The article presents the calculation of the structural and electronic characteristics of a conjugate consisting of the drug carboplatin (C6H12N2O4Pt) and a fullerenol (C60(OH)24) nanocarrier by the HF-3c method. Optimization of the geometric structure of the conjugate in an aqueous medium was carried out using the same level of theory and the polarizable continuum model. To clarify the nature of the intermolecular bond and assess the strength of the interaction between the carboplatin molecule and fullerenol, a topological analysis of the mechanisms of non-covalent interaction was performed based on the quantum theory of atoms in molecules. Individual paired atomic non-covalent interactions in the conjugate were analyzed and their energies were estimated using the correlation between the interaction energy and the characteristics of the electron density at the critical points of the bonds. It is shown that the conjugate is formed due to weak interaction forces between carboplatin and fullerenol, ensuring the release of the drug when delivering it to the corresponding DNA region without significant energy costs. The studied conjugates can be used for targeted drug delivery.

This study investigates rational approaches to the targeted delivery of chemotherapeutic drugs, with a focus on cisplatin, and explores methods to enhance their cytotoxic effects. The work presents results from computer modeling of the structural and electronic characteristics of quinine, fullerene, and cisplatin. Using quantum-chemical modeling with the HF-3c/MINIS/MINIS11(d)(Cl)/def2-SV(P)ECP(Pt) level of theory, and accounting for intermolecular interactions within the ORCA 5.03 software package, the electronic structure and binding energy of cisplatin, quinine, and fullerene adducts, as well as their three- component systems, were investigated. By analyzing the total energies of the systems and the calculated energy diagrams of the highest occupied and lowest unoccupied molecular orbitals for the initial components and the molecular ensembles they form, we concluded the most stable combinations. The study suggests a synergistic effect and outlines the potential use of the three-component system of cisplatin-quinine-fullerene C60(OH)24 in chemotherapy for oncology practice.

Optically detectable magnetic resonance spectra were measured for ensembles of NV-centers in CVD diamonds with different C-13 contents. The obtained spectra were described using a model based on the spin Hamiltonian. The magnitude of the magnetic field applied to the sample was estimated using the constructed model and experimental data.

В данной работе проводится исследование трехспиновой системы 14NV-13C, которая включает электронный спин NV-центра и ядерные спины атомов 13С и 14N. В этой системе наблюдается двукратное вырождение энергетических уровней в нулевом магнитном поле (вырождение Крамерса) из-за инвариантности спинового гамильтониана к обращению времени. Для исследования влияния магнитного и электрического поля на энергетические уровни системы было проведено моделирование спектров оптически детектируемого магнитного резонанса (ОДМР) этой гибридной квантовой системы в рамках метода спин-гамильтониана при одновременном воздействии на систему магнитного и электрического или внутрикристаллического поля. Построенная модель хорошо согласуется с экспериментальным спектром ОДМР одиночного комплекса 14NV-13C, локализованном в образце сверхчистого алмаза с помощью конфокального микроскопа. По расщеплению спектра ОДМР в нулевом магнитном поле и по данным квантово-химического моделирования было определено, что атом 13С расположен в третьей координационной сфере NV-центра, и соответствующий этому положению тензор сверхтонкого взаимодействия электронного спина NV-центра и ядерного спина изотопа углерода 13С использовался в модели. В результате численные расчеты показали, что вырождение снимается только магнитным полем, независимо от наличия какого-либо электрического (кристаллического) поля, что делает данную квантовую систему перспективным для магнитометрии.

Quantum chemical modeling using the Hartree–Fock theory level HF-3c/MINIS/MINIS11 (d)(Cl)/def2-SV(P) ECP(Pt) considering intermolecular interaction within the ORCA 5.03 software package was employed to study the electronic structure and binding energy of cisplatin, quinine, and fullerenol adducts and their three-component systems. Analysis of the total energies of the systems and the calculated energy diagrams of the highest occupied and lowest unoccupied molecular orbitals for the initial components and the molecular ensembles formed by them indicated the probable stability of their combinations. The synergistic effects were examined and the prospects for using the three-component cisplatin–quinine–fullerenol C60(OH)24 system in cancer chemotherapy were discussed.

