Academic CentreThe teaching staff of the chair participates in the implementation of various study courses – General Chemistry, Physical Chemistry, Kinetics and Catalysis, Structure of Atoms and Molecules, X-Ray Methods in Chemistry, Data Processing Methods in Chemistry, Chromatography, etc. Several lecturers are experts of the Latvian Academy of Sciences in their respective fields of chemistry and physics.
| Name and Surname | Position |
Agris Bērziņš | Chair manager, Associate professor, Senior researcher |
| Andris Actiņš | Professor |
| Liāna Orola | Associate professor |
| Elīna Pajuste | Associate professor |
| Guntars Vaivars | Associate professor |
| Ilva Nakurte | Assistant professor |
| Māra Feldmane | Lecturer, Researcher, PhD student |
| Artis Kons | Senior researcher |
| Antons Podjava | Senior researcher |
| Toms Rēķis | Researcher |
| Kristaps Saršūns | Researcher, PhD student |
| Aina Semjonova | Researcher, PhD student |
| Aija Trimdale-Deksne | Researcher, Chemist |
| Valda Valkovska | Researcher, Lecturer, PhD student |
| Marta Kāne | Chemist |
| Zane Čerpakovska | Chemist, PhD student |
| Juris Kostjukovs | Chemist |
| Aldis Zekunde | Chemist |
| Kaspars Meijers | Chemist |
| Anita Kalniņa | Laboratory manager |
| Artūrs Šilaks | PhD student |
Formation, physical properties, transformations, structure, and crystallization process of crystal phases of organic solids
Identification of factors causing different solid form landscape complexity of structurally similar compounds
Structurally similar pharmaceutically relevant compounds are studied to identify factors causing different propensity of these compounds to form solvates, hydrates and polymorphs. Detailed crystallographic analysis, computational calculations of intramolecular and intermolecular energy, specification of preparation conditions for selected crystal forms and association in solution using spectroscopic methods and molecular dynamics simulations are used.
Trimdale-Deksne, A., Kons, A., Orola, L., Mishnev, A., Stepanovs, D., Mazur, L., Skiba, M., Dudek, M.K., Fantozzi, N., Virieux, D., Colacino, E., Bērziņš, A. Crystallographic and Computational Analysis of the Solid-Form Landscape of Three Structurally Related Imidazolidine-2,4-dione Active Pharmaceutical Ingredients: Nitrofurantoin, Furazidin, and Dantrolene. Cryst. Growth Des. 2023, 23, (2), 930–945. DOI: 10.1021/acs.cgd.2c01142
Bērziņš, A., Semjonova, A., Actiņš, A., Salvalaglio, M. Speciation of Substituted Benzoic Acids in Solution: Evaluation of Spectroscopic and Computational Methods for the Identification of Associates and Their Role in Crystallization. Cryst. Growth Des. 2021, 21, (9), 4823–4836. DOI: 10.1021/acs.cgd.0c01605
Trimdale, A., Mishnev, A., Bērziņš, A. Combined Use of Structure Analysis, Studies of Molecular Association in Solution, and Molecular Modelling to Understand the Different Propensities of Dihydroxybenzoic Acids to Form Solid Phases. Pharmaceutics 2021, 13, (5), 734. DOI: 10.3390/pharmaceutics13050734
Bērziņš, A.; Zvaniņa, D.; Trimdale, A. Detailed analysis of packing efficiency allows rationalization of solvate formation propensity for selected structurally similar organic molecules. Cryst. Growth Des. 2018, DOI: 10.1021/acs.cgd.7b01457
Understanding the driving forces of formation, transformation mechanisms, and stability of crystal forms of pharmaceutical compounds
Pharmaceutical compounds forming numerous polymorphs, hydrates and solvates are studied to identify and rationalize the driving forces of formation of these crystal forms, the mechanisms of the observed phase transformations, and the stability of these crystal forms. For this, crystal form screening, crystal structure analysis with different crystallographic and computational chemistry tools and experimental characterization of stability and transformations of crystal forms are used.
