The thermodynamic parameters of formation reactions (total energy at 0 K, enthalpy, and Gibbs free energy at a temperature of 298.15 K and a pressure of 101 325 Pa) were estimated in the B3LYP-D3(BJ)/6-311++G** approximation for the products of ionic alkylation of adamantane and lower alkyladamantanes with ethylene and propylene. Aluminum chloride was used as an acid catalyst model. The quantum-chemical calculations demonstrated the effect of methyl groups in adamantanes and the molecular weight of the olefin on the energetics of formation of the corresponding alkyl- and alkenyladamantanes.

A multi-stage process is considered for the formation of vinyl adamantane via the ionic alkylation of adamantane with ethylene using aluminum chloride as a catalyst. A feature of the ionic alkylation of adamantane with olefins is the formation of saturated and unsaturated derivatives. Quantum chemical methods means are used to study the kinetic and thermodynamic parameters of the corresponding elementary acts of chemical reactions. A comparative analysis of the characteristics of the reaction for the production of unsaturated adamantane derivatives via ionic alkylation with ethylene is performed using alkylation with propylene.

This review discusses various issues related to the synthesis of unsaturated adamantane derivatives, to the development of novel methods for their preparation, and to the polymerization reactions. Furthermore, we appraised the potential of quantum-chemical calculations for investigating the electronic structure of adamantane derivatives and for elucidating the mechanisms for their chemical and catalytic transformations.

The mechanism of interaction of adamantane with propylene has been studied by quantum-chemical calculations within the density functional theory (DFT). It has been shown that the main products of adamantane alkylation with propylene in the presence of acid catalysts are hydrocarbons with unbranched (normal-chain) substituents, 1-n-propyl- and 1-n-propenyladamantanes. The main stages of adamantane alkylation and the geometric and electronic structures of the intermediates have been determined. The thermodynamic characteristics of the studied adamantanes have been found, and the mechanisms of individual steps of their transformations have been proposed. The obtained data make it possible to control the process of preparation of substituted adamantanes with a defined structure that are of interest for the development of efficient energy-rich materials, high-density fuels, and thermally stable polymers.

Quantum-chemical calculations on the mechanism of catalytic alkylation of adamantane with isooctane cracking products using the density functional theory DFT B3LYP/6-31G* have been carried out. It has been shown that the initial stage of transformations is the interaction of AlCl3 · HCl (as a model of an acid catalyst) with isooctane. At the first cracking stage, proton transfer from the catalyst to isooctane occurs (activation energy is calculated to be 24.64 kcal/mol) to give intermediate 1, which consists of three interacting subsystems: the cation (СН3)3С+; the anion $${\text{AlCl}}_{4}^{ - }$$ ; and СН3–СН(СН3)2, i.e., isobutane. The second stage is proton transfer from the carbocation (СН3)3С+ to form the olefin CH2=C(CH3)2. The activation energy of this stage was calculated to be 7.85 kcal/mol. This is the final stage of isooctane cracking, yielding an olefin and an alkane smaller than the parent one. The mechanism of formation of the adamantyl cation has been considered, in which the cation adds the olefin without activation energy and the resulting complex can form either 1-isobutylenyladamantane (unsaturated byproduct of adamantane alkylation) via deprotonation by the catalyst anion or the final product 1-isobutyladmantane via interaction with another adamantane molecule. The latter can also be formed by the joint action of isobutane and the catalyst anion on the adamantyl cation, with the activation energy being 26.79 kcal/mol.

