A new coordination mode of 6‐methylnicotinic acid in trans‐tetraaquabis(6‐methylpyridine‐3‐carboxylato‐κO)cobalt(II) tetrahydrate

The title compound, [Co(C₇H₆NO₂)₂(H₂O)₄]·4H₂O, contains a Co^II ion lying on a crystallographic inversion centre. The Co^II ion is octahedrally coordinated by two 6‐methylpyridine‐3‐carboxylate ligands in axial positions [Co—O = 2.0621 (9) Å] and by four water molecules in the equatorial plane [Co—O = 2.1169 (9) and 2.1223 (11) Å]. There are also four uncoordinated water molecules. The 6‐methylpyridine‐3‐carboxylate ligands are bound to the Co^II ion in a monodentate manner through a carboxylate O atom. There is one strong intramolecular O—H...O hydrogen bond, and six strong intermolecular hydrogen bonds of type O—H...O and one of type O—H...N in the packing, resulting in a complex three‐dimensional supramolecular structure.     

mer‐Bis(1,4‐dibenzoylthiosemicarbazidato‐κ3O,N,O′)cobalt(II)

The title complex, [Co(C₁₅H₁₂N₃O₂S)₂], consists of an octahedrally coordinated Co^II ion, with two crystallographically independent 1,4‐dibenzoylthiosemicarbazidate ligands in a tridentate mer coordination [Co—O = 2.064 (3)–2.132 (3) Å and Co—N = 2.037 (3)–2.043 (3) Å]. There are intermolecular N—H...S hydrogen bonds involving one ligand and strong π–π stacking interactions involving the other ligand, resulting in a three‐dimensional supramolecular framework. The hydrogen bonds and π–π interactions, as well as different intramolecular aryl–benzamide H—C...H(—N) distances, give rise to a difference in conformation between the two ligands.     

The CoIII—C bond in (1‐thia‐4,7‐diazacyclodecyl‐κ3N4,N7,C10)(1,4,7‐triazacyclononane‐κ3N1,N4,N7)cobalt(III) dithionate hydrate

In the title compound, [Co(C₆H₁₅N₃)(C₇H₁₅N₂S)]S₂O₆·H₂O, the Co—C bond distance is 1.9930 (13) Å, which is shorter than for related compounds with the linear 1,6‐di­amino‐3‐thia­hexan‐4‐ide anion in place of the macrocyclic 1‐thia‐4,7‐diazacyclo­decan‐8‐ide anion. The coordinated carbanion produces an elongation of 0.102 (7) Å of the Co—N bond to the 1,4,7‐tri­aza­cyclo­nonane N atom in the trans position. This relatively small trans influence is presumably a result of the tri­amine ligand forming strong bonds to the Co^III atom.     

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.     

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 1:2 complex of mercury(II) chloride with 1,3‐imidazole‐2‐thione

The Hg atom in the title monomeric complex, di­chloro­bis(3‐imidazolium‐2‐thiol­ato‐S)­mercury(II), [HgCl₂(C₃H₄N₂S)₂], is four‐coordinate having an irregular tetrahedral geometry composed of two Cl atoms [Hg—Cl 2.622 (2) and 2.663 (2) Å] and two thione S atoms [Hg—S 2.445 (2) and 2.462 (2) Å]. The monodentate thione ligand adopts a zwitterionic form and exists as the 3‐imidazolium‐2‐thiol­ate ion. The bond angle S1—Hg—S2 of 130.87 (8)° has the greatest deviation from ideal tetrahedral geometry. Intermolecular hydrogen bonds between two of the four N—H groups and one of the Cl atoms [3.232 (8) and 3.238 (7) Å] stabilize the crystal structure, while the other two N—H groups contribute through the formation of N—H?Cl intramolecular hydrogen bonds with the other Cl atom [3.121 (7) and 3.188 (7) Å].     