Orola, L., Mishnev, A., Stepanovs, D., Bērziņš, A. Crystallographic Study of Solvates and Solvate Hydrates of an Antibacterial Furazidin. Cryst. Growth Des. 2023, 23, (2), 873–884 DOI: 10.1021/acs.cgd.2c01114
Kons, A., Mishnev, A, Mukhametzyanov, T.A., Buzyurov, A.V., Lapuk, S.E., Bērziņš, A. Hexamorphism of Dantrolene: Insight into the Crystal Structures, Stability, and Phase Transformations. Cryst. Growth Des. 2021, 21, (2), 1190–1201. DOI: 10.1021/acs.cgd.0c01508
Bērziņš, A., Kons, A., Saršūns, K., Belyakov, S., Actiņš, A. On the rationalization of formation of solvates: experimental and computational study of solid forms of several nitrobenzoic acid derivatives. Cryst. Growth Des. 2020, 20, (9), 5767–5784 DOI: 10.1021/acs.cgd.0c00331
Kons, A., Bērziņš, A., Actiņš, A., Rekis, T., van Smaalen, S., Mishnev, A. Polymorphism of R-Encenicline Hydrochloride: Access to the Highest Number of Structurally Characterized Polymorphs Using Desolvation of Various Solvates. Cryst. Growth Des. 2019, 19, (8), 4765-4773. DOI: 10.1021/acs.cgd.9b00648
Investigation of application of additives for controlling the polymorphic outcome of crystallization
Crystallization process in presence of additives is investigated to search for conditions under which control of the crystallization polymorphic outcome for pharmaceutical molecules and model compounds is provided. The most suitable additive, solvent, crystallization approach and conditions providing reliable control of polymorphic outcome is identified. Mechanism for the additive provided crystallization control is explored using crystallographic analysis, computational tools and exploration of properties and transformations of crystal forms.
Bērziņš, A., Trimdale-Deksne, A., Belyakov, S., ter Horst, J.H. Switching nitrofurantoin polymorphic outcome in solvent mediated phase transformation and crystallization using solvent and additives. 2022. DOI: 10.26434/chemrxiv-2022-cdl0z
Semjonova, A., Bērziņš, A. Surfactant Provided Control of Crystallization Polymorphic Outcome and Stabilization of Metastable Polymorphs of 2,6-Dimethoxyphenylboronic Acid. Crystals 2022, 12, 1738. DOI: 10.3390/cryst12121738
Semjonova, A., Bērziņš, A. Controlling the Polymorphic Outcome of 2,6-Dimethoxybenzoic Acid Crystallization Using Additives. Crystals 2022, 12, 1161. DOI: 10.3390/cryst12081161
Exploration of formation of solid solutions in molecular crystals
Solid solutions in molecular crystals are explored by researching the solid solution formation, structure and properties. The research is conducted in three directions: 1) factors that control the solid solution formation between structurally similar pharmaceutical molecules and model compounds are identified by constructing the phase diagrams and using structure analysis and computational calculations to rationalize the observations, 2) solid solutions allowing fine-tuning of selected properties of the studied phase, such as luminescence properties, are studied, and 3) formation of solid solutions between the enantiomers of selected pharmaceutical compounds are researched to understand the crystallization behavior of these compounds.
