Altering molecular polarity via assembly induced charge transfer for high selectivity detection of Cu2

Abstract In this work, a method of assembly-induced charge transfer for changing the polarity of molecules was proposed to achieve highly selective Cu2+ detection. The colorimetric molecule Erie Garnet (EG) is assembled to the surface of single lay RGO (reduced graphene oxide) through simple molecular assembly. Theoretical calculations and experimental results show that through assembly-induced charge transfer, the polarity of the EG molecule is significantly altered, and the dipole moment increases from 3.579D to 29.552D. This change in polarity improves the chelating properties of EG, even in the presence of certain interfering ions (even trivalent Fe3+ and Al3+), it can selectively sense Cu2+ in complex environments with a detection limit as low as 0.98 μM. The recovery rate and relative standard deviation of Cu2+ are 97.75% ∼ 100.8% and ≤4.8%, respectively. The mechanism of assembly, deaggregation effect, selective detection and optical stability were investigated in detail, respectively.