Tri‐μ2‐chloro‐tetra­chloro‐μ3‐oxo‐hexakis­(tetra­hydro­furan‐κO)­dititanium(III)­samarium(III): a novel trinuclear Sm–Ti mixed species

In the title compound, [SmTi₂Cl₇O(C₄H₈O)₆], the metal ions are linked by a central μ₃‐oxo ion and by three μ₂‐chloro ions, giving a planar moiety containing a binary crystallographic axis. The coordination spheres are completed by terminal chloro ligands and tetra­hydro­furan mol­ecules, with resulting pentagonal bipyramidal and octahedral environments for the Sm and Ti atoms, respectively.     

A twinned triclinic polymorph of dibromidotetra­kis(tetra­hydro­furan‐κO)magnesium(II)

The title compound, [MgBr₂(C₄H₈O)₄], forms crystals which appear to be monoclinic but are actually twinned triclinic. The current form is a new triclinic polymorph, with Z′= 2, in addition to the already known tetra­gonal polymorph. Although the geometric parameters of the two polymorphs agree well, their packing patterns are completely different.     

catena‐Poly­[[heptakis­(di­methyl­form­amide‐κO)­di‐μ4‐oxo‐tetra‐μ3‐oxo‐hexa­deca‐μ2‐oxo‐tetra­oxo­lan­than­um(III)­octamolybdenum(IV)]‐μ‐sodium(I)]

The title compound, [NaLaMo₈O₂₆(C₃H₇NO)₇]_n, contains infinite chains of [Mo₈O₂₆]⁴⁻ units supporting di­methyl­form­amide‐coordinated La^III cations and linked by Na⁺ cations. The lanthanum center adopts a nine‐coordinate geometry and the Na atom is sandwiched between two β‐[Mo₈O₂₆]⁴⁻ units.     

catena‐Poly[sodium(I)‐μ‐tetra­ethoxy­borato]

The title compound, [Na(C₈H₂₀BO₄)]_n, has twofold crystallographic symmetry, with the Na⁺ cations bound by four O atoms [Na—O = 2.251 (3) Å]. The tetra­ethoxy­borate anion acts as a bridging ligand to form one‐dimensional polymers running along the twofold crystal axis. The crystal was treated as a racemic twin.     

An oxo‐centred trinuclear FeIII complex: tri­aqua­hexakis(μ2‐betaine‐O:O′)‐μ3‐oxo‐triiron(III) bis­(tetra­chloro­manganate) trichloride ­hexahydrate

The title compound, [Fe₃(C₅H₁₁NO₂)₆O(H₂O)₃](MnCl₄)₂Cl₃·6H₂O, contains a triiron core linked by a μ₃‐bridging oxide ion. Each of the iron(III) ions has a distorted octahedral environment, being coordinated, in addition to the oxide ion, by four neutral betaine mol­ecules and one water mol­ecule. The N‐alkyl­ated α‐amino acid betaine is present in the dipolar zwitterionic form and chelates pairs of Fe atoms at the vertices of the triangular [Fe₃O]⁷⁺ ionic core. The Fe complex has a crystallographically imposed D3 symmetry. The water mol­ecules fully exhaust their potential as hydrogen donors, forming a two‐dimensional hydrogen‐bond network in planes parallel to (001).     

(Borohydrido)(18‐crown‐6)potassium and (borohydrido)(dibenzo‐18‐crown‐6)(tetra­hydro­furan)potassium

In the two compounds (borohydrido)(1,4,7,10,13,16‐hexa­oxacyclo­octa­decane‐κ⁶O)potassium, [K(BH₄)(C₁₂H₂₄O₆)], (I), and (borohydrido)(1,4,7,10,13,16‐hexa­oxa‐2,3:11,12‐di­benzo­cyclo­octa­deca‐2,11‐diene‐κ⁶O)(tetra­hydro­furan)­potassium, [K(BH₄)(C₄H₈O)(C₂₀H₂₄O₆)], (II), the K atom is bound to the six O atoms of the crown ether and to a tridentate borohydride group, with further coordination to a tetra­hydro­furan mol­ecule in (II). The alkali metal ion environment is thus distorted hexa­gonal–pyramidal in (I) and bipyramidal in (II).     