Saršūns, K., Bērziņš, A. Experimental and Computational Investigation of Benperidol and Droperidol Solid Solutions in Different Crystal Structures. Cryst. Growth Des. 2023, 23, (2), 1133-1144. DOI: 10.1021/acs.cgd.2c01269
Saršūns, K., Kemere, M., Karziņins, A., Klimenkovs, I., Bērziņš, A., Sarakovskis, A., Rekis, T. Fine-Tuning Solid State Luminescence Properties of Organic Crystals via Solid Solution Formation: The Example of 4-Iodothioxanthone–4-Chlorothioxanthone System. Crystal Growth & Design 2022, 22, (8), 4838-4844. DOI: 10.1021/acs.cgd.2c00313
Saršūns, K., Bērziņš, A., Rekis, T. Solid Solutions in the Xanthone–Thioxanthone Binary System: How Well Are Similar Molecules Discriminated in the Solid State? Cryst. Growth Des. 2020, 20, (12), 7997–8004. DOI: 10.1021/acs.cgd.0c01241
Rekis, T. Crystallization of chiral molecular compounds: what can be learned from the Cambridge Structural Database?, Acta Cryst. B 2020, 76, 307-315. DOI: 10.1107/S2052520620003601
Rekis, T., Bērziņš, A. On the structural aspects of solid solutions of enantiomers: an intriguing case study of enantiomer recognition in the solid state. CrystEngComm 2018, 20, 6909-6918. DOI: 10.1039/C8CE01245H
Rekis, T.; Bērziņš, A.; Sarceviča, I.; Kons, A.; Balodis, M.; Orola, L.; Lorenz, H.; Actiņš, A. A Maze of Solid Solutions of Pimobendan Enantiomers: An Extraordinary Case of Polymorph and Solvate Diversity. Cryst. Growth Des. 2018, 18, (1), 264–273. DOI: 10.1021/acs.cgd.7b01203
Chromatographic studies of natural substances and bioanalytical samples and development of methods for the analysis of such samples
Development and use of chromatographic methods for determining the composition of natural substances and bioanalytical samples
Mažylytė, R.; Kaziūnienė, J.; Orola, L.; Valkovska, V.; Lastauskienė, E.; Gegeckas, A. Phosphate Solubilizing Microorganism Bacillus sp. MVY-004 and its Significance for Biomineral Fertilizers’ Development in Agrobiotechnology. Biology 2022, 11, 2, 254. DOI: 10.3390/biology11020254
Ramata-Stunda, A.; Petriņa, Z.; Valkovska, V.; Borodušķis, M.; Gibnere, L.; Gurkovska, E. Nikolajeva, V. Synergistic Effect of Polyphenol-Rich Complex of Plant and Green Propolis Extracts with Antibiotics against Respiratory Infections Causing Bacteria. Antibiotics 2022, 11, 2, 160. DOI: 10.3390/antibiotics11020160
Ramata-Stunda, A.; Valkovska, V.; Borodušķis, M.; Livkiša, D.; Kaktiņa, E.; Silamiķele, B.; Borodušķe, A.; Pentjušs, A.; Rostoks, N. Development of metabolic engineering approaches to regulate the content of total phenolics, antiradical activity and organic acids in callus cultures of the highbush blueberry (Vaccinium corymbosum), Agron. Res. 2020, 18, 1860-1872. DOI: 10.15159/ar.20.054
Phytochemical composition of dye species and their use in wool dyeing
Valkovska, V.; Orola L. Characterization of Pigments from "Malus domestica" Leaves for Wool Dyeing. Key Eng. Mater., 2021, 850, 63-68. 10.4028/www.scientific.net/KEM.903.63
Batarāga, A.; Valkovska, V. Phytochemical Profile of Chokeberry (Aronia melanocarpa). Key Eng. Mater. 2020, 850, 184-189. 10.4028/www.scientific.net/KEM.850.184
Development of chromatography and solid phase extraction sorbents for analysis of specific bioanalytical samples
Podjava, A., Šilaks, A. Synthesis and sorptive properties of molecularly imprinted polymer for simultaneous isolation of catecholamines and their metabolites from biological fluids. J. Liq. Chromatogr. Relat. Technol. 2021, 44, (3-4), 181-188. DOI: 10.1080/10826076.2021.1874980
Podjava, A., Šilaks, A. Study of chromatographic properties of catecholamines and their acidic metabolites using novel molecularly imprinted polymers as stationary phases. Key Eng. Mater. 2021, 903, 15-21. DOI: 10.4028/www.scientific.net/KEM.903.15
Ion-conducting polymer composite membranes with ionic liquids and inorganic nanoparticles
Synthesis of sulfonated polyether ether ketone membranes with different degree of sulfonation and evaluation of the influence of the degree of sulfonation on the physical properties of these membranes. Preparation and characterization of polymer composite membranes with ionic liquids, zirconium oxide nanoparticles and carbon dispersions. Testing of the obtained membranes in alternative energy and solid-state ionic devices (fuel cells, batteries, chemical reactors, such as CO2 reduction reactors). Supervisor of the research direction assoc. prof. Guntars Vaivars, the research is carried out in collaboration with Laboratory of Chemical Technologies, Institute of Solid State Physics, University of Latvia.
