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This is a review of investigations on iodo-benzoic acid, iodohippuric acid, and iodophenol derivatives by NQR, NMR, and emission Mössbauer spectroscopy. The influence of intermolecular, intramolecular, and bifurcated O-H…I and O-H…O bonds on the properties of iodine-carbon bonds is demonstrated. Ionized and non-ionized forms of tyrosine differ by the probability of H-bond formation. The simultaneous use of 127I NQR and emission Mössbauer 125I spectroscopy open the possibility to determine the types of tellurium-organic substances formed in the process of K-decay of 125I.

The full127I NQR spectra of a series of iodo-substituted phenols and phenylmercury phenoxides have been studied. The quadrupole coupling constants and asymmetry parameters have been determined. The character of the OH...Hal hydrogen bond has been found to depend on the nature of substituents in the ring. Correlation dependences of the asymmetry parameters on the sum of the substituents resonance constants have been found for both coordinated as well as for non-coordinated iodine atoms.

We have studied the complete127I spectra and obtained the values of the quadrupole coupling constants e2Qqzz and the asymmetry parameters η in a series of substituted α-iodothiophenes. Using an additive scheme, we have calculated e2Qqzz and determined the substituent increments.

1. For a series of iodonium compounds of the Ar2IX type, it has been found that the127I NQR parameters — the quadrupole coupling constant e2Qqzz, the asymmetry parameter η, and the frequency field constant ϖv/ϖEz -vary regularly with the nature of the cation and the character of substitution in the ring. 2. Strengthening of the coordination interactions leads to a sharp jump in the frequency field constant ∂v/∂Ez and a significant change in the asymmetry parameter η. 3. For this series of compounds, a linear, correlation has been established between the values of e2Qqzz and η.

We were the first to study the complete NQR spectra of iodine for a number of haloaliphatic compounds. An additive scheme for calculating the NQR frequencies in the HnCl4−n series was constructed. The values of the asymmetry parameters in the studied compounds were analyzed.

The127I NQR spectra of the tetraiodo-, triiodonitro-, and diiodonitrotrifluoromethylthioethylenes were studied. The frequencies of the iodine atoms increase when electron-acceptor substituents are inserted into the molecule of iodoethylenes.

Iodonitromethane forms nσ complexes with organic ligands with low127I asymmetry parameters and positive charge on the iodine atom.

NQR spectroscopy was used to find the localization of formal positive charge on the chlorine and bromine atoms in ClOSO2F and BrOSO2F.

A considerable increase in the quadrupole coupling constants (e2Qqzz) and significant decrease in the asymmetry parameterη is found in carborane-containing CBICl2 and PhCBIX compounds in comparison with the corresponding phenyl and diphenyl derivatives.

The complete79Br and127I NQR spectra of a number of bromo and iodo derivatives of acetylene were studied for the first time, and the field constants of the NQR frequencies were determined. It was found that the asymmetry parameters in them are low. Changes in the field constants are determined by the competing conjugation of the iodine atom and the corresponding substituents.