2-(2-{Diphenylarsino}ethyl)-1,3-dioxane (L1) and 2-(diphenylarsinomethyl)tetrahydrofuran (L2) and their palladium(II), platinum(II) and mercury(II) complexes: synthesis and crystal structures of [PdBr2(L1)2] and [HgBr2(L2)

Abstract

Abstract Novel and potentially hemilabile ligands of (As, O) type, 2-(2-{diphenylarsino}ethyl)-1,3-dioxane ( L 1 ) and 2-(diphenylarsinomethyl)tetrahydrofuran ( L 2 ), are synthesised by reacting Ph 2 AsLi generated in situ under a nitrogen atmosphere with an appropriate organic halide. The complexes of L 1 and L 2 with Pd(II), Pt(II) and Hg(II) having composition [M( L 1 / L 2 ) 2 X 2 ] (M=Pd or Pt; X=Cl or Br) or [M( L 1 )Br 2 ] 2 (M=Hg) have been synthesised and characterised by elemental analyses, IR, 1 H- and 13 C{ 1 H}-NMR spectra and molecular weight and conductivity measurements. The crystal structures of [PdBr 2 ( L 1 ) 2 ] and [HgBr 2 ( L 2 )] 2 are solved. The potentially bidentate ligands L 1 and L 2 coordinate with Pd/ Hg through As only. The CH 2 O signals observed in 1 H- and 13 C{ 1 H}-NMR spectra of the present complexes do not show any shift with respect to those of L 1 and L 2 . The PdAs and HgAs bond lengths are 2.414(1) and 2.504(3) A, respectively The Hg complex has bromo-bridges (2.792(3)–2.884(4) A) that are asymmetric. The geometry of Hg is a distorted tetrahedral and that of Pd square planar. The As has tetrahedral geometry as three C atoms and Hg or Pd surround it. The [HgBr 2 ( L 2 )] 2 is the first example of a mercury(II)–arsine complex containing Hg(μ-Br) 2 Hg unit.