Kuppuswamy Kalyanasundaram

White-light phosphorescence emission from a single molecule: application to OLED

A simple mononuclear cyclometallated iridium(iii) complex exhibits white photo- and electro- luminescence in the wavelength range from 440 to 800 nm, which originates from a single emitting excited state of mixed character.

Inter-chromophore electronic interactions in ligand-bridged polynuclear complexes: a comparative study of various bridging ligands

Reference LPI-ARTICLE-1994-021doi:10.1016/0020-1693(94)04089-3View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12

Proflavine-sensitized photoproduction of H2 from water with electron-donors and a colloidal redox catalyst

Efficient photoproduction of H2 from water in the presence of electron donors such as ethylenediaminetetra-acetic acid or triethanolamine and a colloidal Pt-redox catalyst, sensitized by proflavine, is reported; this is a two-component redox system for H2 production as against the common three-component systems with an electron acceptor.

Raman characterization of charge-transfer transitions in ligand-bridged binuclear polypyridyl complexes of ruthenium(II)

In the ligand-bridged complexes [(bipy)2Ru(dpp)Ru(biq)2]4+ and [(biq)2Ru(dpp)Ru(biq)2]4+[dpp = 2,3-bis(2′-pyridyl)pyrazine, bipy = 2,2′-bipyridine and biq = 2,2′-biquinoline], the photophysical and redox properties do not allow differentiation of the low-energy charge-transfer transitions Ru → biq and Ru → dpp. Based on the selective resonance enhancement of the intensities of the Raman bands of the ligand biq by excitation within the lowest-energy absorption band, the lowest excited states in the dinuclear complexes have been assigned unambiguously to Ru → biq charge transfer.

Ground- and excited-state properties of some ligand-bridged ruthenium(II) polypyridyl complexes with spectator-ligand-based emission

From an examination of the absorption, luminescence and redox properties, the lowest excited state of the ligand-bridged polypyridyl complexes [{Ru(biq)2}2(dpp)]4+ and [(bipy)2Ru(dpp)Ru(biq)2]4+[dpp = 2,3-bis(2′-pyridyl)pyrazine, biq = 2,2′-biquinoline and bipy = 2,2′-bipyridine] is assigned to that of the charge-transfer type involving the spectator ligand biq.

Protonation behavior in the ground and excited states of some Os(II) Polypyridyl complexes

Abstract Absorption spectral changes and emission intensity variations during the protonation in the ground and excited charge transfer states of Os(dpp)32+ and Os(44′-dcbpy)34− {dpp = 2,3-bis(2-pyridyl)pyrazine and 44′-dcbpy = 4,4′-dicarboxy-2,2′-bipyridine} have been investigated in aqueous solution.

Ligand-bridged homo- and hetero-binuclear carbonyl polypyridyl complexes of ReI: syntheses, electronic spectra, redox, and luminescence behaviour

Electronic absorption data, redox potentials, and photophysical properties are reported for a series of mono- and ligand-bridged bi-nuclear carbonyl polypyridyl complexes of ReI: [{ReCl(CO)3}nLb] and [(OC)3ClRe(Lb)M(bipy)2]2+[bridging ligand (Lb)= 2,3-bis(2′-pyridyl)pyrazine (dpp) or 2,3-bis(2′-pyridyl) quinoxaline(dpq); bipy = 2,2′-bipyridine; M = RuII or OsII; n= 1 or 2]. For all the binuclear complexes examined, electronic absorption and electrochemical data indicate extensive stabilization of the ligand π* orbital upon binucleation. These are also the first cases of strongly coupled ligand-bridged dimeric complexes of ReI that exhibit luminescence (charge-transfer type) in solution at room temperature. Data on the emission maxima and lifetimes of heterobinuclear complexes of Re and Ru confirm earlier indications that the emitting state is essentially localized on the Ru→Lb charge transfer.

Visible-light-induced oxidation of water and of chloride ions in photoelectrochemical cells

The photoredox reaction between the complex RuL32+(l = di-isopropyl 2,2′-bipyridine-4,4′-dicarboxylate) and S2O82– has been used in a photoelectrochemical cell to demonstrate the visible-light-induced (λ 450 nm) oxidation of water to give O2 and of chloride ions to give Cl2 in acidic solutions; the high redox-potential of the RuL33+/2+ complex and the utilisation of a RuO2-coated Ti anode enable these rather difficult oxidations of occur.