Influence of Coordination on OH/π and NH/π Interactions

The interactions of noncoordinated water or ammonia molecules with aromatic rings, as well as coordintaed water or coordinated ammonia molecules with aromatic rings have been investigated by searching the Cambridge Structural Database (CSD) and through quantum-chemical calculations. The data from the CSD show that for noncoordinated systems distances between the interacting fragments are the shortest in case of negative C6-aromatic groups and the longest in case of positive C6-aromatic groups. In case of contacts between coordinated water or ammonia molecules and C6-aromatic group, oppositely charged fragments are mutually closer than the neutral fragments. The DFT calculations for the water/benzene system yield an interaction energy of -2.97 kcal/mol, while for the [Zn(H2O)6]2+/C6H6 system the interaction energy is -14.72 kcal/mol. For the ammonia/benzene system, the DFT calculations yield an interaction energy of -2.28 kcal/mol, while for the [Zn(NH3)6]2+/C6H6 system it is -15.50 kcal/mol. The results show that there is an influence of water or ammonia coordination on OH/π or NH/π interactions; the interactions of coordinated species are significantly stronger. OH/π and NH/π interactions are comparable in both cases. OH/π interactions are slightly stronger than NH/π interactions in case of noncoordinated molecules due to higher partially positive charge on hydrogen atom of the water molecule, but this is not necessarily the case for the coordinated molecules due to additional interactions that can occur between the benzene ring and the other ligands present in the complex

Supplementary data for article: Vojislavljević-Vasilev, D.; Janjić, G. V.; Ninković, D.; Kapor, A.; Zarić, S. The Influence of Water Molecule Coordination onto the Water-Aromatic Interaction. Strong Interactions of Water Coordinating to a Metal Ion. CrystEngComm 2013, 15 (11), 2099–2105. https://doi.org/10.1039/c2ce25621e

Supplementary material for: [https://doi.org/10.1039/c2ce25621e]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1602

Can Coordinated Water Be a Good Hydrogen Bond Acceptor?

Hydrogen bond is arguably the most famous of all noncovalent interactions. The majority of contacts between water molecules in the solid state are hydrogen bonds, with a substantial number of antiparallel dipolar interactions as well.1 The crystallographic and quantum chemical studies have shown that the strength of hydrogen bonds of water can be increased by metal coordination.2,3 These previous studies considered coordinated water as hydrogen bond donor. In this study, we wanted to investigate the possibility of coordinated water acting as hydrogen bond acceptor. The Cambridge Structural Database (CSD) search yielded 1229 hydrogen bonds between coordinated water as hydrogen bond acceptor and uncoordinated water as hydrogen bond donor. These hydrogen bonds are somewhat longer and less directional than hydrogen bonds with donor coordinated water. The strength of these hydrogen bonds was evaluated at the B97D/def2-TZVP level of theory, both on the structures found in the CSD, as well as on the model systems. The obtained energies cover a wide range of values (Figure 1), depending on the charge of the complex, and they can be comparable to the energy of hydrogen bond between two uncoordinated water molecules (-4.84 kcal/mol),2 or even significantly more favorable if the complex is negatively charged. If the complex is positively charged, these interactions are repulsive (Figure 1), but they are still frequently encountered (444 interactions in crystal structures), simultaneously with other (attractive) interactions. The strength of interactions shows dependence on the orientation of both hydrogen atoms of uncoordinated water, and it is in general greatly influenced by additional contacts of uncoordinated water with neighboring ligands of the metal complex. Even though it is difficult to estimate how strong these interactions are alone, the calculated interaction energies suggest that coordinated water is a better hydrogen bond donor than hydrogen bond acceptor. However, coordinated water acting as hydrogen bond acceptor gives more opportunities for additional interactions, making the supramolecular systems containing studied hydrogen bonds more stable

Supplementary data for the article: Ninković, D. B.; Vojislavljević-Vasilev, D. Z.; Medaković, V. B.; Hall, M. B.; Brothers, E. N.; Zarić, S. D. Aliphatic-Aromatic Stacking Interactions in Cyclohexane-Benzene Are Stronger than Aromatic-Aromatic Interaction in the Benzene Dimer. Physical Chemistry Chemical Physics 2016, 18 (37), 25791–25795. https://doi.org/10.1039/c6cp03734h

Supplementary material for: [https://doi.org/10.1039/c6cp03734h]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2328]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3324

Supplementary data for article: Vojislavljević-Vasilev, D.; Janjić, G. V.; Ninković, D.; Kapor, A.; Zarić, S. The Influence of Water Molecule Coordination onto the Water-Aromatic Interaction. Strong Interactions of Water Coordinating to a Metal Ion. CrystEngComm 2013, 15 (11), 2099–2105. https://doi.org/10.1039/c2ce25621e

