19 research outputs found
Two molecular-type complexes of the octahedral rhenium(III) cyanocluster anion [Re6Se8(CN)6]4- with M2+ (Mn2+, Ni2+)
Two novel octahedral rhenium(III) selenocyanide cluster
complexes [(nBu)(4)N](2)Ni(H2O)(5)[Re6Se8(CN)(6)].2H(2)O (1)
and [(nBU)(4)N](2)Mn(H2O)(4)[Re6Se8(CN)(6)].2H(2)O (2) have
been prepared by the reaction of K-4[Re6Se8(CN)(6)].3.5H(2)O,
(nBu)(4)NBr kand Ni(OAC)(2) (or MnSO4) in aqueous solution. The
complexes have been structurally solved in the orthorhombic
unit cell Pbca with parameters: a = 19.393(2), b = 17.292(2), c
= 37.255(4) Angstrom for 1, and a = 19.518(41), b = 17.488(3),
c = 37.997(5) Angstrom for 2. The cluster anions and M2+ form
ionic pairs (M(H2O)(n)[Re6Se8(CN)(6)])(2-) that are packed in
the solid state with n-tetrabutylammonium cations. Coordinated
and solvate water molecules as well as the nitrogen atoms of
the anions form a network of hydrogen bonds in the structures.
These compounds are isomorphous, although the coordination
environments of the metal cations differ
Octahedral Niobium Thiocyanato Complexes Containing [Nb6Cl9O3] Cluster Core: Syntheses, Crystal Structures and Evidences of NCS Ligand Exchange
Effect of Secondary Metabolites Juniperus sabina L. (Cupressaceae) on the Survival and Nutrition of Galleria mellonella L. (Pyralidae)
Synthesis, Separation, Identification and Interconversion of Riboflavin Phosphates and Their Acetyl Derivatives: A Reinvestigation
Inorganic Niobium and Tantalum Octahedral Cluster Halide Compounds with Three-dimensional Frameworks: A Review on their Crystallographic and Electronic Structures
International audienceThis review summarizes the development of the rich crystal and bonding chemistry of face-capped and edge-bridged inorganic niobium and tantalum octahedral cluster halide compounds, with a particular emphasis on those showing three-dimensional cluster frameworks. Discussion is made on varied structures and bonding which are intimately linked to the valence electron concentration, i.e., the number of electrons that held the octahedral metal cluster architecture. Exploration of the literature indicates that apart from Nb6I11 and derivatives, which show electron-deficient face-capped M6Xi8Xa6 units, compounds containing edge-bridged M6Xi12Xa6 motifs are the most largely encountered. Closed-shell compounds with a valence electron concentration of 16 are predominant, although a few 15-electron open-shell magnetic compounds or even 14-electron closed-shell species have also been reported. Particularly interesting from a structural point of view is the fashion in which these face-capped and edge-bridged clusters “pack” in crystals. The astonishing diversity of structural types, which are observed, is mainly due to the flexibility of the halogen ligands to coordinate in various manners to metal atoms. However, a rigorous structural analysis of these compounds reveals no close relationship between the valence electron concentration and the variability of the intercluster connections and/or the nature of the counterions. Indeed, the main bonding features of these compounds can be understood from the delocalized bonding picture of isolated “molecular-like” M6Xi8Xa6 or M6Xi12Xa6 clusters