Perchlorate coordinated

A concise survey of perchlorate complexes was made by Rosenthal (2) in 1973. A year later, the possibility of perchlorate coordination in aqueous medium was reviewed by Johansson (3). Since the publication of these two accounts a number of papers reporting new findings on perchlorate complexes have appeared, justifying another comprehen-... 

Hathaway and Underhill (15) were the earliest to suggest the use of IR and Raman spectroscopic methods to investigate perchlorate coordination to a metal ion. Perchlorate ion with its T symmetry should... 

Perchlorate coordinated to a metal ion in the solid state generally is displaced in a polar solvent by a solvent (or another ligand) molecule. However, under favorable conditions, perchlorate coordination may persist in solution. In such cases, conductivity measurements are helpful in detecting the coordination of perchlorate (28). For instance, the conductance values of some lanthanide complexes Ln(hmpa)4(C104)3 (Ln = La, Nd, Gd, Dy, Yb) in nitrobenzene correspond to those of uniunivalent electrolytes, implying coordination of two of the perchlorates (29). The coordinated perchlorates are, however, easily displaced by the addition of hmpa as shown by the conductance values, which gradually increase to that corresponding to a 1 3 electrolyte. 

A). The diars complex has been isolated in two crystalline forms— monoclinic and orthorhombic. While the former has IR support for perchlorate coordination (65), the latter has X-ray crystal structure evidence (61) for very weak association of perchlorates with the metal ion in the axial positions. The PhNC complex exists in three isomeric forms, and the X-ray crystal structure of one of the forms (green), determined by Jurnak et al. (64), has indicated a perchlorate oxygen at the sixth coordination position around the metal ion with a Co—O distance of 2.594 A and a Co—O—Cl angle of 135.6°. The coordinated O—Cl bond (1.396 A) is longer than two of the uncoordinated ones (1.319, 1.327 A) but is, however, shorter than the third one (1.413 A). Karayannis and co-workers (33,34,39,40,52,53) have characterized a series of perchlorate coordinated cobalt(II) complexes containing the ligands adHNO, phzNO, quxNO, quxNC>2, and adH (Table IV). 

Stable as well as transitory perchlorate-coordinated species are convenient intermediates for the isolation of novel complexes. With four potential donor sites, the role of C104 acting as a bridging ligand perhaps has interesting possibilities yet to be revealed. 

A complex of holmium perchlorate coordinated with 1-glutamic acid was prepared with a purity of 98.96%. The compound was characterized by chemical, elemental and thermal analysis. Molar heat capacities of the compound were determined by a high-precision automated adiabatic calorimeter from 78 to 370 K. The dehydration temperature, dehydration enthalpy, entropy and the standard enthalpy of formation were reported [183],... 

An enormous amount of work has been done in Russia on perchlorate coordination complexes. A very interesting initiative to find green primary explosives among the cobalt perchlorate complexes has been reported by Ilyushin et al. [14]. The differences in perception of toxicity in various parts of the world make direct comparison misleading. Perchlorates, which are not seen as a problem in many countries, are considered unsuitable from the long-term perspective in the USA [10]. 

In the perchlorate complex [Te(p-C6H40CH3)(S2CNMe2)2(C104)] (353), an oxygen atom of the perchlorate coordinates to the Te in an equatorial position so that, with the exception that the dithiocarbamate ligands are anisobidentate (ATe—S = 0.29 A), it is structurally similar to the [TeXR(S2CNR2)2] complexes. 

Scholer and Merbach, 1975). The Raman band at 436 cm is indicative of a perchlorate having C2v symmetry that is, the perchlorate is a bidentate ligand. The spectra from lanthanum to ytterbium undergo a slow change that is interpreted as indicating a decrease in the amount of ionic perchlorate and a gradual replacement of bidentate perchlorate coordination with monodentate coordination. 

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