Biomedical subjects
François P. Gabbaï
Publications and source records attributed to François P. Gabbaï.
alpha,alpha'-m-Xylenediylbis(indium dichloride). A Novel Bifunctional Lewis Acid.
Reaction of the di-Grignard compound 1,3-(ClMgCH(2))(2)C(6)H(4) with HgCl(2) yields 1,3-(ClHgCH(2))(2)C(6)H(4) (1), which crystallizes in the orthorhombic space group P2(1)2(1)2(1) with a = 8.494(1), b = 10.859(1), and c = 10.906(1) Å, V = 1005.9(2) Å(3), and Z = 4 (R values: R1 = 0.0354, wR2 = 0.0942). Treatment of 1 with InCl results in a transmetalation reaction and affords the tetrakis(tetrahydrofuran) adduct of 1,3-(Cl(2)InCH(2))(2)C(6)H(4) (2), which crystallizes in the monoclinic space group I2/a with a = 15.230(1), b = 13.125(1), and c = 15.299(1) Å, beta = 92.14(1) degrees, V = 3056.0(4) Å(3), and Z = 4 (R values: R1 = 0.0411, wR2 = 0.1003). As indicated by (199)Hg NMR spectroscopy, compound 1 does not form any stable anionic complexes in the presence of chlorides. In contrast, compound 2 readily complexes chloride anions. According to a VT (1)H NMR investigation, the species present in an equimolar mixture of 2 and Ph(4)PCl is the monoanionic complex [1-(Cl(3)InCH(2))-3-((THF)(2)Cl(2)InCH(2))C(6)H(4)](-) (3), whose structure is fluxional at room temperature. From this mixture, the salt [1,3-(Cl(3)InCH(2))(2)C(6)H(4)](2-)[Ph(4)P(+)](2) (4) can been isolated by precipitation. Compound 4 crystallizes in the orthorhombic space group P2(1)2(1)2(1) with a = 14.632(1), b = 17.080(1), and c = 21.384(1) Å, V = 5344.2(5) Å(3), and Z = 4 (R values: R1 = 0.0346, wR2 = 0.0649).
Unusual Ring Systems Containing Indium. Synthesis and Structure of the First Mercuraindacycles.
The mercuraindacycles bis(&mgr;-1,8-naphthalenediyl)mercury(II)(bis(tetrahydrofuran)chloroindium(III)) (5) and bis(&mgr;-1,8-naphthalenediyl)mercury(II)(bis(tetrahydrofuran)bromoindium(III)) (7) are the products of the reaction of indium(I) halides with 1,8-naphthalenediylbis(mercury(II) halides). Their formation involves a partial transmetalation followed by a spontaneous ring closure. Compounds 5 and 7 have been characterized by (1)H, (13)C, and (199)Hg NMR spectroscopy. The X-ray crystal structures of 5.(InCl(3)(THF)(3)) and 7 have been determined. Compound 5 crystallizes as an InCl(3)(THF)(3) adduct in the monoclinic space group P2(1)/c with a = 17.529(2) Å, b = 8.954(1) Å, c = 27.704(1) Å, beta = 107.02(1) degrees, V = 4157.8(7) Å(3), and Z = 4. Compound 7 crystallizes in the orthorhombic space group P2(1)2(1)2(1) with a = 8.368(1) Å, b = 15.357(1) Å, c = 19.446(1) Å, V = 2499.0(4) Å(3), and Z = 4. In both structures, the eight-membered dimetallacycles adopt a twisted conformation with conspicuously short In. Hg transannular distances. Finally, the X-ray crystal structure of the diindacycle bis(&mgr;-1,8-naphthalenediyl)bis(bis(tetrahydrofuran)chloroindium(III)) (8) is reported. This compound is isolated as a low-yield side product in the synthesis of 5. Compound 8 crystallizes in the tetragonal space group P4/n with a = 19.492(1) Å, c = 10.432 Å, V = 3963.5(5) Å(3), and Z = 4.
A Novel Anionic Gold-Indium Cluster Compound: Synthesis and Molecular and Electronic Structure.
The insertion of InBr into the Au-Br bond of [(Ph(3)P)AuBr] in tetrahydrofuran (thf) in the presence of [(CH(2)PPh(2))(2)] (dppe) leads to the formation of an orange complex [(dppe)(2)Au](+)[(dppe)(2)Au(3)In(3)Br(7)(thf)](-), 2. Analytical, spectroscopic, and X-ray structural investigations showed that this product is an anionic analogue of a neutral chloride complex [(dppe)(2)Au(3)In(3)Cl(6)(thf)(3)], 1, prepared recently. Both complexes have an Au(3)In(3) cluster core of approximate C(2)(v)() symmetry with one extremely short Au-Au bond [Au1-Au3 2.575(1) Å] as part of a quasi-linear array P1-Au1-Au3-P4, suggesting the presence of a bis(phosphine) complex of the neutral Au(2) molecule as part of the cluster. The third gold atom (Au2) is then assigned oxidation state +1. To gain deeper insight into the structure and bonding of this novel class of gold cluster compounds, regarding mainly the peculiar cluster geometry, the charge distribution, and the oxidation states, a series of scalar relativistic all-electron density functional (DF) calculations on model systems has been performed. As a model for 1, the neutral cluster {Au(3)(PH(3))(4)[InCl(2)(H(2)O)](3)} was studied. For the examination of the geometry of complexes 1 and 2, the cluster Au(3)(PH(3))(4)I(3) has been considered as a further simplified model, where iodine replaces the InX(2)(thf) units. Experimental and calculated cluster geometries agree satisfactorily, and the formal oxidation states of the gold atoms (0 for Au1 and Au3, +1 for Au2) could be confirmed, but for the In centers no interpretable differences of the Mulliken charges were found.