Transformations of the chameleon ligand 1,10‐phenanthroline‐5,6‐dione/diol: cis‐dichlorido(1,10‐phenanthroline‐5,6‐dione‐κ2N,N′)‐trans‐dipyridinecobalt(II) pyridine disolvate prepared from the diol

The title compound, [CoCl₂(C₅H₅N)₂(C₁₂H₆N₂O₂)]·2C₅H₅N, is a neutral Co^II complex with two chloride anions coordinated in a cis fashion, two pyridine ligands in trans positions and a chelating 1,10‐phenanthroline‐5,6‐dione ligand that completes the octahedral coordination geometry. Two pyridine solvent molecules reside in channels (about 7 × 4 Å wide; the closest atom–atom distance within the channel is 10 Å). The three‐dimensional structure supporting these channels is held together by C—H...Cl [3.466 (8)–3.670 (9) Å] and C—H...O [3.014 (9)–3.285 (8) Å] hydrogen bonds, and can be viewed as a CsCl or bcu (body‐centred cubic) net.     

(1,3‐Dimethylimidazolidine‐2‐selone‐κSe)bis(1,10‐phenanthroline‐κ2N,N′)copper(II) bis(perchlorate) and bis(2,2′‐bipyridyl‐κ2N,N′)(imidazolidine‐2‐thione‐κS)copper(II) bis(perchlorate)

In the first title salt, [Cu(C₁₂H₈N₂)₂(C₅H₁₀N₂Se)](ClO₄)₂, the Cu^II centre occupies a distorted trigonal–bipyramidal environment defined by four N donors from two 1,10‐phenanthroline (phen) ligands and by the Se donor of a 1,3‐dimethylimidazolidine‐2‐selone ligand, with the equatorial plane defined by the Se and by two N donors from different phen ligands and the axial sites occupied by the two remaining N donors, one from each phen ligand. The Cu—N distances span the range 1.980 (10)–2.114 (11) Å and the Cu—Se distance is 2.491 (3) Å. Intermolecular π–π contacts between imidazolidine rings and the central rings of phen ligands generate chains of cations. In the second salt, [Cu(C₁₀H₈N₂)₂(C₃H₆N₂S)](ClO₄)₂, the Cu^II centre occupies a similar distorted trigonal–bipyramidal environment comprising four N donors from two 2,2′‐bipyridyl (bipy) ligands and an S donor from an imidazolidine‐2‐thione ligand. The equatorial plane is defined by the S donor and two N donors from different bipy ligands. The Cu—N distances span the range 1.984 (6)–2.069 (7) Å and the Cu—S distance is 2.366 (3) Å. Intermolecular π–π contacts between imidazolidine and pyridyl rings form chains of cations. A major difference between the two structures is due to the presence in the second complex of two N—H...O hydrogen bonds linking the imidazolidine N—H hydrogen‐bond donors to perchlorate O‐atom acceptors.     

Aqua­chloro(1,10‐phenanthroline‐κ2N,N′)(p‐toluenesulfonato‐κO)copper(II)

In the title compound, [CuCl(C₇H₇O₃S)(C₁₂H₈N₂)(H₂O)], the central Cu atom is coordinated by a water mol­ecule, a chloride ion, an O‐monodentate p‐toluene­sulfonate anion and an N,N′‐bidentate 1,10‐phenanthroline ligand. The copper environment is best described as a slightly distorted square pyramid, with bond distances Cu—Cl 2.2282 (9) Å, Cu—OW 1.984 (3) Å, and Cu—N 2.006 (3) and 2.028 (3) Å; the apical Cu—O distance is 2.281 (2) Å. In the supramolecular structure, π–π‐stacking stabilization is observed, and classical and non‐classical hydrogen bonds also play an important role.     

