Synthesis of a polymetallic Pt, Sn complex containing square planar and trigonal bipyramidal platinum centres. Crystal and molecular structure of bis{chlorotriethylphosphinoplatinum (II)}mu-2,3,5,6-tetrakis(alpha-pyridyl)pyrazinetetrakis(trichlorostannyl) triethylphosphinoplatinate(II)

Reaction between 2,3,5,6-tetrakis(alpha-pyridyl) pyrazine (TPP) and the dim er [Pt-2(PEt3)(2)Cl-4] yielded an ionic complex of formula [{Pt(PEt3)Cl}(2) mu-(TPP)] [Pt(PEt3)Cl-3](2) (1), in which TPP behaves as a bis(bidentate) l igand between the two Pt atoms of the cation. Insertion of SnCl2 into the P t-Cl bonds of this compound led to an unusual rearranged product, [{Pt(PEt3 )Cl}(2)mu-(TPP)] [Pt(SnCl3)(4)(PEt3)] (2), with a rare example of a pentaco ordinate Pt(lI) species in the anionic moiety, where Pt is at the centre of a trigonal bipyramid, in addition to two other square planar Pt atoms in t he cationic moiety. (C) 2000 Elsevier Science Ltd All rights reserved.