Zvonimir B. Maksić

Rudjer Boskovic Institute

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Mirjana Eckert‐Maksić

Rudjer Boskovic Institute

Robert Vianello

Rudjer Boskovic Institute

Borislav Kovačević

Rudjer Boskovic Institute

Damir Kovaček

University of Zagreb

K. Kovačević

Galapagos (Croatia)

Danijela Barić

Rudjer Boskovic Institute

K. Rupnik

Louisiana State University

Milan Randić

National Institute of Chemistry

Ines Despotović

Rudjer Boskovic Institute

Martin Klessinger

University of Göttingen

Cooperative Institutions

Rudjer Boskovic Institute

John Wiley & Sons (United States)

University of Zagreb

University of Copenhagen

Karpov Institute of Physical Chemistry

Bridge University

University of Cambridge

National Institute of Chemistry

Uppsala University

Instituto Venezolano de Investigaciones Científicas

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Hydrogen Bond Dynamics of Histamine Monocation in Aqueous Solution: Car–Parrinello Molecular Dynamics and Vibrational Spectroscopy Study

The Journal of Physical Chemistry B (2011)

Jernej Stare Janez Mavri Jože Grdadolnik Jernej Zidar Zvonimir B. Maksić

Hydration of histamine was examined by infrared spectroscopy and Car–Parrinello molecular dynamics simulation. Histamine is a neurotransmitter and inflammation mediator, which at physiological pH conditions is present mainly in monocationic form. Our focus was on the part of vibrational spectra that corresponds to histamine N–H stretching, since these degrees of freedom are essential for its interactions with either water molecules or transporters and receptors. Assignment of the experimental spectra revealed a broad feature between 3350 and 2300 cm–1, being centered at 2950 cm–1, which includes a mixed contribution from the ring N–H and the aminoethyl N–H stretching vibrations. Computational analysis was performed in two ways: first, by making Fourier transformation on the autocorrelation function of all four N–H bond distances recorded during CPMD run, and second, and most importantly, by incorporating quantum effects through applying an a posteriori quantization of all N–H stretching motions utilizing our snapshot analysis of the fluctuating proton potential. The one-dimensional vibrational Schrödinger equation was solved numerically for each snapshot, and the N–H stretching envelopes were calculated as a superposition of the 0→1 transitions. The agreement with the experiment was much better in the case of the second approach. Our calculations clearly demonstrated that the ring amino group absorbs at higher frequencies than the remaining three amino N–H protons of the protonated aminoethyl group, implying that the chemical bonding in the former group is stronger than in the three amino N–H bonds, thus forming weaker hydrogen bonding with the surrounding solvent molecules. In this way the results of the simulation complemented the experimental spectrum that cannot distinguish between the two sets of protons. The effects of deuteration were also considered. The resulting N–D absorption is narrower and red-shifted. The presented methodology is of general applicability to strongly correlated systems, and it is particularly tuned to provide computational support to vibrational spectroscopy. Perspectives are given for its future applications in computational studies of tunneling in enzyme reactive centers and for receptor activation.

10.1021/jp111175e

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Citations (57)

Notizen: MOA Calculations of CH Stretching Frequencies and Dissociation Energies in Hydrocarbons

Zeitschrift für Naturforschung A (1973)

Zvonimir B. Maksić K. Kovačević

A relation between CH stretching frequencies and s characters of the corresponding bonds is obtained, using the data of CH, CHD and CHD 2 , groups in hydrocarbons and the maximum overlap approximation [MOA] method. A relationship between dissociation energies and overlap integrals of CH bonds is also found. A new formula for calculating bond energies in hydrocarbons is proposed.

Bond-dissociation energy

Bond energy

10.1515/zna-1973-0545

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Citations (18)

Ab Initio Study on the Structural Properties of Hexafluorocyclobutene, 3,3,4,4-Tetrafluorocyclobutene, and Cyclobutene: The Remarkable Length of the C(3)-C(4) Bond

The Journal of Physical Chemistry (1995)

Roland H. Hertwig Wolfram Koch Zvonimir B. Maksić

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAb Initio Study on the Structural Properties of Hexafluorocyclobutene, 3,3,4,4-Tetrafluorocyclobutene, and Cyclobutene: The Remarkable Length of the C(3)-C(4) BondRoland H. Hertwig, Wolfram Koch, and Zvonimir B. MaksicCite this: J. Phys. Chem. 1995, 99, 1, 173–176Publication Date (Print):January 1, 1995Publication History Published online1 May 2002Published inissue 1 January 1995https://pubs.acs.org/doi/10.1021/j100001a030https://doi.org/10.1021/j100001a030research-articleACS PublicationsRequest reuse permissionsArticle Views42Altmetric-Citations16LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts

Cyclobutene

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10.1021/j100001a030

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Citations (16)

Cooperative Intramolecular Hydrogen Bonding Effect and Basicity –An Ab Initio and DFT Study of the Superbasic Properties ofN‐[(Dimethylamino)alkyl]‐2,3‐diaminocycloprop‐2‐ene‐1‐imines

European Journal of Organic Chemistry (2005)

