Koordination von Diazoverbindungen an Cobalt(I)-Zentren / Coordination of Diazo Compounds to Cobalt(I) Centres Struktur von Methyl(diazocyclopentadien)tris(trimethylphosphan)cobalt / Structure of Methyl(diazocyclopentadiene)tris(trimethylphosphane)cobalt

Abstract

Co(cyclo-C5H8)(PMe3)3 is oxidized by diazocyclopentadiene to give Co2(N2C5H4)(PMe3)5 (1). Cobalt(I) compounds CoRL′L3 (R = CH3, 4-CH3C6H4, COCH3; L′ = PMe3, CO; L = PMe3; 3 L = CH3C(CH2PMe2)3) or CoRL3 (R = Cl, C6F5; L = PMe3) accommodate diazoalkane ligands to give 18 electron complexes CoR(N2R′)L3 (3: R = CH3, R′ = C5H4, L = PMe3; 5: R = 4-CH3C6H4, R′ = C5H4, L = PMe3; 6: R = CH3, R′ = C(C6H5)2, L = PMe3; 8: R = C6F5, R′= C5H4, L = PMe3; 9: R = C6F5, R′= C13H8, L = PMe3; 11: R = CH3, R′ = C5H4, 3 L = CH3C(CH2PMe2)3; 12: R = CH3, R′ = C13H8, 3 L = CH3C(CH2PMe2)3; 13: R = COCH3, R′ = C13H8, 3 L = CH3C(CH2PMe2)3). Formation of phosphazines Me3PN2R′ (2b: R′ = C5(C6H5)4; 2c: R′ = C5Cl4; 2d: R′ = C13H8) is observed as destructive side-reaction unless it is easily reversed (2 a: R′ = C5H4). 3 crystallizes in the orthorhombic space group P212121 (Nr. 19); a = 1623.0(7), b = 1520.2(6), c = 838.5(3) pm.