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Dr. Krunoslav Užarević

Head of laboratory
Telephone
+385 1 457 1329
Internal phone number
1946
Address
Bijenicka 54
HR-10000 Zagreb
Croatia
Curriculum vitae

Research Areas

Specific research interests

Projects

  • 2019-2021 European Social Fund and Croatian Science Foundation – 300 000 E “Mechanochemical and solvent-free strategies towards functional porous materials with advanced physicochemical and catalytic properties”.

    2016-2019 Croatian Science Foundation Starting Grant (duration 3 years). 150000 E (PI)

    2019 Grant of Croatian Academy of Sciences and Arts for the organization of an international scientific meeting (Solid-State Science and Research 2019). (PI)

    2019- DESY synchrotron grant: Real-time and in situ monitoring of the mechanical stress and amorphization processes in relevant metal-organic frameworks (PI)

    2016- DESY synchrotron grant: Real-time and in situ monitoring of mechanochemical reaction mechanisms, (PI Tomislav Friščić)

    2015-2017 Bilateral Project “Simultaneous synchrotron X-ray powder diffraction and Raman spectroscopy monitoring of mechanochemical reactions in situ and in real-time”; German partner dr. Franziska Emmerling, BAM institute, Berlin (duration 2 years). (PI)

    2014 Grant of Croatian Academy of Sciences and Arts for the project “Development of Raman spectroscopic methodology for direct and in situ monitoring of mechanochemical reactions “.(PI)

Awards and Achievements

2017 - Regional Editor for Molecular Crystals and Liquid Crystals journal, Taylor&Francis 

2014-2015 NewFelPro Scholarship - Postdoctoral Researcher at McGill University, Montreal

2013 - Award for distinguished scientific contribution from RB Institute

2013-2015 - Awards from Division of Physical Chemistry, RB Institute, for distinguished scientific publications.

2009 - "National award for excellence" obtained from Croatian Ministry of Science, Sports and Education.

Classes

More than 3000 working hours teaching laboratory and seminal courses in General and Inorganic Chemistry for students in chemistry, biology, geology and physics.

2019 Supervision of a postdoc student – Dr. Dijana Saftić – mechanochemical organic synthesis

2017-present Supervision of a postdoc student – Dr. Bahar Karadeniz – mechanochemical synthesis of MOF materials

2018-present Mentor to a Ph. D. student in the field of mechanochemical prebiotic synthesis

2014-2018 Mentor of a Ph. D. student in the field of organic mechanochemical synthesis. Ruđer Bošković Institute, Zagreb, Croatia. Thesis defended in 2018, June 27th. Thesis title: DEVELOPMENT OF MECHANOCHEMICAL SYNTHESIS OF AMIDES, UREAS AND TRIAZOLES

2002 – 2012: Mentoring the experimental work and writing of the Thesis for 10 graduate students in their obtaining of a Master's degree. Faculty of Science, University of Zagreb, Croatia

 

2009-2012 Work from five undergrad students published in four scientific papers: Cryst. Growth Des.  9 (2009), 5327–5333; Croat. Chem. Acta84 (2011) 232-239; Crystengcomm. 13 (2011), 4314-4323; Chem. Eur. J. 18 (2012) 5620-5631.

2009 – Mentoring the student work (Zoran Kokan) awarded by the University of Zagreb Chancellor’s Award – later published as a Cryst. Growth Des.  9 (2009), 5327.

Publications

Books and book chapters

Book chapters

Journal articles

Scientific and review papers

Theses

Doctoral dissertation

  • Užarević, K. (2009) 'DEHYDROACETIC ACID DERIVATIVES AS LIGANDS AND ANION RECEPTORS', doktorska disertacija, Prirodoslovno-matematički fakultet, Zagreb.

Membership in professional associations / societies

Croatian Chemical Society

Croatian Crystallographic Association

Canadian Institute of Chemistry

Reviewer for ACS Applied Materials and Interfaces, Chemical Communications, ACS Sustainable Chemistry and Engineering, Nanoscale, Crystal Growth & Design, CrystEngComm, ChemistrySelect, Chemistry-An Asian Journal, RSC Advances, Dalton Transactions, New Journal of Chemistry, Journal of Molecular Structure, Croatica Chemica Acta, Vibrational Spectroscopy, Contributions, Small Methods, Kemija u industriji.

Scientific interests and motivation

My general scientific interests are in the solid-state chemistry of supramolecular host-guest complexes and in the field of coordination compounds, with special emphasis on microporous metal-organic frameworks. In my research, I combine and compare solution- and solvent-free approaches for synthesis and manipulation of target compounds. These solid-state approaches include mechanochemistry, thermal methods and gas-solid reactions.

In situ methods for monitoring of mechanochemical and vapour-induced solid-state rections

Development of instrumentation and methodology for the in situ monitoring of mechanochemical reactions is performed in collaboration with Friščić Research Group from McGill University, Montreal. It was motivated by almost complete lack of knowledge about the mechanisms of milling reactions, despite their popularity in the materials chemistry and green synthesis. Our recently developed methods for in situ monitoring by synchrotron X-ray diffraction (Nature Chem, (2013), 5, 66; J. Phys. Chem. Lett. (2015), 6, 4129) and by Raman spectroscopy (Angew. Chem. Int. Ed. (2014), 53, 6193) offered unique insight into mechanochemical milling reactivity. They revealed complex behaviour of mechanochemical solid-state reactions, which often proceed in stepwise manner involving different intermediates and provided means for evaluating the role of additives on milling reactions. 

