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Examples of the synthesis of various heterocycles containing an adamantane moiety based on mono- and dicarbonyl adamantane derivatives are considered. Systems in which the adamantane cage is spiro-connected to a heterocyclic ring or is a part of substituent in the heterocycle are presented. Data on the biological activities of such derivatives are given. The bibliography includes 85 references.

Methane has been oxidized stoicheiometrically by cobalt(III) trifluoroacetate in CF3CO2H solution at 150–180 °C and 10–40 atm to give methyl trifluoroacetate in 90 ± 10% yield based on CoIII, which is reduced to CoII; in the presence of O2(1–5 atm) the reaction becomes catalytic with respect to the cobalt(III) salt, giving methyl trifluoroacetate as the sole product of the oxidation of methane by dioxygen.

Ethane reacts with both cobalt(III) and O2–cobalt(II) in trifluoroacetic acid solution to form ethyl trifluoroacetate and 1,2-bistrifluoroacetoxyethane in successive reactions, along with the products of C–C bond cleavage; propane undergoes similar oxidative reactions.

The first palladium carbene cluster, μ 2 -tetrakis(diphenylmethylidene)-μ 2 -tetraacetato- quadro -tetrapalladiurn(4 Pd – Pd ) Pd 4 ( μ -CPh 2 ) 4 ( μ -OAc) 4 , has been obtained by substitution of diphenylcarbene ligands for CO groups in μ 2 -tetrakis(carbonyl)- μ 2 -tetraacetato- quadro -tetrapalladium(4 Pd – Pd ) Pd 4 ( μ -CO) 4 ( μ -OAc) 4 ; the cluster is also the first palladium complex containing carbene ligands of the Schrock type.

A series of palladium clusters containing from 4 to some hundred Pd atoms in the metal skeleton was prepared and characterized with structural data as well as by chemical properties including catalytic activity. An agreement between X-ray and EXAFS data was obtained for single-crystal low-molecular clusters. Giant clusters approximated as Pd56L60(OCOCH3)180 (L=Phen, Bipy) and Pd561Phen60O60X60 (X = PF6, CIO4, SO4, BF4, CF3COO)were characterized with TEM, SAXS, EXAFS, NMR, and magnetic susceptibility data. The clusters consisting of close-packed metal core and L, X ligands at its periphery could be considered as a bridge between low-molecular clusters and the particles of colloidal metals.

The reaction of bromomethyt(1-adarnantyl)ketone with urea, thiourea, ammonium formate, and thiosemicarbazide gave a series of new imidazolin-2-ones, imidazolin-2-thiones and 2-aminothiazoles in the adamantane series.

2-Mercaptoimidazole derivatives were prepared by the reaction of N-R-(adamantanoyl-l-methyl)amines with potassium thiocyanate. An attempt to synthesize pyrroles from the same amines with the Knorr reaction did not produce the anticipated results.

The reactions involving electron transfer between peroxidic oxidant and a substrate capable of coordination to a metal atom are reviewed. A metal ion can act as a mediator between the coordinated reactants in such a redox reaction. Oxidation of acetylacetonate and related compounds, singlet dioxygen formation and decomposition of H 2 O 2 to form ozone are discussed as examples.

New data on the structure and reactivity of palladium clusters are surveyed. The mechanisms of stoichiometric and catalytic reactions of the palladium cluster complexes with alkenes, alcohols, aldehydes, formic acid, CO, and phenol are discussed.

Data on palladium carbonyl complexes are described systematically and subjected to a critical analysis. The methods of synthesis and data on the structures and chemical properties of mono- and poly-nuclear carbonyl-containing palladium complexes in which the formal oxidation state of the metal varies from 0 to +2 are discussed. Virtually all the publications on this question up to 1997 are examined. The bibliography includes 241 references.

The methods for the synthesis of giant clusters and the pathways of their formation from palladium and platinum complexes are discussed. The approaches to the study of these compounds, based on the concepts of both cluster chemistry and physics of solids, are discussed. Giant clusters contain a positively charged, close-packed nucleus of metal atoms, whose number can be several hundreds and have discrete values, magic numbers,' for example, Pt 55 , Pt 309 , and Pd 561 . The metal nucleus is stabilized by the coordinated ligands, for example, PPh 3 , phen, dipy, O 2- , and Cl - , and the outer-sphere anions like OAc - and PF 6 - . The structures of giant clusters are determined by high-resolution electron microscopy, electron diffraction, tunneling microscopy, small-angle X-ray scattering, EXAFS, and other techniques combined with elemental microanalysis. The polynuclear low-valence complexes [Pd 4 phen(OAc) 2 (H) x ] n , [Pt 4 phen(OAc) 3 ] n , and [Pt 8 phen 3 (OAc) 4 (OH)4(H 2 O) 6 ] (n, m ∼ 100), which are the precursors of giant clusters, are isolated and characterized using the same techniques. Their pathways of transformation to giant clusters are studied using temperature-programmed EXAFS combined with thermal analysis (DTA-TG). Giant clusters exhibit high catalytic activity in the oxidation of alkenes, CO, and alcohols, the oxidative acetoxylation of alkenes and alkylarenes, the reduction of nitriles and nitroarenes, acetal formation, and the oxidative carbonylation of phenol.