Nuclear quadrupole resonance in organosilicon nitrogen compounds

Conclusions Based on the¹⁴N NQR data, the p – d interaction in dimethylaminosilanes is weaker than in the amides of phosphorus acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2331–2333, October, 1975.     

Thermochemistry of some barium compounds

The molar enthalpies of reaction of metallic barium with 0.047 mol·dm⁻³ HClO₄ as well as the molar enthalpies of dissolution of BaCl₂ in 1.01 mol·dm⁻³ HCl and in water have been measured at T=298.15 K in a sealed swinging calorimeter with an isothermal jacket. From these results the standard molar enthalpy of formation of the barium ion in an aqueous solution at infinite dilution, as well as the enthalpies of formation of barium chloride and barium perchlorate, are calculated to be: Δ_fH⁰_m(Ba²⁺,aq)=−(535.83±1.25) kJ · mol⁻¹; Δ_fH⁰_m(BaCl₂,cr)=−(855.66±1.28) kJ · mol⁻¹; and Δ_fH⁰_m(BaClO₄,cr)=−(796.26±1.35) kJ · mol⁻¹. The results obtained are discussed and compared with previous experimental values.     

Nuclear quadrupole resonance in MSbClF3 compounds (M=Na,K, Cs,NH4)

Conclusion A study of the temperature dependence of the¹²³Sb NQR parameters for MSbClF₃ complexes (M=K, Cs, NH₄) at from 77 to 390K shows temperature ranges with anomalous change in the electric field gradient asymmetry parameter for the antimony atoms.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1136–1139, May, 1987.The authors express their gratitude to G. K. Semin for a useful discussion of this work.     

Nuclear quadrupole resonance in heteroorganic compounds of group III

Theoretical and Experimental Chemistry -     

Nuclear quadrupole resonance of 14N in imidazole and related compounds

Using the technique of nuclear double resonance with spin mixing by level crossing, the nuclear quadrupole resonance of ¹⁴N has been measured in L-histidine, D-L-histidine, L-histidine hydrochloride monohydrate, sodium urocanate and urocanic acid at 77 K. The nuclear quadrupole resonance of both ¹⁴N and ²D has been measured in deuterated imidazole at 77 K. The previously measured spectra for normal imidazole have been positively assigned with the electric field gradient parameters for the tri-coordinated nitrogen site given by e²qQ/h = 1424 kHz and η = 0.980, and for the di-coordinated nitrogen site by e²qQ/h = 3267 kHz and η = 0.129.     

35Cl Nuclear quadrupole resonance spectra of some carboranecarboxylic chlorides

Conclusions A study was made of the³⁵Cl NQR spectra in the series of o-, m-, and p-carboranecarboxylic acids. Some of the highest NQR frequencies of the chlorine atom in the COCl group are observed in the studied compounds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1676–1678, July, 1973.The authors express their gratitude to G. K. Semin for his interest in the work.     

133Cs NMR Spectroscopic Investigation of the Interaction of 133Cs+ with Monovalent Cations in Aqueous Solution

¹³³Cs NMR spectroscopy was used to study the interaction of ¹³³Cs⁺ with monovalent cations in aqueous solution. The interaction between ¹³³Cs⁺ and the cations causes a repulsive polarization in the electron environment of ¹³³Cs⁺, which is detected by a change in its resonance frequency. The resulting ¹³³Cs chemical shift seemed to be dependent on the activities and the single-ion enthalpies and entropies of hydration of the cations. The hydration cospheres of an ion are the barriers through which ¹³³Cs⁺ must pass in order to come into contact with the cation. These hydration cosphere barriers can be related to the single-ion enthalpy and entropy of hydration of the cation. The experiments revealed that ¹³³Cs⁺ is not nearly as sensitive a probe as ¹²⁹Xe, presumably due to its more tightly bound hydration cospheres. However, ¹³³Cs NMR was moderately successful in predicting trends in the chemical shift behavior induced by the cations studied.