Abstract

Reaction of the thiosemicarbazones 3-FC6H4C(Me)=NN(H)C(=S)NHME a, 4-FC6H4C(Me)=NN(H)C(=S)NHEt b, and 2-BrC6H4C(Me)=NN(H)C(=S)NHPh c, with potassium tetrachloropalladate(II) in ethanol, lithium tetrachloropalladate(II) in methanol or palladium(II) acetate in acetic acid gave the tetranuclear cyclometallated complexes [Pd{3-FC6H3C(Me)=NN=C(S)NHMe}](4) 1a, [Pd{4-FC6H3C(Me)=NN=C(S)NHEt}](4) 1b, and [Pd(2-BrC6H3C(Me)+NN=C(S)NHPh}](4) 1c. Reaction of 1a-c with the diphosphines Ph2P(CH2)(n)PPh2 dppm (n = 1), dppe (n = 2). dppp (n = 3), dppb (n = 4) or Ph2PCH=CHPPh2 trans-dppe, in a 1:2 molar ratio gave the dinuclear phosphine-bridged complexes [(Pd{XC6H3C(Me)=NN=C(S)NHR})2(mu Ph2P(CH2)(n)Ph-2)] 2a-c, 3a-c, 4a-c, 5a-c (n = 1-4) and l(Pd(XC6H3C(Me)=NN=C(S)NHR))(2)(mu-Ph2PCH=CH-PPh2)] 6a-c. Treatment of 1a-c with PPh2CH2PPh2, dppm, in a 1:4 molar ratio gave the mononuclear cyclometallated complexes [Pd{XC6H3C(Me)=NN=C(S)NHR)-(Ph2PCH2PPh2-P)] 7a-c; however, the diphosphines with n >= 2 failed to give the analogous reaction. The molecular structures of 1a, 1b and 3c have been determined by X-ray diffraction analysis and the intra-and intermolecular interactions are discussed. (C) 2011 Elsevier Ltd. All rights reserved.