Search

A facile method for selective N-(hetero)arylation of coordinating 3(5)-amino-1,2,4-triazoles under Pd/NHC catalysis using TPEDO as a new efficient Pd(ii) to Pd(0) reductant has been developed.

Background and Objectives: Studying the dynamical mechanisms of the emergence of nonlinear phenomena that are characteristic for multimode self-oscillating systems consisting of interacting oscillators and an ensemble of passive oscillators or representing active nonlinear systems with complex feedback channels is an important urgent task. The simplest example of a self-oscillating system with a complex feedback is the well-known classical van der Pol oscillator with an additional linear oscillatory circuit included in the feedback channel. We investigate the behavior of the multimode system increasing the number of oscillatory circuits in the oscillator’s feedback loop. The research in this paper can help to better understand the mechanisms of multistability formation in infinite-dimensional self-oscillating systems such as a generator with delayed feedback and a generator with distributed feedback. Materials and Methods: The system equations were derived for the electronic scheme of the self-oscillating system. To describe the existing dynamic modes by numerical simulation methods, the projections of the phase portraits and the Poincare sections were obtained. To study the mechanisms of formation of multistable states, the bifurcation analysis methods were used. Results: It was found that the mechanism underlying the multistability formation is based on a sequence of two supercritical Andronov – Hopf bifurcations and a subcritical Neymark – Saker bifurcation. Therefore, the multistability emerges as a result of gaining stability by the unstable limit set that existed before the multistability appears. Conclusion: The discovered mechanism of multistability formation opens up wide possibilities for managing the multistability, which are inaccessible for systems in which the multistability is realized through tangential bifurcations. In contrast to the tangential bifurcation, the subcritical Neymark – Sacker bifurcation assumes the existence of a limit cycle both before and after the bifurcation. Thus, it is possible to use a wide range of methods and tools to stabilize saddle limit cycles in order to control the boundaries of the multistability region in the space of control parameters of the system.

The effect of static mechanical strain on the splitting of spin sublevels of color centers based on spin 3/2 silicon vacancies in silicon carbide at room temperature has been shown. The deformed heterointerface of the AlN/4H-SiC structure has been studied. Stresses near the heterointerface have been determined using confocal Raman spectroscopy. The spin–strain coupling constants $$\Xi = ( - 0.1 \pm 0.25)$$ GHz/strain and $$\Xi {\kern 1pt} ' = ( - 0.8 \pm 0.1)$$ GHz/strain for the V2 center in 4H-SiC have been experimentally determined for the first time using the optically detected magnetic resonance method. The results obtained can be used to control spin states in SiC by means of the controlled piezoelectric strain in AlN and to estimate the fine-structure parameter D of spin centers using Raman scattering. Such an estimate makes it possible to forecast magnetometric parameters of nanosensors based on SiC nanocrystals.

Introduction. The existing types of connection assignment in the design scheme — hinged and absolutely rigid joints — do not reflect the actual operation of the connection. The lack of calculation of the actual rigidness of joint and its failure to take into account in the design of the frame can lead to a different distribution of efforts from the calculated one and an increase in the movement of the frame elements. The purpose of this work is to researching the influence of the change size of the elements forming the column base on its rotational rigidity. Materials and methods. The calculation of the transverse frame was performed in the Dlubal RFEM software package. The calculated efforts acting in the lower section of the column were transferred to the calculated models of the column base, made in the IDEA StatiCa software package, in which the further calculation of the joint rigidness was performed. Results. The rotational rigidness of the joints with different structural solutions of the column base is determined. The change in the rigidness of the connection between the column and the foundation with an increase in the thickness and height of the support ribs is analyzed. Based on the calculations, graphs of the identified dependencies are constructed. As an example of strengthening the base of the column, the introduction of a traverse was proposed. The article considers six variants of the traverse device, and variants with three support ribs and with traverses, but without support ribs. The calculated rigidness of the column bases is summarized in graphs, where it can be seen that the metal adding is effective only up to a certain point. Variants of the arrangement of column bases with additional transverse ribs are considered. Conclusions. The greatest contribution to the increase in the rotational rigidness of the joint is made by the addition of a traverse. By increasing the thickness or height of the introduced traverse, it is impossible to achieve absolutely rigid fixing, it is necessary to change several parameters in a complex way. The introduction of additional ribs located outside the plane of action of the moment practically does not affect the rigidity of the joint.

