Bidentate counterions

Solvation of two Forms of the Strontium Complex Srcl8C62+ (no Counterion) and Srd8C6(N03)2 with bidentate Counterions... 

ESR spectra (Table 1). The JV-cyclohexylthiosemicarbazone, 13, complex formed the expected [Fe(13-H)2] with FeCl as the counterion [141]. However, [Fe(13) (13-H)H20]C104 was isolated from ethanol. Bulkiness of the cyclohexyl group, and the perchlorate ion s greater ability to hydrogen bond are probably both important to the stability of this cation. The iron(III) center is considered six-coordinate with a tridentate 13-H, bidentate 13, and a coordinated water molecule. 

The reactions of mercury(II) salts with oligo-amines afford informative examples for the fact that counterions induce the formation of a distinct complex or select a distinct complex in an equilibrium to crystallize with. Thus, Hg11 acetate with dien under exactly the same reaction conditions, in the presence of C104- or PF6-, yields the dinuclear complex [Hg2(dien)3](C104)4 or the mononuclear species [Hg(dien)(H20)](PF6)2, respectively, both characterized by IR, H, and 13C NMR spectrometries, by fast-atom bombardment (FAB) MS, cyclovoltammetry, and X-ray structure analyses.209 In the first compound Pna2, Z = 4), one Hg adopts five-coordination with one tridentate and one bidentate dien ligand, which with the remaining N-donor binds to the... 

Boehme, C., Coupez, B., Wipff, G. 2002. Interaction of M3+lanthanide cations with malonamide ligands and their thia analogues A quantum mechanics study of monoden-tate vs bidentate binding, counterion effects and ligand protonation. J. Phys. Chem. A 106 6487-6498. 

Corriu and co-workers [124] pointed out that the results of the NMR measurements depend on the counterion used when generating bidentated cations of type 41. In the case of a strongly interacting counterion (41 with R2Si+ = PhMeSi+ and Z = NMe2), 13C NMR shifts are in line with an exchange process. 

Octaethyl-l,l -biarsole/stibole 19 (E = As, Sb) can be reduced by alkali metals such as sodium, potassium, rubidium, and cesium in DME or TMEDA yielding metal arsolides 69 (E = As) or stibolides 69 (E = Sb) with corresponding counterion and solvents being bidentate co-ligands (Equation 11) <20040M3417>. 

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