A theoretical study on the unusual square-planar structure of bis(imino)pyridine-ligated Group 13 complexes

作者：Li, Weiyi^*; Lyu, Yajing; Zhang, Huifang; Zhu, Maoqin; Tang, Hanping

来源：Dalton Transactions, 2017, 46(1): 106-115.

DOI：10.1039/c6dt03775e

• MOLECULAR-ORBITAL METHODS
• INDEPENDENT CHEMICAL-SHIFTS
• GAUSSIAN-TYPE BASIS
• OLEFIN POLYMERIZATION
• ELECTRONIC-STRUCTURES
• DENSITY FUNCTIONALS
• 3RD-ROW ATOMS
• FORMIC-ACID
• BASIS-SETS
• IRON

The unusual square-planar (SP) structure of four-coordinate Al-III-complexes with the phenyl-substituted tridentate bis(imino) pyridine ((I2P)-I-Ph) ligand has been studied by a combination of density functional theory (DFT) calculations, frontier molecule orbital (FMO), nucleus-independent chemical shift (NICS) and strain/interaction analyses. The calculations disclose that: (i) the aromaticity shifting from the pyridine ring to the alumina-imidazolate metallacycle, and (ii) the small strain energy imposed on the ligand backbone are two favourable factors for driving the overall SP coordination of the Al-III ion. Meanwhile, the calculations reveal that the SP coordination of the Al-III ion is also influenced by the fourth ligand that is bonded to the Al-III ion. The less steric demanding ligand could ensure the stronger aromaticity of the alumina-imidazolate metallacycle and small strain energy on the ligand backbone. Additionally, the calculations predict that Ga-III and In-III ions favour the SP geometry in the analogue (I2P)-I-Ph-ligated complexes, while B-III and Tl-III ions are reluctant to adopt the SP coordination with the (I2P)-I-Ph ligand. Overall, all of these findings would be helpful for the synthesis of more unknown low-valent main-group metal complexes bearing the bis (imino) pyridine ligand.

• 出版日期2017-1-7
• 单位西华大学