The acid-base properties, structures, and tautomerism of protonated and free forms of carboxylic acid guanyl hydrazides (acylaminoguanidines) were studied using experimental and theoretical methods. According to the experimental data, guanyl hydrazides are relatively strong bases (pKa 8.1-8.9 in water at 25 °C) in spite of the presence of the electron-withdrawing carbonyl group in their molecules. The results of studying by NMR spectroscopy, X-ray diffraction analysis, and DFT calculations show that in polar media free guanyl hydrazides predominantly exist as zwitterionic tautomers (inner salts) with positive charge localization on the protonated guanidine moiety and negative charge localization on the deprotonated amide group.

The article is devoted to the problems of legal regulation of the functioning of private universities in Ukraine on the example of one of the first such educational institutions – Kharkov Humanitarian University "People's Ukrainian Academy". The article presents a historical retrospective of the main legal conflicts in the activities of the PUA, which were not only resolved in its favor, but also formed the basis for the correction of the current legislation by amending the regulations governing the activities of educational institutions in Ukraine. The relevance of this topic is mainly due to the need to amend the current legislation in order to ensure the equality of the legal status of educational institutions based on various forms of ownership and which are still in a state of intense competition for consumers of educational services. The analysis of the current educational legislation presented in the article testifies to the continuing normative consolidation of preferences for state educational institutions, which leads to legal discrimination of private universities. This, in turn, not only contributes to a decrease in the quality of educational activities of private educational institutions, but can also lead to their self-liquidation. The article also emphasizes the need to continue work on the correlation of educational and civil legislation. For this purpose, as well as to improve the overall qualitative characteristics of the functioning of the Ukrainian educational industry, the emphasis is placed on the need to systematize the norms of educational legislation as one of the forms for its improvement. At the same time, one of the main means of conceptual renewal of the system of educational legislation of Ukraine is its early codification, which should lead to the creation of a single systematized act – the Code of Ukraine on Education.

The article notes that the integrated sustainable development of regions, urban districts, and municipal districts is one of the fundamental tasks in the implementation of the adopted strategies for sustainable socio-economic development of territories. These concepts are aimed at the comprehensive development of human society, meeting the normal spiritual and moral needs of current and future generations of people.

Complexes of Pd(II) with NHC ligands can suffer facile decomposition in the presence of alkali metal hydroxides, alkoxydes and other strong oxygen-containing bases via the reductive elimination of the NHC and Pd-coordinated base anion, the so-called O–NHC coupling. O–NHC coupling can represent a serious problem for the stability of Pd/NHC catalytic systems in numerous practically important reactions conducted in the presence of bases. In the present study, a new approach to stabilizing the Pd–NHC bond against cleavage by strong bases was developed. The approach relies on the installation of an NH–acidic RNH substituent at position 3 of the triazole ring of the 1,2,4-triazol-5-ylidene ligand. A series of new Pd/NHCs containing RNH substituents (R = Ac, Ph, alkyl) in triazole NHC ligands were synthesized. These complexes undergo reversible deprotonation of the RNH group in strong alkaline media and demonstrate superior stability of the Pd–NHC bond, significantly higher than complexes of similar structure without the RNH group. DFT calculations revealed that the anionic Pd/NHC complex containing an N-deprotonated acetamido group (R = Ac) is more kinetically stable against O–NHC coupling and less prone to lose NHC via heterolytic dissociation of the Pd–NHC bond than the neutral complex. The new complexes with RNH-functionalized NHC ligands were tested as precatalysts in the Suzuki–Miyaura coupling of p-tolyl bromide with phenylboronic acid in the presence of KOH and revealed more than 2 times higher TONs than similar complexes without the RNH group or ligandless Pd system.

In this letter, we report the use of optically addressable spin centers in SiC to probe the static magnetic stray fields generated by a ferromagnetic microstructure lithographically patterned on the surface of a SiC crystal. The stray fields cause shifts in the resonance frequency of the spin centers. The spin resonance in the spin centers is driven by a micrometer-sized microwave antenna patterned adjacent to the magnetic element. The patterning of the antenna is done to ensure that the driving microwave fields are delivered locally and more efficiently compared to conventional, millimeter-sized circuits. A clear difference in the resonance frequency of the spin centers in SiC is observed at various distances to the magnetic element, for two different magnetic states. Our results are a first step toward developing magnon-quantum applications by deploying the local microwave fields and the stray fields at the micrometer length scale.

