The dihydrogen bonds B-H...H-X （X= the complexes of NH3BH3 with HF, HCl, F, Cl, Br, C, O, N） in the dimer （NH3BH3）2 and HBr, H2CO, H20, and CH3OH were theoretically studied. The results show that formation of the ...The dihydrogen bonds B-H...H-X （X= the complexes of NH3BH3 with HF, HCl, F, Cl, Br, C, O, N） in the dimer （NH3BH3）2 and HBr, H2CO, H20, and CH3OH were theoretically studied. The results show that formation of the dihydrogen bond leads to elongation and stretch frequency red shift of the BH and XH bonds, except that in the H2CO system, the CH bond blue shifts. For （NH3BH3）2 and the complexes of the halogenides, red shifts of the XH bonds are caused by the intermolecular hyperconjugation σ（BH）→σ^＊ （XH）. For the system of H2CO, a blue shift of the CH bond is caused by a decrease of the intramolecular hyperconjugation n（O→σ^＊ （CH）. In the other two systems, the red shift of OH bond is a secondary effect of the stronger traditional red-shifted H-bonds N-H... O. In all these systems, red shifts of the BH bonds are caused by two factors： negative repolarization and negative rehybridization of the BH bond, and decrease of occupancy on σ（BH） caused by the intermolecular hyperconjugation σ（BH）→σ^＊ （XH）.展开更多
Second-order Maller-Plesset （MP2） and density functional theory （DFT） calculations have been carried out in order to inves- tigate the structures and properties of dihydrogen-bonded CaH2...HY （Y = CH3, C2H3, C2H,...Second-order Maller-Plesset （MP2） and density functional theory （DFT） calculations have been carried out in order to inves- tigate the structures and properties of dihydrogen-bonded CaH2...HY （Y = CH3, C2H3, C2H, CN, and NC） complexes. Our cal- culations revealed two possible structures for Call2 in CaH2..,HY complexes： linear （I） and bent （II）. The bond lengths, interac- tion energies, and strengths for H...H interactions obtained by both MP2 and B3LYP methods are quite close to each other. It was found that the interaction energy decreases with increasing electron density at the Ca-H bond critical point. At- om-in-molecule （AIM） results show that for all of Ca-H...H-Y interactions considered here, the Laplacian of the electron densi- ty at the H--.H bond critical point is positive, indicating the electrostatic nature of these Ca-H...H-Y dihydrogen bonded systems.展开更多
Pressure, as a thermodynamic parameter, provides an appropriate method to detect weak intermolecular interactions. The C–H···H–B dihydrogen bond is so weak that the experimental evidence of this inter...Pressure, as a thermodynamic parameter, provides an appropriate method to detect weak intermolecular interactions. The C–H···H–B dihydrogen bond is so weak that the experimental evidence of this interaction is still limited. A combination of in situ high pressure Raman spectra and angle-dispersive X-ray diffraction(ADXRD) experiments was utilized to explore the dihydrogen bonds in dimethylamine borane(DMAB). Both Raman and ADXRD measurements suggested that the crystal structure of DMAB is stable in the pressure region from 1 atm(1 atm=1.01325×10~5 Pa) to 0.54 GPa. The red shift of CH stretching and CH_3 distortion modes gave strong evidence for the existence of C–H···H–B dihydrogen bonds. Further analysis of Raman spectra and Hirshfeld surface confirmed our proposal. This work provided a deeper understanding of dihydrogen bonds.And we wish that high pressure could be applied to identify other unconfirmed hydrogen or dihydrogen bond.展开更多
The C--H…H dihydrogen-bonded complexes of methane, ethylene, acetylene, and their derivatives with magnesium hydride were systematically investigated at MP2/aug-cc-PVTZ level. The results confirm that the strength of...The C--H…H dihydrogen-bonded complexes of methane, ethylene, acetylene, and their derivatives with magnesium hydride were systematically investigated at MP2/aug-cc-PVTZ level. The results confirm that the strength of dihydrogen bonding increases in the following order of proton donors： C（sp3）-H〈C（sp2）-H〈C（sp）-H and chlorine substituents enhance the C-H…H interaction. In the majority of the complexes with a cyclic structure, the Mg-H proton-accepting bond is more sensitive to the surroundings than C-H proton-donating bond. The nature of the electrostatic interaction in these C-H…H dihydrogen bonds was also unveiled by means of the atoms in mo- lecules（AIM） analysis. The natural bond orbital（NBO） analysis suggests that the charge transfer in the cyclic com- plexes is characteristic of dual-channel. The direction of the net charge transfer in the cyclic complexes is contrary to that previously found in dihydrogen bonded systems.展开更多
