Seven-Coordinate Vanadium Compounds
To the Editor: Certain inaccuracies in the article by Boggess and Wiegele, [J. Chem. Ed., 55, 156 (1978)], regarding seven-coordinate vanadium compounds should be brought to the attention of readers. Specifically, "[V(C0)4(DAS)]2" (Ref (3) has been shown recently by our group [Ellis,J. E., et al., J. Organometal Chem., 93, 205 (1975)l to be the ionic substance [V(C0)3(DAS)2+][V(C0)6-1, which contains no V-V bond. Indeed, the only vanadium carbonyl species presently known to have a V-V bond is (CsHs)2Vz(C0)6[Cotton, F. A., et al., J. Amer. Chem. Soc., 95,952 (1973)l. Also, "(C,jHs)3PV(C0)6" listed by the authors must be a misprint since it is a nonexistent compound. Another vanadium carbonyl previously suggested to contain seven cwrdinate vanadiums bonded to each other, (W. Hieber and E. Winter, Chem. "[V(C0)4(P(C6H11)3)2]2" Ber., 97, 1037 (1964)) has been shown by a member of our group to be a complex mixture of disproportionation products containing the anion V(C0)5(P(CsHn)3)- and a new cation which may be V(C0)3(P(C6H11)3)4+(R. A. Faltynek, Ph.D. Thesis, University of Minnesota, 1976). John E. Ellis
University of Minnesota Minneapolis, Minnesota 55455
818 / Journal of Chemical Education
