Structures of Some Complexes Containing the Re^IVCl₄ Unit

Abstract

The X-ray crystal structure determinations of five complexes of rhenium(IV) containing the ReCl₄L₂ unit, with L monodentate , are reported, one at 92 K. They are: (1) cis -( HNCMeNHPh )₂ReCl₄, Pccn , a 21.677(4), b 7.253(1), c 12.470(2) Ǻ, R₁(2σ) 0.0217, R_w 0.0473; (2) the di ( acetonitrile ) solvate of (1), Pī , a 10.005(2), b 12.120(2), c 12.744(2) Ǻ, α 72.19(1), β 67.65(1), γ 90.95(1)°, R₁(2σ) 0.0311, R_w 0.0819; (3) cis -(HN= CMeNH (p-C₆H₄Me))2ReCl₄, Pna2₁, a 12.782(2), b 8.237(1), c 21.279(3) Ǻ, R₁(2σ) 0.0497, R_w 0.1066; (4) cis-( thf )₂ReCl₄, P 2₁2₁2₁, a 7.785(2), b 12.666(4), c 14.253(5) Ǻ, R₁(2σ), 0.0326, R_w 0.0827; and (5) trans-(Me₂PhP)₂ReCl₄, P 2₁/c, a 9.701(2), b 13.739(6), c 8.324(2) Ǻ, β 106.83(2), R₁(2σ) 0.0241, R_w 0.0613. The Re-Cl bond lengths in these and six other Re^IVCl₄L₂ octahedral complexes are compared, and no distinct trans-effect of the donor atom on the chlorine atoms is seen either where L is monodentate as in our compounds or where L₂ is a chelate ligand, as in the examples from the literature, although the results are much less clear there.