Chiral poly(4-ethynylbenzoyl-l-valine)-induced helical self-assembly of alkynylplatinum(II) terpyridyl complexes with tunable electronic absorption, emission, and circular dichroism changes.
A chiral amino acid-containing polyacetylene, poly(4-ethynylbenzoyl-L-valine), was found to induce the aggregation and self-assembly of square-planar alkynylplatinum(II) terpyridyl complexes by electrostatic binding of the positively charged metal complexes to the anionic sites of the polyacetylene, as revealed by the appearance of new UV/Vis absorption and emission bands upon mixing under basic conditions. The induced complex self-assembly was found to be influenced by the polyacetylene and/or base concentration, and the effect of pH on the reversibility of the aggregate/monomer interconversion was also studied. The conformational changes of the polyacetylene were probed by circular dichroism (CD) spectroscopy, in which the chirality signal of the corresponding chain helicity in the presence of the base was enhanced and stabilized upon addition of the platinum(II) complexes. The induced complex aggregation was dependent on the structural properties of the polyacetylene, while the chirality of the polyacetylene was strongly influenced by the introduction of the complex.
Chan
Kenneth Hoi-Yiu
KH
Center for Carbon-Rich Molecular and Nanoscale Metal-Based, Materials Research, Department of Chemistry and HKU-CAS Joint Laboratory on New Materials, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
Lam
Jacky Wing-Yip
JW
Wong
Keith Man-Chung
KM
Tang
Ben-Zhong
BZ
Yam
Vivian Wing-Wah
VW