Preparation and properties of tetra(n-butyl)ammonium cis-diacidooxophthalocyaninato(2-)niobates(V) and -tantalates(V); crystal structure of ((Bu4N)-Bu-n)(cis) [Nb(F)(2)Opc(2-)]

Tetra(n-butyl)ammonium cis-diacidooxophthalocyaninato(2-)niobates(V) and -t antalates(V), ((Bu4N)-Bu-n)(cis)[M(X)(2)Opc(2-)] (M = Nb, Ta; X = F, Cl, NC S, N-3), are obtained by the reaction of (cis)[M(Cl)(3)pc(2-)] or (cis)[M(C l)Opc(2-)] (M = Nb, Ta) with the respective tetra(n-butyl)ammonium salt. (( Bu4N)-Bu-n)(cis)[Nb(F)(2)Opc(2-)] crystallizes in the monoclinic space grou p P2(1)/n with cell parameters a = 13.460(5), b = 13.820(5), c = 23.360(5) Angstrom, beta = 92.640(5)degrees, Z = 4. The heptacoordinated Nb(V) atom i s surrounded by four isoindole nitrogen atoms (N-iso) of the pc(2-) ligand, two fluorine atoms and one oxygen atom in a distorted square-base-trigonal -cap polyhedron. Nb(V) is displaced out of the centre of the (N-iso)(4) pla ne (Ct(N-iso)) towards the acido ligands (d(Nb-Ct(N-iso)) = 1.241 Angstrom) . The average (Nb-N-iso), (Nb-F), and (Nb-O) distances are 2.300, 1.957, an d 1.720(5) Angstrom, the (F-Nb-F) and the average (O-Nb-F) angles are 79.8( 2) and 91.8 degrees, respectively. The pc(2-) ligand is concavely distorted . Typical pi-pi*-transitions of the pc(2-) ligand are observed in the UV/Vi s spectra at ca. 14500 and 29300 cm(-1). Vibration frequencies nu(as,s)(M-X ), nu(M-O) and delta(X-M-O) have been assigned.