CYLOMETALLATED SEMICARBAZONE COMPLEXES OF PALLADIUM(II) - CRYSTAL ANDMOLECULAR-STRUCTURE OF =NN(H)C(=O)NH2])(2)(MU-PH2P(CH2)(3)PPH2)][CLO4](2)

Treatment of the semicarbazones 4-MeC6H4C(Me)=NN(H)C(=O)NH2 a, 3,4-Me2 C6H3C(Me)=NN(H)C(=O)NH2 b and C6H5C(Et)=NN(H)C(=O)NH2 c, gave the [C,N ,O] cyclometallated compounds [Pd{4-MeC6H3C(Me)=NN(H)C(=O)NH2}(Cl)] 1a , [Pd{3,4-Me2C6H2C(Me)=NN(H)C(=O)NH2}(Cl)] 1b and [Pd{C6H4C(Et)=NN(H)C (=O)NH2}(Cl)] 1c, after C-H activation. Treatment of compounds 1a, 1b, and 1c with silver perchlorate followed by treatment with tertiary di phosphine ligands gave the dinuclear [C,N,O] cyclometallated compounds d[4-MeC6H3C(Me)=NN(H)C(=O)NH2]}(2)(mu-L)][ClO4](2) 2a-7a, ,4-Me2C6H2C (Me)=NN(H)C(=O)NH2]}(2)(mu-L)][ClO4](2) 2b-7b, [{Pd[C6H4C(Et)=NN(H)C(= O)NH2]}(2)(mu-L)][ClO4](2) 2c-7c, [L = Ph2P(CH2)(4)PPh2 (dppb), Ph2P(C H2)(3)PPh2 (dppp), Ph2P(CH2)(2)PPh2 (dppe), trans-Ph2PCH=CHPPh2 (trans -dppe), Ph2PC(=CH2)PPh2 (vdpp) and Ph2PCH2PPh2 (dppm)] as 1:2 electrol ytes. Reaction of 1a and 1c with diphosphines gave the dinuclear [C,N] cyclometallated compounds [{Pd[4-MeC6H3C(Me)=NN(H)C(=O)NH2](Cl)}(2)(m u-L)] 8a, 9a, [{Pd[C6H4C(Et)=NN-(H)C(=O)NH2](Cl)}(2)(mu-L)] 8c, 9c, [L = Ph2P(CH2)(3)PPh2 (dppp) and Ph2P(CH2)(4)PPh2 (dppb)]. The complexes were characterised by their elemental analysis (C,H,N) and by IR and P-31{H-1} and H-1-NMR data, and =NN(H)C(=O)NH2]}(2)(mu-Ph2P(CH2)(3)PPh 2)][ClO4](2) (3c) was characterised crystallographically. (C) 1998 Els evier Science S.A. All rights reserved.