Zrinka Gattin Borislav Kovačević Zvonimir B. Maksić

Abstract The MP2(fc)/6‐311+G**//HF/6‐31G* and B3LYP/6‐311+G**//HF/6‐31G* calculations show that N ‐[3‐(dimethylamino)propyl] and N ‐[4‐(dimethylamino)butyl] derivatives of 2,3‐diamino‐cycloprop‐2‐ene‐1‐imine (CPI) possess high gas phase proton affinities (PA) and pronounced basicities in acetonitrile (MeCN). Tris[ N ‐dimethylaminopropyl(‐butyl)]‐CPI derivatives achieve superbasic PA and p K a values. The reason behind these remarkable features is the stability of the resulting conjugate acids. They are stabilized by aromatization of the three‐membered ring accompanied by the cationic resonance between the cyclopropyl ring and amino nitrogen atoms of the side chains, and, last but not least, by the cooperative multiple intramolecular hydrogen bonding effect. The latter is particularly enhanced in tris‐substituted CPIs. It was found that the N ‐[4‐(dimethylamino)butyl] side chains contribute more to the stability of the conjugate acids than those of the corresponding compound with a propyl chain, because they undergo a somewhat larger relaxation upon protonation. The studied compounds might be helpful in building up a dense ladder of strong bases and superbases, which could contribute to the development of the chemistry of superacids and superbases. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Aromatization

Imine

Proton affinity

Cationic polymerization

10.1002/ejoc.200500054

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Citations (38)

High basicity of alkylated 2-tetrazenes: an ab initio study

Chemical Physics Letters (1998)

Borislav Kovačević Zvonimir B. Maksić Paul Rademacher

Proton affinity

Conjugate

Affinities

10.1016/s0009-2614(98)00626-5

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Citations (16)

Antiaromaticity and Aromaticity in Carbocyclic Four‐Membered Rings

Patai's chemistry of functional groups (2009)

Mirjana Eckert‐Maksić Zvonimir B. Maksić

Abstract Introduction and Scope Antiaromaticity of Four‐Membered Rings Cyclobutadiene in Excited State Cyclobutadiene Dications and Dianions Squaric Acid, its Anions and Related Compounds Sigma‐Antiaromaticity of Molecules Involving Saturated Four‐Membered Ring(s) Conclusion Acknowledgments

Antiaromaticity

Cyclobutadiene

Alicyclic compound

10.1002/9780470682531.pat0316

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Triadic analysis of substituent effects—gas-phase acidity of para-substituted phenols

Tetrahedron (2006)

Robert Vianello Zvonimir B. Maksić

Superacid

Electron acceptor

10.1016/j.tet.2006.01.049

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Citations (48)

The Mills–Nixon effect and chemical reactivity—methyl cation affinity of some cycloalkabenzenes

Journal of the Chemical Society Perkin Transactions 2 (2001)

Mirjana Eckert‐Maksić Zoran Glasovac Nana Novak Coumbassa Zvonimir B. Maksić

The problem of the methyl cation attack on carbon atoms belonging to the benzene moiety fused to small rings is explored by the ab initio models at the MP2 level of sophistication. It is shown that the β-position is more reactive than the α-site in kinetically controlled reactions, which is in accordance with the original Mills–Nixon postulate. On the other hand, it appears that in thermodynamically controlled electrophilic substitution reactions the α-site should be slightly preferred for three-, four- and five-membered annelated rings. The differences between the methyl cation affinities MCAβ and MCAα are analyzed and resolved into angular strain and the cationic resonance contribution. The latter involves the hyperconjugation/conjugation and relaxation effects. It turns out that the angular strain contribution is inversely proportional to the size of the annelated ring, whereas the opposite is the case for the cationic resonance interaction. Their interplay determines the selectivity and its extent in the electrophilic substitution reactions. The same analysis is applicable to other electrophilic groups.

Cationic polymerization

Moiety

Electrophilic substitution

Reactivity

Hyperconjugation

10.1039/b101985f

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Citations (16)

Ab Initio Study of Cyclobutadieno-p-benzoquinones: Kekulé Isomerization or Not?

The Journal of Physical Chemistry A (1998)

Zvonimir B. Maksić Ines Petanjek Mirjana Eckert‐Maksić Igor Novak

The problem of the existence of two Kekulé isomers 1a and 1b of cyclobutadieno-p-benzoquinone is addressed by the CAS(10,10)/6-31G*//GVB(2)/6-31G* and CASPT2(10,10)/ANO(3s2p1d,2s1p)//GVB(2)/6-31G* theoretical models. It is shown that the barrier separating these isomers on the Born−Oppenheimer surface practically disappears if the zero-point vibrational energies are taken into account. The angular strain and antiaromaticity of the more stable isomer 1a are estimated by employing the appropriate homodesmic reactions. It is concluded that 1a should be experimentally isolable, albeit in extreme conditions.

Antiaromaticity

Potential energy surface

10.1021/jp983167b

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Citations (7)

Derivatives of Azacalix[3](2,6)pyridine are Strong Neutral Organic Superbases: A DFT Study

Organic Letters (2007)

Ines Despotović Borislav Kovačević Zvonimir B. Maksić

The gas phase basicities and pKa values in acetonitrile of azacalix[3](2,6)pyridine and its derivatives are determined by the B3LYP DFT method. It is found that all compounds of this series are neutral organic superbases. The proton attacks the inner pyridine N(sp2) atom, thus forming a bifurcated intramolecular hydrogen bond. The most powerful superbase is provided by the hexakis(dimethylamino) derivative of the title compound. Its gas phase proton affinity is 296.6 kcal mol-1, its basicity is 291.3 kcal mol-1, and its pKa(MeCN) is 30.9 units. [structure: see text]

10.1021/ol0700299

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Citations (23)