Homonuclear chelates

Homonuclear Chelates of H4(PAA)2cn. In the above discussion, it was shown that the reaction of 1 1 molar ratios of Cu(II) and H4-(BAA)26n at elevated temperatures in MeOH yields Cu[H2(BAA)2en] with Cu(II) coordinated to four oxygens. Under diflFerent preparative conditions, however, other products are obtained see Reactions 4 and 5). 

The spectrum of NiCu(BAA)2en is similar to those of Zn and VO, but it is more complex in that P -Cu and related fragments are quite intense. The primary reason for recording the mass spectra was to support the conclusion that these compounds are pure heteronuclear chelates rather than mixtures of hetero- and homonuclear molecules. Since no... 

A mdimentary H-bond nomenclature is given in Scheme 5. H-bonds can be classified according to their strength as weak, moderate, or strong proton position as symmetric (or centric, or proton-centred) or asymmetric X-H-Y angular value as bent or linear (5.1a,b) chemical symmetry as homonuclear or heteronuclear (5.IIa,b) connectivity as two-centered, three-centered (or bifurcated), or chelated (5.IIIa-c) and topology as intermolecular (5.IVa-c) or intramolecular (5.IVd). As a mle, homonuclear H-bonds tend to be stronger than heteronuclear, two-centered than multicentered, and linear than bent ones. 

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