Di‐μ‐phenyl­thio‐bis­[bis(η5‐methyl­cyclo­penta­dienyl)(tetra­hydro­furan)lanthanum(III)] bis­(tetra­hydro­furan) solvate

The title complex, [La₂(C₆H₇)₄(C₆H₅S)₂(C₄H₈O)₂]·2C₄H₈O, is a centrosymmetric dimer bridged through the S atoms of the benzene­thiolate ligands. The bridging La₂S₂ unit is completely planar, while the geometry around the nine‐coordinate La atom is that of a distorted trigonal bipyramid. The La—S—La and S—La—S angles are 117.51 (4) and 62.5 (1)°, respectively, and the average La—S bond length is 2.9759 Å. The crystals contain two tetra­hydro­furan solvate mol­ecules for every complex mol­ecule.     

Di‐μ‐hydro­xo‐bis­(diiso­propyl­gallium)–1,4,8,11‐tetra­methyl‐1,4,8,11‐tetra­aza­cyclo­tetra­decane (1/1)

The hydro­lysis product [Ga₂(C₃H₇)₄(OH)₂]·C₁₄H₃₂N₄, derived from the tetrakis­(triiso­propyl­gallium)–1,4,8,11‐tetra­methyl‐1,4,8,11‐tetra­aza­cyclo­tetra­decane (1/1) adduct, consists of a centrosymmetric [ⁱPr₂Ga(μ‐OH)]₂ unit hydrogen bonded through the hydroxyl group to a nitro­gen on an adjacent centrosymmetric 1,4,8,11‐tetra­methyl‐1,4,8,11‐tetra­aza­cyclo­tetra­decane molecule, resulting in the generation of a molecular chain through the crystal.     

Bis{μ‐2‐[(2,3‐dichloro­phenyl)­amino]­benzoato‐κO}di‐μ2‐ethoxo‐octa­methyl­di‐μ3‐oxo‐tetra­tin(IV)

The title compound, [Sn₄(CH₃)₈(C₁₃H₈Cl₂NO₂)₂(C₂H₅O)₂O₂], is a centrosymmetric dimer, with three linearly fused four‐membered Sn—O—Sn—O rings. The coordination poly­hedron of the Sn atom bonded to the carboxyl­ate can be described as trigonal–bipyramidal distorted toward square‐pyramidal. That of the second Sn atom is similar, but the distortion towards square‐pyramidal geometry is greater. The Sn—O and Sn—C distances are 2.020 (2)–2.226 (2) and 2.096 (4)–2.114 (4) Å, respectively. The benzene rings of the 2‐[(2,3‐dichloro­phenyl)­amino]benzoate ligand subtend an angle of 50.49 (17)°; the conformation of the ligand is stabilized by intra­molecular N—H⋯Cl and N—H⋯O hydrogen bonds. The structure is assembled viaπ–π stacking inter­actions to form chains parallel to [10].     

Tetrakis­(tetra­methyl­ammonium) dodeca‐μ‐chloro‐hexa­chloro‐octahedro‐hexatantalate chloride

The title compound, (C₄H₁₂N)₄[Ta₆Cl₁₈]Cl, crystallizes in the cubic space group . The crystal structure contains two different types of coordination polyhedra, i.e. four tetrahedral [(CH₃)₄N]⁺ cations and one octahedral [(Ta₆Cl₁₂)Cl₆]³⁻ cluster anion, and one Cl⁻ ion. The presence of three different kinds of Cl atoms [bridging (μ₂), terminal and counter‐anion] in one mol­ecule makes this substance unique in the chemistry of hexanuclear halide clusters of niobium and tantalum. The Ta₆ octahedron has an ideal O_h symmetry, with a Ta—Ta interatomic distance of 2.9215 (7) Å.     

