(Acetonitrile){2,6‐bis[1‐(2,4,6‐trimethylphenylimino)ethyl]pyridine}dichloridoruthenium(II) dichloromethane solvate

In the title compound, [RuCl₂(C₂H₃N)(C₂₇H₃₁N₃)]·CH₂Cl₂, the Ru^II ion is six‐coordinated in a distorted octahedral arrangement, with the two Cl atoms located in the apical positions, and the pyridine (py) N atom, the two imino N atoms and the acetonitrile N atom located in the basal plane. The two equatorial Ru—N_imino distances are almost equal (mean 2.087 Å) and are substantially longer than the equatorial Ru—N_py bond [1.921 (4) Å]. It is observed that the N_imino—M—N_py angle for the five‐membered chelate rings of pyridine‐2,6‐diimine complexes is inversely related to the magnitude of the M—N_py bond. The title structure is stabilized by intra‐ and intermolecular C—H...Cl hydrogen bonds, as well as by van der Waals interactions.     

(Acetonitrile){2,6‐bis­[1‐(2‐ethyl‐6‐methyl­phenyl­imino)­ethyl]­pyridine}­dichloro­ruthenium(II) dichloro­methane hemisolvate: a chain of edge‐fused R66(24) rings

In the title compound, [RuCl₂(C₂H₃N)(C₂₇H₃₁N₃)]·0.5CH₂Cl₂, the Ru^II ion is six‐coordinated in a distorted octa­hedral arrangement, with the two Cl atoms located in the apical positions, and the pyridine (py) N atom, the two imino N atoms and the acetonitrile N atom located in the basal plane. The dichloromethane solvent mol­ecule lies on a twofold axis. The two equatorial Ru—N_imino distances are almost equal (mean 2.089 Å) and are substantially longer than the equatorial Ru—N_py bond [1.914 (4) Å]. It is observed that the N_imino—M—N_py bond angle for the five‐membered chelate rings of pyridine‐2,6‐diimine complexes is inversely related to the magnitude of the M—N_py bond. The title structure is stabilized by intra‐ and inter­molecular C—H⋯Cl hydrogen bonds. The inter­molecular hydrogen bonds form an R₆⁶(24) ring and a chain of edge‐fused rings running parallel to the [001] direction.     

(Nitro‐κN)[2‐(phenyldiazenyl‐κN2)pyridine‐κN](2,2′:6′,2′′‐terpyridine‐κ3N)ruthenium(II) tetrafluoroborate

The Ru—N bond distances in the title complex, [Ru(NO₂)(C₁₁H₉N₃)(C₁₅H₁₁N₃)]BF₄ or [Ru(NO₂)(tpy)(azpy)]BF₄, [tpy is 2,2′:6′,2′′‐ter­pyridine and azpy is 2‐(phenyl­azo)­pyridine], are Ru—N_py 2.063 (4), Ru—N_azo 2.036 (4), Ru—N_nitro 2.066 (3) Å, and Ru—N_tpy 2.082 (4), 1.982 (3) and 2.074 (4) Å. The azo N atom is trans to the nitro group. The azo N=N bond length is 1.265 (5) Å, which is the shortest found in such complexes to date. This indicates a multiple bond between Ru and the N atom of the nitro group, and π‐­backbonding [dπ(Ru) π*(azo)] is decreased.     

Dichloro­[(1E,1′E)‐1,1′‐(pyridine‐2,6‐diyl)diethanone bis­(O‐methyl­oxime)‐κ3N1,N2,N6]copper(II)

In the title compound, [CuCl₂(C₁₁H₁₅N₃O₂)], the Cu^II ion is five‐coordinated in a strongly distorted trigonal–bipyramidal arrangement, with the two methyl­oxime N atoms located in the apical positions, and the pyridine N and the Cl atoms located in the basal plane. The two axial Cu—N distances are almost equal (mean 2.098 Å) and are substantially longer than the equatorial Cu—N bond [1.9757 (15) Å]. It is observed that the N(oxime)—M—N(pyridine) bond angle for five‐membered chelate rings of 2,6‐diacetyl­pyridine dioxime complexes is inversely related to the magnitude of the M—N(pyridine) bond. The structure is stabilized by intra‐ and inter­molecular C—H⋯Cl hydrogen bonds which involve the methyl H atoms, except for one of the two acetyl­methyl groups.     