Treatment of RuCl2(PPh3)3 with 6-dimethylaminopentafulvene in THF in the presence of water produced(η5-C5H4CHO) RuCl(PPh3)2, which was reduced by NaBH4 to give the Ru–H···HO dihydrogen bonded complex(...Treatment of RuCl2(PPh3)3 with 6-dimethylaminopentafulvene in THF in the presence of water produced(η5-C5H4CHO) RuCl(PPh3)2, which was reduced by NaBH4 to give the Ru–H···HO dihydrogen bonded complex(η5-C5H4CH2OH) RuH(PPh3)2. The dihydrogen bonded complex(η5-C5H4CH2OH)RuH(PPh3)2 could also be synthesized by the reduction of complex(η5-C5H4CHO)RuH(PPh3)2, which was obtained by the reaction of RuHCl(PPh3)3 with 6-dimethylaminopentafulvene in the presence of water. The analogous dihydrogen bonded osmium complex(η5-C5H4CH2OH)OsH(PPh3)2 was similarly prepared. Single crystal structures and DFT calculations support the presence of intra-molecular H···H interaction, with separations of around 1.9 to 2.0 .展开更多
The optimized geometries, frequencies and interaction energy corrected with basis set superposition error (BSSE) of the multi-dihydrogen bond complexes C4H4NH…BH4.-and CH≡CH…BH4.-have been calculated at both the B3...The optimized geometries, frequencies and interaction energy corrected with basis set superposition error (BSSE) of the multi-dihydrogen bond complexes C4H4NH…BH4.-and CH≡CH…BH4.-have been calculated at both the B3LYP/6-311++G** and the MP2/6-311++G** levels. The calculations were per-formed to study the nature of the N―H…H3―B and C―H…H2―B red shift multi dihydrogen bond in complex C4H4NH…BH-4 and CH≡CH…BH-.4 The BSSE-corrected multi-dihydrogen bond interaction en-ergy of complex I (C4H4NH…BH4-.) and complexⅡ(CH≡CH…BH-.4) is -76.62 and -33.79 kJ/mol (MP2/6- 311++G**), respectively. From the natural bond orbital(NBO)analysis, we detailedly discussed the orbital interactions, electron density transfers, rehybridizations and the essential of the correlative bond length changes in the two complexes. In addition, solvent effect on the geometric structures, vibration frequencies and interaction energy of the monomer and complexes was studied in detail. It is relevant to the relatively dielectric constants (ε).展开更多
The IR spectroscopic data indicate the tautomeric transformations of typical aprotonic organic fluids such as methane halides with gross formulas CHX3 （X = Cl, Br）, CH2X2 （X = CI, Br, I） and CCl4 at normal conditi...The IR spectroscopic data indicate the tautomeric transformations of typical aprotonic organic fluids such as methane halides with gross formulas CHX3 （X = Cl, Br）, CH2X2 （X = CI, Br, I） and CCl4 at normal conditions. These transformations lead to the appearance in molecules of activated hydrogen atoms similar in the spectral behaviour to the bounded proton. The classical analysis of IR bands in 5000-600 cm^-1 region, for studied samples and their deuterated derivatives, proves the existence in the presented organic fluids of hydrogen and dihydrogen bonds. This bonding promotes the formation of supramolecular structure in methane halides. The mechanism of unusual binding in liquid phase in terms of common knowledge for the basic chemical properties of the examined compounds is discussed.展开更多
Polyhedral boranes are a class of well-known boron molecular clusters with unique physical and chemical properties,and great efforts have been made in the past decades to find more effective synthetic methods.However,...Polyhedral boranes are a class of well-known boron molecular clusters with unique physical and chemical properties,and great efforts have been made in the past decades to find more effective synthetic methods.However,the established synthetic methods suffer from low efficiency and low selectivity because the mechanism of the B-H bond condensation reaction,critical for the synthesis of the polyhedral boranes,is not well understood.Here we report highly selective and efficient synthetic methods of the salts of the tetradecahydridoundecaborate(1-)(B_(11)H^(-)_(14)) and dodecahydrido-dodecaborates(2-)(B_(12)H_(12)^(2-)) anions by employing commercially available and inexpensive starting materials.Both theoretical and experimental investigations are carried out to elucidate the reaction mechanisms.We have found that the nature of the B-H bond condensation is the dihydrogen bonding interaction in which the positively charged hydrogens(bridged hydrogens) play a crucial role.The current study has not only led to more effective and selective synthetic methods for B_(11)H^(-)_(14) and B_(12)H_(12)^(2-) but also unveiled the nature of the B-H bond condensation and the general formation mechanisms of polyhedral boranes.This finding will facilitate the development of more effective synthetic methods for polyhedral boranes and spur their wide application.展开更多
基金ACKNOWLEDGMENT This work was supported Science Foundation of China by the National Natural （No.20873103）.
