The polynuclear complex Cu(4)I(4)py(4) loaded in mesoporous silica: photophysics, theoretical investigation, and highly sensitive oxygen sensing application

Author(s)

Ravaro, Leandro P. ; Almeida, Tiago. R. ; Albuquerque, Rodrigo Q. ; de Camargo, Andrea S. S.

• Document type: Journal article
• Source: DALTON TRANSACTIONS; v. 45, n. 44, p. 17652-17661, 2016.
• Web of Science Citations: 12

Abstract

The polynuclear complex Cu(4)I(4)py(4) has been largely studied in solution and in the powder form due to its interesting luminescent properties, which are largely dependent on temperature and pressure. In this work, we present the synthesis of the complex and its wet impregnation in a mesoporous silica host obtained by sol-gel methodology. For optimized loadings, the well-dispersed guest molecules exhibit strong interaction with molecular oxygen, resulting in a significant quenching of the luminescence. The process is highly reversible with a Stern-Volmer constant of K-sv = 33.8, which is the largest value found in the literature for similar complexes in the solid state, suggesting that the new material is a promising candidate for high sensitivity oxygen sensing. Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) calculations reveal a weak intermolecular interaction between the two guest complexes in the excited state, suggesting the formation of an excited state complex (excimer). The assumption of a triplet excimer formation is confirmed by temperature- and concentration-dependent experiments, which provides a new way to explain the giant Stokes shift observed for the guest complex in different media. (AU)

• FAPESP's process: 14/02071-5 - Theoretical investigation of the aggregation of cationic complexes of Ir(III) with potential application in LECs and OLEDs
• Grantee: Rodrigo Queiroz de Albuquerque
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass
• Grantee: Edgar Dutra Zanotto
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 13/24727-7 - New Optical Materials Based on Polynuclear Copper(I) Halide Cluster Complexes Immobilized in Solid Host Matrices
• Grantee: Leandro Piaggi Ravaro
• Support Opportunities: Scholarships in Brazil - Post-Doctoral