Cyclometalated Ir(III) Complex as a Metalloligand and a Selective Cu(II) Sensor: Synthesis and Structural Characterization of a Heterometallic Tetranuclear Ir(III)/Cu(II) Complex

Abstract

A cyclometalated Ir(III) complex, [Ir(ppy) 2 (LH)] ( 2 ) [LH 2 = 1,2-bis(pyridine-2-carboxamido)benzene; ppyH = 2-phenylpyridine] was synthesized and structurally characterized. [Ir(ppy) 2 (LH)] contains free donor sites and functions as a metalloligand. Accordingly, it interacts with a Cu(II) salt to afford the heterometallic tetranuclear complex, [{Ir(ppy) 2 (L)} 2 {Cu 2 Cl 2 }] ( 3 ). In the latter, a Cu 2 Cl 2 dimer bridges the two cyclometalated Ir(III) units, resulting in a Ir III –Cu II –Cu II –Ir III motif. 2 also functions as a selective and reversible sensor for Cu 2+ , as revealed by quenching of its emission and subsequent revival of the luminescence signal upon addition of EDTA.

Modular Imine Chelates with Variable Anionic Donors Promote Red Phosphorescence in Cyclometalated Iridium Complexes

“…Salicylaldimines and 2-picolinamides represent alternative classes of L^X ligands that have been used in a few reports to support luminescent cyclometalated iridium complexes. Salicylaldimine complexes can exhibit enhanced red phosphorescence in the solid state − and circularly polarized luminescence, whereas 2-picolinamide analogues phosphoresce in the green to yellow regions. − One common feature of these recent reports is the use of 2-phenylpyridine or fluorinated 2-phenylpyridine C^N ligands, which results in the emissive T 1 state being a charge-transfer state that intimately involves orbitals from the L^X ligand. This feature leads to rich photophysical behavior, but none of the reported compounds exhibit exceptional photoluminescence quantum yields, particularly those that luminesce in the red region.…”

White light emission produced by CTMA-DNA nanolayers embedded with a mixture of organic light-emitting molecules

“…The energy transfer suggested that the excited charge carriers emerging from CDNA could be transferred onto OLEMs, which in turn were excited and underwent radiative relaxation emitting light with specic colours. [29][30][31][32] The attenuated FTIR, UV absorption, PL spectra, and CIE colour coordinates for white light producing T-CDNA NLs (e.g., W-CDNA) is shown in Fig. 6.…”

A strategically synthesized arseno-discriminatory tetra-phenoxido hetero-trinuclear complex envisioned for the recognition of iAs and oAs from Oryza sp. and aquatic crustaceans

“…The more electron-rich O center forms shorter Mn–O phenoxido bonds and the less electron-rich forms longer Mn–O phenoxido bonds (ESI; Tables S1–S4†). 11–13…”

“…From this standpoint, the designed synthesis of heterometallic complexes with N and O donor ligands has been considered a focal point predominantly owing to their redox activity and spectroscopic features in terms of chromogenic change and luminogenic rapid responses. 11–13 Integration of these features into a single sensory probe uplifts the applicability of the system in the realm of host–guest recognition. Moreover, this category of metal complexes is often found to be electron deficient, which leads to the enhancement of electrostatic interactions with negatively charged anionic species (herein, anionic i As ), ultimately strengthening the binding affinity of anionic species with a higher probability following a better orbital overlap.…”