UNSPECIFIED (1993) CRYSTAL-STRUCTURES, VIBRATIONAL AND P-31 NMR-STUDIES OF COMPLEXES OF TERTIARY PHOSPHINE-LIGANDS WITH MERCURY(II) HALIDES. Inorganica Chimica Acta, 210 (1). pp. 107-124. ISSN 0020-1693

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Abstract

The mercury(II) phosphine complexes (R3P)2HgX2 (R3P - PPh3, PEt3, 1-phenyldibenzophosphole (DBP), 1-phenyl-3,4-dimethylphosphole (DMPP); X = Cl, Br, I and PBu3; X = Cl) have been prepared and their solution and solid state structures determined by a combination of elemental analyses, IR, Raman and NMR spectroscopy. The structures of (DBP)2HgBr2 (1), (PPh3)2Hg2Br4 (2), (DMPP)2Hg2I4 (3) and (Bu3P)2Hg2I4 (4) have been determined from three-dimensional X-ray data collected by counter methods. Compound 1 crystallizes in space group P1BAR with a = 10.568(6), b = 17.390(6), c = 9.610(3) angstrom, alpha = 106.02(4), beta = 100.62(4), gamma = 101.41(5)-degrees and Z = 2. Compound 2 crystallizes in space group P2(1)/a with a = 18.619(7), b = 10.938(4), c = 18.762(5) angstrom, beta = 90.36(2)-degrees and Z = 4. Compound 3 crystallizes in space group Pbc2(1) with a = 8.516(4), b = 19.404(7), c = 19.545(6) angstrom and Z = 4. Compound 4 crystallizes in space group P2(1)/c with a = 16.450(16), b = 20.609(21), c = 24.263(31) angstrom, beta = 109.38(8)-degrees and Z = 8. Compound 1 deviates from ideal C2 symmetry having slightly different Hg-Br (2.618(2), 2.604(2) angstrom) and Hg-P (2.513(3), 2.490(3) angstrom) bond distances. The inequivalence of the phosphines is manifested as a second order ABX CP/MAS P-31{H-1} NMR spectrum for 1. Compound 2 is a symmetric doubly bromide bridged dimer with essentially equivalent Hg-P (2.40(2), 2.44(2) angstrom) bond distances but its Cp/MAS P-31{H-1} NMR spectrum displays two AX resonances, showing that the phosphines are not magnetically equivalent. Compound 3 is a symmetric, doubly iodide bridged dimer having slightly different Hg-P (2.437(7), 2.470(7) angstrom) bond distances and displays three AX resonances in its CP/MAS P-31{H-1} NMR spectrum. Compound 4 is an unsymmetrical doubly iodide bridged dimer [(Bu3P)2HgI2HgI2] having equivalent Hg-P (2.393(21), 2.391(22) A) bond lengths but its CP/MAS P-31{H-1} NMR spectrum shows two ABX resonances arising from the two different molecules in the unit cell with the phosphines being magnetically inequivalent in each molecule. Variable temperature P-31 NMR spectroscopy shows that equilibria between monomeric (R3P)2HgX2 and dimeric [R3PHgX2]2 occur in solution and for R3P = DMPP and BU3P the dimers are very easily formed from the monomers.

Item Type:	Journal Article
Subjects:	Q Science > QD Chemistry
Journal or Publication Title:	Inorganica Chimica Acta
Publisher:	ELSEVIER SCIENCE SA LAUSANNE
ISSN:	0020-1693
Date:	1 August 1993
Volume:	210
Number:	1
Number of Pages:	18
Page Range:	pp. 107-124
Publication Status:	Published
URI:	http://wrap.warwick.ac.uk/id/eprint/21123

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