In this contribution is reported the sensitive properties of the Zn(II) Schiff base complex, 1, in dichloromethane with respect a series of primary, secondary, and tertiary aliphatic amines through the study of fluorescence enhancement upon amine coordination to the Lewis acidic Zn(II) metal center with formation of 1:1 adducts. It is found that complex 1 exhibits selectivity and nanomolar ensitivity for primary and alicyclic amines. A distinct selectivity is also bserved along the series of secondary or tertiary amines, paralleling the ncreasing steric hindrance at the nitrogen atom. The binding interaction can be related to the Lewis basicity of the coordinating amine; thus, complex 1 epresents a suitable reference Lewis acid, and estimated binding constants within the investigated amine series can be related to their relative Lewis basicity. A relative order of the Lewis basicity can be established for acyclic amines, primary > secondary > tertiary, while an inverted order, tertiary > secondary approximate to primary (acyclic), is found in the case of alicyclic amines. The present approach represents a simple, suitable method to ranking the relative Lewis basicity of aliphatic amines in low-polarity, nonprotogenic solvents.
|Titolo:||Sensitive Fluorescent Detection and Lewis Basicity of Aliphatic Amines|
|Data di pubblicazione:||2011|
|Appare nelle tipologie:||1.1 Articolo in rivista|