Flexible Bonding of the Phosph(V)azane Dianions [S(E)P(µ-NtBu)]22-

Abstract

Oxidation of the P(III) dianion [S-P(µ-NtBu)]22- (1) with elemental sulphur, selenium and tellurium gives the P(V) dianions [(S)(E)P(µ-NtBu)]22- (E = S (6a), Se (6b), Te (6c)). Although 6c proves to be too unstable, the S,S-dianion 6a and ambidentate S,Se-dianion 6b are readily transferred intact to main group and transition metal elements, producing a range of new cage and coordination compounds. While their coordination characteristics are in many ways similar to closely-related isoelectronic phosph(V)azane anions [(E)(RN=)P(µ-NtBu)]22-, the sterically unhindered nature of 6 introduces an expanded range of coordination modes, i.e., facial S,S- and Se,Se-bonding as well as side-on S,Se-coordination. All of these bonding modes are observed for the amibidentate S,Se dianion 6b.