Reactivity of [Et4N](2)[MeSb{Fe(CO)(4)}(3)] toward HOAc and [Cu(MeCN)(4)]BF4: formation of [Et4N][Me(OAc)Sb{Fe(CO)(4)}(2)] and [MeSb{Fe(CO)(4)} {Fe-2(CO)(8)}]

Reactions of the tetrahedral methylantimony complex [Et4N](2)[MeSb {Fe(CO)( 4)}(3)] with HOAc and [Cu(MeCN)(4)[BF4] were investigated. While the reacti on of [Et4N](2)[MeSb{Fe(CO)(4)}(3)] with HOAc forms the substituted complex [Et4N][Me(OAc)-Sb{Fe(CO)(4)})(2)] ([Et4N][[I]), the treatment with [Cu(MeC N)(4)][BF4] forms the oxidized product [MeSb{Fe(CO)(4)} {Fe-2(CO)(8)}] (II) . The structures of [Et4N][I] and II are determined by single-crystal X-ray diffraction. [Et4N][I] crystallizes in the orthorhombic space group Pna2(1 ) with a = 16.627(4), b = 9.411(3), c = 17.347(4) Angstrom, V = 2714(1) Ang strom(3), and Z = 4. The crystals of II are triclinic, space group P (1) ov er bar with a = 9.335(1), b = 10.313(3), c = 10.372(1) Angstrom, alpha = 97 .46(1), beta = 93.63(1), gamma = 94.65(1)degrees, V = 984.0 (3) Angstrom(3) , and Z = 2. Cluster I is an OAc group substituted product which displays a tetrahedral metal core with the central antimony atom bonded to two Fe(CO) (4) fragments, one Me group, and one OAc moiety. Compound II is the two-ele ctron oxidized product of [Et4N](2)[MeSb {Fe(CO)(4)}(3)] where one Fe-Fe bo nd is formed upon the addition of [Cu(MeCN)(4)][BF4]. The results are compa red with those of the analogous bismuth system and the role of the main gro up elements is discussed as well. (C) 1999 Elsevier Science S.A. All rights reserved.