磷炔R-C≡P(R=－BH2,－CH3,－NH2,－OH)及其异构体的稳定性

采用B3LYP和CCSD(T)方法对R－C≡P(R=－BH2, －CH3,－NH2, －OH)体系进行了理论研究.结果表明，含C≡P三键的异构体BH2－C≡P和CH3－C≡P在各自的体系中分别是热力学最稳定的结构.而在HO－C≡P和NH2－C≡P体系中，热力学最稳定的结构却是H－P=C=O和含C≡N三键的N≡C－PH2.动力学理论研究表明，没有相关实验研究的R－C≡P(R=－BH2, NH2)体系中共有5种异构体是动力学稳定的. 在HO－C≡P体系的2种动力学稳定的异构体中， H－P=C=O连接方式的异构体已被实验所证实，而另外一种HO－C≡P连接方式的异构体的动力学稳定性较高，实验中可以观察到.对于CH3C≡P体系，研究所预示的2种动力学稳定的异构体中CH3－C≡P已被实验证实，从理论上推测另一种动力学稳定性较高的异构体HC≡C－PH2在实验中也可以检测到.

The Stability of Phosphaalkynes R-C≡P (R=－BH2, －CH3,－NH2, －OH) and Their Isomers

B3LYP and CCSD(T) methods were employed to investigate the systems of R－C≡P(R=－BH2, －CH3,－NH2, －OH). The results indicate that isomers P≡C－BH2 and CH3－C≡P containing C≡P triple bond are thermodynamically the most stable species in BH2－C≡P and CH3－C≡P systems, respectively. But in the systems of HO－C≡P and NH2－C≡P, H－P=C=O and N≡C－PH2 containing C≡N triple bond are thermodynamically the most stable species, respectively. The calculated results on the kinetic stability indicate that for R－C≡P(R=－BH2,－NH2) systems, in which no experimental information are available, five isomers are kinetically stable. In HO－C≡P system, two kinetically stable species are located. Isomer H－P=C=O has been detected in experiment, and in view of higher kinetic stability, another isomer HO－C≡P should be experimentally observable. For CH3－C≡P system, isomer CH3－C≡P has been observed in experiment, and another kinetically stable isomer HC≡C－PH2 ought to be detected in future experiments.