To study the Fe-M interactions and their effects on 31p NMR, the structures of Fe（CO）3（EtPhPpy）2 1, Fe（CO）3（EtPhPpy）2M（NCS）2 （2： M=Zn, 3： M=Cd, 4： M=Hg） and Fe（CO）3（EtPhPpy）2CdX2 （5： X=C1, 6： X=...To study the Fe-M interactions and their effects on 31p NMR, the structures of Fe（CO）3（EtPhPpy）2 1, Fe（CO）3（EtPhPpy）2M（NCS）2 （2： M=Zn, 3： M=Cd, 4： M=Hg） and Fe（CO）3（EtPhPpy）2CdX2 （5： X=C1, 6： X=SCN） were investigated by density functional theory （DFT） PBE0 method. The stabilities S of complexes follow S（2）〉S（3）〉S（4） and S（3）,.~S（6）〉S（5）, indicating that 6 is stable and may be synthesized. The complexes with thiocyanate are more stable than that with chloride in Fe（CO）3（EtPhPpy）2CdX2. The strength I of Fe-M interactions follows I（2）≈I（3）〈I（4）. The Fe-Cd interactions of 3 and 6, which contain thiocyanate, are stronger than that of 5 with chloride. The charge-transfer, which enhances with the increasing of Fe-M interaction strength, comes from Et, Ph, py, CO groups towards P, Fe, and M atoms. Because the delocalization of thiocyanate disperses the charge of M2＋, the charge-transfer of the complexes with thiocyanate is stronger than that with chloride. There is a a-bond between Fe and Hg atoms in 4. However, in binuclear complexes except 4, the Fe-M interactions act as nFe→nM, σP-Fe→nM and σC-Fe→nM delocalization, and the N-M interactions mainly act as nN→nM delocalization. In binuclear complexes, due to the Fe→M interactions, the strong σFe--C→σ＊Fe--p or σFe-Hg→σ＊Fe--I2 delocalization and the charge-transfer, the electron density on P nucleus is increased, and thus upfield 31p chemical shifts are caused （compared with mononuclear complex 1）.展开更多
The reaction of amino acids and phosphorus trichloride in THF was studied by 31P NMR tracing and ESI-MS/MS. A series of hydridophoranes and cyclic dipeptides were obtained. The reaction presented interesting diversity...The reaction of amino acids and phosphorus trichloride in THF was studied by 31P NMR tracing and ESI-MS/MS. A series of hydridophoranes and cyclic dipeptides were obtained. The reaction presented interesting diversity and the reaction mechanism was proposed. The mechanism suggests that phosphorus plays an important role in the synthesis of amino acid hydridophorane and cyclic dipeptides. The results also show that 31P NMR and ESI-MS/MS are useful tools for the investigation of reaction mechanism.展开更多
Chiral alcohols（3, 5） were synthesized in optically pure forms from easily available rosin acid in short-steps. A comprehensive protocol for the enantiomeric excess assays of mono- or di-functional-grouped chiral se...Chiral alcohols（3, 5） were synthesized in optically pure forms from easily available rosin acid in short-steps. A comprehensive protocol for the enantiomeric excess assays of mono- or di-functional-grouped chiral secondary amine or alcohol has been established with them used as chiral auxiliary for chiral phosphorus derivatizing agents（CPDAs） in 3Jp NMR tests. Chemical shift difference（△δp） values ranging from 4.5 to 0.15 between two dias- tereoisomers of the CPDAs and the aryl substrates were obtained. Positive △δR-S was observed for all the tested alco- hol P（III） and P（V） derivatives, while negative △δR-S was observed for all the amines.展开更多
以三甲基磷氧(TMPO)和三丁基磷氧(TBPO)为探针分子,用31P魔角旋转核磁共振(31P MAS NMR)法对稀土改性Y型分子筛的酸性进行了定性和定量分析.结果表明,以TMPO为探针分子的31P MAS NMR谱分别在δ=78,70,65,62,58,55和53处存在与酸中心相...以三甲基磷氧(TMPO)和三丁基磷氧(TBPO)为探针分子,用31P魔角旋转核磁共振(31P MAS NMR)法对稀土改性Y型分子筛的酸性进行了定性和定量分析.结果表明,以TMPO为探针分子的31P MAS NMR谱分别在δ=78,70,65,62,58,55和53处存在与酸中心相关的吸收峰,其中δ=78和70处吸收峰与分子筛内部和外部酸性有关,δ=65,62,58和53处吸收峰归属于TMPO在分子筛内部Brnsted酸中心上的贡献,δ=55处吸收峰归属于TMPO在分子筛内部Lewis酸中心上的贡献.随着稀土含量的增加,中等强度Brnsted酸中心(δ=62和58)数量显著增加,而强Brnsted酸中心(δ=65)和较弱Lewis酸中心(δ=55)数量显著降低.结合分子筛骨架铝和非骨架铝对分子筛酸性的影响进一步探讨了稀土改型Y分子筛的酸性.展开更多
基金This work was supported by the Natural Science Foundation of Guangdong Province （No.5005938） and the Research Project of Ministry of Education and Guangdong Province （No.2007A090302046）.