A DFT study was carried out of how the nature of metal, the oxidation state of the metal (0 and +2), as well as the structures of N-heterocyclic carbene (NHC) and other ligands influence the heterolytic dissociation energies of the metal-ligand bond in the complexes M-NHC (M = Ni, Pd, Pt). It was shown that a change in the oxidation state of the metal can be followed by a considerable change in the M-NHC bond dissociation energy (up to nearly 21 kcal mol−1), which is also strongly influenced by the ligand in the trans-position to NHC.

Introduction. The use of composite materials in agricultural engineering is known as one of the recommended ways to reduce the weight of the structure and protect against corrosion. The main disadvantages of such products are their low resistance to shock loads that occur during operation. The aim of this study is to develop a glass composite multi-layer structure of the trailer side, capable of withstanding shock loads along with statically applied forces, without including additional reinforcing metal elements in the zones of the possible impacts. Materials and Methods. To increase the impact resistance of the product (after an analysis of modern design solutions) the use of visco-elastic non-Newtonian fluids based on polysilicon by introducing an additional layer into the power element to compensate for impact effects is proposed. Results. On the basis of laboratory testing using statistical processing of the obtained data, the basic mechanical characteristics of non-Newtonian fluid (polysilicon) during impact tests (density, Poisson’s ratio, Young’s modulus, shear modulus) are determined, and graphs of the obtained dependencies are constructed. The temperature of the tested polysilicon samples did not significantly affect their mechanical properties. It is established that starting from the value of relative deformation 0.042, during the impact polysilicon shows linearly elastic properties. Discussion and Conclusion. Based on the received mechanical characteristics, the conclusions about resistance to shock loads of polysilicon as a component of a trailer board element are made. The variant of arrangement of the trailer board structural solution as a multilayer sandwich element with external parts made of polymer composite material with internal filling with fiberglass cells and polysilicon placed in large cells is offered.

Catalytic activity of nickel(ii) and palladium(ii) N-heterocyclic carbene (NHC) complexes derived from imidazole, benzimidazole, and 1,2,4-triazole was comparatively evaluated in the cross-coupling reactions of aryl halides with arylboronic acids. Readily available nickel bis-NHC complexes (NHC)2NiX2 (X = Cl, Br, or I) exhibited the activity comparable to that of the structurally related palladium complexes and, consequently, can be applied as efficient catalysts for the Suzuki—Miyaura reaction.

Multicomponent non-aqueous electrolytes based on cyclic carbonates and tetraethylammonium tetrafluoroborate have been developed for the operation of supercapacitors at elevated temperatures. Propylene carbonate, which has a high dielectric constant and a high boiling point, was used as the main solvent of electrolytes. However, a significant drawback of propylene carbonate is its high viscosity, which leads to decrease in the electrical conductivity of electrolytes based on it compared to electrolytes based on acetonitrile. To increase the electrical conductivity, an additional component was introduced into the electrolyte – a cosolvent with the necessary set of properties. When choosing cosolvents, two approaches were used. In the first case, to increase the dielectric permittivity of the liquid phase, ethylene carbonate having a higher dielectric constant than propylene carbonate was introduced into the electrolyte. This approach made it possible to significantly increase the electrical conductivity of the electrolyte and to achieve high resource stability of the supercapacitor. The values of the specific capacitance and energy of the supercapacitor with the introduction of ethylene carbonate in the electrolyte practically did not change. In the second case, butyl acetate, which has a low viscosity but has a moderate polarity and a sufficiently high boiling point, was used as a co-solvent. In this case, not only an increase in the electrical conductivity of the electrolyte was observed, but also a significant increase in the capacitive characteristics of the supercapacitor. It is shown that the use of a mixture of cyclic carbonates and esters as a solvent in the composition of the electrolyte can increase its specific conductivity by 40%, and the specific energy consumption of a supercapacitor by 20%. The developed electrolytes provide long-term operation of supercapacitors both at room temperature and at elevated temperatures up to 80 °С.

