Abstract
The structure and reactivity of ${\pi}$-and metallacycle form in the bis(trimethylphosphine) palladium(0) complexes with acrylic acid, methacrylic acid, crotonic acid(A group) and 3-butenoic acid, 4-pentenoic acid(B group) have been investigated by Molecular Mechanics and Extended Huckel Molecular Orbital method. The calculation shows that A groups with large value of frontier electron density of HOMO and LUMO produce $\pi-complexes$ instead of metallacycle. But B groups with small value of frontier electron density of LUMO, especially 3-butenoic acid, form stable metallacycle. Moreover the methyl-substituted five-membered compared with the six-membered metallacycle is energetically stable conformation.
Acrylic acid, methacrylic acid, crotonic acid(A 그룹), 또는 3-butenoic acid 4-pentenoic acid(B group) 등이 배위된 bis(trimethylphosphine) 팔라듐(O) 착물에서 ${\pi}$-및 metallacycle의 안정한 구조와 반응성을 분자역학법과 확장분자궤도함수법으로 조사하였다. 올레핀의 HOMO 및 LUMO 계수가 큰 A 그룹 리간드는 ${\pi}$-착물이 안정화되고, LUMO 계수가 상대적으로 적은 B 그룹 리간드는 금속함유고리화합물이 안정하였으며, 특히, 3-butenoic acid에서는 6원고리 화합물보다 메틸기를 갖는 5원고리 화합물이 더 안정함을 알 수 있었다.
