HETEROCUMULENES WITH METAL-ARSENIC AND METAL-ANTIMONY MULTIPLE BOND

The chloroarsinidene compound Cp'(CO)2Mn-As(Cl)-Mn(CO)2Cp', 1a, (Cp' = eta-5-C5H4CH3) upon reaction with GaCl3 transforms into the tetrachlorogallate of the dimanganaarsacumuleniumion [Cp'(CO)2Mn = As = Mn(CO)2Cp']+, 2a. The cumulene type bonding in 2a is evidenced by the spectroscopic and structural (X-ray analysis of 2a.GaCl4-) properties. The chloroarsinidene compound (CO)5Cr-As(Cl)-Cr(CO)5, 1b, and the chlorostibinidene complex Cp-star-(CO)2Mn-Sb(Cl)-Mn(CO)2-Cp-star, 1c, (Cp-star = eta-5-C5(CH3)5) are correspondingly transformed into dimetallaarsa- ([(CO)5Cr = As = Cr(CO)5]+, 2b) and dimetallastiba- ([Cp-star-(CO)2Mn = Sb = Mn(CO)2Cp-star]+, 2c) cumuleniumions respectively. The cations 2b, 2c are unequivocally characterized by spectroscopic techniques; however, crystal structure analyses could not yet be obtained. Under similar conditions the chlorostibinidene compound Cp'(CO)2Mn-Sb(Cl)-Mn(CO)2Cp', 1d, gives the trinuclear cation [Cp'(CO)2 activative Mn]-Cp'(CO)2Mn-Sb = Mn(CO)2Cp'+, 4, which, as shown by X-ray analysis of 4.CF3SO3-, contains a trigonally planar coordinated Sb+-cation.