Tris[N‐(4‐fluorophenyl)pyridine‐2‐carboxamidato‐κ2N,N′]cobalt(III) trihydrate: a novel meridional complex

The title complex, [Co(C₁₂H₈FN₂O)₃]·3H₂O, has been synthesized for the first time. The complex comprises three bidentate ligands containing the pyridine‐2‐carbox­amide stem. The distorted octahedral coordination around the Co atom is formed via the pyridine (py) N atom and the deprotonated amide N atom of each ligand, with the three pyridine rings in a meridional arrangement. For each ligand, the pyridine ring and the carbonyl group are nearly coplanar, with torsion angles in the range 0.4 (3)–4.8 (4)°. The Co—N_py distances [1.9258 (16)–1.9656 (17) Å] are shorter than the corresponding Co—N_amide distances [1.9372 (17)–1.9873 (15) Å]. In addition, the Co—N_py distances are closely related to the magnitudes of the chelate angles, a shorter Co—N_py distance corresponding to a larger angle. Five intermolecular hydrogen bonds, involving carbonyl O atoms of the ligands and lattice water mol­ecules, lead to the formation of a mesh structure.     

Bis(2‐{1‐[(2,4,6‐trimethylphenyl)imino]ethyl}pyrrol‐1‐ido‐κ2N,N′)nickel(II): a supramolecular structure formed by C—H...π(arene) hydrogen bonds

<!?tlsb=‐0.2pt>Nitrogen‐based polydentate ligands are of interest owing to their flexible complexation to transition metal atoms. For the title compound, [Ni(C₁₅H₁₇N₂)₂], a transition metal complex formed by the coordination of two identical N,N′‐bidentate mono(imino)pyrrolyl ligands to an Ni^II centre, an X‐ray crystal diffraction study indicates that the two ligands show an inverted arrangement with respect to one another around the Ni^II centre, which is located on a crystallographic inversion centre. The planes of the aromatic substituents at the imine N atoms of the ligands show dihedral angles of 85.91 (5)° with respect to the NiN₄ plane. The Ni—N bond lengths are in the range 1.9072 (15)–1.9330 (15) Å and the N_imino—Ni—N_pyrrole bite angles are 83.18 (6)°. The Ni—N_pyrrole bond is substantially shorter than the Ni—N_imino bond. Molecules are linked into an extensive network by means of intermolecular C—H...π(arene) hydrogen bonds in which every molecule acts both as hydrogen‐bond donor and acceptor. The supramolecular assembly takes the form of an infinite two‐dimensional sheet.     

catena‐Poly­[[[cis‐bis(1‐phenyl­tetra­zole‐κN4)copper(II)]‐di‐μ‐chloro] hemi(1‐phenyl­tetrazole)]

The title compound, {[CuCl₂(PhTz)₂]·0.5PhTz}_n (PhTz is 1‐­phenyl­tetrazole, C₇H₆N₄), has a polymeric structure, with uncoordinated disordered PhTz mol­ecules in the cavities. The coordination polyhedron of the Cu atom is a highly elongated octahedron. The equatorial positions are occupied by two Cl atoms [Cu—Cl = 2.2687 (9) and 2.2803 (7) Å] and two N atoms of the PhTz ligands [Cu—N = 2.0131 (19) and 2.0317 (18) Å]. The more distant axial positions are occupied by two Cl atoms [Cu—Cl = 3.0307 (12) and 2.8768 (11) Å] that lie in the equatorial planes of two neighbouring Cu octahedra. The [CuCl₂(PhTz)₂] units are linked by Cu—Cl bridges into infinite chains extending parallel to the a axis. The chains are linked into two‐dimensional networks by intermolecular C—H⋯N interactions between the phenyl and tetrazole fragments, and by face‐to‐face π–π interactions between symmetry‐related phenyl rings. These two‐dimensional networks, which lie parallel to the ac plane, are connected by intermolecular π–π stacking interactions between phenyl rings, thus forming a three‐dimensional network.     

trans‐Di­chloro­tetrakis(4‐methylpyrimidine‐N1)­ruthenium(II)

The title compound, trans‐[Ru^IICl₂(N¹‐mepym)₄] (mepym is 4‐methylpyrimidine, C₅H₆N₂), obtained from the reaction of trans,cis,cis‐[Ru^IICl₂(N¹‐mepym)₂(SbPh₃)₂] (Ph is phenyl) with excess mepym in ethanol, has fourfold crystallographic symmetry and has the four pyrimidine bases coordinated through N¹ and arranged in a propeller‐like orientation. The Ru—N and Ru—Cl bond distances are 2.082 (2) and 2.400 (4) Å, respectively. The methyl group, and the N³ and Cl atoms are involved in intermolecular C—H?N and C—­H?Cl hydrogen‐bond interactions.     