Many reactions catalyzed by Pd complexes with N-heterocyclic carbene (NHC) ligands are performed in the presence of amines which usually act as coupling reagents or mild bases. However, amines can react with Pd/NHC complexes in a number of ways: enhancing molecular catalysis, causing the catalyst deactivation or triggering the ligandless modes of catalysis by producing NHC-free active palladium species. This study gains insight into conditions required for the efficient use of amines as activators of molecular Pd/NHC catalysis and preventing the undesirable reductive cleavage of the Pd–NHC bond in catalytic systems. Reactions of Pd/NHC complexes with various amines within a temperature range of 25–140 °C and thermal stability of the resulting amino-complexes are examined. The results indicate the major influence of the amine structure and reaction temperature on the catalyst transformation. In particular, thermal decomposition of Pd/NHC complexes with aliphatic amine ligands predominantly leads to reductive Pd–NHC bond cleavage, while deprotonation of the complexes with primary and secondary aliphatic amine ligands in the presence of strong bases at 25–60 °C promotes the activation of molecular Pd/NHC catalysis. Efficient Pd–PEPPSI complex–amine systems suitable for strong-base-promoted C–S cross-coupling reactions between aryl halides and thiols are suggested on the basis of these findings.

The article discusses some aspects of staffing sustainable development of the municipal formation. The article presents the results of a sociological study of human resources, qualitative and quantitative characteristics of municipal employees. It is emphasized that the staffing of sustainable development is the aggregate ability of the population to ensure the strategic socio-economic development of the municipality on the basis of the practical implementation of the professional activity of human resources and is one of the determining factors and the most important resource for sustainable socio-economic development.

Optically addressable spin defects in silicon carbide (SiC) are an emerging platform for quantum information processing compatible with nanofabrication processes and device control used by the semiconductor industry. System scalability towards large-scale quantum networks demands integration into nanophotonic structures with efficient spin–photon interfaces. However, degradation of the spin-optical coherence after integration in nanophotonic structures has hindered the potential of most colour centre platforms. Here, we demonstrate the implantation of silicon vacancy centres (VSi) in SiC without deterioration of their intrinsic spin-optical properties. In particular, we show nearly lifetime-limited photon emission and high spin-coherence times for single defects implanted in bulk as well as in nanophotonic waveguides created by reactive ion etching. Furthermore, we take advantage of the high spin-optical coherences of VSi centres in waveguides to demonstrate controlled operations on nearby nuclear spin qubits, which is a crucial step towards fault-tolerant quantum information distribution based on cavity quantum electrodynamics. Colour centres are a promising quantum information platform, but coherence degradation after integration in nanostructures has hindered scalability. Here, the authors show that waveguide-integrated VSi centres in SiC maintain spin-optical coherences, enabling nuclear high-fidelity spin qubit operations.

Negatively charged boron vacancies ($V_B^-$) in hexagonal boron nitride (hBN) exhibit a broad emission spectrum due to strong electron-phonon coupling and Jahn-Teller mixing of electronic states. As such, the direct measurement of zero-phonon line (ZPL) of $V_B^-$ has remained elusive. Here, we measure the room-temperature ZPL wavelength to be $773\pm2$ nm by coupling the hBN layer to the high-Q nanobeam cavity. As the wavelength of cavity mode is tuned, we observe a pronounced intensity resonance, indicating the coupling to $V_B^-$. Our observations are consistent with the spatial redistribution of $V_B^-$ emission. Spatially resolved measurements show a clear Purcell effect maximum at the midpoint of the nanobeam, in accord with the optical field distribution of the cavity mode. Our results are in good agreement with theoretical calculations, opening the way to using $V_B^-$ as cavity spin-photon interfaces.

PANDA (anti-proton annihiliation at Darmstadt) is planned to be one of the four main experiments at the future international accelerator complex FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany. It is going to address fundamental questions of hadron physics and quantum chromodynamics using cooled antiproton beams with a high intensity and and momenta between 1.5 and 15 GeV/c. PANDA is designed to reach a maximum luminosity of 2 × 1032 cm−2 s. Most of the physics programs require an excellent particle identification (PID). The PID of hadronic states at the forward endcap of the target spectrometer will be done by a fast and compact Cherenkov detector that uses the detection of internally reflected Cherenkov light (DIRC) principle. It is designed to cover the polar angle range from 5° to 22° and to provide a separation power for the separation of charged pions and kaons up to 3 standard deviations (s.d.) for particle momenta up to 4 GeV/c in order to cover the important particle phase space. This document describes the technical design and the expected performance of the novel PANDA disc DIRC detector that has not been used in any other high energy physics experiment before. The performance has been studied with Monte-Carlo simulations and various beam tests at DESY and CERN. The final design meets all PANDA requirements and guarantees sufficient safety margins.

