53495-46-8Relevant academic research and scientific papers
Chemistry of coordinated nitroxyl. Reagent-specific protonations of trans-Re(CO)2(NO)(PR3)2 (R = Ph, Cy) that give the neutral nitroxyl complexes cis,trans-ReCl(CO)2(NH=O)(PR3)2 or the cationic hydride complex [trans,trans-ReH(CO)2(NO)(PPh3)2 +][SO3CF3-]
Southern,Green,Hillhouse,Guzei,Rheingold
, p. 6039 - 6046 (2008/10/08)
The reactions of hydrochloric and triflic acids with the five-coordinate nitrosyl complexes trans-Re(CO)2(NO)(PR3)2 (2a, R = Ph; 2b, R = Cy) have been investigated. Reaction of anhydrous HCl with 2 results in a formal protonation of the nitrosyl ligand and addition of chloride to the metal, giving the neutral nitroxyl complex cis,trans-ReCl(CO)2(NH=O)(PR3)2 (3a, R= Ph; 3b, R = Cy). Reaction of Bronsted bases with 3a or 3b results in clean conversion of 3 to 2 when the base is appropriately strong (pKb ? 7). Addition of HOSO2CF3 to solutions of 2a results in protonation at the metal and formation of the cationic rhenium hydride [trans,trans-ReH(CO)2(NO)(PPh3)2 +][SO3CF3-] (4) in 74% yield; the deuteride [trans, trans-Re(2H)(CO)2(NO)(Pph3)2 +][SO3CF3-] (4-d) was analogously prepared from 2HOSO2CF3. 4 crystallized from CH2Cl2/Et2O solution in the orthorhombic space group Pnma, with a = 17.2201(2) A, b = 23.6119(3) A, c = 9.2380(2) A, and Z = 4. The least-squares refinement converged to R(F) = 0.039 and R(wF2) = 0.063 for the 4330 unique data with I > 2σ(I). The structure of 4 shows that the hydride (Re - H = 1.74 A) occupies the position trans to the linear nitrosyl ligand (Re - N - O = 178.1(4)°) in the pseudooctahedral complex cation. Complex 4 does not react with chloride to give 3a. DFT calculations carried out on free nitroxyl and its model complexes [Re(CO)5(NH=O)+] (5), [mer, trans-Re(CO)3(NH=O)(PH3)2+] (6), and cis,trans-ReCl(CO)2(NH=O)(PH3)2 (7) indicate that coordinated nitroxyl acts as both a σ-donor and π-acceptor ligand, consistent with the observed trend for ν(NO) in free HN=O (1563 cm-1), [mer,trans-Re(CO)3(NH=O)(PPh3)2+] (1, 1391 cm-1), 3a (1376 cm-1), and 3b (1335 cm-1).
New synthetic routes to some nitrosyl rhenium complexes. Crystal, molecular and electronic structure of [ReCl3(NO)(PPh3)2] and [ReCl2(CO)(NO)(PPh3)2] complexes
Bartczak,Czurak,Dziegielewski,MacHura,Jankowska,Kusz,Warczewski
, p. 2313 - 2320 (2008/10/09)
The reactions of the nitrosyl rhenium(II) complex [ReCl3(NO)(OPPh3)(PPh3)] with triphenylphosphine, NaBH4 in the presence of PPh3, and CO in the presence of PPh3 were examined. The rhenium
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.