Recent experiments on the detection, imaging, characterization and control of multiple 13C nuclear spins, as well as of individual 13C–13C dimers in diamond using a single nitrogen-vacancy (NV) center as a sensor, along with the impressive progress in increasing the spectral resolution of such sensor (up to sub-Hertz), have created a request for detailed knowledge of all possible spin interactions in the studied systems. Here, we focus on the indirect interaction (J-coupling) of 13C nuclear spins in diamond, which was not previously taken into account in studies of NV centers. Using two different levels of the density functional theory (DFT), we simulated the full tensors nJKL (K, L = X, Y,Z), describing n-bond J-coupling of nuclear spins 13C in H-terminated diamond-like clusters C10H16 (adamantane) and C35H36, as well as in the cluster C33[NV−]H36 hosting the negatively charged NV− center. We found that, in addition to the usually considered isotropic scalar nJ-coupling constant, the anisotropic contributions to the nJ-coupling tensor are essential. We also showed that the presence of the NV center affects the J-coupling characteristics, especially in the case of 13C–13C pairs located near the vacancy of the NV center.

The possibility of using NV-defects in diamond at room temperature on nanometer spatial scales to measure magnetic fields was studied. For these purposes, samples with high concentrations of NV-centers are usually used, which increases the signal level but prevents the measurement of inhomogeneous fields on the scale of molecules or nanostructures. The parameters of a weak magnetic field were measured taking into account Earth's field by measuring the hyperfine structure of the optically detected magnetic resonance spectrum to calibrate and determine the resolution of a magnetic field sensor on a single NV-defect.

A method for estimating the isotopic composition and concentration of NV-centers in diamond using Raman scattering and photoluminescence spectra is presented. The proposed laboratory technique was used to study the spatial distribution of the 13C isotope and NV-centers in samples of CVD-diamond with isotopically modified layers.

Tetraeicosahydroxyfullerene C60(OH)24 has a wide range of unique and useful properties that allow it to be successfully used in a number of sectors of the national economy. Interest in this compound is due to its extremely high biological potential, which manifests itself in a potentiating effect against malignant neoplasms (when used together with cisplatin) and as an agent for the delivery of radioactive isotopes in radiation medicine. This paper presents a convenient and easily scalable procedure for the synthesis and purification of C60(OH)24 tetraeicosahydroxyfullerene by catalytic bromination of C60 fullerene in liquid bromine in the presence of metallic iron. The technology of purification of the target product using ion exchange resins AB-17-8 and TOKEM-100 has been developed.

In the era of increasing the effectiveness of treatment methods and drugs used in modern neuro-oncology, the targeted delivery of diagnostic and medicinal substances to the tumor is of great importance. The aim of the work is to study in silico optimal and rational approaches to the creation of nanocontainers for targeted drug delivery. Here we present the results of DFT simulation of the molecular and electronic structure, as well as possible mechanisms for the formation of water-soluble conjugate of the cytotoxic drug cisplatin (cis-[Pt(NH3)2Cl2]) and fullerenol (C60(OH)24). The calculations were performed using the DFT/CAM-B3LYP/cc-pvdz/LanL2DZ(Pt) level of theory. Polarizable Continuum Model (PCM) was used for solvent phase calculations. From the results of the calculation of structural parameters and electronic structure for the C60(OH)24 - cisplatin conjugate, was concluded that in the aqueous solution stable hydrogen bonds are formed between the molecules of fullerenol and cisplatin. Biological activity descriptors were calculated, which showed that the conjugate has a higher reactivity than the cisplatin molecule.

A method of vector magnetometry, implemented using a single NV–13C spin system in a diamond, is proposed. The method is based on a priori knowledge of the hyperfine interaction characteristics and on the presence of experimentally measured line positions in the optically detectable magnetic resonance spectrum of such a system. The method was experimentally tested on the NV–13C system, in which the 13С atom is located in the third coordination sphere of the NV center.

