RESUMEN
In the title compound (C(17)H(17)N(2))(2)[Fe(2)Cl(6)O], obtained from the solid-state reaction of FeCl(2) and N,N'-dibenzyl-imidazolium chloride, the complex anion has approximate D(3d) symmetry with crystallographically imposed inversion symmetry coincident with the bridging µ-O atom. The stereochemistry about each FeCl(3)O centre is distorted tetra-hedral [Fe-Cl = 2.2176â (5)-2.2427â (5)â Å and Fe-O = 1.7545â (2)â Å]. The Cl atoms are involved in weak anion-cation C-Hâ¯Cl inter-actions, giving a network structure.
RESUMEN
Synthesis and characterisation of cyano-bridged complexes of the form [(eta-C5R4Me)L(ON)Mn(mu-XY)Mn(CO)2-L'(dppm)]z (X,Y = C,N; z = 1-3) shows that systematic variation of the orientation of the CN bridge and the nature and geometric arrangement of the ancillary ligands affords control of the direction and energy of metal-metal charge transfer in the mixed valence dications.
RESUMEN
Several rhodium(I) complexes of the type [RhX(CO)(PePy2)], [Rh(diene)(PePy)]+, and [Rh(diene)(PePy2)]+ (PePyn = P(CH2CH2Py)nPh3-n; Py = 2-pyridyl; n = 1, 2) have been prepared. The two former are square planar; the latter are pentacoordinated for diene = tetrafluorobenzobarrelene or norbornadiene (confirmed by X-ray diffraction), but an equilibrium of 4- and 5-coordinate isomers exists in solution for diene = 1,5-cyclooctadiene. The fluxional behavior of all these complexes is studied by NMR spectroscopy. The complex [Rh(NBD)(PePy2)]PF6.Cl2CH2 crystallizes in the monoclinic space group P21/n with a = 8.455(1) A, b = 18.068(3) A, c = 19.729(3) A, beta = 99.658(3)degrees, and Z = 4. The complexes [Rh(diene)(PePy2)]+ react with CO to give the dimeric complex [Rh2(CO)2[P(CH2CH2Py)2Ph]2](BF4)2 with the pyridylphosphine acting as P,N-chelating and P,N-bridging.
RESUMEN
The origins, scope and utility of compilations of metal-ligand and intraligand bond lengths based on the Cambridge Structural Database are discussed. The limitations on the apparent uncertainty of metal-ligand bond lengths derived from crystallographic data and recent evidence of metal-assisted hydrogen bonding involving ligands are reviewed in the light of the transferability of bond-length values from one crystal structure determination.