Perchlorate vibrations

In the complexes of TBPO with lanthanide perchlorates, absorptions at 400 cm-1 have been ascribed to i>Ln o (210). Absorptions due to lanthanide-perchlorate vibrations (Ln—OC103) have been identified in the region 290—360 cm-1 for the complexes of lanthanide perchlorates with 2,6-DMePyO (171), TBPO (210), DMMP (210), and for the complexes of Ce(III) perchlorate with TPPO and TBPO (206, 211). Ln-Cl vibrations occur at 230 cm-1 in the complexes of lanthanide chlorides with TBP (195) and TPPO (202). In the complexes of lanthanide bromides with TBP (295), i Ln— Br occurs in the region of 195 cm-1. 

Perchlorate vibrations for free perchlorate, monodentate and bidentate obtained with lanthanides in acetonitrile are given in Table 4.4. 

Fig, 2. FT-IR difference spectra of R(C104)3 solutions 0.05 M in anhydrous acetonitrile, in the spectral range of the main perchlorate vibrations. The arrow points to absorption from the coordinated solvent., solvent absorptions not completely compensated u, unassociated m, monodentate b, bidentate (Biinzli and Kasparek 1991). 

Enamines in which the double-bond shift is sterically prevented afford only the ammonium salts. Their spectra in the C=C stretching vibration region does not differ greatly from that of the free amine spectrum (171). For example, neostrychnine (159) has vc c 1666 cm and its perchlorate at 1665 cm . Salts of quinuclideine (92) and the polycyclic alkaloid trimethylconkurchine have similar properties. 

Lick Observatory. The success of the LLNL/AVLIS demonstration led to the deployment of a pulsed dye laser / AO system on the Lick Observatory 3-m telescope (Friedman et al., 1995). LGS system (Fig. 14). The dye cells are pumped by 4 70 W, frequency-doubled, flashlamp-pumped, solid-state Nd YAG lasers. Each laser dissipates 8 kW, which is removed by watercooling. The YAG lasers, oscillator, dye pumps and control system are located in a room in the Observatory basement to isolate heat production and vibrations from the telescope. A grazing incidence dye master oscillator (DMO) provides a single frequency 589.2 nm pulse, 100-150 ns in length at an 11 kHz repetition rate. The pulse width is a compromise between the requirements for Na excitation and the need for efficient conversion in the dye, for which shorter pulses are optimum. The laser utilizes a custom designed laser dye, R-2 perchlorate, that lasts for 1-2 years of use before replacement is required. 

Dederichs, F., Friedrich, K F. and Daum, W. (2000) Sum-frequency vibrational spectroscopy of CO adsorption on Pt(l 11) and Pt(llO) electrode surfaces in perchloric acid solution effects of thin-layer electrolytes in spectro-electrochemistry. J. Phys. Chem. B, 104, 6626-6632. 

The nature of coordination of anions such as nitrate, perchlorate, and thiocyanate has been studied by both infrared and Raman techniques. In the case of anions, such as nitrate and perchlorate, the vibrational spectra indicate whether they are ionic or coordinated and if coordinated, whether they are unidentate, bidentate or bridging. In the case of thiocyanate, the vibrational spectra are useful in deciding the site of coordination. The change in the site symmetry of the anion upon coordination leads to changes in vibrational spectra of anions like perchlorate, nitrate, perrhenate and hexa-fluorophosphate. These changes in the vibrational spectra have been used to indicate the nature of coordination. 

The metal-oxygen and related vibrations occur in the far IR region and these vibrations have been studied only in a few cases. In the complexes of lanthanide perchlorates with PyO, i>Ln o occurs in the region of 270-370 cm-1 (148). Three i n-o... 

Fractionations for gas-phase molecules and aqueous perchlorate (gas-phase approximation) calculated using ab initio force-held vibrational models normalized to measured frequencies. Fractionation factors are also calculated for crystalline chlorides using empirical force helds. Includes an indirect model of aqueous CF (aa-(ag)-ci 1.0021-1.0030 at 295K) based on measured NaCl-CF(aq) and KCl-CF(aq) fractionations (Eggenkamp et al. 1995) and the theoretically estimated for NaCl and KCl. 