(2‐Methyl­quinolin‐8‐olato)­iron(III) and ‐copper(II) complexes

The crystal structures of tris(2‐methyl­quinolin‐8‐olato‐N,O)­iron(III), [Fe­(C₁₀­H₈­NO)₃], (I), and aqua­bis(2‐methyl­quinolin‐8‐olato‐N,O)­copper(II), [Cu­(C₁₀­H₈NO)₂­(H₂O)], (II), have been determined. Compound (I) has a distorted octahedral configuration, in which the central Fe atom is coordinated by three N atoms and three O atoms from three 2‐methylquinolin‐8‐olate ligands. The three Fe—O bond distances are in the range 1.934 (2)–1.947 (2) Å, while the three Fe—N bond distances range from 2.204 (2) to 2.405 (2) Å. In compound (II), the central Cu^II atom and H₂O group lie on the crystallographic twofold axis and the coordination geometry of the Cu^II atom is close to trigonal bipyramidal, with the three O atoms in the basal plane and the two N atoms in apical positions. The Cu—N bond length is 2.018 (5) Å. The Cu—O bond length in the basal positions is 1.991 (4) Å, while the Cu—O bond length in the apical position is 2.273 (6) Å. There is an intermolecular OW—H?O hydrogen bond which links the mol­ecules into a linear chain along the b axis.     

Helical catena‐poly[[tris(1H‐benzimidazole‐κN3)cobalt(II)]‐μ‐maleato‐κ3O,O′:O′′]

The crystal structure of the title compound, [Co(C₄H₂O₄)(C₇H₆N₂)₃]_n, consists of polymeric chains of the Co^II complex. Two maleate dianions and three benz­imidazole ligands coordinate to the Co^II atom with a distorted octahedral geometry. The maleate dianions bridge neighbouring Co^II atoms via both terminal carboxylic acid groups, one of which is monodentate and the other bidentate, to form a helical structure of alternating maleate dianions and Co^II atoms, with a pitch height of 9.2667 (17) Å. The absolute structure has been determined, and the crystal contains only right‐handed helices. Intrahelical N—H⋯O hydrogen bonds stabilize the helical structure, while interhelical N—H⋯O hydrogen bonds link neighbouring helices to form the supramolecular structure.     

Supramolecular interactions in a copper(II) 4′‐(4‐bromophenyl)‐2,2′:6′,2′′‐terpyridine complex

The title compound, [4′‐(4‐bromophenyl)‐2,2′:6′,2′′‐terpyridine]chlorido(trifluoromethanesulfonato)copper(II), [Cu(CF₃O₃S)Cl(C₂₁H₁₄BrN₃)], is a new copper complex containing a polypyridyl‐based ligand. The Cu^II centre is five‐coordinated in a square‐pyramidal manner by one substituted 2,2′:6′,2′′‐terpyridine ligand, one chloride ligand and a coordinated trifluoromethanesulfonate anion. The Cu—N bond lengths differ by 0.1 Å for the peripheral and central pyridine rings [2.032 (2) (mean) and 1.9345 (15) Å, respectively]. The presence of the trifluoromethanesulfonate anion coordinated to the metal centre allows Br...F halogen–halogen interactions, giving rise to the formation of a dimer about an inversion centre. This work also demonstrates that the rigidity of the ligand allows the formation of other types of nonclassical interactions (C—H...Cl and C—H...O), yielding a three‐dimensional network.     

Bis­[S‐methyl 3‐(2‐bromo­benzyl­idene)­di­thio­cab­aza­to‐N3,S]­platinum(II)

The Schiff base ligand in the title complex, [Pt(C₉H₈BrN₂S₂)₂], is deprotonated from its tautomeric thiol form and coordinated to Pt^IIvia the mercapto S and β–N atoms. The configuration about Pt^II is a perfect square‐planar, with two equivalent Pt—N [2.023 (3) Å] and Pt—S [2.293 (1) Å] bonds. The phenyl ring is twisted against the coordination moiety Pt1/N1/N1′/S2′/S2 by 31.8 (2)°, due to the steric hindrance induced by ortho‐substituted bulky Br atom.     