文摘The dihydrogen bonds B-H...H-X （X= the complexes of NH3BH3 with HF, HCl, F, Cl, Br, C, O, N） in the dimer （NH3BH3）2 and HBr, H2CO, H20, and CH3OH were theoretically studied. The results show that formation of the dihydrogen bond leads to elongation and stretch frequency red shift of the BH and XH bonds, except that in the H2CO system, the CH bond blue shifts. For （NH3BH3）2 and the complexes of the halogenides, red shifts of the XH bonds are caused by the intermolecular hyperconjugation σ（BH）→σ^＊ （XH）. For the system of H2CO, a blue shift of the CH bond is caused by a decrease of the intramolecular hyperconjugation n（O→σ^＊ （CH）. In the other two systems, the red shift of OH bond is a secondary effect of the stronger traditional red-shifted H-bonds N-H... O. In all these systems, red shifts of the BH bonds are caused by two factors： negative repolarization and negative rehybridization of the BH bond, and decrease of occupancy on σ（BH） caused by the intermolecular hyperconjugation σ（BH）→σ^＊ （XH）.
基金supported by the National Natural Science Foundation of China (20973076,20703021)the Basic Science Research Funding of Jilin University
文摘Second-order Maller-Plesset （MP2） and density functional theory （DFT） calculations have been carried out in order to inves- tigate the structures and properties of dihydrogen-bonded CaH2...HY （Y = CH3, C2H3, C2H, CN, and NC） complexes. Our cal- culations revealed two possible structures for Call2 in CaH2..,HY complexes： linear （I） and bent （II）. The bond lengths, interac- tion energies, and strengths for H...H interactions obtained by both MP2 and B3LYP methods are quite close to each other. It was found that the interaction energy decreases with increasing electron density at the Ca-H bond critical point. At- om-in-molecule （AIM） results show that for all of Ca-H...H-Y interactions considered here, the Laplacian of the electron densi- ty at the H--.H bond critical point is positive, indicating the electrostatic nature of these Ca-H...H-Y dihydrogen bonded systems.
基金supported by the National Natural Science Foundation of China(21725304,21673100,91227202,11774120,11774125)the Chang Jiang Scholars Program of China(T2016051)+3 种基金Changbai Mountain Scholars Program(2013007)Program for Innovative Research Team(in Science and Technology)in University of Jilin Province and Graduate Innovation Fund of Jilin University(2017050)ADXRD experiments were performed at Beijing Synchrotron Radiation Facility(4W2 beamline)which is supported by Chinese Academy of Sciences(KJCX2-SW-N20,KJCX2-SW-N03)
文摘Pressure, as a thermodynamic parameter, provides an appropriate method to detect weak intermolecular interactions. The C–H···H–B dihydrogen bond is so weak that the experimental evidence of this interaction is still limited. A combination of in situ high pressure Raman spectra and angle-dispersive X-ray diffraction(ADXRD) experiments was utilized to explore the dihydrogen bonds in dimethylamine borane(DMAB). Both Raman and ADXRD measurements suggested that the crystal structure of DMAB is stable in the pressure region from 1 atm(1 atm=1.01325×10~5 Pa) to 0.54 GPa. The red shift of CH stretching and CH_3 distortion modes gave strong evidence for the existence of C–H···H–B dihydrogen bonds. Further analysis of Raman spectra and Hirshfeld surface confirmed our proposal. This work provided a deeper understanding of dihydrogen bonds.And we wish that high pressure could be applied to identify other unconfirmed hydrogen or dihydrogen bond.
基金Supported by the National Natural Science Foundation of China（Nos.21003057, 21173096）, the National Basic Research Program of China（No.2013CB834801） and the Specialized Research Fund for the Doctoral Program of Higher Education of China（No.20110061110018）.
文摘The C--H…H dihydrogen-bonded complexes of methane, ethylene, acetylene, and their derivatives with magnesium hydride were systematically investigated at MP2/aug-cc-PVTZ level. The results confirm that the strength of dihydrogen bonding increases in the following order of proton donors： C（sp3）-H〈C（sp2）-H〈C（sp）-H and chlorine substituents enhance the C-H…H interaction. In the majority of the complexes with a cyclic structure, the Mg-H proton-accepting bond is more sensitive to the surroundings than C-H proton-donating bond. The nature of the electrostatic interaction in these C-H…H dihydrogen bonds was also unveiled by means of the atoms in mo- lecules（AIM） analysis. The natural bond orbital（NBO） analysis suggests that the charge transfer in the cyclic com- plexes is characteristic of dual-channel. The direction of the net charge transfer in the cyclic complexes is contrary to that previously found in dihydrogen bonded systems.