文摘To study the Fe-M interactions and their effects on 31p NMR, the structures of Fe（CO）3（EtPhPpy）2 1, Fe（CO）3（EtPhPpy）2M（NCS）2 （2： M=Zn, 3： M=Cd, 4： M=Hg） and Fe（CO）3（EtPhPpy）2CdX2 （5： X=C1, 6： X=SCN） were investigated by density functional theory （DFT） PBE0 method. The stabilities S of complexes follow S（2）〉S（3）〉S（4） and S（3）,.~S（6）〉S（5）, indicating that 6 is stable and may be synthesized. The complexes with thiocyanate are more stable than that with chloride in Fe（CO）3（EtPhPpy）2CdX2. The strength I of Fe-M interactions follows I（2）≈I（3）〈I（4）. The Fe-Cd interactions of 3 and 6, which contain thiocyanate, are stronger than that of 5 with chloride. The charge-transfer, which enhances with the increasing of Fe-M interaction strength, comes from Et, Ph, py, CO groups towards P, Fe, and M atoms. Because the delocalization of thiocyanate disperses the charge of M2＋, the charge-transfer of the complexes with thiocyanate is stronger than that with chloride. There is a a-bond between Fe and Hg atoms in 4. However, in binuclear complexes except 4, the Fe-M interactions act as nFe→nM, σP-Fe→nM and σC-Fe→nM delocalization, and the N-M interactions mainly act as nN→nM delocalization. In binuclear complexes, due to the Fe→M interactions, the strong σFe--C→σ＊Fe--p or σFe-Hg→σ＊Fe--I2 delocalization and the charge-transfer, the electron density on P nucleus is increased, and thus upfield 31p chemical shifts are caused （compared with mononuclear complex 1）.
基金Project supported by the National Natural Science Foundation of China （Nos. 20672104, 20732004）
文摘The reaction of amino acids and phosphorus trichloride in THF was studied by 31P NMR tracing and ESI-MS/MS. A series of hydridophoranes and cyclic dipeptides were obtained. The reaction presented interesting diversity and the reaction mechanism was proposed. The mechanism suggests that phosphorus plays an important role in the synthesis of amino acid hydridophorane and cyclic dipeptides. The results also show that 31P NMR and ESI-MS/MS are useful tools for the investigation of reaction mechanism.
基金Supported by the National Basic Research Program of China（No.2011CB512005）, the National Natural Science Foundation of China（Nos.81260472 and 21101035）, Guangxi Natural Science Foundation of China（Nos.2011GXNSFD018010 and 2010GXNSFF013001）, the Project of Ten, Hundred, Thousand Distinguished Talents in New Century of Guangxi, China （No.2007228） and the State Key Laboratory Cultivation Base for the Chemistry and Molecular Engineering of Medicinal Resources, Ministry of Science and Technology of China （No.CMEMR2012-A14）.
文摘Chiral alcohols（3, 5） were synthesized in optically pure forms from easily available rosin acid in short-steps. A comprehensive protocol for the enantiomeric excess assays of mono- or di-functional-grouped chiral secondary amine or alcohol has been established with them used as chiral auxiliary for chiral phosphorus derivatizing agents（CPDAs） in 3Jp NMR tests. Chemical shift difference（△δp） values ranging from 4.5 to 0.15 between two dias- tereoisomers of the CPDAs and the aryl substrates were obtained. Positive △δR-S was observed for all the tested alco- hol P（III） and P（V） derivatives, while negative △δR-S was observed for all the amines.
基金supported by the National Basic Research Program of China (973 Program 2003CB615804)+1 种基金the National Natural Science Foundation of China (20673054)the National Key Technology R&D Program (2012BAE05B00)~~
文摘以三甲基磷氧(TMPO)和三丁基磷氧(TBPO)为探针分子,用31P魔角旋转核磁共振(31P MAS NMR)法对稀土改性Y型分子筛的酸性进行了定性和定量分析.结果表明,以TMPO为探针分子的31P MAS NMR谱分别在δ=78,70,65,62,58,55和53处存在与酸中心相关的吸收峰,其中δ=78和70处吸收峰与分子筛内部和外部酸性有关,δ=65,62,58和53处吸收峰归属于TMPO在分子筛内部Brnsted酸中心上的贡献,δ=55处吸收峰归属于TMPO在分子筛内部Lewis酸中心上的贡献.随着稀土含量的增加,中等强度Brnsted酸中心(δ=62和58)数量显著增加,而强Brnsted酸中心(δ=65)和较弱Lewis酸中心(δ=55)数量显著降低.结合分子筛骨架铝和非骨架铝对分子筛酸性的影响进一步探讨了稀土改型Y分子筛的酸性.