Supplementary material for: [https://doi.org/10.1039/c2ce25621e]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1602

Supplementary data for the article: Ninković, D. B.; Vojislavljević-Vasilev, D. Z.; Medaković, V. B.; Hall, M. B.; Brothers, E. N.; Zarić, S. D. Aliphatic-Aromatic Stacking Interactions in Cyclohexane-Benzene Are Stronger than Aromatic-Aromatic Interaction in the Benzene Dimer. Physical Chemistry Chemical Physics 2016, 18 (37), 25791–25795. https://doi.org/10.1039/c6cp03734h

Supplementary material for: [https://doi.org/10.1039/c6cp03734h]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2328]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3324

Noncovalent interactions of metal complexes and aromatic molecules

Наше истраживање се заснива на анализи података у кристалним структурама из Кембичке базе структурних података (CSD) и на квантнo хемијским прорачунима. Анализа података из CSD-а омогућава да се препознају интеракције у кристалним структурама и да се опишу геометрије ових интеракција, док помоћу квантно-хемијских прорачуна можемо проценити интеракционе енергије и пронаћи најстабилније геометрије интеракција. Користећи ову методологију успели смо да препознамо и опишемо неколико нових типова интеракција. Наше проучавање интеракција планарних метал-хелатних прстенова показало је могућност стекинг интеракција са органским ароматичним прстеновима и интеракције између два хелатна прстена. Израчунате енергије указују на јаке стекинг интеракције метал-хелатних прстенова; стекинг метал-хелатних прстенова је јачи од стекинга између два молекула бензена. Испитивања интеракција координираних молекула воде и амонијака указују на јаче водоничне везе и јаче ОH/π и NH/π интеракције координираних у односу на некоординоване молекуле воде и амонијака. Прорачуни ОH/М интеракција између металног јона у квадратнo планарним комплексима и молекулa воде указују да су ове интеракције међу најјачим водоничним везама у било ком молекулском систему. Студије о ароматичним молекулима указују на стекинг интеракције са великим хоризонталним померањима између два ароматична молекула са значајно јаким интеракцијама, енергија је 70% најјаче стекинг интеракције. Наши подаци такође указују на то да су интеракције алифатичних прстенова са ароматичним прстеном јаче од интеракција између два ароматична молекула, док су алифатично/ароматичне интеракције веома честе у протеинским структурама.Our research is based on analyzing data in crystal structures from the Cambridge Structural Database (CSD) and on quantum chemical calculations. The analysis of the data from the CSD enable to recognize interactions in crystal structures and to describe the geometries of these interactions, while by quantum chemical calculations we can evaluate interaction energies and find the most stable interaction geometries. Using this methodology we were able to recognize and describe several new types of noncovalent interactions. Our study of planar metal-chelate rings interactions showed possibility of chelate ring stacking interactions with organic aromatic rings, and stacking interactions between two chelate rings. The calculated energies indicate strong stacking interactions of metalchelate rings; the stacking of metal-chelate rings is stronger than stacking between two benzene molecules. Studies of interactions of coordinated water and ammonia indicate stronger hydrogen bonds and stronger OH/π and NH/π interactions of coordinated in comparison to noncoordianted water and ammonia. The calculations on OH/M interactions between metal ion in square-planar complexes and water molecule indicate that these interactions are among the strongest hydrogen bonds in any molecular system. The studies on aromatic molecules indicate stacking interactions at large horizontal dispacements between two aromatic molecules with significantly strong interacitons, the energy is 70% of the strongest stacking geometry. Our data also indicate that stacking interactions of an aliphatic rings with an aromatic ring are stonger than interactions between two aromatic molecules, while aliphatic/aromatic interactions are very frequent in protein structures

Study of noncovalent interactions using crystal structure data in the Cambridge Structural Database