Poly(vinylferrocenium perchlorate). Hydroperoxide biosensor, 688 POM (polyoxometaUates), 429-30, 1057 POP (persistent organic pollutants), 747 Poppyseed oil, vibrational spectra, 692 Porphyrin, O NMR spectroscopy, 185 Potassium carbonate, alcohol oxidation, 492 Potassium hexacyanoferrate(II), hydrogen peroxide biosensor, 653 Potassium hydrogen phthalate hemiperhydrate, 98-100... 

Another area of laser use applied to expl materials involves its employment to excite Raman spectra for studies of crystal structure, lattice dynamics, phase transitions and vibrational mode frequencies. Compds studied include T1N3 (Refs 10, 17 23), NaN3 (Ref 18), KN3 and RbN3 (Ref 4), NH4N3 (Ref 7), BaN3 (Refs 5, 8 24), LA (Ref 9), HMX (Ref 25), RDX (Ref 11) and Amm perchlorate (Ref 26)... 

The infrared (IR) spectra of 1,10-phenanthroline, its hydrate and perchlorate in the region 600-2000 cm-1 have been obtained, and the principal features of the spectra interpreted.66 Further studies on the IR spectra of 1,10-phenanthroline,67-69 substituted 1,10-phenanthrolines,70,71 and 1,7-phenanthroline67 have also been reported. The IR spectrum of 4,7-phenanthroline in the region 650-900 cm-1 has been analyzed, and the C—H out-of-plane deformation frequencies were compared with those of phenanthrene and benzo[/]quinoline.72 The IR spectra of salts of 1,10-phenanthroline have been taken, and the NH vibrations determined.28,73 Infrared spectroscopy has been used to detect water associated with 1,10-phenanthroline and some of its derivatives on extraction into nitromethane from aqueous solution.74 The Raman spectrum of 1,10-phenanthroline has been compared with its IR spectrum.75 Recently, the Raman and IR spectra of all ten isomeric phenanthrolines were measured in solution and solid states, and the spectra were fully discussed.76... 

Quaternary bismuth compounds are generally unstable. When the anionic ligand is chloride or bromide, the compounds decompose spontaneously on standing azides and selenocyanates decompose more rapidly. The perchlorates, tetrafluoroborates, and hexafluorophophates, however, are considerably more stable but eventually decompose. The vibrational spectra of the latter compounds show the presence of the free ion and are consistent with a tetrahedral BiC4 skeleton for the cation. The acetonyltriphenyl compounds, [(C(5H5)3BiCH2COCH3]Y, where Y is C10- 4 or BF- 4, also appear to be true bismuthonium salts. 

Bands at 1280-1260 cm-1 and 1040-1010cm l are responsible for vibrations of the methoxy groups in spectra of the methoxy-substituted salts, and frequencies of the perchlorate anion were found at 1090 and 623 cm-1. 

Monodentate attachment to a metal ion lowers the symmetry of perchlorate to C3v and bidentate attachment to C2v (15-17). Consequently the number of vibrational modes should increase (Table I). In addition, a metal-oxygen stretching frequency would also be expected in the far-IR region and has been located in the range 360-290 cm-1 (18). These effects resulting on coordination, particularly the increase in the number of vibrational modes, may be used for identifying coordination of perchlorate. 

It must, however, be borne in mind that minor shifts and weak splittings of the IR bands may arise on account of lowering of site symmetry because of strong lattice effects or of coupling of vibrations between perchlorate groups or from a purely isotopic effect within the group (15, 16). For example, the broad and strong band due to the v mode of ionic perchlorate is often split because of lattice effects. Despite these limitations, with a little care and caution, coordinated and noncoordinated perchlorate(s) are conveniently identified by IR spectroscopy. 

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