Synthesis and crystal structure analysis of ferrocenylthiosemicarbazone complexes of palladium(II): Unusual σPd–C bond cleavage

Abstract The reaction of the thiosemicarbazones (η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 )C(H) NN(H)C( S)NHR (R = H, a ; R = Me, b ) with K 2 PdCl 4 afforded octanuclear cyclometallated complexes [Pd{(η 5 -C 5 H 5 )Fe(η 5 -C 5 H 3 )C(H) NN C(S)NHR}] 4 (R = H, 1a ; R = Me, 1b ). Reaction of complexes 1a and 1b with tertiary diphosphines in 1:2 molar ratio and subsequent recrystallization from CH 2 Cl 2 / n -C 6 H 14 gave rise to tetranuclear complexes [{Pd[(η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 )C(H) NN C(S)NHR](Cl)} 2 (μ-Ph 2 P(CH 2 ) n PPh 2 )] (R = H, n  = 4, 2a ; R = Me, n  = 1, 2b ; n  = 4, 3b ). Treatment of complexes 1a and 1b with tertiary monophosphines in 1:4 molar ratio and subsequent recrystallization from CH 2 Cl 2 / n -C 6 H 14 gave rise to dinuclear complexes [Pd{(η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 )C(H) NN C(S)–NHR}(Cl)(P)] (R = H: P = PPh 3 , 3a ; P = PPh 2 Et, 4a ; P = P(C 6 D 5 ) 3 , 5a ; R = Me: P = PPh 3 , 4b ; P = PPh 2 Et, 5b ; P = P(C 6 D 5 ) 3 , 6b ). The crystal structures of 2a and 2b have been determined by X-ray crystallography.