A Magic Equation: Delta Bonds Plus Bicyclic Guanidinates Equals Strong Reducing Agents

Abstract

Reactions of bicyclic guanidinates with dimolybdenum and ditungsten precursors having quadruple bonded units with a σ2π4δ2 (Q) electronic configuration have generated the most easily ionized, chemically stable species and very strong reducing agents. Analogous rhenium compounds have led to the formation of species having dimetal units in unusually high oxidation states. Here we review this chemistry and the accounts that explain such behaviour that has been attributed to the interaction of the π electrons of the guanidinate C(N)3 core with the electrons that give rise to the delta bond of the dimetal units.