title: Extremely bent cyanide coordination at a preorganized dinickel site and assembly of a starlike nonanuclear complex from the constrained dinickel building blocks.
abstract: An extremely bent cyanide coordination at a dinickel scaffold is reported. Preorganization of two nickel ions is achieved by means of a compartmental dinucleating pyrazolate ligand L(-), setting up a bimetallic coordination pocket with constrained metal-metal separation. The mixed-spin dinickel(II) complex [LNi2(CN)(MeCN)](ClO4)2 (1) has been characterized by X-ray diffraction. The MeCN bound to the high-spin nickel(II) ion can be removed or replaced by other ligands, e.g., by the cyanide ligand of a tetracyanonickelate(II) moiety to give the starlike nonanuclear complex ([LNi2(CN)]4[Ni(CN)4])(ClO4)6 (2) that contains four of the constrained pyrazolate-based dinickel(II) fragments grouped around a central tetracyanonickelate(II) unit, as revealed by X-ray crystallography. Spectral and electrochemical properties of 1 and 2 are reported, and the formation of reduced mixed-valent Ni(I)Ni(II) species is investigated by IR and UV/vis spectroelectrochemistry.
authors.affiliation: Anorganisch-Chemisches Institut der Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany. franc.meyer@urz.uni-heidelberg.de
authors.forename: F
authors.initials: F
authors.lastname: Meyer
authors.forename: R F
authors.initials: RF
authors.lastname: Winter
authors.forename: E
authors.initials: E
authors.lastname: Kaifer