水液相下两性α丙氨酸K+配合物旋光异构的理论研究

采用密度泛函理论的M06-2X方法,结合自洽反应场理论的SMD模型方法,研究了水液相下两性S型α丙氨酸与一价钾离子配合物(S-α-Ala·K^(+))的旋光异构.反应通道研究发现:S-α-Ala·K^(+)旋光异构反应有a、b和c 3个通道,a是质子只以羰基氧为桥迁移;b是α氢迁移到羰基氧后,质子再从质子化氨基向α碳迁移;c是质子从质子化氨基迁移到羰基氧后,再以氨基氮为桥迁移.势能面计算表明:隐性溶剂效应下,c通道具有优势,决速步能垒是241.7 kJ·mol^(-1);a和b通道为劣势通道,具有共同的决速步能垒261.3 kJ·mol^(-1).显性溶剂效应下,a、b和c 3个通道的决速步能垒基本相同,大约在136.6至142.0 kJ·mol^(-1)之间.结果表明:水液相下S-α-Ala·K^(+)的旋光异构反应进行的极其缓慢,生命体利用S-α-Ala·K^(+)同补K^(+)和丙氨酸具有较好的安全性.

Synthesis and Crystal Structure of O,O-Dimethyl-N-(β-triphenylgermanyl)propionyl-α- aminobenzylphosphonates

The title compound (C30H32NO4PGe), O,O-dimethyl-N-(β-triphenylgermanyl) propionyl-α-aminobenzylphosphonates was synthesized by a convenient method, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal is triclinic, space group P-1 with parameters: a=9.7753(5), b=11.5773(5), c=13.5059(6) ?, α=104.185(1),β= 95.971(1), γ =96.727(1)°, V=1457.63(12) ?3, Z=2, Mr=574.13, Dc=1.308 g/cm3, λ=0.71073 ?, μ = 1.139mm-1, and F(000)=596. The structure was solved by direct methods. The structure was refined to R=0.0257, wR=0.0705 for 5080 observed reflections with I >2σ(I).The result of structure analysis indicates that atom Ge is sp3 hydridized because the arrangement of the four carbon atoms bonded to it is a distorted tetrahedron. The geometry of the three phenyl groups linking with the Ge atom looks like a propeller form.