An N-heterocyclic carbene phenanthroline ligand: synthesis, multi-metal coordination and spectroscopic studies

Abstract

Dimetal complexes of a new N-heterocyclic carbene/phenanthroline ligand have been synthesized. Coordination of both ruthenium and rhenium to the phenanthroline moiety in combination with platinum at the carbene moiety are reported. Steady-state and time-resolved optical absorption and photoluminescence spectra were obtained for the complexes. These results illustrate significant changes occur with the incorporation of the second metal, and that the specific metal bound to the phenanthroline moiety is important to the photophysical characteristics of this system.

Oxygen‐Dependent Photocatalytic Water Reduction with a Ruthenium(imidazolium) Chromophore and a Cobaloxime Catalyst

“…The dinuclear RRip-type ruthenium complex Ru 2 (dd(ip) 2 )w as synthesized according to the well-established synthetic scheme, [35,[37][38][39][40] starting with stepwise introductiono ft he substituentsa tt he ip system followed by coordination of the ligand to the ruthenium precursor.…”

“…[34] An ew intramolecular system for photocatalytic water splitting has recently been presentedb ased on ac hromophore containing an N-heterocyclic carbene functional group with the ability to coordinate to the catalytic active center. [35][36][37] In [Ru(tbbpy) 2 (RR'ip)] (abbreviated as Ru(RR'ip);R R 'ip = 1,3-disub-stituted-1H-imidazo [4,5-f] [1,10]phenanthrolinium), the RR'ip ligands may serve as bridging ligands between ac hromophoric and ac atalytic center (see Figure 1). These complexesr epresent promising photosensitizers, especially in view of their well-established synthetica ccessibility and flexibility.…”

“…These complexesr epresent promising photosensitizers, especially in view of their well-established synthetica ccessibility and flexibility. [35,[37][38][39][40] For instance, the ease of tuning the steric demanda bout the putative catalytic center of the carbene carbona tom by changing the imidazolium substituents has been demonstrated, and this does not interfere with their remarkably high emission quantum yields and long excited-state lifetimes under aerobic conditions. [35,41] Furthermore, the relevant properties of the complexesh ave been shown to become even more insensitivet o oxygen withi ncreasing number of RRip ligands.…”

Heterobimetallic Complexes for Theranostic Applications

“…Indeed, recent review articles have highlighted their interesting biological activities as potential antitumor metallodrugs . Despite the fact that heterobimetallic carbene derivatives have been already described in the literature, only a few examples deal with their biological properties, leaving the path free for future investigations in this area, Figure …”

Ruthenium Imidazophenanthrolinium Complexes with Prolonged Excited‐State Lifetimes

“…[26] This chromophore contains the potential bridging ligand bbip, which combines a phenanthroline moiety for coordination to the ruthenium center as well as an imidazolium part as a protonated Nheterocyclic carbene (NHC) precursor for the coordination of low-valent metal catalysts on the other side. [26][27][28][29] Heterodimetallic complexes with a Pd(Cl) 2 or Rh(cod)Cl (cod = cyclooctadiene) catalytic moiety bound to the carbene carbon atom of the NHC scaffold are active catalysts for photocatalytic hydrogen formation. [26] Complex 1 shows remarkable luminescence properties and prolonged excited-state lifetimes compared with those of the benchmark complex [Ru(tbbpy) 3 ] 2+ under inert conditions as well as in the presence of oxygen.…”