Date of Award
Doctor of Philosophy
John G. Verkade
Metal-halide complexes containing phosphorus esters undergo Arbozov rearrangements analogous to those observed in organophosphorus systems. Such a rearrangement has been found to lead to the formation of the unexpected trinuclear cobalt(II) complex (CpCo(P(O)(OMe)[subscript]2) [subscript]2I) [subscript]2Co (Cp = C[subscript]5H[subscript]5) in which the central cobalt(II) may be in either an octahedral or a tetrahedral geometry. This is the first reported instance of true isomerism between tetrahedral and octahedral cobalt(II) species. Similar results are obtained when Cp[superscript]* (Cp[superscript]* = C[subscript]5Me[subscript]5) rather than Cp is bound to the cobalt(III) atoms;Until very recently isolable square pyramidal pnictogen compounds were unknown. Study of the reactivity of such species is desirable since intermediates of similar geometry are believed to play an important role in many reactions of pnictogen-containing compounds. One system which appears particularly suited to the study of square pyramidal species is 1, in which a pentacoordinate pnictogen derivative would be restricted to a square pyramidal geometry (2).(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI);Pnictogen derivatives of 1 have been prepared and their reaction chemistry investigated. Although little or no strain is present in the phosphorus derivatives of 1, the Lewis basicity of phosphorus in these compounds is almost identical to that of P(OCH[subscript]2)[subscript]3CMe. Deprotonation studies of these compounds and their derivatives have also been performed in an attempt to synthesize stable pentacoordinate pnictogen derivatives of 1. Although no evidence of a stable square pyramidal species has been observed, data consistent with a fluxional anion with a square pyramidal transition state have been obtained in the case of two arsenic derivatives of 1.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Ronald Verne Davis
Davis, Ronald Verne, "Synthetic approaches to rigid square pyramidal pnictogens and synthesis of new trinuclear cobalt(II) complexes " (1989). Retrospective Theses and Dissertations. 9116.