Completing the bis[hydroxybis(pyridin‐2‐yl)methanesulfonato‐κ3N,O,N′]MII series (M = Mn to Zn) with the copper(II) and cobalt(II) structures

The Cu^II complex bis[hydroxybis(pyridin‐2‐yl)methanesulfonato‐κ³N,O,N′]copper(II) hexahydrate, [Cu(C₁₁H₉N₂O₄S)₂]·6H₂O, (I), crystallizes in the space group P, compared with P2₁/c for the anhydrous Co^II analogue bis[hydroxybis(pyridin‐2‐yl)methanesulfonato‐κ³N,O,N′]cobalt(II), [Co(C₁₁H₉N₂O₄S)₂], (II). However, both molecules sit on a crystallographic inversion centre and are thus very similar in appearance. Jahn–Teller elongation of the Cu—O bonds [2.347 (3) Å in (I) and 2.064 (2) Å in (II)] influences the S—O bond lengths, which are all around 1.455 (3) Å in (I) and 1.436 (2)–1.473 (2) Å in (II).     

Synthesis and Crystal Structure of Bis(methyltriphenylphosphonium) Hexabromotellurate(IV)‐bis{dibromoselenate(II)}, [PMePh3]2[TeBr6(SeBr2)2], the Salt of a Mixed‐valence Bromotellurate(IV)‐Selenate(II) Anion

Brown crystals of [PMePh₃]₂[TeBr₆(SeBr₂)₂] ( 1 ) were obtained when selenium and bromine (1:1) react in acetonitrile solution in the presence of tellurium(IV) bromide and methyltriphenylphosphonium bromide. The salt 1 crystallizes in the triclinic space group P1¯ with the cell dimensions a = 10.3630(14)Å, b = 11.5140(12)Å, c = 11.7605(17)Å, α = 108.643(9)°, β = 106.171(10)° and γ = 99.077(9)° (296 K). In the solid state the [TeBr₆(SeBr₂)₂]^2— anion contains a nearly regular [TeBr₆] octahedron where the four equatorial bromo ligands each have developed a bond to the Se^II atom of a SeBr₂ molecule. The contacts between the bridging bromo and the Se^II atoms of the SeBr₂ molecules are observed in the range 3.11—3.21Å, and can be interpreted as bonds of the donor‐acceptor type with the bridging bromo ligands as donors and the SeBr₂ molecules as acceptors. The Te^IV—Br distances are in the range 2.67—2.72Å, and the Se^II—Br bond lengths in coordinated SeBr₂ molecules in the range 2.33—2.34Å.     

[1,5‐Bis(1‐methyl‐1H‐imidazol‐2‐yl­methyl‐κN3)‐1,5‐di­aza­cyclo­octane‐N,N′]chlorocobalt(II) perchlorate

The crystal structure of the title compound, [CoCl‐(C₁₆H₂₆N₆)]ClO₄, consists of discrete [CoCl­(C₁₆­H₂₆N₆)]⁺ cations and perchlorate anions. The five‐coordinate Co^II atom has four nitro­gen donors from the new mesocyclic ligand 1,5‐bis(1‐methyl‐1H‐­imidazol‐2‐ylmethyl)‐1,5‐di­aza­cyclo­octane [Co—N 2.046 (3)–2.214 (4) Å], and a chloride anion at the apical site [Co—Cl 2.3184 (13) Å]. The coordination geometry of the complex is essentially square pyramidal. The mesocyclic ligand takes a boat–chair configuration and the two imidazole pendants are not coplanar. The dihedral angle between the two imidazole planes is 15.97°. An H atom from the 1,5‐diaza­cyclo­octane group effectively blocks the axial coordination site opposite the Cl ligand.     

