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Bridge length

Disilicic acid [(H0)3Si]20 has been the subject of numerous investigations (201,202). At the 6-31G level of theory with polarization functions on the bridging oxygen, the Si-O(bridging) length is 1.617 A and the Si-O-Si angle 141° (203). [Pg.192]

In order to determine the influence of the bridge length on the efficiency of the hole transfer between guanines, we studied double strands where the number of (A T)n base pairs between the guanines were varied (Fig. 9). In these experiments the GGG unit acts as a thermodynamic sink for the charge [17]. [Pg.46]

Lippard characterized the structural effect of variation in the alkyl bridge length in tropocoro-nand complexes of zinc (80). Six complexes of ligands with bridge lengths from n = m = 3 to n = m = 6 were structurally characterized.702 The complexes had distorted tetrahedral-square planar geometries, with the exception of the m = n = 3 adduct which was five-coordinate with an additional pyridine ligand. [Pg.1207]

In 1992, an important breakthrough appeared in the patent literature when Babin and Whiteker at Union Carbide reported the asymmetric hydroformylation of various alkenes with ees up to 90%, using bulky diphosphites derived from homochiral (2i ,4R)-pentane-2, 4-diol, UC-PP (1 19).359 360 van Leeuwen et al. studied these systems extensively. The influence of the bridge length, of the bulky substituents and the cooperativity of chiral centers on the performance of the catalyst has been reported.217 218 221 361-363... [Pg.172]

In order to gain more control over this reaction, chromium salphen dimers were synthesized. The synthetic route was developed in such a manner that the bridging length between the two salphen units can easily be varied and that the synthesis of heteronuclear metal complexes is possible. Since the ligand substitution pattern is highly important for the activity of the catalyst as well as the characteristics of produced polymer, an analogous monomeric Cr(lll) complex was synthesized for comparison [102] (Fig. 35). [Pg.79]

By assuming no change in the oxygen-oxygen distance during a vibration, we can treat the bridge length i 0 0 as a parameter in... [Pg.148]

It can be seen that the doublet separation increases and the height of the potential hill decreases rapidly with decreasing of the bridge length or v0H, With very short hydrogen bonds, the central potential hill between the two minima is almost perfectly flattened out. [Pg.150]


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See also in sourсe #XX -- [ Pg.216 ]




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