Abstract
The TCNX ligands TCNE (tetracyanoethene) and TCNQ (7,7,8,8-tetracyano-p-quinodimethane) react instantaneously with (C5R5)2(CO)2Ti, R = H or Me, to yield highly air-sensitive mononuclear complexes (C5R5)2(CO)Ti(TCNX) of which the sol. species (R = Me) were characterized also in the oxidized and reduced forms through cyclic voltammetry, EPR, IR and UV-visible spectroelectrochem. While oxidn. at rather low potentials yields labile carbonyltitanium(IV) species of the TCNX.bul.- ligands, the redn. occurs stepwise at unusually neg. potentials, first on the ligand (to yield coordinated TCNX2-) and then on the metal (to form TiII). For the neutral complexes (C5R5)2(CO)Ti2+q(TCNX-q) the results support a rather large amt. of charge transfer 1 \textless q \textless 2 from the metal to the acceptors TCNX. Evidence for the previously formulated (μ-TCNE2-)(C5H5)2TiIV(CO)2(TCNE2-) could not be found. (C5R5)2(CO)Ti(TCNE) are compared with related compds. (C5R5)2BrV(TCNE), (C6R6)(CO)2Cr(TCNE) and (C5R5)(CO)2Mn(TCNE). on SciFinder(R)
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