| 16075115 |
Novio F, Mas-Balleste R, Gallardo I, Gonzalez-Duarte P, Lledos A, Vila N: Influence of the terminal ligands on the redox properties of the {Pt2 (mu-S) 2} core in [Pt2 (Ph2X (CH2) 2XPh2) 2 (mu-S) 2] (X = P or As) complexes and on their reactivity towards metal centres, protic acids and organic electrophiles. Dalton Trans. 2005 Aug 21;(16):2742-53. Epub 2005 Jul 11.
In order to explore possible ways for modulating the unusually rich chemistry shown by complexes of formula [L2Pt (mu-S) 2PtL2] we have studied the influence of the nature of the terminal ligand L on the chemical properties of the {Pt2 (mu-S) 2} core. The systematic study we now report allows comparison of the behaviour of [Pt2 (dpae) 2 (mu-S) 2](dpae = Ph2As (CH2) 2AsPh2) (1) with the already reported analogue [Pt2 (dppe) 2 (mu-S) 2](dppe = Ph2P (CH2) 2PPh2). Complex 1 as well as the corresponding multimetallic derivatives [Pt (dpae){Pt2 (dpae) 2 (mu-S) 2}](BPh4) 2 2, [M{Pt2 (dpae) 2 (mu-S) 2}2] X2 (M = Cu (II), X = BF4 3; M = Zn (II), X = BPh4 4; M = Cd (II), X = ClO4 5; M = Hg (II), X = Cl 6 or X2 = Cl (1.5)[HCl2](0.5) 6') have been characterized in the solid phase and in solution. Comparison of structural parameters of 1 and 3-6' with those of the corresponding phosphine analogues, together with the results of the electrochemical study for 1, allow us to conclude that replacement of dppe by dpae causes a decrease in basicity of the {Pt2 (mu-S) 2} core. The study of the reactivity of 1 towards CH2Cl2 and protic acids has led to the structural characterization of [Pt (dpae)(S2CH2)] 9 and [PtCl2 (dpae)] 10. Moreover, comparison with the reactivity of [Pt2 (dppe) 2 (mu-S) 2] indicates that the stability of the intermediate species as well as the nature of the final products in both multistep reactions are sensitive to the nature of the terminal ligand. |
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