Cobalt(II) and nickel(II) complexes of isoquinoline‐1‐carboxylate

trans‐Di­aqua­bis­(iso­quinoline‐1‐carboxyl­ato‐κ²N,O)­cobalt(II) dihydrate, [Co(C₁₀H₆NO₂)₂(H₂O)₂]·2H₂O, and trans‐di­aqua­bis­(iso­quinoline‐1‐carboxyl­ato‐κ²N,O)­nickel(II) dihydrate, [Ni(C₁₀H₆NO₂)₂(H₂O)₂]·2H₂O, contain the same isoquinoline ligand, with both metal atoms residing on a centre of symmetry and having the same distorted octahedral coordination. In the former complex, the Co—O(water) bond length in the axial direction is 2.167 (2) Å, which is longer than the Co—O(carboxylate) and Co—N bond lengths in the equatorial plane [2.055 (2) and 2.096 (2) Å, respectively]. In the latter complex, the corresponding bond lengths for Ni—O(water), Ni—O(carboxylate) and Ni—N are 2.127 (2), 2.036 (2) and 2.039 (3) Å, respectively. Both crystals are stabilized by similar stacking interactions of the ligand, and also by hydrogen bonds between the hydrate and coordinated water molecules.     

Di­iodo­bis(1‐methyl‐1,3‐imidazolium‐2‐thiol­ato‐S)­mercury(II)

The reaction of 1‐methyl‐1,3‐imidazole‐2‐thione (meimtH) with mercury(II) iodide in methanol in a 2:1 molar ratio resulted in the formation of single crystals of the title compound, [HgI₂(C₄H₆N₂S)₂]. The Hg atom is coordinated by two I [2.7809 (9) and 2.7999 (8) Å] and two thione S atoms [2.520 (3) and 2.576 (3) Å] with irregular tetrahedral coordination geometry. The NH groups of the imidazole ring take part in intra‐ and intermolecular hydrogen bonds with I atoms [N?I 3.596 (8) and 3.611 (9) Å, respectively] joining mol­ecules into infinite chains parallel to the z axis.     

A new complex of HgBr2 and pyrimidine‐2‐thione: (pyrimidine‐2‐thionato‐κS)(pyrimidinium‐2‐thionato‐κS)mercury(II) tetrabromomercury(II)

The title compound, [Hg(C₄H₄N₂S)(C₄H₃N₂S)]₂[HgBr₄], con­sists of [Hg(pymt)(pymtH)]⁺ complex cations (pymtH is pyrimidine‐2‐thione) lying across twofold rotation axes in space group Fddd, with linearly coordinated mercury at an Hg—S distance of 2.357 (3) Å, and [HgBr₄]²⁻ anions lying at sites of 222 symmetry. The Hg atom is additionally coordinated by two N and two Br atoms, forming a 2+4 effective coordination sphere. The protonated ligand is connected via N—H⋯N hydrogen bonds to the neighbouring unprotonated ligand, thus forming infinite chains of cations.     

A helical coordination polymer of zinc(II), 4‐hydroxybenzohydrazide and sulfate ions

In the structure of the novel zinc complex catena‐poly[[diaqua(4‐hydroxybenzohydrazide)zinc(II)]‐μ‐sulfato], [Zn(SO₄)(C₇H₈N₂O₂)(H₂O)₂]_n, the complex cations are linked by sulfate counter‐ions into helical polymeric chains extending along the b axis. Each helix is stabilized by six intrachain hydrogen bonds involving stronger O—H...O (1.83–2.06 Å) and weaker N—H...O (2.20–2.49 Å) interactions. The Zn^II atom displays a distorted octahedral geometry formed by the 4‐hydroxybenzohydrazide ligand, two water molecules and two SO₄²⁻ ions, which is very similar to the metal‐atom environment in a previously reported Co^II complex [Zasłona, Drożdżewski & Kubiak (2010). J. Mol. Struct. 982 , 1–8], especially the Zn—O and Zn—N bond lengths of 2.0453 (12)–2.1602 (9) and 2.1118 (12) Å, respectively.