Übergangsmetallstabilisierte As I- und Sb I-Chelate

Abstract

The dimetallaarsacumuleniumion [Cp′(CO) 2MnAsMn(CO) 2Cp′] +, 2, (Cp′ = η 5-C 5H 4CH 3) obtained from the arsinidene compound ▪, 1a, reacts with dipy to give the cationic arsenic(I) chelate compound [Cp′(CO) 2Mn] 2 As[dipy] +, which has been isolated and structurally characterized as its CF 3SO 3 − salt, 3a. ortho-Phenanthroline as the chelate ligand gives the corresponding o-phen chelate, isolated as its triflate 3b. In contrast to the arsinidene compound ▪, 1a, which has first to be transformed into the cumulenic system [Cp′(CO) 2MnAsMn(CO) 2Cp′] +, 2, in order to synthesize 3a, 3b, the “inidene” compounds (CO) 5 ▪, 1b, and ▪ Cp′, 1c, undergo a spontaneous reaction with dipy to form the salts [L n M] 2Xdipy +[L n M] 2XCl 2 (L n M = (CO) 5Cr, X = As: 3c; L n M = Cp′(CO) 2Mn, X = Sb: 3d). X-ray analyses of 3c, 3d reveal the tetrahedral coordination around the main group centers X(I) in the cationic as well as in the anionic constituents of 3a (X = As) and 3d (X = Sb). Comparison of the structures known for chelate compounds of the type [L n M] 2dipy + (X = As, Sb, Bi) shows a systematic trend in the relative importance of XN- vs. XM-bonding for these species.