Hexa-amines

Dimethyl-diaminobutane, cobalt(lU) hexa-amines, 35 130-131, 155-156 Dimethyldiazidosilane, preparation, 9 138 Dimethyldivinylsilane, molybdenum complex of, 4 83... 

Table 2.2. Experimentally determined and calculated1 Co-N bond distances of some cobalt(III) hexa-amines.<,)...

A general approach for predicting Jahn-Teller distortions of copper(II) hexa-amines has recently been published, and it has the potential to be applied to donor atoms other than nitrogen, metal centers other than copper(II), and various types of coordination polyhedra11641. The method is based on a harmonic first-order model11651 where the Jahn-Teller stabilization energy is the result of the Qg distortion mode (Fig. 11.1, Eqs. 11.3, 11.4). 

The most typical hexa-amine ligands are also compounds, 178 180 [285e] ... 

To test specifically the role of the DNA 7r-way, we monitored the quenching of [Ru(phen)2(dppz)]2+ in DNA by hexa(amine)ruthenium (III). [Ru(NH3)6]3+ is an effective oxidative quencher of the luminescence of ruthenium(II) polypyridyl complexes (62) and binds to DNA by electrostatic and hydrogen bonding interactions (63). The resulting Stern-... 

A series of hexa-amines (27) has been reported for which the ionization behavior has been determined, together with the microscopic or intrinsic protonation constants for the different chemical environment and ionic strengths.37 A study carried out on copper(II) complexes of hexa-amines (27) has revealed how a preference for bimetallic, bis-tridentate coordination of the hexa-amine ligands in this series may be promoted either by extension of the bridging polymethylene chain (disfavoring chelation), or by A-methylation of the terminal amine groups (steric effects).38... 

Diformylpyridine and 2,6-diacetylpyridine undergo template condensations with hexa-amines (143) to form dinuclear diimine cations (144), which reduce to the bis(2,5-pyridiyl)tetra-amines (145) (Scheme 34). 

This approach has been applied in an MM study of the effect of ligand structure on the one-electron reduction of ten hexa-amine Co(III) complexes. A plot of AU versus reduction potential revealed the expected trend, although the correlation was poor (r = 0.781). The poor correlation can be attributed in large part to the differences in the electronic contribution from ammonia to primary and secondary amine moieties. An excellent correlation (r = 0.999) is obtained, however, if the data is restricted to a subset of ligands bearing constant donor atom types, e.g., primary amines. 

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