Pajuste, E., Reinholds, I., Vaivars, G., Antuzevičs, A., Avotiņa, L., Sprūģis, E., Mikko, R., Heikki, K., Meri, R.M., Kaparkalējs, R. Evaluation of radiation stability of electron beam irradiated Nafion® and sulfonated poly (ether ether ketone) membranes. Polym. Degrad. Stab. 2022, 200, 109970. DOI: 10.1016/j.polymdegradstab.2022.109970
Vaivars, G., Krūkle-Bērziņa, K., Markus, M. Modelling IR spectra of sulfonated polyether ether ketone (SPEEK) membranes for fuel cells. Key Eng. Mater. 2020, 850, 138-143.DOI: 10.4028/www.scientific.net/KEM.850.138
Innovative materials for energy
Studies of radionuclides, their behavior, separation methods and application in various sectors of the economy are being conducted. Supervisor of the research direction assoc. prof. Elīna Pajuste, he research is carried out in collaboration with Department of Radiation Processes, Institute of Chemical Physics, University of Latvia.
E. Pajuste, A.S. Teimane, G. Kizane, L. Avotina, M. Halitovs, A. Lescinskis, A. Vitins, P. Kalnina, E. Lagzdina, R.J.J. Zabolockis. Tritium in plasma-facing components of JET with the ITER-Like-Wall, Phys. Scr. 2021, 96, 124050. DOI: 10.1088/1402-4896/ac29db
E. Pajuste, G. Kizane, L. Avotina, A.S. Teimane, K. Vonda, A. Lescinskis. Novel method for determination of tritium depth profiles in metallic samples, Nucl. Fusion 2019, 59, 106006. DOI: 10.1088/1741-4326/ab3056
E. Pajuste, G. Kizane, A. Vitins, I. Igaune, L. Avotina, R. Zarins. Structure, tritium depth profile and desorption from 'plasma-facing' beryllium materials of ITER-Like-Wall at JET, Nucl. Mater. Energy 2017, 12, 642 - 647. DOI: 10.1016/j.nme.2017.03.017
Studies of new application possibilities of Latvian clay minerals in the national economy
In the laboratory of clay research, Faculty of Chemistry, research on the sustainable and diverse use of underground resources, including the development of new products (materials) and technologies, is conducted. The most active research directions are:
- Characterization, enrichment and modification of clays and clay minerals;
- Scaling and optimization of technological processes (e.g., organophilization);
- Development, testing and application of new products (materials) in real-life conditions – clay-based additive for "in-can" paints for protection, reducing the use of biocides, as well as for the sustainability of the paint; https://www.paintsforlife.eu/;
- Search for effective sorbents for the collection/recovery of the critical element phosphorus – a potential alternative to agricultural fertilizers;
- Material synthesized from the Latvian underground resources for the treatment of domestic and industrial wastewater.
J. Kostjukovs, J. Karasa, S. Kostjukova. A metal free antimicrobial and UV protection additive. EU patent application WO2018130880.
J. Kostjukovs, A. Actinš, J. Karasa. Mechanochemical method for obtaining organoclays from smectites. EU patent Nr. EP2690067 B1.
J. Kostjukovs, Actiņš A., I. Sarceviča, J. Karasa. Method for obtaining smectites from clay having low levels of smectites. EU patent Nr. EP2465820 B1.
J. Karasa, S. Kostjukova, J. Kostjukovs, D. Štēbelis, I. Putna-Nīmane. Clay-based additive as a restorer’s tool to tackle the algae growth. European Coatings Journal 2022, 4, 30-33. ISSN 0930-3847
S. Kostjukova, J. Karasa, J. Kostjukovs, D. Štēbelis, Ieva Putna-Nīmane. Additive auf Tonbasis – Hilfsmittel für Restauratoren zur Bekämpfung von Algenbewuchs (Für ein algenfreies Kulturerbe). Farbe und Lack, 2022, 2, 48-55. ISSN 0014-7699.