Propyladamantanes were synthesized by alkylation of adamantane with isopropyl alcohol in the temperature range from 5 to 40 °C in the presence of 96% sulfuric acid. Tetramethyl- and dimethylethyladamantanes were synthesized by isomerization of perhydroanthracene in the presence of aluminium oxide catalyst on the setup of the flow type. Isomers of butyladamantanes were obtained by the reaction of alkylation of the adamantane with isooctane. For each molecule, the optimization of the geometric parameters of atoms was carried out using analytical calculation methods. By calculating the frequencies of normal vibrations using the second derivatives, it was confirmed that the stationary points determined by optimizing the geometry correspond to the minima of the potential energy surface. The structure of 1-n-propyladamantane (I), 1-isopropyl-adamantane (II), 2-n-propyladamantane (III), 1,2-di-n-propyladamantane (IV), 1,3-dimethyl-5-ethyladamantane (V), 1,3,5,6-tetramethyladamantane (VI), 1,3,5,7-tetramethyladamantane (VII), perhydroanthracene (VIII), 1-n-butyladamantane (IX), 1-isobutyladamantane (X), 1-sec-butyladamantane (XI) has been studied using the DFT method with the Becke–Lee–Yang–Parr hybrid energy functional of electron density with the 6-31G* basis set. The geometric and electronic characteristics of the compounds and their total energy, normal vibration frequencies have been calculated. It has been shown that the calculated Gibbs free energies of formation for the perhydroanthracene isomerization products are in qualitative agreement with the experimental product composition of the isomerate and alkylation of adamantane with isopropyl alcohol are in qualitative agreement with the experimental composition of the products. A good agreement of calculated and experimental data on the composition of equilibrium mixtures was obtained. The theoretical geometry of the synthesized alkyladamantanes with Td symmetry very well agrees with the results of electron diffraction. Closest to the results obtained experimentally, the geometry was predicted by B3LYP, in which the lengths of C-C and C-H bonds are close to 1.544 and 1,100Ả, respectively, and the C-Csec-C and C-Cter-C angles are 109°. The results of the calculation using the B3LYP method are in good agreement with the experimental data. There is no definite relationship between the size of the molecules and the convergence of the calculated and experimental data. A practically important conclusion arising from the results of this and previous studies is that the use of the calculation method leads to “chemically accurate” data.

The results of studies in the area of oxidative functionalization of hydrocarbons of the adamantane series over the last two decades have been summarized and oxidation, carbonylation, and carboxylation reactions involving oxidizing agents and catalysts of various types, possible reaction mechanisms, properties and promising directions of the use of the obtained products have been considered.

Quantum-chemical calculations of dimethyl-, trimethyl-, and methylethyladamantyl cations have been performed using the density functional theory method DFT B3LYP/6-31G* with full optimization of energy and computation of normal vibration frequencies and changes in these parameters during the course of their mutual isomeric transformations. The geometric parameters of the compounds, electronic characteristics, electron density distribution, the total energy, transformation energies, transformation entropies, activation energies, and normal vibration frequencies have been calculated. The calculation results confirm earlier experimental data on the occurrence of the direct 2,4-migration of the methyl group during the isomerization of methyladamantyl cations and the preference of this rearrangement to the well-known 1,2-methyl shift in alicyclic carbocations.

The structure of perhydrofluorene and its isomerization products 1,3,5-trimethyladamantane, 1,3,6-trimethyladamantane, cis-1,3,4-trimethyladamantane, trans-1,3,4-trimethyladamantane, 1-ethyl-3-methyladamantane, cis-1-ethyl-4-methyladamantane, trans-1-ethyl-4-methyladamantane, 1,2,6-trimethyladamantane, and 1,2,8-trimethyladamantane of the general formula C13H22 has been studied using the Becke—Lee—Yang—Parr (B3LYP) hybrid energy functional of electron density with the 6-31G* basis set. The geometric and electronic characteristics of the compounds and their total energy, transformation energies, entropies of transformations, and normal vibration frequencies have been calculated. It has been shown that the calculated Gibb free energies of formation for the perhydrofluorene isomerization products are in qualitative agreement with the experimental product composition of the isomerate.

Hydrogenation of the tricyclic aromatic hydrocarbons acenaphthene and fluorene on industrial aluminum oxide catalysts in a flow system has been studied. It has been found that total these hydrocarbons are exhaustively hydrogenated in the presence of a nickel-chromium catalyst at 200°C and a pressure of 100 atm to give isomer mixtures of the corresponding perhydroaromatic hydrocarbons decahydroacenaphthene and dodecahydrofluorene. The liquid products obtained can be of interest as components of hydrocarbon fuels with increased density. Certain conformational features of the stereoisomers obtained have been considered. It has been assumed that some spatial isomers of decahydroacenaphthene have six-membered rings in the boat conformation.

Some esters of dimethyladamantanedicarboxylic acids with aliphatic alcohols and the ester of dimethyladamantanedicarbinol with an aliphatic acid have been synthesized, and their properties have been studied; their viscosity-temperature properties and thermo-oxidative stability as potential components of high-temperature lubricating oils have been examined.

Осуществлен синтез и изучены свойства некоторых сложных эфиров диметиладамантандикарбоновой кислоты и алифатических спиртов, а также диметиладамантандикарбинола и алифатической кислоты; исследованы их вязкостно-температурные свойства и термоокислительная стабильность, как возможных компонентов высокотемпературных смазочных масел.