I.L. Zhuravleva

Radical polymerization of water-soluble monomers in various solvents

Abstract The NMR-spectra of acrylamide and polyacrylamide in various mixtures of water with DMSO have been studied as well as of N -vinylpyroolidone and its polymer in various solvents. The results indicate that, while the carbonyl groups of acrylamide and N -vinylpyrrolidone in aqueous solution are practically completely bonded with water molecules, in the case of the corresponding polymers only some of the carbonyl groups take part in the formation of H-bonds because of the hydrophobic interactions arising in aqueous solutions of these polymers. These results make it possible to propose a mechanism for the solvent effects in the radical polymerization of water-soluble monomers.

Synthesis and1H NMR spectra of ferrocene and cymantrene derivatives of divalent ytterbium

Abstract The interaction of Yb0 with (C5H5FeC5H4)2Hg and [(OC)3MnC5H4]2 Hg in THF resulted in the formation of ferrocenyl and cymantrenyl derivatives of divalent ytterbium. Derivatives of the RLnI type may be obtained in low yields from the basis of ferrocene (cymantrenyl) iodides and Yb0 in THF. The structures of the resulting compounds were characterized by1H NMR spectra.

Radical polymerization of diethylaminoethyl methacrylate and its salts in various solvents

Abstract NMR-spectral data for diethylaminoethyl methacrylate and its salts in various solvents have been considered with the kinetics of polymerization of these monomers. The data on the interaction of a monomer with a solvent obtained using NMR-spectroscopy lead to ideas about the effect of the formation of hydrogen bond between solvent and monomer molecules, protonization and ionization of the monomer on its reactivity in the polymerization. The effect of various conformations of growing polymer chains upon the rate of polymerization is also very important.

Effect of intermolecular hydrogen bonding on the polymerization of methylmethacrylate and acrylamide in solution

Abstract The 1 H and 13 C NMR spectra of MMA and acrylamide in proton-donor and proton-acceptor solvents have been studied and the data obtained have been compared with the rates of polymerization of these monomers in the same solvents. As the ability of the solvent to form intermolecular hydrogen bonds increases, the rate of polymerization of the monomers studied also increases.

The radical polymerization of acrylamide in dimethyl sulfoxide-water mixtures☆

1H and 13C NMR spectra have been studied for acrylamide in dimethyl sulfoxide-water mixtures of various compositions. It has been shown that, as a consequence of the formation of a complex between acrylamide and water, increased water content in the mixture leads to downfield displacement of the 13C chemical shifts of the CH2 and CO groups. A linear dependence has been found between the chemical shifts of carbon atoms in the groups mentioned and the water content of the solvent. Comparison of the data for complex formation between acrylamide and water together with the values of the velocity constant of propagation, which have been already determined, leads to the conclusion that the conformation of a polymer coil influences the polymerization of acrylamide in solution.

1H and 13C NMR analysis of the influence of protonation and of formation of the intermolecular hydrogen bond on the polymerization of diethylaminoethyl methacrylate and its salts

A study has been made of the 1H and 13C NMR spectra of diethylaminoethyl methacrylate and its acetic and hydrochloric acid salts in various solvents, and the data obtained have been compared with rates of polymerization of these compounds in the same solvents. In view of changes in chemical shifts it appears that the formation of an H bond formed between the C=O group of the monomer and solvent molecules, and the protonation effect, lead to a diminution of electron density on hydrogen and carbon atoms of the CH2=group near the double bond in the monomer. This apparently increases the rate of monomer-radical interaction in view of the nucleophilic properties of alkyl radicals. This would account for the increased rate of polymerization of the studied monomers following the addition of water to an inorganic solvent, and likewise in aqueous solutions.

Solvation of water-soluble polymers in aqueous solutions☆

The fraction of carbonyl groups bound by H-bonds in aqueous solutions of some water-soluble polymers has been determined, using a method based on the previously found features of changes in chemical shifts of the carbonyl carbon 13C due to substituent variations and to H-bond formation. In addition calculated and experimental values of the chemical shifts were compared. In contrast to the monomer molecules that were completely bound to H2O molecules by H-bonds via the carbonyl group oxygen, only ∼70% of the carbonyl groups in the polymer molecules form H-bonds.

The PMR spectroscope study of the isomer composition of aromatic polyamic acids

The isomeric composition of the aromatic polyamic acids (PAA) based on the dianhydrides of 3,3′, 4,4′-diphenylsulphone tetracarboxylic, 3,3′, 4,4′-benzophenone tetracarboxylic, 3,3′, 4,4′-diphenyltetracarboxylic, 3,3′, 4,4′-diphenyloxide tetracarboxylic, 3,3′, 4,4′-diphenyl sulphide tetracarboxylic acids and p-phenylene diamine, p-benzidine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl oxide and 4,4′-diaminodisulphone have been studied. The PAAs from the dianhydrides with electron-acceptor bridge units are rich in m-isomers, whilst those formed from dianhydrides with electron donor bridge units have mainly p-isomer structures. The structure of the diamines hardly affects the isomeric composition of the PAAs.

IR and NMR spectroscopic study of substituted N-phenylphthalimides as model compounds of aromatic polyimides

Abstract To establish the nature of the electron interaction of the imide cycle with the aromatic fragments attached to it a number of substituted N-phenylphthalimides and polypyromellitimides have been investigated by IR and NMR spectroscopy. The imide cycle of the phthalimides is characterized by a high degree of coupling of the unshared electron pair of the nitrogen atom with the carbonyl groups. Transfer of the electron effects through the imide cycle is virtually absent. The frequency of the vibrations of the group of N-phenylphthalimides and polypyromellitimides rises with increase in the donor capacity of the N-attached aromatic fragment, which is explained by the redistribution of the σ electron density in the imide cycle. The character of the absorption of the N-phenylphthalimides in the region 1700–1800 cm −1 is due to Fermi resonance ν (C=O) of the imide cycle with the overtone 2ν (Ph-CO).

Fluorenyl derivatives of lanthanides

ConclusionsFluorenyl derivatives of lanthanides were synthesized for the first time. Their structure was confirmed by IR and PMR spectra.