A Cyclometallated (Azobenzene)palladium(II) Complex of 1,4,7‐Trithiacyclononane: Synthesis and Reactivity with Thioether‐Dithiolate Metalloligands, Single‐Crystal X‐ray Diffraction Analyses and Electrochemical Studies

Abstract

AbstractThe treatment of [{Pd(C6H4N=NC6H5)(μ‐Cl)}2] (5) with AgPF6/NH4PF6 in acetone, followed by the addition of two molar equivalents of 1,4,7‐trithiacyclononane (9S3), gives the deep red complex [Pd(C6H4N=NC6H5)(9S3)][PF6] (6A) in high yield, whereas the direct reaction of 5 with two molar equivalents of 9S3 gives [Pd(C6H4N=NC6H5)(9S3)][Pd(C6H4N=NC6H5)Cl2] (6B) in quantitative yield based on 5. The subsequent reaction of 5 and 6A with the metalloligand [(HMB)RuII{η3‐tpdt}] [3; HMB = η6‐C6Me6, tpdt = S(CH2CH2S–)2] results in displacement of the chloride and 9S3 ligands, respectively, to give the Ru‐Pd heterobimetallic complex [{(HMB)RuII(μ‐η2:η3‐tpdt)}{Pd(C6H4N=NC6H5)}][PF6] (7) in 85 % yield. Similar reactions with the Cp* analogue of 3, namely [(Cp*)RuIII{η3‐tpdt}] (4), give the trinuclear complex [{Cp*RuIII(μ‐η2:η3‐tpdt)}2Pd](PF6)2 (8), in which all the ligands on palladium have been displaced, in a yield of around 80 %. X‐ray diffraction analyses of 6A, 6B and its solvates (6B·H2O and 6B·CHCl3) have shown that short atom–atom interactions between the cation and the counterion and lattice solvent molecules have a significant effect on the bond parameters of the molecules, and 1H NMR spectroscopy indicates that these interactions persist even in solution. The single‐crystal X‐ray structure of 7 has also been determined. Cyclic voltammetry experiments have been performed on 6A, 6B and 7 in CH2Cl2 and CH3CN at GC and Pt electrodes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)