Di­bromo­tetra‐μ3‐methoxo‐di‐μ2‐methoxo‐hexakis­(tetra­hydro­furan‐d8)­tetramagnesium

The crystal structure of the title compound, [Mg₄Br₂(CH₃O)₆(C₄D₈O)₆], consists of discrete mol­ecules with imposed symmetry C_i. The tetranuclear compound exhibits two crystallographically independent Mg atoms having distorted octahedral and trigonal–bipyramidal ­coordination spheres. The Mg atoms are bridged by two μ₃‐OMe and four μ₂‐OMe ligands, and their coordination is completed by two terminal Br and six tetra­hydro­furan ligands.     

catena‐Poly[tetra­kis(3‐phenyl­propyl­ammonium) [iodo­plumbate(II)‐tri‐μ‐iodo‐plumbate(II)‐tri‐μ‐iodo‐iodo­plumbate(II)‐di‐μ‐iodo]]

The title compound, {(C₉H₁₄N)₄[Pb₃I₁₀]}_n, crystallizes as an organic–inorganic hybrid. As such, the structure consists of a two‐dimensional inorganic layer of [Pb₃I₁₀]_n⁴ⁿ⁻ ions extending along [100]. The asymmetric unit contains two independent Pb atoms, viz. one in a general position and the other on an inversion centre. Each Pb atom is octa­hedrally coordinated by six iodide ions and exhibits both face‐ and corner‐sharing with adjacent atoms in the inorganic layer. These anionic layers alternate with 3‐phenyl­propyl­ammonium cations, which hydrogen bond to the iodides. Simple face‐to‐edge σ–π stacking inter­actions are observed between the aromatic rings that stabilize the overall three‐dimensional structure. This net structure has only been observed five times previously.     

Tetra‐μ‐chloro‐1:2κ4Cl;1:3κ4Cl‐di­methyl‐2κC,3κC‐tetra­kis(tetra­hydro­furan)‐1κ2O,2κO,3κO‐chromium(II)dizinc(II)

The title compound, [CrZn₂(CH₃)₂Cl₄(C₄H₈O)₄], contains a central distorted octa­hedral Cr atom, located at an inversion center, bound to two tetra­hydro­furan ligands and four chloro ligands that bridge to two symmetry‐related tetra­hedral Zn atoms. The coordination around zinc is completed by methyl and tetra­hydro­furan ligands. This structure is compared with a previously reported complex of vanadium, and their differences in metric parameters are explained.     

A new pseudopolymorph of hexa­kis(4‐cyano­phenyl)benzene

The title compound (systematic name: benzene‐4,4′,4′′,4′′′,4′′′′,4′′′′′‐­hexayl­hexa­benzo­nitrile dichloro­methane disolvate), C₄₈H₂₄N₆·2CH₂Cl₂, crystallizes as an inclusion compound during the slow diffusion of methanol into a solution of hexa­kis(4‐cyano­phenyl)­benzene in CH₂Cl₂. The hexa­kis(4‐cyano­phenyl)benzene mol­ecule lies on an axis of twofold rotation in the space group Pbcn. Weak C—H⋯N inter­actions between hexa­kis(4‐cyano­phenyl)benzene mol­ecules define an open network with space for including guests. The resulting structure is a new pseudopolymorph of hexa­kis(4‐cyano­phenyl)benzene. The eight known pseudopolymorphs have few shared architectural features, in part because none of the inter­molecular inter­actions that are present plays a dominant role or forces neighboring mol­ecules to assume particular relative orientations.     

Bis(μ‐6‐hydroxy­picolinato)‐μ‐oxo‐bis­[di­pyridine­manganese(III)] monohydrate

The title compound, [Mn₂(μ‐O)(C₆H₃NO₃)₂(C₅H₅N)₄]·H₂O, was isolated from the reaction of 2,6‐pyridine­di­carboxylic acid with [Mn₁₂O₁₂(CH₃COO)₁₆(H₂O)₄] in pyridine. The dimanganese complex has twofold symmetry; the Mn^III atoms are bridged by one oxo and two amidate ligands and show compressed octahedral Jahn–Teller distortion. The molecular packing comprises a three‐dimensional structure constructed by means of extensive intermolecular interactions, including three kinds of hydrogen bonds and π–π interactions.     

(RS)‐6‐Ethyl 2‐carboxy‐1,2,3,4‐tetra­hydro­azulene‐6‐carboxylate

The title compound, C₁₄H₁₆O₄, was obtained during the synthesis of 2,6‐disubstituted azulene derivatives. In the partially reduced azulene skeleton, the absence of a H atom at the ester substitutent position of the seven‐membered ring, as well as lengthened double bonds, indicate a conjugative stabilized system with two overlaid tautomers.     