Masers as telecommunication amplifiers have been known for decades, yet their application is strongly limited due to extreme operating conditions requiring vacuum techniques and cryogenic temperatures. Recently, a new generation of masers has been invented based on optically pumped spin states in pentacene and diamond. In this study, we pave the way for masers based on spin S = 3/2 silicon vacancy (V$_{Si}$) defects in silicon carbide (SiC) to overcome the microwave generation threshold and discuss the advantages of this highly developed spin hosting material. To achieve population inversion, we optically pump the V$_{Si}$ into their $m_S$ = $\pm$1/2 spin sub-states and additionally tune the Zeeman energy splitting by applying an external magnetic field. In this way, the prerequisites for stimulated emission by means of resonant microwaves in the 10 GHz range are fulfilled. On the way to realising a maser, we were able to systematically solve a series of subtasks that improved the underlying relevant physical parameters of the SiC samples. Among others, we investigated the pump efficiency as a function of the optical excitation wavelength and the angle between the magnetic field and the defect symmetry axis in order to boost the population inversion factor, a key figure of merit for the targeted microwave oscillator. Furthermore, we developed a high-Q sapphire microwave resonator (Q ~ 10$^4$ - 10$^5$) with which we find superradiant stimulated microwave emission. In summary, SiC with optimized spin defect density and thus spin relaxation rates is well on its way of becoming a suitable maser gain material with wide-ranging applications., Comment: 15 pages, 4 figures

Description, Simultaneous strain-driven transitions in ground and excited state of spin qubits lead to the coherent trapping of the spin state., Spin centers are promising qubits for quantum technologies. Here, we show that the acoustic manipulation of spin qubits in their electronic excited state provides an approach for coherent spin control inaccessible so far. We demonstrate a giant interaction between the strain field of a surface acoustic wave (SAW) and the excited-state spin of silicon vacancies in silicon carbide, which is about two orders of magnitude stronger than in the ground state. The simultaneous spin driving in the ground and excited states with the same SAW leads to the trapping of the spin along a direction given by the frequency detuning from the corresponding spin resonances. The coherence of the spin-trapped states becomes only limited by relaxation processes intrinsic to the ground state. The coherent acoustic manipulation of spins in the ground and excited state provides new opportunities for efficient on-chip quantum information protocols and coherent sensing.

The drift parameters and indicators of the quantitative development of zoobenthos in the watercourses of this island in the Kuril Islands archipelago have been estimated for the first time. Hydrobionts drifting during the day are smaller than those drifting in the dark, which may be a consequence of the food selectivity of visually oriented drift-feeding fish. Since the upstream movement of zoobenthos contributes to the overestimation of the coefficients of a specific drift rate, it is proposed to use the drift intensity during one exposure of the net for calculations.

Surface activation of carbon materials produced by chemical vapor deposition onto a nickel plate is described. The products of pyrolysis of a gas mixture composed of propane, butane, and isobutane were for the most part nanofibers. This material was used as the active mass for electrodes of supercapacitors. The elec¬trodes were activated with a potassium hydroxide (KOH) at temperatures of 700 and 800°C in the atmosphere of argon. The activation efficiency was evaluated by the capacitance of supercapacitor cells by measurement of the electrochemical properties based on activated and unactivated materials. The salt 1.1-dimethylpyrrolidinium tetrafluoroborate (DMP) in acetonitrile (AN) was used as an electrolyte. The specific surface area of the electrodes was determined from adsorption data. It was shown that the specific surface areas of non-activated samples and samples activated at 700 and 800°C were 190, 338, and 586 m2 g-1, respectively. The specific capacitance of the samples also became higher with increasing specific surface area.

The data on carbonization and surface activation of raw hogweed (Heracleum) are presented. The structural and electrochemical properties of thus synthesized carbon materials which can be used as the electrode materials in supercapacitors are studied. The hogweed samples are preliminarily carbonized at 400°C and then activated with potassium hydroxide (KOH) at temperatures of 700, 800, and 900°C in argon atmosphere. According to isotherms of nitrogen adsorption and the BET equation, the specific surface area of samples activated at 700, 800, and 900°C is 913 ± 22, 1215 ± 70, and 1929 ± 99 m2/g, respectively. As the activation temperature increases, the specific surface area and the mesopore volume of samples also increases, whereas the micropore fraction decreases. 1,1-Dimethylpyrrolidinium tetrafluoroborate in acetonitrile was used as an electrolyte. The specific capacitance of samples activated at 700, 800, and 900°C at the current density of 1 A/g is 51 ± 4, 114 ± 2, and 108 ± 3 F/g, respectively. The 40% increase in the specific surface area and the 35% increase in the volume of mesopores results in the increase in the specific capacitance. The further increase in the specific surface area and the volume of mesopores up to 70% does not increase the specific capacitance.

