Natural coordinates

Two-coordinate (Silylamino)phosphines. Certain chloro(silylamino)phosphines bearing a trimethylsilyl-methyl group can be dehydrohalogenated to yield stable (methylene)phosphines. The very low field (6 309.9) shift confirms the two-coordinate nature of this compound while the low field (6 7.09) signal shows it to be the P=CH rather than the P=N isomer. Three modes of reactivity of this (methylene)phosphine have been observed addition to the P=C bond, oxidative... 

In Eqn. (54) the density matrices of the initial and final states of the intermolecular system are present. It should be taken into consideration that the equilibrium coordinates, natural frequencies, and directions of the principal axes may not coincide for the initial and final states consequently, the... 

This transformation is one of the most convenient syntheses of chelating polyfunctional ligands, studied extensively in organometallic chemistry. In this reaction, the practically non-coordinating nature of proton sponges (cf. equation 13) is effectively used. In the case of other bases, the process does not proceed (EtsN) or results in the formation of complex mixtures (f-BuOK). 

The Lewis base-free cationic lanthanide metallocene complexes of the type [Cp"2Ln]Y (Y = BPhF, CBnBr6H6, Cp" = CsH3(SiMe3)2-l,3) were synthesized by treatment of unsolvated Cp"2Ln(n) or [Cp"2LnI]2 with lequiv. of Ag(l)Y or with two molar equivalents of Ag(CB 11 Bq,I f.) in toluene at room temperature. The reactivity of these complexes with respect to the coordinating nature of the counter ions was investigated.315... 

In a very comprehensive study by Finn and co-workers the synthesis, properties and reactions of several titanium-substituted ylides are described. The complexes were prepared from titanium alkoxides and (Me2N)3P=CH2 (scheme 9). The structure of one of the complexes was determined crystallographically which showed it to exist as a chloride bridged dimer (53). The ylidic P-C distance and /pc coupling constant are charactersitic of a P-C single bond which, together with the six-coordinate nature of the Ti centres, verify the zwitterionic nature of the species in both the solid state and in solution. The titanium ylide... 

Of the actinides, plutonium is potentially a particularly dangerous biological hazard because of the chemical and biological similarities between Pu(IV) and Fe(III). With this similarity in mind, a series of tetracatechol ligands with both linear and cyclic tetramines as backbone were synthesized in accordance with the general scheme outlined above 24,118) (see Fig. 7a and b). The eight-coordinate nature of Pu(IV)... 

The rate depends on the coordinating nature of the solvent, the more coordinating, the slower (despite the opposite trend for the self-exchange of CdMej, which can be explained, assuming a four-centered intermediate, by the competition of solvent and exchanging group for the vacant orbitals of the metal. 

In developing an ab initio PES for a chemical reaction in terms of a single reaction path potential, we first located the stationary points on the PES, then followed the reaction path by the steepest descent or distinguished coordinate methods, then chose coordinates, natural collision coordinates or internals, and finally expressed the PES as a series expansion about the... 

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