Unusual O‐coordination of caffeine in tetra­kis(μ‐3,5‐dinitro­benzoato‐κ2O:O′)bis­[(caffeine‐κO)copper(II)]

The title compound {systematic name: tetra­kis(μ‐3,5‐dinitro­benzoato‐κ²O:O′)bis­[(3,7‐dihydro‐1,3,7‐trimethyl‐1H‐purine‐2,6‐dione‐κO²)copper(II)]}, [Cu₂(C₇H₃N₂O₆)₄(C₈H₁₀N₄O₂)₂], consists of paddle‐wheel dimeric tetra­kis(μ‐3,5‐dinitro­benzoato‐κ²O:O′)dicopper(II) units with O‐coordinated caffeine mol­ecules in both apical positions. The entire dimeric mol­ecule lies on a tetra­gonal inversion axis, and thus one nitro­benzoate anion with one Cu atom in a special position belong to the independent part of the mol­ecule. The caffeine ligand bonded to the Cu atom is disordered on a local twofold non‐crystallographic axis coincident with the axis. A π–π stacking inter­action is observed between the caffeine rings and adjacent symmetry‐related benzene rings of the 3,5‐dinitro­benzoate anions.     

Two isomers of Pd2(S2NC7H4)4

The dichloromethane solvates of the isomers tetrakis(μ‐1,3‐benzothiazole‐2‐thiolato)‐κ⁴N:S;κ⁴S:N‐dipalladium(II)(Pd—Pd), (I), and tetrakis(μ‐1,3‐benzothiazole‐2‐thiolato)‐κ⁶N:S;κ²S:N‐dipalladium(II)(Pd—Pd), (II), both [Pd₂(C₇H₄NS₂)₄]·CH₂Cl₂, have been synthesized in the presence of (o‐isopropylphenyl)diphenylphosphane and (o‐methylphenyl)diphenylphosphane. Both isomers form a lantern‐type structure, where isomer (I) displays a regular and symmetric coordination and isomer (II) an asymmetric and distorted structure. In (I), sitting on an centre of inversion, two 1,3‐benzothiazole‐2‐thiolate units are bonded by a Pd—N bond to one Pd atom and by a Pd—S bond to the other Pd atom, and the other two benzothiazolethiolate units are bonded to the same Pd atoms by, respectively, a Pd—S and a Pd—N bond. In (II), three benzothiazolethiolate units are bonded by a Pd—N bond to one Pd atom and by a Pd—S bond to the other Pd atom, and the fourth benzothiazolethiolate unit is bonded to the same Pd atoms by, respectively, a Pd—S bond and a Pd—N bond.     

A ternary complex of aqua(18‐crown‐6)bis(o‐nitrophenolato)barium(II), the triaqua(18‐crown‐6)(o‐nitrophenolato)barium(II) cation and the o‐nitrophenolate anion

In the title compound [systematic name: tri­aqua(1,4,7,10,13,16‐hexaoxa­cyclo­octa­decane‐κ⁶O)(2‐nitro­phenolato‐κO)­barium(II)–aqua(1,4,7,10,13,16‐hexaoxa­cyclo­octa­decane‐κ⁶O)‐ bis(2‐nitro­phenolato‐κ²O,O′)­barium(II)–2‐nitro­phenolate (1/1/1)], [Ba(C₁₂H₂₄O₆)(C₆H₄NO₃)(H₂O)₃][Ba(C₁₂H₂₄O₆)(C₆H₄NO₃)₂(H₂O)](C₆H₄NO₃), the two Ba^II atoms encapsulated by the 18‐crown‐6 rings have different coordinations. Although both Ba^II atoms are coordinated to the six O atoms of the crowns, in the neutral moiety, the Ba^II atom is coordinated to one terminal O atom from a water mol­ecule, two phenolate O atoms and two nitro‐group O atoms, while in the cationic moiety, the Ba^II atom is coordinated to three terminal O atoms from water mol­ecules and one phenolate O atom. Both the crowns are eclipsed and translated along the b direction. In the asymmetric unit, the three components are interconnected by four O—H?O interactions. The packing is stabilized by two intermolecular C—H?O interactions and by one O—H?O interaction.     

