The dynamic H-1, C-13, and N-15 NMR spectroscopic method was used to study the kinetics and mechanism of stereodynamic transformations of the 2,5-diformylpyrrolemono- and 2,5-diformylpyrroledi(N-alkylimine)-based Zn(II) and Cd(II) bischelate compounds and structurally similar 3,3-diaryl-1,3,2-diazaborols in solutions. X-ray diffraction analysis was performed for bis[5-cyclohexyliminoformylpyrrole-2-(N-cyclohexylaldiminato)]zinc(II) and bis[5-formylpyrrole-2-(N-isopropylaldiminato)]zinc(II). It is found that the trigonal-bipyramidal configuration of the coordination core is completed as a result of intramolecular coordination. The tetrahedral configuration of the central metal atom in the former complex and other analogous zinc(II) and cadmium(II) complexes is found to undergo inversion through the intramolecular associative mechanism.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Kinetics and reaction mechanisms governing inversion of the tetrahedral configuration at the metal center in the series ofbis-chelate Zn(II) complexes of 3,2-, 1,2-, and 2,1-oxy(mercapto)naphthaldimines, respectively4–6, have been studied with the use of dynamic1H NMR spectroscopy. A polytopal rearrangement of the diagonal twist type has been found to be an energetically preferable pathway of the inversion reaction for complexes4 and5 with a ZnN2O2 coordination site, whereas the inversion reaction for complexes with a ZnN2S2 coordination site occurs by an intramolecular dissociation-recombination pathway that involves cleavage of a Zn-N coordination bond. In the case of complexes6, the inversion reaction is governed mainly by intramolecular degenerate ligand exchange reactions.

We have synthesized and characterized by IR, UY,1H, and13C NMR spectroscopy new spiropyrans based on 2-thioxo-3 phenyl-5,5-dimethyl-1,3-oxazolidine. We have studied their photochromic properties in 2 propanol at -80°C. In the electronic spectra of photo-induced farms, we have detected two long-wavelength absorption bands in the 370–438 and 480–677 nm region.

New spiropyrans with p-acceptor azomethine and ketovinyl substituents in the 8' position were synthesized using the functional possibilities of the carbonyl group. The structures of the compounds obtained and their photochromic properties in 2-propanol at -70°C were studied.

New spiropyrans with π-acceptor azomethine and ketovinyl substituents in the 8′ position were synthesized using the functional possibilities of the carbonyl group. The structures of the compounds obtained and their photochromic properties in 2-propanol at −70°C were studied.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Combination of nonselective and selective excitation in NMR experiments of discriminating and assigning spin systems is proposed.

This chapter discusses dynamic NMR spectroscopy in inorganic and organometallic chemistry. The study of chemical exchange phenomena using NMR techniques rests on the measurements of the four basic NMR parameters: relative signal intensities, internal chemical shifts, nuclear spin–spin couplings, and nuclear spin relaxation times. These parameters and their temperature dependences can be measured with great precision using one- and two-dimensional techniques, thus providing chemists with almost a plethora of methods for the precise measurement of molecular dynamics. The chapter focuses on developments in measurements of intramolecular rearrangements of molecules in chemical equilibrium and also includes intermolecular processes and time-dependent studies of nonequilibrium systems. The main advances in the theory and methodology of dynamic NMR (DNMR) are described in the chapter. Inorganic coordination complexes and organometallic compounds provide the widest variety of internal dynamic or fluxional rearrangement.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.