基金supported by the Hong Kong Research Grant Council(HKUST 602611,HKUST-601812,CUHK7/CRF/12G-2)
文摘Treatment of RuCl2(PPh3)3 with 6-dimethylaminopentafulvene in THF in the presence of water produced(η5-C5H4CHO) RuCl(PPh3)2, which was reduced by NaBH4 to give the Ru–H···HO dihydrogen bonded complex(η5-C5H4CH2OH) RuH(PPh3)2. The dihydrogen bonded complex(η5-C5H4CH2OH)RuH(PPh3)2 could also be synthesized by the reduction of complex(η5-C5H4CHO)RuH(PPh3)2, which was obtained by the reaction of RuHCl(PPh3)3 with 6-dimethylaminopentafulvene in the presence of water. The analogous dihydrogen bonded osmium complex(η5-C5H4CH2OH)OsH(PPh3)2 was similarly prepared. Single crystal structures and DFT calculations support the presence of intra-molecular H···H interaction, with separations of around 1.9 to 2.0 .
基金Support by the Natural Science Education Foundation of Gansu Province (Grant NO. 07-08-12)"QingLan" Talent Engineering Fund of Tianshui Normal University
文摘The optimized geometries, frequencies and interaction energy corrected with basis set superposition error (BSSE) of the multi-dihydrogen bond complexes C4H4NH…BH4.-and CH≡CH…BH4.-have been calculated at both the B3LYP/6-311++G** and the MP2/6-311++G** levels. The calculations were per-formed to study the nature of the N―H…H3―B and C―H…H2―B red shift multi dihydrogen bond in complex C4H4NH…BH-4 and CH≡CH…BH-.4 The BSSE-corrected multi-dihydrogen bond interaction en-ergy of complex I (C4H4NH…BH4-.) and complexⅡ(CH≡CH…BH-.4) is -76.62 and -33.79 kJ/mol (MP2/6- 311++G**), respectively. From the natural bond orbital(NBO)analysis, we detailedly discussed the orbital interactions, electron density transfers, rehybridizations and the essential of the correlative bond length changes in the two complexes. In addition, solvent effect on the geometric structures, vibration frequencies and interaction energy of the monomer and complexes was studied in detail. It is relevant to the relatively dielectric constants (ε).
文摘The IR spectroscopic data indicate the tautomeric transformations of typical aprotonic organic fluids such as methane halides with gross formulas CHX3 （X = Cl, Br）, CH2X2 （X = CI, Br, I） and CCl4 at normal conditions. These transformations lead to the appearance in molecules of activated hydrogen atoms similar in the spectral behaviour to the bounded proton. The classical analysis of IR bands in 5000-600 cm^-1 region, for studied samples and their deuterated derivatives, proves the existence in the presented organic fluids of hydrogen and dihydrogen bonds. This bonding promotes the formation of supramolecular structure in methane halides. The mechanism of unusual binding in liquid phase in terms of common knowledge for the basic chemical properties of the examined compounds is discussed.
基金supported by the National Natural Science Foundation of China(22171246,U1804253 to X.C.and 21773214 to D.W.)the National Science Foundation(CHE-2053541 to L.-S.W.)。
文摘Polyhedral boranes are a class of well-known boron molecular clusters with unique physical and chemical properties,and great efforts have been made in the past decades to find more effective synthetic methods.However,the established synthetic methods suffer from low efficiency and low selectivity because the mechanism of the B-H bond condensation reaction,critical for the synthesis of the polyhedral boranes,is not well understood.Here we report highly selective and efficient synthetic methods of the salts of the tetradecahydridoundecaborate(1-)(B_(11)H^(-)_(14)) and dodecahydrido-dodecaborates(2-)(B_(12)H_(12)^(2-)) anions by employing commercially available and inexpensive starting materials.Both theoretical and experimental investigations are carried out to elucidate the reaction mechanisms.We have found that the nature of the B-H bond condensation is the dihydrogen bonding interaction in which the positively charged hydrogens(bridged hydrogens) play a crucial role.The current study has not only led to more effective and selective synthetic methods for B_(11)H^(-)_(14) and B_(12)H_(12)^(2-) but also unveiled the nature of the B-H bond condensation and the general formation mechanisms of polyhedral boranes.This finding will facilitate the development of more effective synthetic methods for polyhedral boranes and spur their wide application.