Paddlewheel dirhodium complexes bridged by para‐substituted benzoates

The dirhodium complex bis­(benzonitrile)tetra­kis[μ‐4‐(diethyl­amino)benzoato‐κ²O:O′]dirhodium(II)(Rh—Rh) benzonitrile disolvate, [Rh₂(C₁₁H₁₄NO₂)₄(C₇H₅N)₂]·2C₇H₅N, lies about an inversion centre. The dirhodium complex (methanol)tetra­kis(μ‐4‐nitro­benzoato‐κ²O:O′)(pyridine)dirhodium(II)(Rh—Rh) dichloro­methane solvate, [Rh₂(C₇H₄NO₄)₄(C₅H₅N)(CH₄O)]·CH₂Cl₂, lies in a general position in the unit cell, but the complexes dimerize around an inversion centre via O—H⋯O hydrogen bonding of the axial MeOH to a carboxyl­ate O atom. In the latter crystal structure, π–π stacking inter­actions between the bridging 4‐nitro­benzoate ligands and the axial pyridine ligand are observed between adjacent mol­ecules.     

Tetrakis(μ‐2,3‐dimethoxybenzoato)bis[(2,2′‐bipyridine)(2,3‐dimethoxybenzoato)lanthanum(III)]

The title compound, tetrakis(μ‐2,3‐di­methoxy­benzoato)‐κ⁴O:O′;κ⁶O,O′:O′‐bis[(2,2′‐bi­pyridine‐N,N′)(2,3‐di­methoxy­benzoato‐O,O′)lanthanum(III)], [La₂(2,3‐DMOBA)₆(2,2′‐bpy)₂], where 2,3‐DMOBA is 2,3‐di­methoxy­benzoate (C₉H₉O₄) and 2,2′‐bpy is 2,2′‐bi­pyridine (C₁₀H₈N₂), is a dimer with a centre of inversion between the La atoms bridged by four carboxyl­ate ligands. The central La atom is ennea‐coordinated and has a distorted monocapped square‐antiprism geometry.     

catena‐Poly[potassium [copper(II)‐μ‐isothiocyanato‐μ‐N‐salicylidene‐β‐alaninato(2–)]]

The title polymeric compound, catena‐poly­[dipotassium [bis­[μ‐N‐salicyl­idene‐β‐alaninato(2−)]‐κ⁴O,N,O′:O′′;κ⁴O′′:O,N,O′‐dicopper(II)]‐di‐μ‐iso­thio­cyanato‐κ²N:S;κ²S:N], {K[Cu(NCS)(C₁₀H₉NO₃)]}_n, consists of [iso­thio­cyanato(N‐salicyl­idene‐β‐alaninato)copper(II)]⁻ anions connected through the two three‐atom thio­cyanate (μ‐NCS) and the two anti,anti‐μ‐­carboxyl­ate bridges into infinite one‐dimensional polymeric anions, with coulombically interacting K⁺ counter‐ions with coordination number 7 constrained between the chains. The Cu^II atoms adopt a distorted tetragonal–bipyramidal coordination, with three donor atoms of the tridentate Schiff base and one N atom of the bridging μ‐NCS ligand in the basal plane. The first axial position is occupied by a thio­cyanate S atom of a symmetry‐related μ‐NCS ligand at an apical distance of 2.9770 (8) Å, and the second position is occupied by an O atom of a bridging carboxyl­ate group from an adjacent coordination unit at a distance of 2.639 (2) Å.     

A liquid crystal derived from ­ruthenium(II,III) and a long‐chain carboxylate

The title compound, catena‐poly[[tetrakis(μ‐decanoato‐κ²O:O′)diruthenium(II,III)(Ru—Ru)]‐μ‐octanesulfonato‐κ²O:O′], [Ru₂(C₁₀H₁₉O₂)₄(C₈H₁₇O₃S)], is an octane­sulfonate derivative of the mixed‐valence complex diruthenium tetradecanoate. The equatorial carboxyl­ate ligands are bidentate, bridging two Ru atoms to form a dinuclear structure. Each of the two independent dinuclear metal complexes in the asymmetric unit is located at an inversion centre. The octane­sulfonate anion bridges the two dinuclear units through axial coordination. The alkyl chains of the carboxyl­ate and sulfonate ligands are arranged in a parallel manner. The global structure can be seen as infinite chains of polar moieties separated by a double layer of non‐polar alkyl groups, without interdigitation of the alkyl chains.     

Tetrameric di­chloro­(tri­methyl­ammonio‐p‐toluene­sulfonamidate)­mercury(II)

In the title compound, hexa‐μ‐chloro‐di­chloro­tetrakis(N‐tri­methyl­ammonio‐p‐toluene­sulfonamidate‐κ²N,O)­tetramer­cury(II), [Hg{Me₃N(+)N(−)SO₂C₆H₄CH₃‐p}Cl₂]₄ or [Hg₄Cl₈(C₁₀H₁₆N₂O₂S)₄], four nearly linear and parallel Cl—Hg—Cl units associate through pairwise Hg⋯Cl interactions of 3.1–3.2 Å. Each Hg atom is also coordinated through N and O atoms to a yl­ide mol­ecule. The available structural data indicate that coordination of a sulfonyl‐stabilized nitro­gen yl­ide to a metal atom (Hg or Ag) has no detectable effect on its geometry.     

