Abstract
The cothermolysis of As-4 and [Cp"Zr-2-(CO)(2)] (Cp" = eta(5)-C(5)H(3)tBu(2)) results in the formation of [Cp"Zr-2(eta(1:1)-As-4)] (1) in high yields and the arsenic-rich complex [(Cp"Zr-2)(Cp"Zr)(mu,eta(2:2:1)-As-5)] (2) as a minor product. In contrast to yellow arsenic, 1 is a light-stable, weighable and storable arsenic source for subsequent reactions. The transfer reaction of 1 with ...
Abstract
The cothermolysis of As-4 and [Cp"Zr-2-(CO)(2)] (Cp" = eta(5)-C(5)H(3)tBu(2)) results in the formation of [Cp"Zr-2(eta(1:1)-As-4)] (1) in high yields and the arsenic-rich complex [(Cp"Zr-2)(Cp"Zr)(mu,eta(2:2:1)-As-5)] (2) as a minor product. In contrast to yellow arsenic, 1 is a light-stable, weighable and storable arsenic source for subsequent reactions. The transfer reaction of 1 with [Cp"'Fe(mu-Br)](2) (Cp"' = eta(5)-C(5)H(2)tBu(3)) yields the unprecedented bond isomeric complexes [(Cp"' Fe)(2)(mu,eta(4:4)-As-4)] (3a) and [(Cp"' Fe)(2)(mu,eta(4:4)-cycio-As-4)] (3b). In contrast, the analogous reaction with the Cp-Bn derivative [(CpFe)-Fe-Bn(mu-Br)](2) (Cp-Bn = eta(5)-C-5(CH2(C6H5)(5)) leads exclusively to the triple decker complex [((CpFe)-Fe-Bn)(2)(mu,eta(4:4)-As-4] (4) possessing the tetraarsabutadiene-type ligand analogous to 3a. To elucidate the stability of the bonding isomers 3a and 3b, DFT calculations were performed. The oxidation of 4 with AgBF4 affords [((CpFe)-Fe-Bn)(2)(mu,eta(5:5)-As-5)][BF4] (5), which is a product expanded by one arsenic atom, instead of the expected complex [((CpFe)-Fe-Bn)(2)(mu,eta(4:4)-cyclo-As-4](+).
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