A cationic organoiridium(iii) complex-based AIEgen for selective light-up detection of rRNA and nucleolar staining

Abstract

A green emissive cationic organoiridium(iii) complex, 2[PF6], with a benzimidazole-substituted 1,2,3-triazole-pyridine (BiPT) ligand has been synthesized for target-specific cellular imaging and selective detection of ribosomal RNA (rRNA) over other competitive biomolecules in aqueous buffer solution at physiological pH. Complex 2 shows aggregation-induced emission enhancement (AIEE) properties and forms nano-aggregates in the presence of poor solvents. DFT and TD-DFT-based quantum mechanical calculations were performed to substantiate some photophysical features and to establish the intermolecular π-π interactions which detain the vibrational as well as rotational motions to form the aggregates, resulting in enhanced photoluminescence (PL). To corroborate the formation of nano-aggregates and to understand the morphology of the aggregated particles, dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) measurements were performed. 2[PF6] showed low cytotoxicity and good biocompatibility and was successfully employed in organelle-specific intracellular imaging. The in vivo and in vitro photoluminescence investigations affirmed that the probe stains cell nucleoli and selectively binds rRNA. It is assumed that the supramolecular π-π interactions between the benzimidazole of the BiPT ligand and the secondary structures of rRNA may facilitate aggregation and enable PL enhancement.

Highly Selective Detection of Hypochlorous Acid by a Bis-heteroleptic Ru(II) Complex of Pyridyl-1,2,3-triazole Ligand via C(sp2)–H Hydroxylation

“…The ESI-MS of the Ru-1 and NaOCl mixture shows a clear peak at m / z = 770.13, corresponding to [C 39 H 26 ­N 9 ORuS] + , which indicates oxidation in Ru-1 (Figure S21). While Ru-1 may undergo HOCl/ClO – mediated S-oxidation of benzothiazole to sulfoxide or sulfonate, the possibility of oxidation in 1,2,3-triazole is considered since our previous work on Ru­(II) based probes attests that the reactive C-H of 1,2,3-triazole is responsible for the PL enhancement …”

“…Probe Ru-1 , readily prepared from BtPT and cis -[Ru­(phen) 2 ]­Cl 2 (Scheme ), was characterized by 1D ( 1 H and 13 C) and 2D (COSY, HSQC, and HMBC) NMR, ESI-MS (Figures S6–S11), and single-crystal X-ray diffraction (Figure and Tables S2 and S3). Like previously reported Ru­(II) based probes, , here, the Ru­(II) center adopts a distorted octahedral geometry with the trans angles ranging from 170.69(18)° to 172.54(17)°. Additionally, complex Ru-2 of the methyl substituted pyridyl triazole ligand was synthesized to support the mechanistic details of the probe analyte reaction (Scheme , inset).…”

“…The photochemistry of d 6 -metal complexes containing a 1,2,3-triazole ligand has been expansively studied, but the sensing field is quiet unexplored . We have developed few Ru­(II) and Ir­(III) based probes of the 1,2,3-triazole ligand for sensing and bioimaging based on C-H analyte interaction . Ru­(II) polypyridyl complexes have been extensively used as sensors, PDT agents, and bioimaging due to the excellent photochemical properties, stability in aqueous media, and good cell permeability. , While a few Ru­(II) based HOCl selective probes via oxidation of hydrazide-derived linker and sulfur containing heterocycles have been reported, a metal complex based HOCl specific probing by new protocol will need to be developed.…”

Enhanced three-photon activity triggered by the AIE behaviour of a novel terpyridine-based Zn(ii) complex bearing a thiophene bridge

“…5c shows that the proton signals Ha, Hb, Hc and Hd on the pyridine ring moved towards high magnetic fields after RNA addition, with the signal intensity decreasing gradually. These data indicated that the location of hydrogen atoms may be the binding sites of RNA 42. Molecular-docking simulation showed that the interaction between the DZ1 molecule and RNA was a charge–charge interaction because the RNA surface was anionic and DZ1 possessed a positive charge (Fig.…”

Ruthenium(II) Polypyridine Complex-Based Aggregation-Induced Emission Luminogen for Rapid and Selective Detection of Phosgene in Solution and in the Gas Phase

“…Upon aggregation, the RIM process blocks the nonradiative decay from the excited state and populates the radiative decay channels. In addition to RIM, several processes such as planarization, J-aggregate formation, internal charge transfer (ICT), and E – Z isomerization also contribute to the AIE effect. , Extensive applications of AIE-active luminogens such as organic light-emitting diodes, bio/chemosensing, cell imaging, drug delivery, etc., have attracted the attention of numerous scientists. , Scientists have expanded this exciting AIE field mostly by developing organic-based AIEgens, together with a few metal complexes. , However, among metal complex-based AIEgens, Ru­(II) complex-based AIE materials are very rare. , …”