Bis{2‐[(phenylimino)ethyl]‐1H‐pyrrol‐1‐ido‐κ2N,N′}nickel(II): a supramolecular structure formed by C—H...π hydrogen bonds

In the title compound, [Ni(C₁₂H₁₁N₂)₂], the Ni^II cation lies on an inversion centre and has a square‐planar coordination geometry. This transition metal complex is composed of two deprotonated N,N′‐bidentate 2‐[(phenylimino)ethyl]‐1H‐pyrrol‐1‐ide ligands around a central Ni^II cation, with the pyrrolide rings and imine groups lying trans to each other. The Ni—N bond lengths range from 1.894 (3) to 1.939 (2) Å and the bite angle is 83.13 (11)°. The Ni—N(pyrrolide) bond is substantially shorter than the Ni—N(imino) bond. The planes of the phenyl rings make a dihedral angle of 78.79 (9)° with respect to the central NiN₄ plane. The molecules are linked into simple chains by an intermolecular C—H...π interaction involving a phenyl β‐C atom as donor. Intramolecular C—H...π interactions are also present.     

Dichloro­(O‐ethyl 3‐methyl­pyridine‐2‐carboximidic acid‐κ2N,N′)copper(II)

In the title compound, [CuCl₂(C₉H₁₂N₂O)], the Cu^II atom is coordinated by two Cl⁻ anions and two N atoms of one O‐ethyl 3‐methyl­pyridine‐2‐carboximidic acid mol­ecule in a slightly distorted square‐planar geometry, with Cu—N distances of 2.0483 (17) and 1.9404 (18) Å, and Cu—Cl distances of 2.2805 (10) and 2.2275 (14) Å. In addition, each Cu^II atom is connected by one Cl⁻ anion and the Cu^II atom from a neighbouring mol­ecule, with Cu⋯Cl and Cu⋯Cu distances of 2.9098 (13) and 3.4022 (12) Å, respectively, and, therefore, a centrosymmetric dimer is formed. Adjacent mol­ecular dimers are connected by π–π stacking inter­actions between pyridine rings to form a zigzag mol­ecular chain. The mol­ecular chains are also enforced by N—H⋯Cl and C—H⋯Cl inter­actions.     

Dichloro­[(1E,1′E)‐1,1′‐(pyridine‐2,6‐di­yl)diethanone bis­(O‐methyloxime)‐κ3N1,N2,N6]cobalt(II)

In the title compound, [CoCl₂(C₁₁H₁₅N₃O₂)], the Co^II ion is five‐coordinated in a strongly distorted square‐pyramidal arrangement, with one of the two Cl atoms located in the apical position, and the other Cl atom and the three N‐donor atoms of the tridentate methyloxime ligand located in the basal plane. The non‐H atoms, except for the Cl atoms, lie on a mirror plane. The two equatorial Co—N_oxime distances are almost equal (mean 2.253 Å) and are substanti­ally longer than the equatorial Co—N_pyridine bond [2.0390 (19) Å]. The structure is stabilized by intra‐ and inter­molecular C—H⋯Cl contacts, which involve one of the methyl C atoms belonging to the methyloxime groups.     

5‐n‐Butylpyridine‐2‐carboxylate–copper(II) and –iron(III) complexes

In trans‐bis(5‐n‐butyl­pyridine‐2‐carboxyl­ato‐κ²N,O)­bis­(methanol‐κO)copper(II), [Cu(C₁₀H₁₂NO₂)₂(CH₄O)₂], the Cu atom lies on a centre of symmetry and has a distorted octahedral coordination. The Cu—O(methanol) bond length in the axial direction is 2.596 (3) Å, which is much longer than the Cu—­O(carboxylate) and Cu—N distances in the equatorial plane [1.952 (2) and 1.977 (2) Å, respectively]. In mer‐tris(5‐n‐bu­tyl­pyridine‐2‐carboxyl­ato‐κ²N,O)­iron(III), [Fe(C₁₀H₁₂NO₂)₃], the Fe atom also has a distorted octahedral geometry, with Fe—O and Fe—N bond‐length ranges of 1.949 (4)–1.970 (4) and 2.116 (5)–2.161 (5) Å, respectively. Both crystals are stabilized by stacking interactions of the 5‐n‐butyl­pyridine‐2‐carboxyl­ate ligand, although hydrogen bonds also contribute to the stabilization of the copper(II) complex.     

