Direct photolytic route to trans-Cr(CO) 4(AsPh 3) 2 and crystal structures of cis-Mo(CO) 4(AsPh 3) 2 and cis-W(CO) 4(AsPh 3) 2

Abstract

The preparation of trans-Cr(CO) 4(AsPh 3) 2 is accomplished in reasonable yield by the direct photolysis of a solution of Cr(CO) 6 and an excess of AsPh 3 in heptane. The structures of cis-Mo(CO) 4(AsPh 3) 2 and cis-W(CO) 4(AsPh 3) 2 are reported. These are found to be isostructural and consist of distorted octahedral geometries with AsMAs angles of 102.56(2) and 102.62(2)° for M=Mo and W, respectively. The MoAs distances of 2.6428(9) and 2.6489(9) Å are significantly longer than those in the W analogue at 2.6384(6) and 2.6361(6) Å. On the basis of a comparison to literature data, the AsPh 3 ligands in these molecules can be described as extremely compressed.