73690-56-9Relevant academic research and scientific papers
Dihydrogen: A better ligand than water? IR and X-ray evidence for aquo coordination in W(CO)3(PR3)2(H2O), thermodynamics of H2O versus η2-H2 binding, and H2O/D2 isotopic exchange. Implications on the biological activation of hydrogen
Kubas, Gregory J.,Burns, Carol J.,Khalsa, Guru Rattan K.,Van Der Sluys, Lori Stepan,Kiss, Gabor,Hoff, Carl D.
, p. 3390 - 3404 (2008/10/08)
Reactions of water with M(CO)3(PR3)2 and M(CO)3(PR3)2(η2-H2) (M = Mo, W; R = Cy (cyclohexyl), i-Pr) have been studied in various organic solvents. The products contained reversibly bound H2O, and infrared studies showed v(OH) modes at widely varying positions. IR of 18O-labeled complexes and 1H NMR gave no evidence for hydride or hydroxide ligands, indicating that oxidative addition of water did not occur. NMR of the aquo complexes showed rapid exchange between free and coordinated water at 298 K. The aquo complex W(CO)3(P-i-Pr3)2(H2O)·THF was isolated from THF and structurally characterized. A long W-O distance of 2.320 (5) A? was observed for the reversibly bound H2O ligand, which also undergoes hydrogen-bonding interactions with both lattice THF and a CO on an adjacent molecule. Water was found to instantaneously displace the dihydrogen ligand in W(CO)3(PR3)2(η2-H2) in THF solution to give aquo complexes, but in hexane H2 remained bound under a H2 atmosphere. Thermodynamic measurements of the equilibrium W(CO)3(PR3)2(H2) + H2O ? W(CO)3(PR3)2(H2O) + H2 in THF showed that the ΔH value for binding was 3-4 kcal/mol higher for H2O. However, a higher entropy change related to hydrogen-bonding interactions between H2O and solvent resulted in ΔG favoring H2 coordination at 25°C by 1-2 kcal/mol. Isotopic exchange of W(CO)3(P-i-Pr3)2(η2-D 2) with H2O under a D2 atmosphere took place in THF, giving W(CO)3(P-i-Pr3)2(D2O). Both the favored binding of H2 versus H2O and the latter exchange are relevant to the function of H2-activating enzymes such as hydrogenase. Crystal data for W(CO)3(P-i-Pr3)2)(H2O)·THF: space group P21/n, a = 13.554 (2) A?, b = 16.417 (5) A?, c = 15.059 (4) A?, β = 116.24 (2)°, Z = 4.
Reactivity of Some Transition-Metal Systems toward Liquid Carbon Dioxide
Mason, Michael G.,Ibers, James A.
, p. 5153 - 5157 (2007/10/02)
The reactivity of several transition-metal complexes toward liquid CO2 has been investigated as a means of screening such complexes for their ability to bind CO2.Although the known Ni(CO2)(PCy3)2 complex was prepared by the reaction of 2(μ-N2) with CO2(l), the compounds Pd(PCy3)2 and Pt(PCy3)2 do not react with CO2(l) to afford CO2 complexes.But the compound Pt(PCy3)2 does react with wet CO2 to afford PhH(O2COH)(PCy3)2, a bicarbonato complex.Similar reactivity was seen for W(CO)3(PCy3)2, which produces WH(O2COH)(CO)3(PCy3)2 in wet CO2(l).The compounds Na and 2(μ-N2) react with CO(l) to form complexes that contain carbonyl and carbonato ligands.Peroxocarbonato complexes, IrR(OCO3)(CO)(PPh3)2 (R = Me, Ph), were prepared from IrR(O2)(CO)(PPh3)2 with CO2(l).
Five-co-ordinate Molybdenum and Tungsten Complexes, , which Reversibly add Dinitrogen, Dihydrogen, and Other Small Molecules
Kubas, Gregory J.
, p. 61 - 62 (2007/10/02)
New complexes of molybdenum and tungsten with dinitrogen and other small molecules, trans- (L = N2, H2, C2H4, or SO2), have been synthesized by the reaction of with 2PCy3 in the presence of L; removal of L yield
