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31.
Guohai Deng Dr. Sudip Pan Dr. Jiaye Jin Prof. Dr. Guanjun Wang Prof. Lili Zhao Prof. Dr. Mingfei Zhou Prof. Gernot Frenking 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(1):412-418
Two structural isomers containing five second-row element atoms with 24 valence electrons were generated and identified by matrix-isolation IR spectroscopy and quantum chemical calculations. The OCBNO complex, which is produced by the reaction of boron atoms with mixtures of carbon monoxide and nitric oxide in solid neon, rearranges to the more stable OBNCO isomer on UV excitation. Bonding analysis indicates that the OCBNO complex is best described by the bonding interactions between a triplet-state boron cation with an electron configuration of (2s)0(2pσ)0(2pπ)2 and the CO/NO− ligands in the triplet state forming two degenerate electron-sharing π bonds and two ligand-to-boron dative σ bonds. 相似文献
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Alexander S. Ivanov Prof. Dr. Alexander I. Boldyrev Prof. Dr. Gernot Frenking 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(9):2431-2435
A theoretical study of Li90P90, which possesses a circular double‐helix structure that resembles the Watson–Crick DNA structure, is reported. This is a new bonding motif in inorganic chemistry. The calculations show that the molecule might become synthesized and that it could be a model for other inorganic species which possess a double‐helix structure. 相似文献
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Guohai Deng Shujun Lei Dr. Sudip Pan Jiaye Jin Prof. Guanjun Wang Prof. Lili Zhao Prof. Mingfei Zhou Prof. Gernot Frenking 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(46):10487-10500
Homoleptic Group 4 metal carbonyl cation and neutral complexes were prepared in the gas phase and/or in solid neon matrix. Infrared spectroscopy studies reveal that both zirconium and hafnium form eight-coordinate carbonyl neutral and cation complexes. In contrast, titanium forms only the six-coordinate Ti(CO)6+ and seven-coordinate Ti(CO)7. Titanium octacarbonyl Ti(CO)8 is unstable as a result of steric repulsion between the CO ligands. The 20-electron Zr(CO)8 and Hf(CO)8 complexes represent the first experimentally observed homoleptic octacarbonyl neutral complexes of transition metals. The molecules still fulfill the 18-electron rule, because one doubly occupied valence orbital does not mix with any of the metal valence atomic orbitals. Zr(CO)8 and Hf(CO)8 are stable against the loss of one CO because the CO ligands encounter less steric repulsion than Zr(CO)7 and Hf(CO)7. The heptacarbonyl complexes have shorter metal−CO bonds than that of the octacarbonyl complexes due to stronger electrostatic and covalent bonding, but the significantly smaller repulsive Pauli term makes the octacarbonyl complexes stable. 相似文献
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Polymer-coated cation exchangers in high-performance ion chromatography: preparation and application
Low-capacity cation-exchange stationary phases for ion chromatography were prepared by coating a vinyl-modified silica gel with polystyrene or poly(glycidyl methacrylate). Strong acid ion-exchange groups were formed by sulphonation with concentrated sulphuric acid or by ring opening of the polymer-coated silica gels with sulphite solution. Carbon-sulphur elemental analyses of the polymer-coated cation exchangers (PCCEs) were applied to determine the average polymer film thickness. The pH stability depended on the polymer film thickness. The PCCEs were stable in the pH range 0.5–9. The low-capacity PCCEs (capacities 18–91 μmol/g) were applied to determine alkali and alkaline earth metal ions in tap and mineral waters. 相似文献
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The nature of the chemical bonds in the diatomic molecules E2 (E=N–Bi, F–I), CO and BF has been studied with an energy partitioning analysis using gradient-corrected density functional theory calculations. The results make it possible to estimate quantitatively the strength of covalent and electrostatic attractions and the Pauli repulsion between the atoms. The data suggest that some traditional explanations regarding the strength of the molecules should be modified. The energy partitioning analysis shows that the chemical bonds in the group 15 diatomic molecules have significant electrostatic character, which increases from 30.1% in N2 to 58.3% in Bi2. The contribution of the electrostatic attraction to the binding interactions in Sb2 and Bi2 is larger than the covalent bonding. The strength of the bonding in the triply bonded dinitrogen is less than that of the bonding. The calculations indicate that E is between 32.2% (Bi2) and 40.0% (P2) of the total orbital interaction energy (Eorb). The much stronger bond of N2, as compared with the heavier group 15 E2 homologues, is not caused by a particularly strong contribution by the bonding, but rather by the relatively large interactions. The comparison of N2 with isoelectronic CO shows that the electrostatic character in the heteroatomic molecule is slightly smaller (28.8%) than in the homoatomic molecule. The contribution of the bonding in CO is larger (49.2%) than in N2 (34.3%). The reason why CO has a stronger bond than N2 is the significantly weaker Pauli repulsion in CO. The electrostatic character of the bonding in BF is slightly larger (32.0%) than in CO and N2. BF has much weaker -bonding contributions that provide only 11.2% of the covalent interactions, which is why BF has a much weaker bond than CO and N2. The chemical bonds in the dihalogen molecules have much higher covalent than electrostatic character. The Eorb term contributes between 74.4% (Br2) and 79.7% (F2) to the total attractive interactions. The relatively weak bond in F2 comes from the rather large Pauli repulsion.Contribution to the Jacopo Tomasi Honorary Issue 相似文献
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