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Kawa S, Knorke H, Jin J, Rohdenburg M, Asmis KR, Tonner-Zech R, Bernhardt E, Jenne C, Finze M, Warneke J. Binding Properties of Small Electrophilic Anions [B 6 X 5 ] - and [B 10 X 9 ] - (X=Cl, Br, I): Activation of Small Molecules Based on π-Backbonding. Chemistry 2023; 29:e202302247. [PMID: 37749942 DOI: 10.1002/chem.202302247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/25/2023] [Accepted: 09/25/2023] [Indexed: 09/27/2023]
Abstract
Superelectrophilic anions constitute a special class of molecular anions that show strong binding of weak nucleophiles despite their negative charge. In this study, the binding characteristics of smaller gaseous electrophilic anions of the types [B6 X5 ]- and [B10 X9 ]- (with X=Cl, Br, I) were computationally and experimentally investigated and compared to those of the larger analogues [B12 X11 ]- . The positive charge of vacant boron increases from [B6 X5 ]- via [B10 X9 ]- to [B12 X11 ]- , as evidenced by increasing attachment enthalpies towards typical σ-donor molecules (noble gases, H2 O). However, this behavior is reversed for σ-donor-π-acceptor molecules. [B6 Cl5 ]- binds most strongly to N2 and CO, even more strongly than to H2 O. Energy decomposition analysis confirms that the orbital interaction is responsible for this opposite trend. The extended transition state natural orbitals for chemical valence method shows that the π-backdonation order is [B6 X5 ]- >[B10 X9 ]- >[B12 X11 ]- . This predicted order explains the experimentally observed red shifts of the CO and N2 stretching fundamentals compared to those of the unbound molecules, as measured by infrared photodissociation spectroscopy. The strongest red shift is observed for [B6 Cl5 N2 ]- : 222 cm-1 . Therefore, strong activation of unreactive σ-donor-π-acceptor molecules (commonly observed for cationic transition metal complexes) is achieved with metal-free molecular anions.
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Affiliation(s)
- Sebastian Kawa
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, 04103, Leipzig, Germany
| | - Harald Knorke
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, 04103, Leipzig, Germany
| | - Jiaye Jin
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, 04103, Leipzig, Germany
| | - Markus Rohdenburg
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, 04103, Leipzig, Germany
| | - Knut R Asmis
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, 04103, Leipzig, Germany
| | - Ralf Tonner-Zech
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, 04103, Leipzig, Germany
| | - Eduard Bernhardt
- Anorganische Chemie, Fakultät für Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, Gaußstr. 20, 42119, Wuppertal, Germany
| | - Carsten Jenne
- Anorganische Chemie, Fakultät für Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, Gaußstr. 20, 42119, Wuppertal, Germany
| | - Maik Finze
- Institut für Anorganische Chemie, Institut für Nachhaltige Chemie & Katalyse mit Bor (ICB), Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Jonas Warneke
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstr. 2, 04103, Leipzig, Germany
- Leibniz Institute of Surface Engineering (IOM), Permoserstr. 15, 04318, Leipzig, Germany
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Fielicke A. Probing the binding and activation of small molecules by gas-phase transition metal clusters via IR spectroscopy. Chem Soc Rev 2023. [PMID: 37162518 DOI: 10.1039/d2cs00104g] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Isolated transition metal clusters have been established as useful models for extended metal surfaces or deposited metal particles, to improve the understanding of their surface chemistry and of catalytic reactions. For this objective, an important milestone has been the development of experimental methods for the size-specific structural characterization of clusters and cluster complexes in the gas phase. This review focusses on the characterization of molecular ligands, their binding and activation by small transition metal clusters, using cluster-size specific infrared action spectroscopy. A comprehensive overview and a critical discussion of the experimental data available to date is provided, reaching from the initial results obtained using line-tuneable CO2 lasers to present-day studies applying infrared free electron lasers as well as other intense and broadly tuneable IR laser sources.
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Affiliation(s)
- André Fielicke
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, 14195 Berlin, Germany.
- Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany
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Preparation, Characterization of New Antimicrobial Antitumor Hybrid Semi-Organic Single Crystals of Proline Amino Acid Doped by Silver Nanoparticles. Biomedicines 2023; 11:biomedicines11020360. [PMID: 36830897 PMCID: PMC9952970 DOI: 10.3390/biomedicines11020360] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/06/2022] [Accepted: 01/12/2023] [Indexed: 01/28/2023] Open
Abstract
Proline is water soluble amino acid extensively used in drug delivery systems. Compounds of cobalt (Co) transition metal have potent antimicrobial and anticancer activities. However, a drug delivery system combining proline cobalt is not reported yet. For the first time, new hybrid semi-organic single crystals of proline cobalt chloride (PCC) are prepared. The novelty of the article is also that single crystal proline cobalt chloride showed potent antimicrobial and antitumor activity. Doping of PCC by Ag0NPs significantly increased these biological activities. The anisotropic magnetic properties of single crystals can mitigate the cytotoxicity of Ag0NPs on normal cells. Silver nanoparticles (Ag0NPs) improved the crystal habits and physicochemical properties. Ag0NPs showed the best performance, paramagnetic materials n-type semiconductors due to delocalized excess electrons of Ag0NPs incorporated in the crystal lattice interstitially. Crystals have high absorptivity for UV-radiation electromagnetic radiation. Ag0NPs enhanced AC electrical conductivity up to 2.3 × 104 Ω cm-1 due to high electron density. Proline doped crystals are obtained in good purity as triclinic unit cell with having anisotropic magnetism. PCCAg0NPs crystal exhibited: high antimicrobial activities to various bacterial and fungal species, inhibition zone (mm): 21, 25, 24, 26, 30, 28, 12, and 46 for S. aureus, E. faecalis, S. typhi, E. coli, P. aerugino, K. pneumoniae, A. braselienses, and C. albicans, respectively, in comparison to ciprofloxacin antibiotic (23, 0, 26, 26, 25, 0, 0, 0) for the same tested species, respectively; higher cytotoxicity against breast cancer cells (IC50 22.1 μM) than the reference drug cisplatin (IC50 11.7 μM); and lower cytotoxicity to normal healthy lung cells MRC-5, (IC50 145.5 μM) than cisplatin (IC50 30.2 μM). Hence, this crystal is a candidate for chemotherapy of breast cancer.
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Pietro WJ, Lever ABP. Ligand Electrochemical Parameter Approach to Molecular Design. σ-Donation, π-Back Donation, and Other Metrics in Ruthenium(II) Dinitrogen Complexes. Inorg Chem 2022; 61:1869-1880. [PMID: 35016502 DOI: 10.1021/acs.inorgchem.1c02707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Using the density functional theory, [(N2)RuIIL5]n+ species are studied in silico. The properties of the Ru-N2 bond are derived, including σ-donation, π-back donation, Ru-N and N-N bond lengths and bond orders, net charges and NN stretching frequencies, and so forth. These data are correlated using the ligand electrochemical parameter (EL) theory, whereby the availability of electrons in the [RuL5]n+ fragment is defined by its electron richness, which is the sum of the EL parameters, ΣEL(L5). The objective is to better understand the binding of the N2 ligand, leading to a molecular design whereby a specific species is constructed to have a desired property, for example, a particular bond length or charge. We supply cubic expressions linking ΣEL(L5) with these many metrics, allowing researchers to predict metric values of their own systems. The extended charge decomposition analysis is used. For the given target, N2, σ-bonding does not vary greatly with the nature of ligand L, and π-back donation is the dominant property deciding the magnitudes of the various metrics. The EL parameter provides the path to design the desired species. This contribution is devoted to dinitrogen, but the method is expected to be general for any ligand, including polydentate ligands.
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Affiliation(s)
- William J Pietro
- Department of Chemistry, York University, Toronto, M3J1P3 Ontario, Canada
| | - A B P Lever
- Department of Chemistry, York University, Toronto, M3J1P3 Ontario, Canada
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