Formation, physical properties, transformations, structure, and crystallization process of crystal phases of organic solids
Crystal engineering of pharmaceutical multicomponent phases for more efficient crystalline phase design
Supervisor: Dr.chem. Agris Bērziņš
Latvian Council of Science Fundamental and applied research project lzp-2018/1−0312. 01.09.2018 – 31.08.2021
Funding 300 000 EUR
Crystal engineering can be used as a tool for optimization of properties of pharmaceuticals. Nevertheless, the available knowledge still limits the use of this tool, as there are many aspects of formation of intermolecular interactions in the solid state which are far from being rationalized. The aim of this research project is to develop general models and approaches for rationalization of formation of multicomponent phases of pharmaceuticals. The multicomponent phases selected for this study are solvates and solid solutions of pharmaceutical substances. The findings of this study would allow simpler and more efficient design of pharmaceutical multi-component phases, therefore improving production efficiency and reducing costs associated with the design of the final commercial form of new pharmaceutical solids for Latvian pharmaceutical companies.
AI driven IP intelligence engine for early stage drug discovery
UL supervisor: assoc. prof. Agris Bērziņš
IT Health InnoStars RIS innovation project. 06.2020 – 12.2020.
Funding 74 000 EUR, UL share 24 000 EUR.
Collaboration partner: Semantic Intelligence, Ltd.
The aim of the project is to develop an artificial intelligence tool for targeted search of information in patents and other scientific literature, which would allow the search to be performed both using field-specific keywords and using in a traditional way drawn structural formulas of organic compounds.
Development of method to control the crystallization of selected pharmaceutical molecules using templates and study of the control mechanism
Supervisor: Dr.chem. Agris Bērziņš
ERDF funded individual postdoctoral project 1.1.1.2/VIAA/1/16/195. 01.11.2017 – 31.10.2020
Funding 133 806 EUR
Collaboration partners: University College London, Department of Chemistry, Prof. Sally L. Price; University College London, Department of Chemical Engineering, Dr. Matteo Salvalaglio; University of Strathclyde, EPSRC Centre for Innovative Manufacturing in Continuous Manufacturing and Crystallisation, Prof. Joop ter Horst.
The aim is to develop a method for controlling the crystallization of solvates and/or polymorphs of selected model pharmaceuticals using templates using innovative approach for template design and selection, as well as use multidisciplinary contemporary analytical and computational tools to rationalize the crystallization mechanism.
Development of integrated experimental and computational methods to aid prediction of properties and crystal form diversity of active pharmaceutical ingredients.
Supervisor: Dr.chem. Toms Rēķis
Project funded by Mikrotikls Ltd., administrated by University of Latvia Foundation. 01.01.2018 – 31.12.2019.
Funding 51 863 EUR
In this project general rules will be identified to understand the relationship between the molecular structure of organic substances and crystal structures and crystal form diversity of these compounds, which are valid for a wide range of active pharmaceutical ingredients (API). The formation of solid phases of selected API model substances will be studied using experimentally observed phase formations and computational modeling tools. The obtained results are expected to be practically useful and used for the development of new pharmaceutical substances.
Chromatographic studies of natural substances and bioanalytical samples and development of methods for the analysis of such samples
Synthesis and application of a novel molecularly imprinted polymer for selective solid-phase extraction of catecholamines and their metabolites
Supervisor: Dr.chem. Antons Podjava
Latvian Council of Science Fundamental and applied research project lzp-2022/1-0141. 2023 –2025
Funding 300 000 EUR
Development and characterization of genome-edited blueberry (Vaccinium corymbosum L.) cultures for production of high-value secondary metabolites
Supervisor: assoc. prof., Dr.biol. Nils Rostoks
Latvian Council of Science Fundamental and applied research project lzp-2018/1-0101. 01.09.2018 – 31.08.2021
Funding 300 000 EUR
Development of new selective solid-phase extraction sorbents for the simultaneous separation of catechylamines and their acid-type metabolites from samples of biological origin
Supervisor: Dr.chem. Antons Podjava
ERDF funded individual postdoctoral project 1.1.1.2/VIAA/1/16/224. 01.11.2017 – 31.10.2020
Funding 133 806 EUR
Ion-conducting polymer composite membranes with ionic liquids and inorganic nanoparticles
All projects of this research direction are primarily implemented by Institute of Solid State Physics, University of Latvia.
Advanced polymer – ionic liquid composite sodium-ion electrolytes.
