Photochemical Synthesis of (η6-Arene)chromium Hydrido Stannyl and (η6-Arene)chromium Bis(stannyl) Complexes

Abstract

Photolysis of (eta(6)-arene)Cr(CO)(3) complexes and HSnPh(3) in aromatic solvents at room temperature has led to two classes of complexes: hydrido stannyl compounds containing the eta(2)-H-SnPh(3) ligand and bis(stannyl) compounds containing two SnPh(3) ligands. The ratio between the two complexes simultaneously produced depends on the choice of the arene. Complexes with different arenes (mesitylene, toluene, benzene, fluorobenzene, and difluorobenzene) have been obtained and characterized including X-ray structures for (eta(6)-C(6)H(3)(CH(3))(3))Cr(CO)(2)(H)(SnPh(3)) (1a), (eta(6)-C(6)H(3)(CH(3))(3))Cr(CO)(2)(SnPh(3))(2) (1b), (eta(6)-C(6)H(5)F)Cr(CO)(2)(SnPh(3))(2) (4b), and (eta(6)-C(6)H(4)F(2))Cr(CO)(2)(SnPh(3))(2) (5b). X-ray crystallography of the last three compounds has given the following results: 1b, monoclinic, space group P2(1)/c (No. 14), a = 13.905(4) Å, b = 18.499(2) Å, c = 17.708(2) Å, Z = 4, V = 4285(1) Å(3); 4b, orthorhombic, space group Pca2(1) (No. 29), a = 16.717(2) Å, b = 18.453(2) Å, c = 25.766(2) Å, Z = 8, V = 7948(2) Å(3); 5b, monoclinic, space group P2(1)/c (No. 14), a = 13.756(2) Å, b = 18.560(2) Å, c = 17.159(2) Å, Z = 4, V = 4372(2) Å(3). The relatively high J((119)Sn-Cr-H) and J((117)Sn-Cr-H) values as well as the X-ray structural data provide evidence for the existence of three-center two-electron bonds in the hydrido stannyl complexes. The (1)H NMR data of the complexes are compared with chromium-arene bond distances, and a sensible trend is observed and discussed.