Tetra‐μ‐2‐fluoro­benzoato‐bis[aqua(4,4′‐bi­pyridine)(2‐fluorobenzoato)lanthanum(III)]

Each La³⁺ ion in the title complex, tetra‐μ‐2‐fluorobenzoato‐κ¹⁰O:O′;O:O,O′;O:O′;O,O′:O′‐bis[aqua(4,4′‐bipy­ridine‐κN)(2‐fluorobenzoato‐κO)lanthanum(II)], [La(C₇H₄FO₂)₆(C₁₀H₈N₂)₂(H₂O)₂], is coordinated by six O atoms from the carboxyl­ate groups of five 2‐fluoro­benzoate ligands, one O atom from a water mol­ecule and one N atom from a 4,4′‐bi­pyridine mol­ecule, thus forming a dimeric mol­ecule. An infinite one‐dimensional dimeric supramolecular chain is formed via intermolecular hydrogen bonds.     

Two new soluble iron–oxo complexes: [Fe2(μ‐O)(μ‐O2CCF3)2(O2CCF3)2(C10H8N2)2] and [Fe4(μ3‐O)2(μ‐O2CCF3)6(O2CCF3)2(C10H8N2)2]·CF3CO2H

Two new iron–oxo clusters, viz. di‐μ‐tri­fluoro­acetato‐μ‐oxo‐bis­[(2,2′‐bi­pyridine‐κ²N,N′)(tri­fluoro­acetato‐κO)­iron(III)], [Fe₂O(CF₃CO₂)₄(C₁₀H₈N₂)₂], and bis(2,2′‐bi­pyridine)­di‐μ₃‐oxo‐hexa‐μ‐tri­fluoro­acetato‐bis­(tri­fluoro­acetato)­tetrairon(III) tri­fluoro­acetic acid solvate, [Fe₄O₂(CF₃CO₂)₈(C₁₀H₈N₂)₂]·CF₃CO₂H, contain dinuclear and tetranuclear Fe^III cores, respectively. The Fe^III atoms are in distorted octahedral environments in both compounds and are linked by oxide and tri­fluoro­acetate ions. The tri­fluoro­acetate ions are either bridging (bidentate) or coordinated to the Fe^III atoms via one O atom only. The fluorinated peripheries enhance the solubility of these compounds. Formal charges for all the Fe centers were assigned by summing valences of the chemical bonds to the Fe^III atom.     

A polymeric zinc thio­sulfate complex containing anionic and cationic chains based on tetra­hedral and octa­hedral zinc sites

catena‐Poly[[[tetra­aqua­zinc(II)]‐μ‐4,4′‐bipyridine‐κ²N:N′] [[μ‐thio­sulfato‐κ²O:S‐bis­[(thio­sulfato‐κS)zinc(II)]]‐di‐μ‐4,4′‐pyridine‐κ⁴N:N′] dihydrate], {[Zn(C₁₀H₈N₂)(H₂O)₄][Zn₂(S₂O₃)₃(C₁₀H₈N₂)₂]·2H₂O}_n, is a polymeric zinc complex built up from thio­sulfate‐containing anionic chains, where the Zn atom is tetra­hedrally coordinated, and aqua‐containing cationic chains incorporating octa­hedrally coordinated Zn. In each type of chain, the 4,4′‐bipyridine units act as spacers, and the chains run along three non‐inter­secting almost orthogonal directions in space. The profusion of hydrogen‐bond donors (all the H atoms of the water mol­ecules) and acceptors (the thio­sulfate O and S atoms) generates a very complex hydrogen‐bonding scheme.     