Supervisor: assoc. prof. Guntars Vaivars
Latvian Council of Science Fundamental and applied research project lzp- 2020/1-0391. 2021 –2023
Funding 300 000 EUR
Collaboration partner: Institute of Solid State Physics, University of Latvia
CO2-based Electrosynthesis of ethylene oXIDE – CO2EXIDE.
Coordinator: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Corresponding UL representative: assoc. prof. Guntars Vaivars
Horizon 2020 project. 2018 - 2021.
Collaboration partner: Institute of Solid State Physics, University of Latvia
Innovative materials for energy
All projects of this research direction are primarily implemented by Institute of Chemical Physics, University of Latvia.
Graphene-based electrochemical pumping for radioactive hydrogen isotope separation
Supervisor: assoc. prof. Elīna Pajuste
ERDF co-financed project. 04.2020. – 03.2023.
UL funding 407 337.68 EUR.
Collaboration partner: SIA Baltic Scientific Instruments.
Novel and efficient approach of medical 43Sc, 44Sc and 47Sc radionuclide separation and purification from irradiated metallic targets towards radiopharmaceutical development for theranostics
Supervisor: assoc. prof. Elīna Pajuste
Latvian Council of Science Fundamental and applied research project lzp-2021/1-0539. 03.01.2022. – 30.12.2024.
Funding: 299 999.70 EUR
Top quark and Higgs physics at the CMS experiment, development of crystal scintillator detectors and sub-detectors of the CMS detector, and the development of particle accelerator technology for societal applications in collaboration with CERN
UL supervisor: assoc. prof. Elīna Pajuste
National Research Program project. VPP-IZM-CERN-2020/1-0002. 10.2020. – 10.2022.
UL funding 125 000 EUR.
Collaboration partners: Riga Technical University, Institute of Solid State Physics, University of Latvia.
Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium
UL supervisor: assoc. prof. Elīna Pajuste
Horizon 2020 project. 01.2014. – 12.2022.
UL funding 150 000 EUR.
Collaboration partners: project coordinated by Max-Planck-Gesellschaft zur Forderung der Wissenschaften EV, Germany, other institutions of the consortium
PRISMAP: The European medical isotope programme: Production of high purity isotopes by mass separation
UL supervisor: assoc. prof. Elīna Pajuste
Horizon 2020 project. 05. 2021. – 04.2025.
UL funding 110 750 EUR.
Collaboration partners: project coordinated by European Organization for Nuclear Research (CERN), Switzerland, other institutions of the consortium
Studies of new application possibilities of Latvian clay minerals in the national economy
The research is carried out in collaboration with the Faculty of Geography and Earth Sciences, University of Latvia.
LIFE ALFIO – Alina Life Formulations in Open-Source Platform (ALOSP).
Project Manager: Solvita Kostjukova
EU LIFE+ Programme, and the Administration of Latvian Environment Protection Fund. LIFE17EVN/LV000318. 01.07.2018. – 31.12.2022.
Collaboration partners: ALINA, Ltd. and Riga Technical University
Funding: 2 398 160 EUR
Unused Latvia's natural mineral resources for the development of innovative composite materials for phosphorus recovery from small municipal and industrial wastewater treatment plants to implement the principles of circular economy (CircleP)
Supervisor: Andrejs Krauklis
Latvian Council of Science Fundamental and applied research project lzp-2021/1-0090. 03.01.2022. – 30.12.2024
Collaboration partners: Riga Technical University
Funding: 300 000 EUR
Clay mineral – anthocyanin composite material sensors for food quality control
Supervisor: Rūta Ozola-Davidāne
ERDF co-financed projects. KC-PI-2020/11. 01.04.2020. – 30.06.2022.
Funding: 288 038,98 EUR
Trimdale-Deksne, A., Kons, A., Orola, L., Mishnev, A., Stepanovs, D., Mazur, L., Skiba, M., Dudek, M.K., Fantozzi, N., Virieux, D., Colacino, E., Bērziņš, A. Crystallographic and Computational Analysis of the Solid-Form Landscape of Three Structurally Related Imidazolidine-2,4-dione Active Pharmaceutical Ingredients: Nitrofurantoin, Furazidin, and Dantrolene. Cryst. Growth Des. 2023, 23, (2), 930–945. DOI: 10.1021/acs.cgd.2c01142
Factors determining why three chemically similar active pharmaceutical ingredients, antibacterial drugs nitrofurantoin and furazidin and the muscle relaxant dantrolene, have a different propensity to form crystalline phases such as solvates, hydrates and polymorphs have been identified. Detailed studies of the crystalline structures and computational calculations were carried out by analyzing the ability of these compounds to adopt different conformation, their tendency to form various intermolecular interactions and the possibility to adopt different energetically efficient molecular packing.
