Electrophilic behaviour of nitrosyls: the Boedeker reaction, the reactions of sulphite with nitrosyls, and the crystal and molecular structure of cis-bis(2,2′-bipyridine)chloro(nitrosylsulphito)ruthenium

Abstract

Similar adducts to that, [Fe(CN)₅{(NO)(SO₃)}]^4–, formed in the Boedeker reaction have been obtained by the reaction of SO₃^2– with trans-[RuCl(py)₄(NO)]²⁺(py = pyridine) or cis-[RuX(bipy)₂(NO)]²⁺(X = Cl or Br, bipy = 2,2′-bipyridine). These adducts, [RuCl(py)₄{N(O)SO₃}] and cis-[RuX(bipy)₂{N(O)SO₃}], are shown, principally by i.r. spectroscopy, to contain identical [N(O)SO₃]^– ligands to [Fe(CN)₅{N(O)SO₃}]^4–. The structure of cis-[RuCl(bipy)₂{N(O)SO₃}] has been determined by X-ray diffraction. It is best regarded as a ruthenium(II) complex containing the hitherto unknown ligand [ONSO₃]^– which is N-co-ordinated to Ru^II. The ligand has a long (1.82 Å) and weak (force constant 137 N m^–1) N–S bond. The reversibility of the adduct formation is demonstrated. Crystal data for cis-[RuCl(bipy)₂{N(O)SO₃}]: orthorhombic, space group Pbca, a= 14.48(2), b= 19.49(2), c= 14.49(1)Å, final R= 0.063 for 290 variables and 1 370 observed reflections. The ruthenium is in a distorted octahedral environment.