Wing-Kin Chu

Synthesis, characterisation and photophysical studies of leucotriarylmethanes-containing ligands and their rhenium(I) tricarbonyl diimine complexes

A series of pyridine- and bipyridine-containing leucotriarylmethane ligands has been successfully synthesised and incorporated into tricarbonyl rhenium(I) diimine complexes. The X-ray crystal structures of two of the complexes have also been determined. The photoreactivity, photophysical and electrochemical properties of these ligands and their rhenium complexes were investigated. The photo-ionisation of the leucotriarylmethanes in the free ligands and their metal complexes and the subsequent change in absorption properties were also studied. Additionally, the electrochemistry of these ligands and complexes were investigated.

Luminescent Rhenium(I) Pyridyldiaminocarbene Complexes: Photophysics, Anion-Binding, and CO2-Capturing Properties.

A series of luminescent isocyanorhenium(I) complexes with chelating acyclic diaminocarbene ligands (N^C) has been synthesized and characterized. Two of these carbene complexes have also been structurally characterized by X-ray crystallography. These complexes show blue-to-red phosphorescence, with the emission maxima not only considerably varied with a change in the number of ancillary isocyanide ligands but also extremely sensitive to the electronic and steric nature of the substituents on the acyclic diaminocarbene ligand. A detailed study with the support of density functional theory calculations revealed that the lowest-energy absorption and phosphorescence of these complexes in a degassed CH2Cl2 solution are derived from the predominantly metal-to-ligand charge-transfer [dπ(Re) → π*(N^C)] excited state. The unprecedented anion-binding and CO2-capturing properties of the acyclic diaminocarbene have also been described.

Luminescence behaviour of Pb2+-based cage-containing and channel-containing porous coordination polymers

Luminescent porous coordination polymers, cage-containing chains [Pb5(L1)6(N3)2(OH)2]n (1) and 1-D double helical chains [Pb(L2)(N3)]n (2) with 1-D channels were prepared by solvothermal reactions. These polymers can take up metal ions and induce different luminescence responses depending on the metal ions.

Synthesis, structures and photophysical properties of luminescent cyanoruthenate(II) complexes with hydroxylated bipyridine and phenanthroline ligands

Treatment of (PPh4)2[RuII(PPh3)2(CN)4] (1) with bpyOH and phenOH in DMF afforded two mononuclear compounds fac-(PPh4)[RuII(bpyOH)(PPh3)(CN)3] (2) and fac-(PPh4)[RuII(phenOH)(PPh3)(CN)3] (3), respectively (bpyOH = 6-hydroxy-2,2′-bipyridine; phenOH = 2-hydroxy-1,10-phenanthroline). These complexes have been characterized by various spectroscopic techniques. The structures of 1 and 2 have also been determined by X-ray crystallography. Their photophysical and electrochemical properties have been investigated. Compound 3 displays intense emission with much higher quantum efficiency (Φem = 19.4%) in solution, compared with other related ruthenate(II) diimine complexes. In addition, their solvatochromism, pH effects, and ion perturbation have also been investigated. The different photoluminescent behaviors between these complexes and the previously reported complex [RuII(phen)(PPh3)(CN)3]− suggest that the introduction of the hydroxyl group into the diimine ligand would significantly affect their emission properties. Through spectrophotometric titrations, the ground state pKa and excited state pKa* values, as well as the dynamic pH response ranges of these complexes have been determined. Their photophysical response towards various metal ions have also been studied.

CCDC 1498291: Experimental Crystal Structure Determination

Related Article: Lin-Li Hu, Chang Shen, Wing-Kin Chu, Jing Xiang, Fei Yu, Ge Xiang, Yan Nie, Chun-Leung Kwok, Chi-Fai Leung, Chi-Chiu Ko|2017|Polyhedron|127|203|doi:10.1016/j.poly.2017.01.046