Influence of chiral substituents on the Δ and Λ helicity of metal string complexes
Date Issued
2014
Date
2014
Author(s)
Kuo, Min-Shiang
Abstract
Recently, Prof Peng, Shie-Ming and his coworkers have successfully synthesized 100% Δ and Λ forms of (Ni5((+)camnpda)4) by using ligands consisting of naphthyridyl-pyridyldiamine (npda) connected with chiral camphor groups. In this work, we investigate the influence the chiral camphor groups on the helicity of four ligands spiraling around the central nickel string by using DFT calculation and semiempircal PM7 method. Particularly, we show that the degeneracy of Δ and Λ forms of an EMAC complex will be removed by introducing a chiral substituent on each ligand. The results indicate that one of these two helical forms of surrounding ligands will be becomes energetically unfavorable by about 100 kcal/mol due to the strong steric repulsion between chiral camphor groups and hydrogens on neighbor naphthyridyl groups. We also construct hypothetical three core and four core EMACs then compare Δ and Λ forms of same chiral head group also shows that certain chiral head group fit certain helicity . Finally we make a conclusion that the position of chiral substituent is decided by its chirality and the helicity is decided by the position of head group(2-2 trans form) which can be a chiral group, combine those point of view, we can conclude that the helicity of EMACs can be control by chiral substituent of the head group .
Subjects
螺旋性之影響
Type
thesis
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