Synthesis, X-ray structures and reactivity of the first bis(amino)metallastibanes and bis(amino)metallabismuthanes

Abstract

The reaction of Me2Si(N-t-Bu)2ECl (E = Sb, Bi) with NaM(CO)nCp (M = Fe, Mo, W; Cp = ?5-C5H5) affords metallastibanes and bismuthanes, Cp(CO)nME(N-t-Bu)2SiMe2 (4a-c, 5a-c). The structures of 4c (E = Sb, M = W) and 5c (E = Bi, M = W) have been determined by X-ray crystallography. Both compounds are isotypic and isostructural and crystallize in the triclinic space group with a = 7.030 (9) A°, b = 10.51 (1) A°, c = 16.22 (2) A°, a = 94.1 (1)°, ß = 90.4 (1)°, ? = 104.9 (1)°, Z = 2 for 4c and a = 7.014 (9) A°, b = 10.57 (1) A°, c = 16.25 (2) A°, a = 94.1 (1)°, ß= 90.1 (1)°, ? = 104.6 (1)°, Z = 2 for 5c. The E-W s-bond lengths are 3.010 (1) A° for E = Sb and 3.082 (1) A° for E = Bi. The reaction of the antimony derivatives with Fe2(CO)9 yields [Fe(CO)4]Cp(CO)nMSb(N-t-Bu)2SiMe2 (6a-c) as a result of the complexation of the antimony lone pair. The crystal structures of 6a (M = Fe) and 6b (M = Mo) have been determined. 6a crystallizes in the monoclinic space group with a = 10.399 (9) A°, b = 16.76 (2) A°, c = 15.74 (1) A°, ß = 94.16 (6)°, and Z = 4. Both Sb-Fe bond lengths are almost similar: 2.547 (1) A° for the covalent bond and 2.530 (1) A° for the dative bond. 6b crystallizes in the monoclinic space group with a = 12.305 (7) A°, b = 13.812 (7) A°, c = 16.75 (1) A°, ß = 99.03 (5)°, and Z = 4. The Sb-Mo covalent bond length is 2.871 (1) A° and the Sb-Fe dative bond 2.539 (1) A°.