Kons, A., Bērziņš, A., Actiņš, A., Rekis, T., van Smaalen, S., Mishnev, A. Polymorphism of R-Encenicline Hydrochloride: Access to the Highest Number of Structurally Characterized Polymorphs Using Desolvation of Various Solvates. Cryst. Growth Des. 2019, 19, (8), 4765-4773. DOI: 10.1021/acs.cgd.9b00648
It has been discovered that the pharmaceutical compound R-encenecline hydrochloride forms 12 polymorphs, 10 of which have been structurally characterized in this study, by making this substance the compound with the largest number of crystallographically characterized polymorphs at the time of the publication. It was found that the large variety of polymorphs is observed because during the desolvation of R-encenecline hydrochloride solvates only small structural changes often occur. Moreover, in contrast to other compounds forming large number of polymorphs, R-encenecline hydrochloride in all structures adopt the same molecular conformation.
Saršūns, K., Kemere, M., Karziņins, A., Klimenkovs, I., Bērziņš, A., Sarakovskis, A., Rekis, T. Fine-Tuning Solid State Luminescence Properties of Organic Crystals via Solid Solution Formation: The Example of 4-Iodothioxanthone–4-Chlorothioxanthone System. Crystal Growth & Design 2022, 22, (8), 4838-4844. DOI: 10.1021/acs.cgd.2c00313
The possibility to fine-tune the solid-state luminescence properties of a solid solution formed by two organic luminophores by changing the ratio of the components has been investigated. It was found that in the studied system it is possible to obtain a solid solution in two different structures. In one of the structures change of the component ratio in a wide interval did not provide a possibility to significantly influence the photoluminescence spectrum, whereas in the other structure, despite the component ratio could be changed in smaller range, a significant influence of the component ratio on the photoluminescence spectrum was observed.
Sarceviča, I.; Orola, L.; Nartowski, K.P; Khimyak, Y.Z.; Round, A.N.; Fábián, L. Mechanistic and Kinetic Insight into Spontaneous Cocrystallization of Isoniazid and Benzoic Acid. Mol. Pharmaceutics 2015, 12, (8), 2981-2992. DOI: 10.1021/acs.molpharmaceut.5b00250
The isoniazid - benzoic solid-phase co-crystallization reaction was studied by attempting to obtain the information on the mechanism and rate of this reaction. Although the reaction is spontaneous, it was determined that the rate is significantly affected by temperature and relative humidity, as well as sample pretreatment. Particular attention was paid to investigating the role of the moisture.
Mažylytė, R.; Kaziūnienė, J.; Orola, L.; Valkovska, V.; Lastauskienė, E.; Gegeckas, A. Phosphate Solubilizing Microorganism Bacillus sp. MVY-004 and its Significance for Biomineral Fertilizers’ Development in Agrobiotechnology. Biology 2022, 11, 2, 254. DOI: 10.3390/biology11020254
Podjava, A., Šilaks, A. Synthesis and sorptive properties of molecularly imprinted polymer for simultaneous isolation of catecholamines and their metabolites from biological fluids. J. Liq. Chromatogr. Relat. Technol. 2021, 44, (3-4), 181-188. DOI: 10.1080/10826076.2021.1874980
Pajuste, E., Reinholds, I., Vaivars, G., Antuzevičs, A., Avotiņa, L., Sprūģis, E., Mikko, R., Heikki, K., Meri, R.M., Kaparkalējs, R. Evaluation of radiation stability of electron beam irradiated Nafion® and sulfonated poly (ether ether ketone) membranes. Polym. Degrad. Stab. 2022, 200, 109970. DOI: 10.1016/j.polymdegradstab.2022.109970
Luo, H., Vaivars, G., Agboola, B., Mu, S., Mathe, M. Anion exchange membrane based on alkali doped poly(2,5-benzimidazole) for fuel cell. Solid State Ion. 2012, 208, 52-55. DOI: 10.1016/j.ssi.2011.11.029
E. Pajuste, A.S. Teimane, G. Kizane, L. Avotina, M. Halitovs, A. Lescinskis, A. Vitins, P. Kalnina, E. Lagzdina, R.J.J. Zabolockis. Tritium in plasma-facing components of JET with the ITER-Like-Wall, Phys. Scr. 2021, 96, 124050. DOI: 10.1088/1402-4896/ac29db
E. Pajuste, G. Kizane, L. Avotina, A.S. Teimane, K. Vonda, A. Lescinskis. Novel method for determination of tritium depth profiles in metallic samples, Nucl. Fusion 2019, 59, 106006. DOI: 10.1088/1741-4326/ab3056
J. Kostjukovs, A. Actinš, J. Karasa. Mechanochemical method for obtaining organoclays from smectites. EU patent Nr. EP2690067 B1.