Individual electron–nuclear spin systems in solids are promising platforms for implementation of second-generation quantum technologies. The recognized leader among such systems is the negatively charged nitrogen–vacancy color center (NV center) in diamond with hyperfine coupling to nuclear spins of carbon-13 (13C), which are widely used as a quantum memory in emerging quantum technologies because of their weak interaction with the environment. Recently, pairs of 13C–13C nuclei (dimers) in diamond with NV centers have been proposed and actively studied for this purpose because they have extremely long coherence times (minutes at room temperature) in the singlet state. The eigenstates of the spin Hamiltonian of the NV–13C–13C system were found and used to calculate the probabilities of EPR transitions between nuclear-spin sublevels of NV-center states with electron spin projections mS = 0 and mS = –1. The obtained expressions form the basis for choosing the optimal parameters of microwave and radiofrequency pulses transforming a particular dimer into the singlet state. An example of such a prediction for a specific NV–13C–13C spin system using data for the spatial positions of the 13C spins and the internal spin–spin couplings obtained earlier by quantum chemistry methods is presented.

Fully optimized structures of the fullerenol (Fl=C-60(OH)(24)) - cisplatin conjugate (Fl + Cis) were obtained using the DFT simulation. The DFT/B3LYP/SV/Lanl2DZ level of theory has been used. From the results of calculation of the structural parameters, it can be concluded, that the interaction of Fl with Cis in vacuum leads to the increase of the Pt-N bond length compared to the result for Cis and decrease of the Pt-Cl bond length. The solvation effect for the Fl + Cis complex leads to the decrease of the Pt-N bond length compared to the result for vacuum and increase of the Pt-Cl bond length compared to the result for vacuum and increase of the Pt-Cl bond length compared to the result for vacuum. From the results of the calculation of structural parameters for the Fl with Cis conjugate, it can be concluded that the Pt-N bond in the aqueous solution is enhanced while the Pt-Cl bond is weakened, which can affect the biological activity of the Cis in this complex. The influence of the localization of HOMO and LUMO orbitals on the biological activity of the conjugate under consideration was analyzed. The paper presents the results of DFT simulation of the atomic and electronic structure of water-soluble cisplatin conjugate derivatives and nanocarbon structures, such as fullerenol Fl, as well as the results of studying the possible mechanisms of their biological activity.

In order to therapeutically destroy neoplasms, chemotherapy or radiotherapy is usually applied, and in isotope medicine short-lived radionuclides are injected into the tumor ( 59 Fe, 90 Y, 95 Zr, 99 mTc, 106 Ru, 114* In, 147 Eu, 148 Eu, 155 Eu, 170 Tm, 177 mLu, 188 Re, 210 Po, 222 Rn, 230 U, 237 Pu, 240 Cm, 241 Cm, 253 Es). Binary (or neutron capture) therapy is a technology designed to selectively treat malignant tumors and using drugs tropic to tumors containing non-radioactive nuclides ( 10 B, 113 Cd, 157 Gd at al.). Triadic therapy is the sequential introduction into the body of a combination of two or more separately inactive and harmless components, tropic to tumor tissues and capable of selectively accumulating in them or entering into chemical interaction with each other and destroying tumor neoplasms under certain sensitizing external influences. The aim of this work is to quantum-chemically simulate the electronic structure and to analyze the thermodynamic stability of new doxorubicino-fullerenol agents for the treatment of tumor neoplasms. The need for preliminary studies on the modeling of such objects is due to the extremely high labor intensity, cost and complexity of their practical production.

Using the ORCA 5.0.2 software package we have simulated for a first time the full tensors nJKL (K,L=X,Y,Z), describing n-bond J-coupling of nuclear spins 13C in H-terminated diamond-like clusters C10H16 (adamantane) and C35H36 as well as in the cluster C33[NV-]H36 hosting the negatively charged NV- center. We found that, in addition to usually considered isotropic scalar nJ-coupling constant the anisotropic contributions to the nJ-coupling tensor are essential. We have also shown that the presence of the NV center affects the J-coupling characteristics, especially in the case of 13C-13C pairs located near the vacancy of the NV center.

