PHOSPHOLE COMPLEXES OF GOLD(I) HALIDES - COMPARISON OF SOLUTION AND SOLID-STATE STRUCTURES BY A COMBINATION OF SOLUTION AND CP MAS P-31 NMR-SPECTROSCOPY AND X-RAY CRYSTALLOGRAPHY

A series of complexes of 1-phenyldibenzophosphole (DBP), l-phenyl-3,4-dimethylphosphole (DMPP), and triphenylphosphine of the type LnAuX (n = 1, L = DBP, DMPP, Ph3P, X = Cl, Br, I; n = 3, L = DBP, X = Cl, Br, I; n = 3, L = Ph3P, X = Cl; n = 4, L = DBP, DMPP, X = PF6) have been prepared and characterized. The structures of (DBP)AuCl (1), (DBP)3AuCl (2), and (DMPP)AuCl (3) have been determined from three-dimensional X-ray data collected by counter methods. Compound 1 crystallized in space group Pl with a = 10.257 (1) υ,b = 10.992 (2) A, c = 17.131 (3) υ, β = 83.04 (1)°, β = 81.62 (1)°, γ = 66.96 (1)°, and Z = 4. Compound 2 crystallized in space group Pl with a = 11.152 (2) υ, b = 10.729 (2) υ, c = 19.168 (5) υ, α = 84.92 (2)°, β = 87.22 (2)°, γ = 76.08 (2)°, and Z = 2. Compound 3 crystallized in space group C2/c with a = 10.281 (2) υ, b = 14.812 (4) υ, c = 16.867 (4) υ, α = 89.96 (2)°, β = 91.71 (2)°, γ = 90.00 (2)°, and Z = 8. The three structures were refined by least-squares methods with RF= 0.0286 for 1, RF= 0.0364 for 2, and RF= 0.0265 for 3 for 4715, 6086, and 1787 unique reflections with I/σ(I) ≥ 3.0 for 1–3 respectively. A moderately strong relativistic interaction occurs between the two independent molecules of 1 with an Au-Au distance of 3.116 (2) υ. One of these molecules is nearly linearly coordinated (<PAuCl = 178.8 (1)°) while the other is slightly bent (<PAuCl = 172.4 (1)°). The CP/MAS 3IP{1H} NMR spectrum of this complex shows two resonances in a 1:1 intensity ratio. Complex 3 is nearly linear in the solid state (<PAuCl = 176.1 (1)°), and its CP/MAS 3lP{1H) NMR spectrum shows three resonances in a 1:1:1 intensity ratio for reasons that are not yet understood. Complex 2 is a distorted tetrahedral molecule that exhibits an attractive interaction between two adjacent dibenzophosphole planes. Though the three phospholes are crystallographically inequivalent (d(AuP) = 2.359 (1), 2.382 (1), and 2.374 (2) υ) the molecule has effective Cssymmetry as evidenced by the observation of two 31P resonances in a 2:1 intensity ratio in its CP/MAS 31P{1H) NMR spectrum. Variable-temperature 31P{1H} NMR spectra obtained on solutions of LAuCl + L in various ratios were analyzed to determine the nature of the species present in solution and to gain information regarding their relative stabilities as a function of the nature of the phosphine. © 1990, American Chemical Society. All rights reserved.