1D Coordination Polymers from Zinc(II) and Cadmium(II) Halides and 2,2′‐Dithiobis(pyridine N‐oxide): Isostructurality and Structural Diversity

Group 12 halides and 2,2′‐dithiobis(pyridine N‐oxide) (dtpo) form the crystalline the 1D coordination polymers [ZnX₂(μ‐dtpo‐κ²O:O′)]_n [X = Cl ( 1 ), Br ( 2 ), I ( 3 )], [Cd₃(μ‐Cl)₄Cl₂(μ‐dtpo‐κ²O:O′)₂(CH₃OH)₂]_n ( 4 ), [(CdBr₂)₂(μ₃‐dtpo‐κ³O,O:O′)₂(H₂O)₂]_n ( 5 ), and [(CdI₂)₂(μ‐dtpo‐κ²O:O′)₃]_n ( 6 ) in methanol. The compounds were structurally characterized by single‐crystal X‐ray analysis. Compounds 1 – 3 represent an isomorphous series of single‐stranded coordination polymers, whereas the Cd^II derivatives are structurally diverse. The metal nodes in 4 and 5 are trinuclear and dinuclear cadmium clusters, respectively. In 4 and 5 , the metal nodes are linked into double‐stranded 1D coordination polymers by two dtpo bridging ligands. Compound 6 contains mononuclear CdI₂ units as nodes and can be viewed as an alternating copolymer of CdI₂(μ‐dtpo‐κ²O:O′)₂ and CdI₂(μ‐dtpo‐κ²O:O′) entities. Owing to the disulfide moiety, the dtpo bridging ligand inevitably exhibits an axially chiral angular structure. The dtpo ligand adopts various coordination modes through the pyridine N‐oxide oxygen atoms.     

A pyrazine bis‐adduct of a binuclear rhodium(II) carboxylate containing 3,4,5‐triethoxybenzoate as the ­equatorial ligand

The title compound, tetrakis(μ‐3,4,5‐triethoxy­benzoato‐κ²O:O′)­bis­[(pyrazine‐κN)­rhodium(II)](Rh—Rh), [Rh₂(C₁₃H₁₇O₅)₄(C₄H₄N₂)₂], crystallizes on an inversion centre in the triclinic space group . The equatorial carboxyl­ate ligands bridge the two Rh^II atoms, giving a binuclear lantern‐like structure. The pyrazine mol­ecules occupy the two axial coordination sites. The phenyl rings are tilted by ca 10° with respect to the attached carboxyl­ate groups. The pyrazine planes have a torsion angle of ca 19° around the Rh—N bond with respect to the plane of the nearer carboxyl­ate group and are not coplanar with the Rh—Rh bond.     

The cyclic vanadylacetate (C24H20P)[V4O8(C2H3O2)4(NO3)]

In the title complex, tetraphenylphosphonium μ₄‐nitrato‐κ⁴O‐cyclo‐tetrakis(μ‐acetato‐O:O′)tetra‐μ‐oxo‐tetrakis[oxovana‐dium(V)], the anion lies about a twofold axis and consists of the cyclic [V₄O₈] unit coordinated by four acetato ligands with interatomic V?V distances of 3.269 (1) and 3.273 (1) Å. The double‐bonded O atom [N=O 1.102 (6) and N—O 1.268 (4) Å] of the nitrato ligand links the four V atoms with V—O bond distances of 2.613 (2) and 2.813 (2) Å. The negative charge of the complex is balanced by tetraphenyl­phosphonium cations occupying the Na positions in the NaCl‐type ionic packing of the structure.     

Platinum complexes of oxopurines: cis‐bis(theophyllinato‐N7)bis(triphenylphosphine)platinum(II) and cis‐chloro(theobrominato‐N1)bis(triphenylphosphine)platinum(II) ethanol hemisolvate

The syntheses and structures of two mixed‐ligand complexes of platinum(II) with deprotonated oxopurine bases and tri­phenyl­phosphine are reported, namely the theophyllinate complex cis‐bis(1,2,3,6‐tetra­hydro‐1,3‐di­methyl­purine‐2,6‐dionato‐κN⁷)­bis(tri­phenyl­phosphine‐κP)­platinum(II), [Pt(C₇H₇N₄O₂)₂(C₁₈H₁₅P)₂], (I), and the theobrominate complex cis‐chloro(1,2,3,6‐tetrahydro‐3,7‐dimethylpurine‐2,6‐dionato‐κN¹)­bis(tri­phenyl­phosphine‐κP)­platinum(II) ethanol hemisolvate, [PtCl(C₇H₇N₄O₂)(C₁₈H₁₅P)₂]·0.5C₂H₅OH, (II). In (I), the coordination geometry of Pt is square planar, formed by the two coordinating N atoms of the theophyl­linate anions in a cis arrangement and two P atoms from the tri­phenyl­phosphine groups. In (II), there are two crystallographically independent mol­ecules. They both exhibit a square‐planar coordination geometry around Pt involving one Cl atom, the coordinating N atom of the theobrominate anion and two P atoms from the tri­phenyl­phosphine groups. The two tri­phenyl­phosphine groups are arranged in a cis configuration in both structures. The heterocyclic rings are rotated with respect to the coordination plane of the metal by 82.99 (8) and 88.09 (8)° in complex (I), and by 85.91 (16) and 88.14 (18)° in complex (II). Both structures are stabilized by intramolecular stacking interactions involving the purine rings and the phenyl rings of adjacent tri­phenyl­phosphine moieties.     