To estimate possible biological activity of conjugates based on nanodiamond with an NV center inside (ND[NV]), with various functional groups located on its surface, their structural, electronic, and spin properties were calculated using the PM6 method. The energy gap between HOMO and LUMO of the complex was used as a main indicator of biological activity. It has been shown that complexes with OH or H groups attached to the (111) surface are most stable in an aqueous medium. Analysis of spin density and HOMO and LUMO localization shows that complexes ND[NV] may be not just an inert carrier of a biologically active drug or means of visualizing drug delivery, but are also directly involved in the formation of the biological activity of the conjugate.

In order to therapeutically destroy oncological neoplasms, chemotherapy or radiotherapy is usually applied, and in isotope medicine – short-lived radio nuclides are injected into the tumor (59Fe, 90Y, 95Zr, 99mTc, 106Ru, 114*In, 147Eu, 148Eu, 155Eu, 170Tm, 188Re, 210Po, 222Rn, 230U, 237Pu, 240Cm, 241Cm, 253Es). Binary (or neutron capture) therapy is a technology developed for the selective effect on malignant tumors using drugs that are tropic to tumors and contain non-radioactive nuclides (10B, 113Cd, 157Gd at al.). Triadic therapy involves the sequential introduction into the body of a combination of two or more separately inactive and harmless components, which are tropic to tumor tissues and capable of selectively accumulating in them or chemically interacting with each other and destroying tumor neoplasms under the action of certain sensitizing external influences. The aim of this work is quantum-chemical simulation of the electronic structure and analysis of the thermodynamic stability of new cortisone-fullerenol agents for the treatment of tumor neoplasms. The need for preliminary studies of modeling such objects is due to the very high labor intensity, cost and complexity of their practical production.

Nanostructured diamonds hosting optically active paramagnetic color centers (NV, SiV, GeV, etc.) and hyperfine-coupled with them quantum memory 13C nuclear spins situated in diamond lattice are currently of great interest to implement emerging quantum technologies (quantum information processing, quantum sensing and metrology). Current methods of creation such as electronic-nuclear spin systems are inherently probabilistic with respect to mutual location of color center electronic spin and 13C nuclear spins. A new bottom-up approach to fabricate such systems is to synthesize first chemically appropriate diamond-like organic molecules containing desired isotopic constituents in definite positions and then use them as a seed for diamond growth to produce macroscopic diamonds, subsequently creating vacancy-related color centers in them. In particular, diamonds incorporating coupled NV-13C spin systems (quantum registers) with specific mutual arrangements of NV and 13C can be obtained from anisotopic azaadamantane molecule. Here we predict the characteristics of hyperfine interactions (hfi) for the NV-13C systems in diamonds grown from various isotopically substituted azaadamantane molecules differing in 13C position in the seed, as well as the orientation of the NV center in the post-obtained diamond. We used the spatial and hfi data simulated earlier for the H-terminated cluster C510[NV]-H252. The data obtained can be used to identify (and correlate with the seed used) the specific NV-13C spin system by measuring, e.g., the hfi-induced splitting of the mS = ±1 sublevels of the NV center in optically detected magnetic resonance (ODMR) spectra being characteristic for various NV-13C systems.

One of the methods for treating oncological diseases is application of short-lived radionuclides. Existing risks of intoxication and radioactive contamination can be eliminated by introduction of a short-lived radon isotope into a hard strong fullerene coat. To increase the effectiveness of these drugs it is promising to introduce structural fragments of amino acids, peptides, steroid hormones, nucleic bases or heterocyclic compounds being able to accumulate exactly in tumoral but not in healthy tissues of the body. The article presents data on quantum-chemical simulation of electronic structure and thermodynamic stability of fullerenol radon-containing agents of radionuclide therapy on the example of a model cortisonefullerenol bioconjugate.

The relationship between the photoluminescence intensity of the ensemble of NV centers in diamond and external magnetic field was studied. The magnetic spectra exhibit two resonances. The broader one has a width of 20 G and its amplitude is independent of the polarization of the incident radiation. The narrow resonance with a width of 4 G is found to be polarization dependent and is only visible if the direction of magnetic field is more or less perpendicular to the laser light polarization. To describe the appearance of these resonances we have modified the 8-level model of the NV center by taking into account the cross-relaxation between the ground-state spin of the center and other surrounding electronic spins (those of differently aligned NV centers, substitutional N spins etc.).