Photochromic DTE-Substituted-1,3-di(2-pyridyl)benzene Platinum(II) Complexes: Photomodulation of Luminescence and Second-Order Nonlinear Optical Properties

Abstract

We disclose a new family of photochromic cyclometalated platinum(II) complexes (PtDTE1 and PtDTE2), where a dithienylethene (DTE) unit is connected at the para-position of the central phenyl ring of (N^C^N) cyclometalated ligand, through two different linkages. Their syntheses are presented along with the X-ray characterizations of both the open and closed isomers of PtDTE1. The investigation of their photophysical properties is made, including absorption, photochromism, emission, and second-order nonlinear properties. We report a quantitative photoisomerization for both PtDTE1 and PtDTE2, irrespective of the nature of the connecting mode between the DTE unit and the platinum(II) moiety. The efficient photochromism allows a significant NLO photomodulation, both in solution and in thin films. In addition, we show that the photoluminescence of the PtDTE1 and PtDTE2 can be controlled by the open/closed isomerization of the DTE unit.

Novel cyclometallated 5-π-delocalized donor-1,3-di(2-pyridyl)benzene platinum(ii) complexes with good second-order nonlinear optical properties

“…We found that the µβ EFISH of the known complex with a methyl group on the thiophene (Pt6) measured in DMF (-520 x 10 -48 esu) is similar to that previously reported in CH 2 Cl 2 , 33 showing that the nature of the solvent doesn't affect the second-order NLO response of this kind of complexes. The EFISH study of the four novel related complexes (Pt2, Pt3, P4, Pt5; Table 1) puts in evidence the effect of the nature of the substituent on the position 5 of the thiophene moiety.…”

“…These results prompted us to prepare a Pt(II) chloro complex bearing a novel π−delocalized cyclometallated 5-guaiazulene-CH=CH-1,3-di(2-pyridyl)benzene (Pt1, Chart 1) in order to investigate its second-order NLO properties. Besides we prepared four novel complexes (Pt2, Pt3, P4, Pt5) bearing variously 5-substituted thiophene moieties in position 5 of the 1,3-di(2-pyridyl)benzene, in order to compare their NLO response with that of the known related complex with a methyl group on the thiophene (Pt6) 33 and thus to understand the effect of the nature of thiophene substituents. Their NLO response was determined by the EFISH technique [34][35][36] in DMF,…”

A trip in the nonlinear optical properties of iridium complexes

“…Whereas efficient second-order NLO switches have been reported in the case of ruthenium [17,18,99], zinc [40,55,100], platinum [82,83,[101][102][103], nickel [102], and palladium [102] complexes, to the best of our knowledge no example has been reported involving iridium complexes. Nevertheless, iridium complexes, which have abundant valence states and rich electrochemical properties, could be excellent second-order NLO redox-switch molecular materials, as suggested by recent theoretical investigations [104][105][106].…”

Cyclometalated Ir(III) Complexes with Curcuminoid Ligands as Active Second-Order NLO Chromophores and Building Blocks for SHG Polymeric Films

“…The use of tetrahydrocurcumin as an ancillary ligand (complex Ir2) affords a similar second-order NLO response (µβ 1.907 = −930 × 10 −48 esu; µβ 0 = −661 × 10 −48 esu by using Equation (2) and λ max = 470 nm [54]). This is a significant result, because compounds showing both luminescent and nonlinear optical properties are of growing interest as multifunctional molecular materials for optoelectronics [68][69][70][71][72][73][74][75][76][77].…”