N-inversion and C-N rotational barriers in HX=CH-NH2 (X = N,P,As) compounds:: an ab initio study

被引:14
作者
Prasad, BV [1 ]
Grover, G [1 ]
Uppal, P [1 ]
Kaur, D [1 ]
机构
[1] Guru Nanak Dev Univ, Dept Chem, Amritsar 143005, Punjab, India
来源
JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM | 1999年 / 458卷 / 03期
关键词
ab initio calculations; inversion barrier; rotational barrier; resonance model;
D O I
10.1016/S0166-1280(98)00191-2
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Ab initio calculations at HF/6-31G* and MP2/6-31G* levels are performed on methanimidamide, 1-phosphinidene methanamine and 1-arsenidene methanamine in their E and Z conformations. All of them are found to have pyramidal arrangement around nitrogen of the amino group. Pyramidalization in the amino group could be identified only after including electron correlation. The N-inversion barrier and the C-N rotational barriers in these molecules have been calculated to understand the electron distribution in these molecules. The C-N bond length decreases, bond strength increases, N-inversion barrier decreases, C-N rotation barrier increases, flow of charge from N to X increases in the order methanimidamide < 1-phosphinidene methanamine < 1-arsenidene methanamine. It is found that the electronegativity of X can not be taken as the driving force for the delocalization of electrons onto the a framework of the HX = C(H)-NH2 molecules. (C) 1999 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:227 / 237
页数:11
相关论文
共 39 条
[1]  
ABANGO A, 1996, L PHYS CHEM, V100, P1536
[2]  
ANDRES J, 1992, J MOL STRUC-THEOCHEM, V86, P465
[3]  
[Anonymous], 1955, RESONANCE ORGANIC CH
[4]  
BANGNO A, 1996, J PHYS CHEM, V100, P1545
[5]   Electromagnetic waves of 1.1 cm wave-length and the absorption spectrum of ammonia [J].
Cleeton, CE ;
Williams, NH .
PHYSICAL REVIEW, 1934, 45 (04) :0234-0237
[6]  
COTTON FA, 1988, ADV INORG CHEM, P307
[7]  
FRISCH MJ, 1995, GAUSSIAN94 REVISION
[8]   A MOLECULAR ORBITAL STUDY OF ISOMERIZATION MECHANISM OF DIAZACUMULENES [J].
GORDON, MS ;
FISCHER, H .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1968, 90 (10) :2471-&
[9]  
HAFELINGER G, 1992, Z NATURFORSCH B, V47, P1480
[10]  
Hehre W. J., 1986, Ab initio molecular orbital theory