Department of Chemistry

Publications [#233410] of Andrew T. McPhail

Journal Articles

1. Crumbliss, AL; Topping, RJ; Szewczyk, J; McPhail, AT; Quin, LD, "The synthesis, x-ray crystal structure, and solution characterization of a bis(diphosphine)-bridged dirhodium(I) complex containing a Rh2P4 six-membered ring", Journal of the Chemical Society Dalton TransactionsJanuary,, 1986(9), 1895-1899, Royal Society of Chemistry (RSC) [doi].
   (last updated on 2026/01/21)

   Abstract:
   The preparation of [{Rh(cod)}2(μ-L¹)2][BF4] 2 (1) from (CH2CMe=CH2P)2 (L¹) and [Rh(cod)2]-BF4 (cod = cyclo-octa-1,5-diene) is described. The compound crystallizes in the monoclinic space group P21/c (C⁵2h), with a = 9.650(1), b = 11.609(1), c = 21.884(3) Å, β = 117.07(1)°, and Z = 2. The structure was refined to R = 0.033 for 3 434 reflections. The solid-state structure shows two diphosphine ligands L¹ bridging two rhodium(I) atoms to form a six-membered Rh2P4 ring in a chair conformation. Solution studies (¹H and ¹³C-{¹H} variable-temperature n.m.r. spectra) exhibit characteristics of a ring inversion equilibrium with ΔG271 = 14.0(0.2) kcal mol^-1. Computer simulation of the ³¹P-{¹H} n.m.r. spectrum is used to analyse the internuclear couplings of the AA′A″A‴XX′ pattern (A = ³¹P, X = ¹⁰³Rh). The bridging diphosphine ligands exhibit a deshielding effect on the trans olefinic carbon atoms of cod in (1) which is in the range normally found for phosphine ligands.