Mechanistic disparity in the electron transfer reactions of thiosulfate with di‐μ‐oxo‐bis(1,4,8,11‐tetraazacyclotetradecane)‐dimanganese(III,IV) and di‐μ‐oxo‐bis(1,4,7,10‐tetraazacyclododecane)‐dimanganese(III,IV) complexes

A comparative kinetic study of the reactions of two mixed valence manganese(III,IV) complexes of macrocyclic ligands, [L¹Mn^IV(O)₂Mn^IIIL¹], 1 (L¹ = 1,4,8,11‐tetraazacyclotetradecane) and [L²Mn^IV(O)₂Mn^IIIL²], 2 (L² = 1,4,7,10‐tetraazacyclododecane) with thiosulfate has been carried out by spectrophotometry in aqueous buffer at 30°C. Reaction between complex 1 and thiosulfate follows a first‐order rate saturation kinetics. The pH dependency and kinetic evidences suggest the participation of two complex species of Mn^III(μ‐O)₂Mn^IV under the experimental conditions. Detailed kinetic study shows that reduction of 2 proceeds through an autocatalytic path where the intermediate (Mn^III)₂ species has been assumed to catalyze the reaction. The difference in the reaction mechanisms is ascribed to the difference in stability of the intermediate complex species, the evidence for which comes from the electrochemical behavior of the complexes and time dependent EPR spectroscopic measurements during the reduction of 2 . © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 36: 119–128, 2004     

A comparative kinetic study for the oxidation of 2‐mercaptoethanol by di‐μ‐oxo‐bis(1,4,7,10‐tetraazacyclododecane)‐dimanganese(III,IV) and di‐μ‐oxo‐bis(1,4,8,11‐tetraazacyclotetradecane)‐dimanganese(III,IV) complexes: Influence of copper(II)

A comparative kinetic study of the reactions of two mixed valence manganese(III,IV) complexes with macrocyclic ligands, [L¹Mn^IV(O)₂Mn^IIIL¹], 1 (L¹ = 1,4,7,10‐tetraazacyclododecane) and [L²Mn^IV(O)₂Mn^IIIL²], 2 (L² = 1,4,8,11‐tetraazacyclotetradecane) with 2‐mercaptoethanol (RSH) has been carried out by spectrophotometry in aqueous buffer at (30 ± 0.1)°C. Rate of the reactions between the oxidants and the reductant was found to be negligibly slow with no systematic dependence on either redox partners. Externally added copper(II) (usually 5 × 10^?7 mol dm^?3), however, increases the rate of the reduction of 1 and 2 significantly. In the presence of catalytic amount of copper(II), the rate of the reaction is nearly proportional to [RSH] at lower concentration of the reductant but follows a saturation kinetics at higher concentration of the latter for the reaction between 1 and the thiol. Reaction rate was found to be strongly influenced by the variation of acidity of the medium and the observed kinetics suggests that the two reductant species ([Cu(RSH)]²⁺ and [Cu(RS)]⁺) are significant for the reaction between 1 and the thiol. The dependence of the rate on [RSH] for the reduction of 2 by the thiol was complex and rationalized considering two equilibria involving the catalyst (Cu²⁺) and the reductant. The pH rate profile suggests that both the μ‐O protonated [Mn^III(O)(OH)Mn^IV] and the deprotonated [Mn^III(O)₂Mn^IV] forms of the oxidant 2 become important. The kinetic results presented in this study indicate the domination of outer‐sphere path. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 36: 129–137, 2004     

Tetrakis­(tetra­hydro­furan‐κO)­lithium mer‐tris­(carbazolyl‐κN)‐trans‐di­chloro(tetra­hydro­furan‐κO)­zirconate

In the title compound, [Li(C₄H₈O)₄][ZrCl₂(C₁₂H₈N)₃(C₄H₈O)], the environment of the Zr atom is pseudo‐octahedral, with the three carbazolyl ligands in a mer configuration. The counter‐ion of the zirconium complex is composed of an Li atom surrounded by four tetra­hydro­furan (THF) mol­ecules. The THF mol­ecule attached to the Zr atom is disordered over two sites, as are two of the THF mol­ecules in the lithium moiety. All bond distances and angles are consistent with those in complexes with similar structural entities. The Zr—N bond distances are 2.2185 (18) and 2.167 (3) Å.