58694-74-9Relevant academic research and scientific papers
Classical and nonclassical nitrosyl hydride complexes of rhenium in various oxidation states
Gusev, Dimitri,Llamazares, Angela,Artus, Georg,Jacobsen, Heiko,Berke, Heinz
, p. 75 - 89 (1999)
The paramagnetic rhenium complex [NEt4]2[Re(Br)5(NO)] (1) has been used to prepare a series of novel mononitrosyl hydride and dihydrogen rhenium complexes: [Re(Br)2(NO)(η2-H2)(PR3) 2] (R = iPr, 2a; Cy, 2b) and [Re(H)(BH4)(NO)(PR3)2] (R = iPr, 3a; Cy, 3b). The coordinated BH3 of the derivatives 3 can be replaced by the H2 or the NO ligand, thus leading to the tetrahydride and dinitrosyl species [Re(H)4(NO)L2] (R = iPr, 4a; Cy, 4b) or [Re(H)(NO)2(PR3)2] (R = iPr, 5a; Cy, 5b). While [Re(H)4(NO)(PPh3)2] does not seem to be stable, [Re(H)(NO)2(PPh3)2] (5c) has been obtained in a fashion similar to the preparation of 3a,b from the reaction of [Re(H)(BH4)(NO)(PPh3)2] and NOBF4. Detailed investigations of the reactions of 3a,b with NOBF4 have revealed that the compounds initially formed are the isolable BF3 adducts [Re(H)(NO)(NOBF3)(PR3)2] (R = iPr, 6a; Cy, 6b). The source of BF3 is the nitrosonium salt. Dissociation of BF3 from 6a,b takes place in donor solvents such as THF, affording the BF3-free compounds 5a,b, whereas in noncoordinating solvents such as toluene, benzene, or CH2Cl2 only the species 6a,b are observable. Apparently due to an unfavorable position of the dissociation equilibrium, the existence of the complex [Re(H)(NO)(NOBF3)(PPh3)2] could only be made plausible from dynamic NMR spectroscopic observations. Attempts to isolate it failed even from nonpolar solvents. X-ray diffraction studies have been carried out on the complexes [Re(Br)2(NO)(η2-H2)(PiPr 3)2] (2a), [Re(H)(BH4)(NO)(PR3)2] (R = iPr, 3a; Ph, 3c), [Re(H)(NO)2(PiPr3)2] (5a), and [Re(H)(NO)(NOBF3)(PiPr3)2] (6a). The hydrogen atoms of the η2-H2 moiety of 2a could not be located in the X-ray diffraction study, but their most probable position in the molecule has been traced by an extensive search based on DFT calculations.
Nitrosyl complexes of rhenium. Synthesis of some fluoro complexes of rhenium(I), including the novel cationic complex fluorocarbonylnitrosyltris(triphenylphosphine)rhenium(I) tetrafluoroborate
Stanley Cameron,Grundy, Kevin R.,Robertson, Katherine N.
, p. 4149 - 4155 (2008/10/08)
The complex previously reported as ReCl2(NO)(PPh3)2 has been reformulated as a methoxide complex, ReCl2-(OCH3)(NO)(PPh3)2. ReCl2(OCH3)(NO)(PPh3)2 reacts with NaBH4 and PPh3 in ethanol to give much improved yields of ReH2(NO)(PPh3)3. ReH2(NO)(PPh3)3 reacts with HCl in ethanol suspension to form air-sensitive ReCl2(NO)(PPh3)3, which in turn reacts with CO or CNR (R = p-tolyl) to give ReCl2(CO)(NO)(PPh3)2 and ReCl2(CNR)2(NO)(PPh3), respectively. ReH2(NO)(PPh3)3 reacts with HBF4 (or HPF6) in the presence of CO to give the novel fluoro cation [ReF(CO)(NO)(PPh3)3]+, which reacts with certain coordinating anions to give neutral ReXF(CO)(NO)(PPh3)2 (X = H, OCH3, F). ReHF(CO)(NO)(PPh3)2 is unusual in that its stereochemistry can be determined absolutely by a combination of IR and 1H NMR spectroscopy. The structure has been determined of fluorocarbonylnitrosyltris(triphenylphosphine)rhenium(I) perchlorate, prepared from [ReF(CO)(NO)(PPh3)3]BF4 and NaClO4 in ethanol. Solvated crystals of [ReF(CO)(NO)(PPh3)3]ClO4 from dichloromethane-cyclohexane are monoclinic, with a = 14.981 (2) ?, b = 25.560 (3) ?, c = 15.133 (4) ?, β = 104.84°, space group P21/n, and Z = 4. Data were collected by four-circle diffractometry with 2092 reflections with I > σ(I) being observed. Refinement was by large-block least squares to R = 0.057. The unit cell contains molecules of crystallization disordered about a center of symmetry. There appears to be a random mixture of cyclohexane and dichloromethane, and atomic locations have not been assigned to the solvent atoms. The structure of the cation is that of a distorted octahedron with a meridional array of phosphine ligands and the fluoride ligand (r(ReF) = 1.973 (13) ?) trans to the linear nitrosyl group.