trans‐Bis[3‐(2‐fluorophenyl)‐1‐(4‐nitrophenyl)triazenido‐κN3]bis(pyridine‐κN)palladium(II)

In the title complex, [Pd(C₁₂H₈FN₄O₂)₂(C₅H₅N)₂] or trans‐[Pd(FC₆H₄N=N—NC₆H₄NO₂)(C₅H₅N)₂], the Pd atom lies on a centre of inversion in space group P. The coordination geometry about the Pd²⁺ ion is square planar, with two deprotonated 3‐(2‐fluoro­phenyl)‐1‐(4‐nitro­phenyl)­triazenide ions, FC₆H₄N=N—NC₆H₄NO₂^?, acting as monodentate ligands (two‐electron donors), while two neutral pyridine mol­ecules complete the metal coordination sphere. The whole triazenide ligand is not planar, with the largest interplanar angle being 16.8 (5)° between the phenyl ring of the 2‐­fluorophenyl group and the plane defined by the N=N—N moiety. The Pd—N(triazenide) and Pd—N(pyridine) distances are 2.021 (3) and 2.039 (3) Å, respectively.     

Di­aqua­bis­(di­methyl sulfoxide)­bis(3,5‐di­nitro­benzoato)­zinc(II) and the synthesis of the Cu,Ni and Co analogs

In order to model processes of chemisorption in organic salts formed between di­nitro­benzoic acids (DNBH) and secondary amines (R₂NH), a series of compounds of composition [M^II(3,5‐DNB)₂(DMSO)₂(H₂O)₂] (where M^II is Zn, Cu, Ni or Co, 3,5‐DNB is the 3,5‐di­nitro­benzoate ion, and DMSO is di­methyl sulfoxide) have been prepared. In di­aqua­bis­(di­methyl sulf­oxide)­bis(3,5‐DNB)­zinc(II), [Zn(C₇H₃N₂O₆)₂(C₂H₆OS)₂(H₂O)₂], the 3,5‐DNB ions and mol­ecules of DMSO are monodentate ligands that are coordinated to the Zn atom through their O atoms. These ligands, together with two mol­ecules of water, form a slightly distorted octahedral coordination environment for the Zn atom, which lies on a center of symmetry.     

A lithium complex of pyridine‐2,6‐dicarboxylic acid

The crystal structure of catena‐poly­[[(6‐carboxy­pyridine‐2‐carb­oxyl­ato‐κ³O,N,O′)­lithium(I)]‐μ‐aqua‐κ²O:O], [Li(C₇H₄NO₄)­(H₂O)]_n, contains the Li⁺ ion coordinated to two O atoms and the N atom of the 6‐carboxy­pyridine‐2‐carboxyl­ate ligand, and to two water O atoms, forming a pentavalent coordination geometry. The molecule resides on a mirror plane which contains the Li and N atoms, the para‐CH unit, and the O atom of the coordinated water mol­ecule. The O atom of the water mol­ecule is coordinated to two Li atoms, forming an infinite polymeric chain.     

(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.     

Tetrakis(dimethyl sulfide)palladium(II) bis(tetrafluoroborate) and tetrakis(1,4‐oxathiane‐κS)palladium(II) bis(tetrafluoroborate)

Tetrakis(dimethyl sulfide)palladium(II) bis(tetrafluoroborate), [Pd(C₂H₆S)₄](BF₄)₂, (I), and tetrakis(1,4‐oxa­thiane‐κS)palladium(II) bis­(tetra­fluoro­borate), [Pd(C₄H₈OS)₄](BF₄)₂, (II), both crystallize as mononuclear square‐planar complexes with tetra­fluoro­borate as the counter‐ions. The Pd atom accepts four S‐donor atoms and is positioned at an inversion centre in both compounds. The two unique S atoms in the di­methyl sulfide complex, (I), are disordered. The Pd—S distances are in the range 2.3338 (12)–2.3375 (12) Å in (I), and the corresponding distances in the thio­xane complex, (II), are 2.3293 (17) and 2.3406 (17) Å. The anions in both compounds interact weakly with the Pd atom.