A new method is reported for the preparation of [Nb(cO),]- and [Ta(CO)6]- by reductive carbonylation of M2ClIo (M = Nb, Ta) with the magnesium-zinc-pyridine-CO system. In the case of niobium, the reductive carbonylation occurs at atmospheric pressure and room temperature with yields as high as 48%. The tetrahydrofuran-stabiliied sodium derivatives [Na(THF)] [M(CO),] and the bis(triphenylphosphie)nitrogen( 1+) derivatives, PPN[M(CO),] (M = Nb, Ta), are reported. The crystal and molecular structures of both niobium and tantalum ppN[M(CO),] complexes are described. Both compounds are isostructural with the corresponding vanadium derivative: rhombohedral, space group Rg, one molecule per cell; M = Nb, a = 9.832 (4) A, a = 91.98 ( S ) ' , V = 948.7 (7) A3, paid = 1.399 g ~ m -R~ =, 0.0391; M = Ta, a = 9.814 (4) A, a = 92.02 (8)', V = 943.4 (7) A', pal& = 1.562 g ~ m -R~ =, 0.0294 (Mo Ka,X = 0.71069 A). The geometry of the two hexacarbonylmetalates is that of an almost perfect octahedron. Chemical and spectroscopic comparisons of the three [M(CO),]- (M = V, Nb, Ta) anions are made.
STUDIES ON CARBONYL DERIVATIVES OF EARLY TRANSITION-ELEMENTS - A CONVENIENT METHOD FOR THE PREPARATION OF THE [NB(CO)6]- ANION AT ATMOSPHERIC-PRESSURE AND ROOM-TEMPERATURE - CRYSTAL AND MOLECULAR-STRUCTURE OF [NB(CO)6]-,[TA(CO)6]- AS THEIR "BIS(TRIPHENYLPHOSPHINE)NITROGEN(1+) DERIVATIVES
CALDERAZZO, FAUSTO;PAMPALONI, GUIDO;ZAMBONI, ROBERTO
1983-01-01
Abstract
A new method is reported for the preparation of [Nb(cO),]- and [Ta(CO)6]- by reductive carbonylation of M2ClIo (M = Nb, Ta) with the magnesium-zinc-pyridine-CO system. In the case of niobium, the reductive carbonylation occurs at atmospheric pressure and room temperature with yields as high as 48%. The tetrahydrofuran-stabiliied sodium derivatives [Na(THF)] [M(CO),] and the bis(triphenylphosphie)nitrogen( 1+) derivatives, PPN[M(CO),] (M = Nb, Ta), are reported. The crystal and molecular structures of both niobium and tantalum ppN[M(CO),] complexes are described. Both compounds are isostructural with the corresponding vanadium derivative: rhombohedral, space group Rg, one molecule per cell; M = Nb, a = 9.832 (4) A, a = 91.98 ( S ) ' , V = 948.7 (7) A3, paid = 1.399 g ~ m -R~ =, 0.0391; M = Ta, a = 9.814 (4) A, a = 92.02 (8)', V = 943.4 (7) A', pal& = 1.562 g ~ m -R~ =, 0.0294 (Mo Ka,X = 0.71069 A). The geometry of the two hexacarbonylmetalates is that of an almost perfect octahedron. Chemical and spectroscopic comparisons of the three [M(CO),]- (M = V, Nb, Ta) anions are made.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
