that they essentially behave as isolated redox centers.

Structural, magnetic, and optoelectronic properties of (diimine)(dithiolato)platinum(II) and -palladium(II) complexes and their charge-transfer adducts with nitrile acceptors.

Two new diimine dithiolato complexes, (dbbpy)Pt(dmid), 1, and (dbbpy)Pd(dmid), 2, were prepared and characterized (dbbpy = 4,4'-di-tert-butyl-2,2'-bipyridine; dmid = 2-oxo-1,3-dithiole-4,5-dithiolate). Both complexes interact with the nitrile acceptor TCNQ, and 1 also interacts with TCNQF(4) and TCNE (TCNQ = 7,7,8,8-tetracyanoquinodimethane; TCNQF(4) = 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane; TCNE = tetracyanoethylene) to form supramolecular 2:1 charge-transfer solids that stack in the manner -DDADDADDA- (D = electron donor; A = electron acceptor). All compounds have been fully characterized by magnetic, spectroscopic, electrochemical, and single-crystal X-ray crystallographic analyses. Magnetic susceptibility studies of the charge-transfer compounds revealed that the platinum-based complexes exhibit temperature-independent paramagnetism of approximately 10(-3) emu/mol. The donor complexes exhibit continuous absorption bands across the UV/visible and into the NIR region. Upon interaction with the nitrile acceptors, the extinction coefficients of the absorption bands increase and the energies of some d-d transitions in the NIR region change. The donor-acceptor compounds possess desired spectral features for solar cell dyes, but low conversion efficiencies resulted when a representative compound was tested in a TiO(2) solar cell. The results, however, serve to illustrate that the donor-acceptor interactions persist in solution and the adsorption of the dye molecules to the semiconductor surface occurs in the absence of typical anchoring groups. Evaluation of the spectral and electrochemical data for the title compounds and the results of the preliminary solar cell study serve as guides for future research in choosing promising candidates for efficient solar cell dyes.