73690-54-7Relevant academic research and scientific papers
Kinetic and thermodynamic studies of the reactivity of (trimethylsilyl) diazomethane with HMo(CO)3(C5R5) (R = H, Me). Estimation of the Mo-N2CH2SiMe3 bond strength and experimental determination of the enthalpy of formation of (trimethylsilyl)diazomethane
Fortman, George C.,Isrow, Derek,McDonough, James E.,Von Rague Schleyer, Paul,Schaefer III, Henry F.,Scott, Brian,Kubas, Gregory J.,Kegl, Tamas,Ungvary, Ferenc,Hoff, Carl D.
, p. 4873 - 4884 (2008)
The rates of reaction of N2CHSiMe3 with HMo(CO) 3Cp (Cp = η5-C5H5) in heptane obey the rate law -d[HMo(CO)3Cp]/dt = k[HMo(CO)3Cp][N 2CHSiMe3] (k = 0.035 ± 0.01 M-1 s -1 at 0 °C; Δ H?= 11.7 ± 2.0 kcal/mol and ΔS? = -22.0 ± 3.0 cal/(mol K)). Isotopic scrambling between DMo(CO)3Cp and N2CHSiMe 3 occurs at a rate faster than the overall reaction. Reversible 1,2-addition to form the tightly bound intermediate [Me3SiCH 2Nβ=Nαδ+]][ δ-M(CO)3Cp] is proposed as the first step of the reaction. Spectroscopic and computational data support this formulation. The contact ion pairs can undergo heterolytic cleavage to ions or homolytic cleavage to radicals, and the solvent influence on kobs (THF > toluene > heptane) is interpreted in terms of this model. The enthalpy of this reaction has been measured by solution calorimetry at 272 K in THF: ΔH = -11.6 ± 1.2 kcal/mol. These data, together with computed organic reaction energies allow estimation of the bond strength between the three-electron donors · N2CHSiMe3 and · Mo(CO) 2Cp to be 25 ± 5 kcal/mol stronger than the two-electron Mo-CO bond. Coordination of N2CHSiMe3 to the complexes M(PR3)2(CO)3 (M = Mo, W; R = Cy, iPr; Cy = cyclohexyl; iPr = isopropyl) alters the course of reaction with HMo(CO)3Cp. The stoichiometric reaction of Me3SiCH= N=NMo(PiPr3)2(CO)3 with 2 equiv of HMo(CO)3Cp produces SiMe4, Mo(N2)(P iPr3)2(CO)3, and [Mo(CO) 3Cp]2. In the presence of excess N2CHSiMe 3 this reaction is catalytic and has been used to experimentally measure the heat of hydrogenation of N2CHSiMe3 to N 2 and SiMe4 by 2 equiv of HMo(CO)3Cp. The derived enthalpy of formation of N2CHSiMe3 (5.8 ± 3.0 kcal/mol) is in reasonable agreement with high-level theoretical calculations. X-ray crystal structure data are reported for W(CO) 2(N2CH2SiMe3)Cp: triclinic, space group P1, a = 6.3928(7) A, b = 10.6551(12) A, c = 10.8766(12) A, α = 100.632(2)°, β= 96.254(2)°, V = 721.32 A3, Z = 2.
Reversible hydrogen adsorption at room temperature using a molybdenum-dihydrogen complex in the solid state
Iguchi, Hiroaki,Kishimoto, Naoki,Noro, Shin-Ichiro,Takaishi, Shinya,Uchida, Kaiji
supporting information, p. 12630 - 12634 (2021/09/28)
Reversible H2storage under mild conditions is one of the most important targets in the field of materials chemistry. Dihydrogen complexes are attractive materials for this target because they possess moderate adsorption enthalpy as well as adsorption without cleavage of the H-H bond. In spite of these advantages, H2adsorption studies of dihydrogen complexes in the solid state are scarce. We herein present H2adsorption properties of the 16-electron precursor complex ([Mo(PCy3)2(CO)3]) in the solid state synthesized by two procedures. One is the direct synthesis under an Ar atmosphere (1), and the other is removal of the N2-adduct under vacuum (2).2showed ideal Langmuir type reversible ad/desorption of H2above room temperature, whereas1showed irreversible adsorption. The adsorption enthalpy of2was larger than that in THF solution. Using DFT calculation, this difference was explained by the absence of the agostic interaction in the solid state.
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