2,6‐Bis[bis(2‐pyridiniomethyl)aminomethyl]‐4‐tert‐butylphenol dichloride diperchlorate hydrate

The title compound, C₃₆H₄₄N₆O⁴⁺·2Cl^?·2ClO₄^?·0.132H₂O, is shown to be protonated at all the pyridine N atoms; the two chloride ions are hydrogen bonded to three pyridine N atoms and to the phenolic O atom of the same cation [Cl?N = 3.045 (2)–3.131 (2) Å and Cl?O = 2.938 (2) Å], and the remaining pyridine N atom is hydrogen bonded to the phenolic O atom [N?O = 2.861 (2) Å]. The mean value of the C—N—C angle of the protonated pyridine rings is 123.4 (1)°, which is significantly larger than that found for unprotonated pyridine rings.     

Chloro{2,2′‐[(1S,2S)‐1,2‐di­phenyl‐1,2‐ethanediyl­bis­(nitrilo­methyl­idyne)]­diphenolato‐κ4O,N,N′,O′}(ethanol‐κO)­manganese(III)

The crystal structure of the title compound, [MnCl(C₂₈H₂₂N₂O₂)(C₂H₆O)], has been determined at 173 (2) K in the non‐centrosymmetric space group P2₁2₁2₁. The asymmetric unit contains two molecular units. An intermolecular O—H⋯Cl hydrogen bond is formed between the OH group of an ethanol mol­ecule coordinated to the Mn atom and the coordinated Cl⁻ anion, and so polymeric chains of Mn‐containing fragments are formed [O—H⋯Cl = 3.1281 (16) and 3.1282 (15) Å]. The Mn atoms have a pseudo‐octahedral coordination sphere, with the four donor atoms of the Schiff base forming an equatorial plane [Mn—O distances are 1.8740 (13), 1.8717 (13), 1.8749 (13) and 1.8823 (13) Å, and Mn—N distances are 1.9868 (15), 1.9910 (14), 1.9828 (15) and 1.9979 (14) Å]. The axial positions are occupied by an ethanol mol­ecule [Mn—O distances of 2.3069 (15) and 2.3130 (15) Å] and a Cl⁻ ligand [Mn—Cl distances of 2.5732 (6) and 2.5509 (6) Å].     

Bis(2,2′‐bipyridine)(dicyanamido)­copper(II) tetrafluoroborate

In the title compound, [Cu(C₂N₃)(C₁₀H₈N₂)₂]BF₄, the Cu^II atom shows distorted trigonal‐bipyramidal geometry, with the dicyan­amido ligand in the equatorial plane. The two out‐of‐plane Cu—N bond lengths to bi­pyridine are 2.006 (3) and 1.998 (3) Å, whereas the in‐plane Cu—N distances are 2.142 (3) and 2.043 (3) Å to the bi­pyridine, and 2.015 (3) Å to the dicyan­amide.     

fac‐Trichloro(quinolin‐8‐ylimido‐N,N′)(triphenylphosphine‐P)rhenium(V)

The Re atom in [Re(C₉H₆N₂)Cl₃(C₁₈H₁₅P)] is octahedrally coordinated by three Cl atoms in facial positions, two N atoms from 8‐imido­quinoline (imq) and one P atom from tri­phenyl­phosphine. The Re—N(imido) distance [1.760 (9) and 1.772 (8) Å] for imq is very short and implies double‐bond character. The trans influence of the P atom is indicated. Intra‐ and intermolecular π–π interactions between the π‐rings in the complex are also observed.     

catena‐Poly[[chloro­dipyridine­manganese(II)]‐μ3‐6‐oxo‐1,6‐dihydro­pyridine‐2‐carboxyl­ato]

The title one‐dimensional chain polymer complex, [Mn(C₆H₄NO₃)Cl(C₆H₅N)₂]_n, was isolated from the reaction of MnCl₂ with 6‐oxo‐1,6‐dihydro­pyridine‐2‐carboxylic acid (HpicOH) in pyridine. The asymmetric unit contains one [Mn(HPicO)Cl(py)₂] moiety (py is pyridine), with the (HpicO)⁻ ligand acting in a tridentate manner via the two carboxyl­ate O atoms and the pyridone O atom. The operation of inversion centres generates eight‐ and 14‐membered rings and, in conjunction with an a‐axis translation, leads to an infinite chain extending along [100]. The Mn⋯Mn separations in this chain are 5.1069 (6) and 7.1869 (6) Å. The Mn^II atom has a distorted octahedral coordination, with trans‐axial pyridine ligands and with three O atoms and the Cl atom in the equatorial plane. The conformation of the 14‐membered ring is stabilized by pairs of inversion‐related N—H⋯O hydrogen bonds.     

