Synthesis, spectroscopic characterization and crystal and molecular structure of μ-(dimethylstannado)-μ-(hydrido) dodecacarbonyltrirhenium

Abstract

Abstract The title compound, Re3(μ-H)(μSnMe2)(CO)12 (I) prepared by treatment of [(C6H5)As]2[Re3(μ-H)(CO)12] · 1 2 C4H8O (II) with (CH3)2SnCl2 or (CH3)3- SnCl, has been characterized by IR, Raman, 1H NMR and mass spectra. An absorption due to bridging hydrogen in I has been identified in the Raman at 1680 (Δv 1 2 ≈ 110) cm-1; this is replaced by an absorption at 1185 (Δv 1 2 ≈50) cm-1 in the deuterated derivative Re3(μ-D)(μ-SnMe2)(CO)12 (I-d1) The crystal and molecular structure of I has been determined by a three-dimensional X-ray diffraction study. The compound crystallizes in the form of yellow-orange platelets in the centrosymmetric space group P21/c (C52h, No. 14) with a 16.929(5) A, b 16.968(9) A, c 16.699(4) A, β  114.80(2)°; Z8, θ pcalc 3.187 and Ppobs 3.19(1) g cm-3. Diffraction data to 2ϱmax  45° (Mo-Kα radiation) were collected on a Picker FACS-1 diffractometer equipped with a graphite monochromator. The structure has been solved using direct methods, Fourier, and full-matrix least-squares refinement techniques. The final discrepancy index is Rf0.066 for 4366 independent observed reflections.The asymmetric unit contains two similar crystallographically independent molecules, and, in each, the three rhenium atoms define an approximately equilateral triangle with the tin atom asymmetrically bridging one edge and essentially coplanar with the Re3 triangle; SnRe(2) 2.87 A and SnRe(3) 2.68 A. The Me2Sn-bridged ReRe distance is 3.15 A. Each rhenium atom is associated with four terminal carbonyl ligands, of which two can be considered axial and two equatorial. Indirect evidence implies that the hydrido—hydrogen atom bridges the longest ReRe edge (3.23 A). The remaining ReRe distance is 3.01 A