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Compounds of the compositions [2(18-crown-6)⋅6(H2O)⋅2(C2H4Cl2)⋅{Pt2+(C2H4)}⋅(Pt2Cl10)2−], [4(18-crown-6)⋅2(OH3)+⋅2(OH2)⋅2(NH3)⋅(Pt2Cl10)2−], [(dibenzo-18-crown-6)⋅6(H2O)⋅{Pt2+(C2H4)}⋅(Pt2Cl10)2−], and [4(dibenzo-18-crown-6)⋅2(OH3)+⋅2(OH2)⋅2(NH3)⋅Pt2Cl10)2−] were prepared by reactions of H2PtCl6 with 18-crown-6 and dibenzo-18-crown-6.

Under conditions of the phase transfer catalysis, acylation of (thio)phosphorylacetonitriles by (het)aroyl chlorides affords the Z-enol forms of C-acylation products in high yields. Their configurations were studied by IR spectroscopy, dipole moment measurements, and ab initio quantum-chemical calculations [B3LYP/6-31G(d)]. The C=C double bond and the phosphoryl or thiophosphoryl group have an s-cis arrangement. The possibility of strong intramolecular hydrogen bonding in these conformers is the governing factor responsible for the three-dimensional structures of the compounds under investigation. Derivatives of nicotinic acid existing in the individual form as zwitterions are the only exceptions.

The products of the reactions between potassium hexachloroplatinate {K2PtCl6} and 18-crown-6 or dibenzo-18-crown-6 in acetonitrile were studied. Pure crystalline compounds [2K·2(18-crown-6)· 2CH3CN]2+·[PtCl6]2-·2H2O, [2K·dibenzo-18-crown-6·CH3CN]2+·[PtCl6]2-, and [2K·dibenzo-18-crown-6·CH3CN]2+·[Pt2Cl10]2- were obtained. Physicochemical properties of these compounds were studied, and their near- and far-IR IR spectra and thermogravimetric curves were considered. The composition of the complexes is determined by metal:ligand molar ratio and crown ether nature. It was found that acetonitrile is coordinated via the nitrogen atom.

Under conditions of the phase transfer catalysis, acylation of (thio)phosphorylacetonitriles by (het)aroyl chlorides affords the Z-enol forms of C-acylation products in high yields. Their configurations were studied by IR spectroscopy, dipole moment measurements, and ab initio quantum-chemical calculations [B3LYP/6-31G(d)]. The C=C double bond and the phosphoryl or thiophosphoryl group have an s-cis arrangement. The possibility of strong intramolecular hydrogen bonding in these conformers is the governing factor responsible for the three-dimensional structures of the compounds under investigation. Derivatives of nicotinic acid existing in the individual form as zwitterions are the only exceptions.

The spectral characteristics and ionization constants of some five-, seven-, and eight-membered cyclic arylenephosphorous acids were determined, and a conclusion regarding the effect of the size of the ring on the tautomerism of these compounds was made on their basis.