J. Kostjukovs, Actiņš A., I. Sarceviča, J. Karasa. Method for obtaining smectites from clay having low levels of smectites. EU patent Nr. EP2465820 B1.
PXRD diffractometer D8 Advance (Bruker)
Diffractometer is equipped with a Cu X-ray tube and a 1D position sensitive detector. PXRD can be used for identification and quantification of crystalline phases. Database ICDD PDF-2 allows identification of inorganic phases and common organic phases.
PXRD diffractometer D8 Discover (Bruker)
Diffractometer is equipped with a Cu X-ray tube and a 1D position sensitive detector. Diffraction patterns can be measured at a very wide temperature range (from –190 to 450°C) or different relative humidity (0−90% in temperature range of 25 − 90°C).
Differential scanning calorimeter DSC25 (TA Instruments)
Analysis of phase transitions and heat capacity can be performed in a temperature range from −90 to 725°C in open or closed pans.
Thermogravimeter / Differential scanning calorimeter TG/DSC 2 (Mettler Toledo)
Analysis of phase transitions and weight change can be performed in a temperature range from 20 to 1600°C.
Dynamic vapour sorption device DVS Advantage (Surface Measurement Systems)
Measurement of sorption and desorption of water and other solvent vapour at different relative humidity / solvent vapor pressure can be performed in a temperature range of 5 − 60°C and relative humidity / solvent vapor pressure range from 0 to 98%.
Multi-reactor parallel crystallizer Crystal16 (Technobis)
Crystallization and dissolution processes can be studied in 16 separate reactors at a scale of ~1 mL with adjustable heating and cooling regimes and stirring mode by detecting crystallization or dissolution by turbidity measurements. Crystal16 allows solid form (polymorph, co-crystal, salt) screening, solubility determination, construction of phase diagrams, optimization of crystallization process, etc.
Wavelength-Dispersive X-ray fluorescence spectrometer S8 Tiger (Bruker)
XRF spectrometer S8 Tiger allows elemental analysis of different samples in non-destructive manner. Elements with Z ≥ 11 (starting from Na) can be determined by performing the measurement in vacuum of He atmosphere. Solid and liquid samples of different scientific and industrial applications can be measured.
High-performance liquid chromatograph/mass spectrometer (HPLC/MS) with time-of-flight (TOF) detector 6230A (Agilent Technologies)
Liquid chromatography coupled with a mass spectrometer detector allows not only quantitative and qualitative analysis of the studied objects, but also to clarify their structure by determining the mass of fragments ions formed during ionization. Time-of-flight mass spectrometry allows the analysis of compounds according to their exact masses. It is the only analysis method that accurately determines the molar mass of the analyzed compounds.
Fourier transform infrared (FTIR) spectrometer Frontier FTIR (Perkin Elmer)
Samples can be analysed using ATR sample stage with diamond crystal or in KBr discs. Liquid samples can be analysed in transmission cell.
Potentiostat PGSTAT204 (AutoLab)
Various electrochemical analyzes in potentiostatic and galvanostatic modes and impedance measurements can be performed, electrode cyclic voltammetry curves can be recorded.
