Synthesis and characterization of cationic gold-rhodium phosphite cluster complexes. X-ray crystal and molecular structure of {Au4Rh(H)2[P(O-iso-C3H7)3]2(PPh3)4}PF6

Abstract

= 3) have been investigated. |Au4Rh(H)2[P(0-i-C3H7 )3]2(PPh3)4jPF6 (1) and |Au5Rh(H)[P(OCH3)3]2(PPh3)5|PF6 (2) were synthesized by the reaction of Au(PPh3)N03 and |Rh(H)[P(0-z-C3H7)3]2]2 or |Rh(H)[P(OCH3)3]2)3, respectively, with THF as solvent. |Au6Rh(H)[P-(OCH3)3]2(PPh3)6|(PF6)2 (3) was made by further reaction of Au(PPh3)N03 and 2 with CH2C12 as solvent. Compound 1 was characterized by single-crystal X-ray diffraction in the solid state [1, Pi (No. 2), a = 14.38 (1) Á, 6 = 14.50 (2) A, c = 26.81 (2) A, a = 101.98 (10)°, ß = 89.03 (7)°, y = 117.82 (10)°, T = -95 °C, Z = 2, R = 0.042 for 8,142 observations] and by 31P and NMR spectroscopy in solution. The molecular structure of complex 1 consists of an approximately trigonal-bipyramidal (TBP) RhAu4 core with a Rh[P(0-/-C3H7)3]2 unit occupying an equatorial position. The four AuPPh3 units occupy the axial positions and the two remaining equatorial positions. The major deviation from ideal TBP geometry is reflected in the shorter Au-Rh distances (average 2.685 (1) A) compared with the bonded Au-Au separations (average 2.904 (1) A). The hydride ligands were not directly observed by X-ray diffraction in 1; however, spectroscopic evidence, potential energy calculations, and the solid-state structural results (average distances: axial Au-Rh = 2.717 (1) A; equatorial Au-Rh = 2.654 (1) A) indicate the presence of one hydride bridging each of the longer Au-Rh bonds. Compounds 2 and 3 were characterized by IR and *H and 31P NMR spectroscopies. Compounds 2 and 3 were each determined to possess one bridging hydride ligand.

Control of the Bridgehead Donor Atom in the Tripodal Ligand over Oxidative Addition of Au(PPh3)+ to [X(CH2CH2PPh2)3RhH] (X = N, P). X-ray Diffraction and Multinuclear (103Rh, 31P, 1H) NMR Studies

“…[21][22][23] In some cases, the µ-hydride ligands have unambiguously been localized by X-ray methods;24-27 in most instances, however, the bonding mode of the µ-hydride has been established only from indirect structural data, NMR spectroscopy, or potential energy calculations. [21][22][23][28][29][30][31][32][33][34] In the present case, the presence of a bridging hydride ligand is confirmed, beyond any reasonable c bpy = bypyridine. d The hydride ligand was not located by X-ray methods.…”

H+/AuPPh3+Exchange for the Hydride Complexes CpMoH(CO)2(L) (L = PMe3, PPh3, CO). Formation and Structure of [Cp(CO)2(PMe3)Mo(AuPPh3)2]+[BF4]-

“…In this case, stable complexes of type II have been isolated and characterized in numerous occasions. [11][12][13][14][15][16][17][18][19][20][21][22][23][24] Whenever these adducts are not stable, the † Current address: Laboratoire de Synthe `se et d'Electrosynthe `se Organometallique, Faculte ´des Sciences "Gabriel", 6 Boulevard Gabriel, 21100 Dijon, France.…”

“…Cu + , Tl + , Ag + , AuL + ) have received some attention, especially the gold-based cation AuPPh 3 + . In this case, stable complexes of type II have been isolated and characterized in numerous occasions. − Whenever these adducts are not stable, the typical pattern is deprotonation (path e ) resulting in the overall replacement of an H + with the isolobal AuPPh 3 + unit.

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