完全交替的聚碳酸亚环己酯可用作微电子牺牲材料,文中用水杨醛,邻苯二胺和叔丁醇铝制备了SalenAlOC(CH3)3,以N,N-二甲胺基吡啶(DMAP)作为共催化剂催化二氧化碳和氧化环己烯共聚,用核磁共振(1H-NMR)对共聚产物进行了结构分析。结果表明,...完全交替的聚碳酸亚环己酯可用作微电子牺牲材料,文中用水杨醛,邻苯二胺和叔丁醇铝制备了SalenAlOC(CH3)3,以N,N-二甲胺基吡啶(DMAP)作为共催化剂催化二氧化碳和氧化环己烯共聚,用核磁共振(1H-NMR)对共聚产物进行了结构分析。结果表明,催化效率最高可达494 g Polym/g Cat,共聚产物中的碳酸酯键含量为99.9%,-Mn=30300 g/mol,分子量分布PDI=1.46;与SalenAl(OiPr)相比,SalenAlOC(CH3)3得到交替度大于99%的共聚产物的反应条件更宽,更加容易控制。展开更多
采用CCSD(T)//B3LYP/6-311+G(d,p)方法研究了Criegee中间体CH_3CHOO与OH自由基反应的微观机理.结果表明,上述反应存在抽氢、加成-分解和氧化3类反应通道,其中,syn-CH3CHOO+OH以抽β-H为优势通道,表观活化能为-4.88 k J/mol;anti-CH_3CHO...采用CCSD(T)//B3LYP/6-311+G(d,p)方法研究了Criegee中间体CH_3CHOO与OH自由基反应的微观机理.结果表明,上述反应存在抽氢、加成-分解和氧化3类反应通道,其中,syn-CH3CHOO+OH以抽β-H为优势通道,表观活化能为-4.88 k J/mol;anti-CH_3CHOO+OH则以加成-分解反应为优势通道,表观活化能为-13.25 k J/mol.在加成-分解和氧化反应通道中,anti-构象的能垒均低于syn-构象,而抽氢反应则是syn-(β-H)的能垒低于anti-构象.速率常数计算表明,anti-构象的加成-分解反应通道具有显著的负温度效应;syn-和anti-构象的氧化通道具有显著的正温度效应.3类反应具有显著不同的温度效应,说明通过改变温度可显著调节3类反应的相对速率.展开更多
Inverse halogen bonds interactions involving Br in the electronic deficiency systems of CH3＋...Br-Y （Y=H, CCH, CN, NC） have been investigated by B3LYP/6- 311＋＋G（d, p） and MP2/6-311＋＋G（d, p） methods. The cal...Inverse halogen bonds interactions involving Br in the electronic deficiency systems of CH3＋...Br-Y （Y=H, CCH, CN, NC） have been investigated by B3LYP/6- 311＋＋G（d, p） and MP2/6-311＋＋G（d, p） methods. The calculated interaction energies with basis set super-position error correction of the four IXBs complexes are 218.87, 219.48, 159.18, and 143.05kJ/mol （MP2/6-311＋＋G（d, p））, respectively. The relative stabilities of the four complexes increased in the order： CH3＋ … BrCN〈CH3＋…- BrNC〈CH3＋… BrH≈CH3＋ …BrCCH. Natural bond orbital theory analysis and the chemical shifts calculation of the related atoms revealed that the charges flow from Br-Y to CH3e. Here, the Br of Br-Y acts as both a halogen bond donor and an electron donor. Therefore, compared with conventional halogen bonds, the IXBs complexes formed between Br-Y and CH3＋. Atoms-in-molecules theory has been used to investigate the topological properties of the critical points of the four IXBs structures which have more covalent content.展开更多
文摘完全交替的聚碳酸亚环己酯可用作微电子牺牲材料,文中用水杨醛,邻苯二胺和叔丁醇铝制备了SalenAlOC(CH3)3,以N,N-二甲胺基吡啶(DMAP)作为共催化剂催化二氧化碳和氧化环己烯共聚,用核磁共振(1H-NMR)对共聚产物进行了结构分析。结果表明,催化效率最高可达494 g Polym/g Cat,共聚产物中的碳酸酯键含量为99.9%,-Mn=30300 g/mol,分子量分布PDI=1.46;与SalenAl(OiPr)相比,SalenAlOC(CH3)3得到交替度大于99%的共聚产物的反应条件更宽,更加容易控制。
文摘采用CCSD(T)//B3LYP/6-311+G(d,p)方法研究了Criegee中间体CH_3CHOO与OH自由基反应的微观机理.结果表明,上述反应存在抽氢、加成-分解和氧化3类反应通道,其中,syn-CH3CHOO+OH以抽β-H为优势通道,表观活化能为-4.88 k J/mol;anti-CH_3CHOO+OH则以加成-分解反应为优势通道,表观活化能为-13.25 k J/mol.在加成-分解和氧化反应通道中,anti-构象的能垒均低于syn-构象,而抽氢反应则是syn-(β-H)的能垒低于anti-构象.速率常数计算表明,anti-构象的加成-分解反应通道具有显著的负温度效应;syn-和anti-构象的氧化通道具有显著的正温度效应.3类反应具有显著不同的温度效应,说明通过改变温度可显著调节3类反应的相对速率.
基金This work was supported by the National Natural Science Foundation of China （No.51063006 and No.50975273） and the ＂QingLan＂ Talent Engineering Funds of Tianshui Normal University.
文摘Inverse halogen bonds interactions involving Br in the electronic deficiency systems of CH3＋...Br-Y （Y=H, CCH, CN, NC） have been investigated by B3LYP/6- 311＋＋G（d, p） and MP2/6-311＋＋G（d, p） methods. The calculated interaction energies with basis set super-position error correction of the four IXBs complexes are 218.87, 219.48, 159.18, and 143.05kJ/mol （MP2/6-311＋＋G（d, p））, respectively. The relative stabilities of the four complexes increased in the order： CH3＋ … BrCN〈CH3＋…- BrNC〈CH3＋… BrH≈CH3＋ …BrCCH. Natural bond orbital theory analysis and the chemical shifts calculation of the related atoms revealed that the charges flow from Br-Y to CH3e. Here, the Br of Br-Y acts as both a halogen bond donor and an electron donor. Therefore, compared with conventional halogen bonds, the IXBs complexes formed between Br-Y and CH3＋. Atoms-in-molecules theory has been used to investigate the topological properties of the critical points of the four IXBs structures which have more covalent content.