One of the challenges in the field of quantum sensing and information processing is to selectively address and coherently manipulate highly homogeneous qubits subject to external perturbations. Here, we present room-temperature coherent control of high-dimensional quantum bits, the so-called qudits, associated with vacancy-related spins in silicon carbide enriched with nuclear spin-free isotopes. In addition to the excitation of a spectrally narrow qudit mode at the pump frequency, several other modes are excited in the electron spin resonance spectra whose relative positions depend on the external magnetic field. We develop a theory of multipole spin dynamics and demonstrate selective quantum control of homogeneous spin packets with sub-MHz spectral resolution. Furthermore, we perform two-frequency Ramsey interferometry to demonstrate absolute dc magnetometry, which is immune to thermal noise and strain inhomogeneity., High-dimensional quantum bits advance the application of quantum sensing and information processing technologies but suffer from the low spectral selectivity and working temperature. Here the authors present the selective excitation and control of spin qudits modes based on an ensemble of silicon vacancy defects in silicon carbide at room temperature.

The mercury test is a rapid and widely used method for distinguishing truly homogeneous molecular catalysis from nanoparticle metal catalysis. In the current work, using various M0 and MII complexe...

The effect of electrically conductive additives in the active layer of electrodes on the electrochemical parameters of supercapacitor cells was studied. Carbon nanofibers (CNFs) obtained by pyrolysis of hydrocarbon mixtures (propane, butane, and isobutane) were used as a conductive additive. The obtained carbon nanofibers were introduced into the active layer of the carbon electrode at 10 to 40 wt %. The electrochemical characteristics of the electrodes were studied by galvanostatic charge–discharge and cyclic voltammetry in the range from 0 to 2.7 V. The impedance spectra were measured in the frequency range from 100 kHz to 10 mHz with an alternating current voltage of 10 mV. A 1 M solution of 1,1-dimethylpyrrolidinium tetrafluoroborate in acetonitrile was used as an electrolyte. The content of of carbon nanofibers in the active electrode layer decreases the internal electrical resistance of the supercapacitor cell. The use of carbon nanofibers at 30 wt % in the active layer leads to a decrease in the internal series resistance and also increases the speed of ions inside the pores of the active electrode layer. The use of carbon nanofibers at up to 40 wt % leads to a decrease in the total specific surface area of the active layer, which reduces the specific capacity of the cells.

Silicon, a ubiquitous material in modern computing, is an emerging platform for realizing a source of indistinguishable single photons on demand. The integration of recently discovered single-photon emitters in silicon into photonic structures is advantageous to exploit their full potential for integrated photonic quantum technologies. Here, we show the integration of an ensemble of telecom photon emitters in a two-dimensional array of silicon nanopillars. We developed a top-down nanofabrication method, enabling the production of thousands of nanopillars per square millimeter with state-of-the-art photonic-circuit pitch, all the while being free of fabrication-related radiation damage defects. We found a waveguiding effect of the 1278 nm-G center emission along individual pillars accompanied by improved brightness compared to that of bulk silicon. These results unlock clear pathways to monolithically integrating single-photon emitters into a photonic platform at a scale that matches the required pitch of quantum photonic circuits.

Optically active spin centers associated with atomic scale defects in $\mathrm{Si}\mathrm{C}$ are promising candidates for quantum technology, owing to their outstanding optical and spin properties. Photoluminescence as a mature optical investigating tool is widely used for the identification of spin defects and exploration of their properties. However, in the case of spectrally overlapping contributions from different types of defects, traditional photoluminescence measurements cannot be used to separately obtain their optical and vibrational properties, such as the local phonon energy and the Debye-Waller factor. Here, we apply spin-resonant microwave-assisted spectroscopy to investigate the optical and vibrational properties of silicon vacancies in 6H-$\mathrm{Si}\mathrm{C}$ and divacancies in 4H- and 6H-$\mathrm{Si}\mathrm{C}$. We isolate contributions from each type of defect, investigate their local vibrational modes, and obtain the Debye-Waller factor. This work proves that microwave-assisted spectroscopy is a suitable tool for the investigation of optical and vibrational properties of a large variety of spin defects.