In the recent review it was point out that the crystal structures in the Cambridge Structural Database (CSD), collected, have contributeto various fields of chemical research such as geometries of molecules, noncovalent interactions of molecules, and large assemblies ofmolecules. The CSD also contributed to the study and the design of biologically active molecules and the study of gas storage anddelivery [1].In our group we use analysis of the crystal structures in the CSD to recognize and characterize new types of noncovalent interactionsand to study already known noncovalent interactions. Based on the data from the CSD we can determine existence of the interactions,frequency of the interactions, and preferred geometries of the interactions in the crystal structures. In addition, we perform quantumchemical calculations to evaluate the energies of the interactions. Based on the calculated potential energy surfaces for theinteractions, we can determine the most stable geometries, as well as stability of various geometries. We also can determine theinteraction energies for the preferred geometries in the crystal structures. In the cases where the most preferred geometries in thecrystal structures are not the most stable geometries at the potential energy surface, one can find significant influence of thesupramolecular structures in the crystals.Using this methodology our group recognized stacking interactions of planar metal-chelate rings; stacking interactions with organicaromatic rings and stacking interactions between two chelate rings. The calculated energies indicate strong stacking interactions ofmetal-chelate rings; the stacking of metal-chelate rings is stronger than stacking between two benzene molecules [2]. The data indicateinfluence of the metal and ligand type in the metal chelate ring on the strength of the interactions. Our results also indicate strongstacking interactions of coordinated aromatic rings [3]. Studies of interactions of coordinated water indicate stronger hydrogen bondsand stronger OH/π interactions of coordinated in comparison to noncoordianted water molecule [4,5]. The calculations on OH/Minteractions between metal ion in square-planar complexes and water molecule indicate that these interactions are among the strongesthydrogen bonds in any molecular system [6].The studies on stacking interactions of benzene molecules in the crystal structures in the CSD show preference for interactions at largehorizontal displacements, while high level quantum chemical calculations indicate significantly strong interactions at large offsets; theenergy is 70% of the strongest stacking geometry [7]

Study of noncovalent interactions using crystal structure data in the Cambridge Structural Database

In the recent review it was point out that the crystal structures in the Cambridge Structural Database (CSD), collected, have contribute to various fields of chemical research such as geometries of molecules, noncovalent interactions of molecules, and large assemblies of molecules. The CSD also contributed to the study and the design of biologically active molecules and the study of gas storage and delivery [1]. In our group we use analysis of the crystal structures in the CSD to recognize and characterize new types of noncovalent interactions and to study already known noncovalent interactions. Based on the data from the CSD we can determine existence of the interactions, frequency of the interactions, and preferred geometries of the interactions in the crystal structures. In addition, we perform quantum chemical calculations to evaluate the energies of the interactions. Based on the calculated potential energy surfaces for the interactions, we can determine the most stable geometries, as well as stability of various geometries. We also can determine the interaction energies for the preferred geometries in the crystal structures. In the cases where the most preferred geometries in the crystal structures are not the most stable geometries at the potential energy surface, one can find significant influence of the supramolecular structures in the crystals. Using this methodology our group recognized stacking interactions of planar metal-chelate rings; stacking interactions with organic aromatic rings and stacking interactions between two chelate rings. The calculated energies indicate strong stacking interactions of metal-chelate rings; the stacking of metal-chelate rings is stronger than stacking between two benzene molecules [2]. The data indicate influence of the metal and ligand type in the metal chelate ring on the strength of the interactions. Our results also indicate strong stacking interactions of coordinated aromatic rings [3]. Studies of interactions of coordinated water indicate stronger hydrogen bonds and stronger OH/π interactions of coordinated in comparison to noncoordianted water molecule [4,5]. The calculations on OH/M interactions between metal ion in square-planar complexes and water molecule indicate that these interactions are among the strongest hydrogen bonds in any molecular system [6]. The studies on stacking interactions of benzene molecules in the crystal structures in the CSD show preference for interactions at large horizontal displacements, while high level quantum chemical calculations indicate significantly strong interactions at large offsets; the energy is 70% of the strongest stacking geometry [7]

Study of noncovalent interactions using crystal strucutre data and quantum chemical calculations

The analysis of the crystal structures in the CSD was used to recognize and characterize new types of noncovalent interactions. It was also used to study already known noncovalent interactions. Based on the data from the CSD we can determine existence of the interactions, frequency of the interactions, and preferred geometries of the interactions in the crystal structures [1,2]. The quantum chemical calculations were performed to evaluate the energies of the interactions. For the preferred geometries in the crystal structures we can calculate the interaction energies. By calculating potential energy surfaces for the interactions, we can determine the most stable geometries, as well as stability of various geometries [1,2]. Using this methodology our group recognized stacking interactions of planar metal-chelate rings; stacking interactions with organic aromatic rings, and stacking interactions between two chelate rings. The calculated energies showed that the stacking of metal-chelate rings is stronger than stacking between two benzene molecules. Studies of interactions of coordinated ligands indicate stronger noncovalent interactions that interactions of noncoordinated molecules [2]. REFERENCES [1] Ninković, D. B., Blagojević Filipović, J. P., Hall, M. B., Brothers, E. N., Zarić, S. D. (2020) ACS Central Science, 6, 420. [2] Malenov, D. P., Zarić, S. D. (2020) Cood. Chem. Rev. 419, 213338