Chiral phosphine ligands derived from sugars .3. Syntheses, structures, and spectroscopic properties of gold(I) complexes with chiral phosphines from glucose. X-ray structures of [Au(2-MBPA)Cl] and [Au(3-MBPA)(2-pyS)]

A series of gold(I) complexes of the type [AuP'X] (F = 2-MBPA: X = Cl, 1; X = 2-pyS, 2; X = 2-bimS, 3. F = 3-MBPA: X = Cl, 4; X = 2-pyS, 5; X = 2-bimS, 6. 2-pySH = pyridine-2-thiol; 2-bimSH = 2-mercaptobenzimidazole) containing phosphine ligands (methyl 4,6-O-benzylidene-2-deoxy-2-(diphenylphosphino)-α-D-altropyranoside, 2-MBPA; methyl 4,6-O-benzylidene-3-deoxy-3-(diphenylphosphino)-α-D-altropyranoside, 3-MBPA) derived from glucose have been prepared and characterized by 1H, 13C, and 31P NMR and infrared spectra in which the assignments of the gold-ligand vibrations have been carried out. The structures of [Au(2-MBPA)Cl] (1) and Au(3-MBPA)(2-pyS)] (5) have been determined by X-ray crystallographic techniques. Compound 1 crystallizes in the monoclinic space group P21 with unit-cell dimensions a = 9.907(4) Å, b = 10.394(4) Å, c = 13.542(7) Å, β = 110.70(4)°, V = 1304(2) Å3, and Z = 2. Compound 5 crystallizes in orthorhombic space group P212121 with unit-cell dimensions a = 9.857(3) Å, b = 14.466(2) Å, c = 20.263(6) Å, V = 2889(1) Å3 and Z = 4. The structures were refined to final R = 5.6% and R = 4.1% for 1 and 5, respectively. Complex 5 features a nearly linear gold atom geometry defined by phosphorus and sulfur atoms with Au-P = 2.256(3) Å, Au-S = 2.303(4) Å and P-Au-S = 177.6(1)°, in which 2-pyS adopts a complete monodentate coordination mode involving only the S-donor atom ligated to the Au(I) ion, and complex 1 is also linear with larger deviation (P-Au-Cl angle = 174.5(3)°) with distances Au-P = 2.232(6) Å and Au-Cl = 2.275(7) Å.