Methane coordination

Estimates of the rotational diffusivity may be made from MD calculations by fitting an exponential function to Legendre polynomials that express the decorrelation of a unit vector that is fixed in the methane coordinate frame (11). The rotational diffusivity was found to increase with concentration (as a result of sorbate-sorbate collisions which act to decorrelate the molecular orientation). The values are of the same order as those for liquid methane and are 2 orders of magnitude larger than those found by Jobic et al. (73) from a quasi-elastic neutron scattering study of methane in NaZSM-5. 

Bis(aryloxo) complexes, with mono-Cp Ti(IV), 4, 474 Bis(aiyloxo) titanacyclopent-2-ene, synthesis, 4, 358 Bis(A7-azain do Mi methane-coordinated complexes, with platinum(II), 8, 475... 

The one-dimensional coordination polymer 158 with hexacoordinated tin atoms resulted from the reaction of diphenyltin dibromide with bis(l,2,4-triazol-l-yl)methane347. The bis(triazol-l-yl)methane coordinates to the tin atom in a bidentate bridging fashion through the nitrogen atoms at the 4-position of the triazole rings with intermolecular Sn—N distances of 2.454(7) A. 

Figure 2. Synthesis of bis(8-hydroxy-5-quinolyl)methane coordination polymers...

The bimetallic species bis(dichloromethylstannyl)methane coordinates one equivalent of bipy to form the asymmetric (45) with both four- and six-coordinate tin centers (Scheme 15). Bis(chloro-dimethylstannyl)methane has been used to explore the bridging capability of pyrazine ligands (Scheme 16). ... 

Parkin and Bercaw reported that Cp 2W(Me)(H) eliminates methane to form Cp (ri5,ri1-C5Me4CH2)WH.26 For the mixed isotopomer, Cp 2W(CH3)(D), H/D scrambling to give Cp 2W(CH2D)(H) is competitive with the methane elimination process (Scheme 11.7). Although the authors point out that the H/D exchange process could occur by pathways other than formation of a methane-coordinated intermediate, the observation of an inverse kinetic isotope effect (KIE) for the methane reductive elimination (see bottom of Scheme 11.7) provides additional support for the reversible formation of coordinated alkane (see below for a more detailed discussion of KIEs for reductive elimination of C—H bonds). Furthermore, at relatively low concentrations, heating a mixture of Cp 2W(CH3)(H) and Cp 2W(CD3)(D) produces only CH4 and CD4 with no observation of H/D crossover, which is consistent with intramolecular C—H(D) processes. Similar results have been obtained for... 

SCHEME 11.7 H/D exchange reactions of Cp 2W(H)(Me) and isotopomers are consistent with methane-coordinated intermediates. 

Bis(A7-azaindolyl)methane-coordinated complexes have been prepared and fully characterized, and addition of [H(OEt2)2] to the dimethylplatinum(ii) complex 200 forms the cationic methylplatinum complex with the ligand, whereas the reaction in benzene forms the cationic phcnylplatinum complex 201 via C-H bond activation of the solvent by the cation (Equation (52)). 

Figure 7. Calculated quasicomponent distribution function xcfKj vs. methane coordination number K for the dilute aqueous solution of methane...

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