trans‐Bis(dimethyl sulfoxide‐κO)bis(3‐oxo‐3,4‐dihydroquinoxaline‐2‐carboxylato‐κ2N1,O2)copper(II)

The title compound, [Cu(C₉H₅N₂O₃)₂(C₂H₆OS)₂], consists of octahedrally coordinated Cu^II ions, with the 3‐oxo‐3,4‐dihydroquinoxaline‐2‐carboxylate ligands acting in a bidentate manner [Cu—O = 1.9116 (14) Å and Cu—N = 2.1191 (16) Å] and a dimethyl sulfoxide (DMSO) molecule coordinated axially via the O atom [Cu—O = 2.336 (5) and 2.418 (7) Å for the major and minor disorder components, respectively]. The whole DMSO molecule exhibits positional disorder [0.62 (1):0.38 (1)]. The octahedron around the Cu^II atom, which lies on an inversion centre, is elongated in the axial direction, exhibiting a Jahn–Teller effect. The ligand exhibits tautomerization by H‐atom transfer from the hydroxyl group at position 3 to the N atom at position 4 of the quinoxaline ring of the ligand. The complex molecules are linked through an intermolecular N—H...O hydrogen bond [N...O = 2.838 (2) Å] formed between the quinoxaline NH group and a carboxylate O atom, and by a weak intermolecular C—H...O hydrogen bond [3.392 (11) Å] formed between a carboxylate O atom and a methyl C atom of the DMSO ligand. There is a weak intramolecular C—H...O hydrogen bond [3.065 (3) Å] formed between a benzene CH group and a carboxylate O atom.     

A structural systematic study of four isomers of difluoro‐N‐(3‐pyridyl)benzamide

The four isomers 2,4‐, (I), 2,5‐, (II), 3,4‐, (III), and 3,5‐difluoro‐N‐(3‐pyridyl)benzamide, (IV), all with formula C₁₂H₈F₂N₂O, display molecular similarity, with interplanar angles between the C₆/C₅N rings ranging from 2.94 (11)° in (IV) to 4.48 (18)° in (I), although the amide group is twisted from either plane by 18.0 (2)–27.3 (3)°. Compounds (I) and (II) are isostructural but are not isomorphous. Intermolecular N—H...O=C interactions form one‐dimensional C(4) chains along [010]. The only other significant interaction is C—H...F. The pyridyl (py) N atom does not participate in hydrogen bonding; the closest H...N_py contact is 2.71 Å in (I) and 2.69 Å in (II). Packing of pairs of one‐dimensional chains in a herring‐bone fashion occurs viaπ‐stacking interactions. Compounds (III) and (IV) are essentially isomorphous (their a and b unit‐cell lengths differ by 9%, due mainly to 3,4‐F₂ and 3,5‐F₂ substitution patterns in the arene ring) and are quasi‐isostructural. In (III), benzene rotational disorder is present, with the meta F atom occupying both 3‐ and 5‐F positions with site occupancies of 0.809 (4) and 0.191 (4), respectively. The N—H...N_py intermolecular interactions dominate as C(5) chains in tandem with C—H...N_py interactions. C—H...O=C interactions form R₂²(8) rings about inversion centres, and there are π–π stacks about inversion centres, all combining to form a three‐dimensional network. By contrast, (IV) has no strong hydrogen bonds; the N—H...N_py interaction is 0.3 Å longer than in (III). The carbonyl O atom participates only in weak interactions and is surrounded in a square‐pyramidal contact geometry with two intramolecular and three intermolecular C—H...O=C interactions. Compounds (III) and (IV) are interesting examples of two isomers with similar unit‐cell parameters and gross packing but which display quite different intermolecular interactions at the primary level due to subtle packing differences at the atom/group/ring level arising from differences in the peripheral ring‐substitution patterns.     

Pentacarbonyl(4‐phenylpyridine)­tungsten(0) and pentacarbonyl(2‐phenylpyridine)chromium(0)

In penta­carbonyl(4‐phenyl­pyridine)­tungsten(0), [W­(C₁₁H₉N)(CO)₅], the mol­ecules have mm site symmetry and the pyridine ligand, with m symmetry, is completely planar. In penta­carbonyl(2‐phenyl­pyridine)­chromium(0), [Cr(C₁₁­H₉N)(CO)₅], the mol­ecules are in general positions and the phenyl and pyridine rings of the ligand are twisted by 67.7 (3)° with respect to one another by rotation about the C—C bond joining them. In both compounds, the axial M—C_carbonyl bond trans to the M—N_ligand bond is significantly shorter than the equatorial M—C_carbonyl bonds.