A new type of noncovalent surface–π stacking interaction occurring on peroxide-modified titania nanosheets driven by vertical π-state polarization
Shenqian Ma, Weixin Zhao, Jun Zhou, Jiaou Wang, Shengqi Chu, Zigeng Liu, Guolei Xiang
Abstract
-hybridized atoms. Here we reveal a new type of noncovalent surface-π stacking unusually occurring between aromatic groups and peroxide-modified titania (PMT) nanosheets, which can drive versatile aromatic adsorptions. We experimentally explore the underlying electronic-level origin by probing the perturbed changes of unoccupied Ti 3d states with near-edge X-ray absorption fine structures (NEXAFS), and find that aromatic groups can vertically attract π electrons in the surface peroxo-Ti states and increase their delocalization regions. Our discovery updates the concept of noncovalent π-stacking interactions by extending the substrates from carbon-based structures to a transition metal oxide, and presents an approach to exploit the surface chemistry of nanomaterials based on noncovalent interactions.