Flexible anion receptors

Major part of my research in the field deals with flexible anion receptors, i.e. molecules that employ specific binding functionalities to recognise and selectively bind target specie. During the recognition process, such receptors can change their conformation to adapt to the specific requirements of the guest, and they rarely display high peak selectivity in solution. However, in such systems selectivity is often achieved by selective crystallisation. In our studies, we have developed highly adaptable[1,2] and at the same time highly selective receptor for environmentally important nitrate and sulfate anions. By crystallisation of receptor-anion complexes to hydrogen-bonded networks, these anions were separated form solutions containing large excess of competing anions.

Selective grinding

In our latest study[3] we proved that flexible polyamine receptor is capable to recognise and selectively bind  isomeric organic guests from their solid mixtures during the milling process. Regardless of whether the recognition takes place in the solid state via milling or by crystallisation from solution, the resulting supramolecular complexes are the same and the selectivity bias of the receptor towards the guest acids is fully retained. Milling improved yields to quantitative and almost eliminated the use of solvent.

Mechanosensitive metal-ligand bonds in the synthesis of new coordination compounds

In the design of discrete and extended coordination systems, synthesis from preorganized homoleptic or heteroleptic coordination compounds is often utilised. Although each of the types is valuable under specific synthetic requirements, heteroleptic complexes tend to be more advantageous when only a certain amount and type of ligands need to be replaced (ancillary).[4] Such an approach also allows a high level of control over the resulting structure because substitution takes place only at strictly defined coordination sites. We employed various solvent-free approaches (mechanochemistry, thermal methods) to selectively remove specific ligand from the central metal coordination sphere, resulting in coordinatively unsaturated compound. Coordinatively unsaturated complexes, due to their higher reactivity, can be considered as “activated” species and as such are better precursors since there is no competition (discrimination) between the departing and the incoming ligand.[4] In our studies we compare solution and solvent-free synthetic approaches which prove to be superior under specific conditions and their respective advantages and weaknesses are object of examination.[5] While our recent studies included complexes with one mechanosensitive bond, we are concentrated on the study of precursors with two or more mechanosensitive sites and they potential application in the controllable synthesis of higher-ordered coordination networks.

Solid-State Tautomerism

Specific class of ligands used in our laboratory for synthesis of coordination compounds are characterised by strong intramolecular N…H…O hydrogen bond and can occur in the solid state as keto-amino or enol-imino tautomers. Proton transfer in such compounds is usually related with their reactivity, but also with macroscopic properties such as thermochromism and photochromism. Although such compounds and accompanying phenomena have been widely studied, the mechanism of this apparently simple solid-state rearrangement still presents a number of challenges. Main reason for this is that, in contrast to solution, where different tautomers coexist, in the solid state usually only one tautomer appears. Our studies included synthesis of the compounds comprising keto-amino and enol-imino subunits[6] and a unique example of a Schiff base which have crystallised separately as a two polymorphic pairs of keto-amino and enol-imino tautomers, i.e. desmotrops.[7] The relative stabilities and interconversions of the four phases were assessed via various solution and solid-state methods and evaluated against the results of a computational study. Our findings emphasize the importance of intermolecular forces in stabilization of the less stable keto tautomer in the solid state.

References

[1] K. Užarević, I. Ðilović, D. Matković-Čalogović, D. Šišak, and M. Cindrić, Angew. Chem. Int. Ed. (2008) 47, 7022–7025.

[2] K. Užarević, I. Ðilović, N. Bregović, V. Tomišić, D. Matković-Čalogović, and M. Cindrić,  Chem. Eur. J. (2011), 17, 10889-10897. (corresponding author)

[3] K. Užarević, I. Halasz, I. Đilović, N. Bregović, M. Rubčić, D. Matković-Čalogović and V. Tomišić, Angew. Chem. Int. Ed. (2013) prihvaćen za objavljivanje, doi: 10.1002/anie.201301032. (corresponding author)

[4] K. Užarević, M. Rubčić, I. Ðilović, Z. Kokan, D. Matković-Čalogović, and M. Cindrić, Cryst. Growth Des. (2009), 9,5327–5333. (corresponding author).

[5] K. Užarević, M. Rubčić, M. Radić, A. Puškarić, and M. Cindrić, CrystEngComm (2011), 13, 4314-4323. (corresponding author)

[6] K. Užarević, M. Rubčić, V. Stilinović, B. Kaitner and M. Cindrić,  J. Mol. Struct. 984 (2010), 232-239. (corresponding author)

[7] M. Rubčić, K. Užarević, I. Halasz, N. Bregović, M. Mališ, I. Đilović, Z. Kokan, R. S. Stein, R. E. Dinnebier and V. Tomišić, Chem. Eur. J. (2012)  18, 5620–5631. (corresponding author)

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