Photochemical and Photophysical Properties of Fac-Re(I) Tricarbonyl Complexes:  A Comparison of Monomer and Polymer Species with −Re^I(CO)₃Phen Chromophores

Abstract

The photochemical and photophysical properties of a polymer containing nearly 200 pendant groups Re(CO)3(1,10-phenanthroline)+ bonded to poly-(vynilpyridine)600 and the related monomer pyRe(CO)3(1,10-phenanthroline)+ were investigated in solution phase. The yield of formation and the kinetics of decay of the MLCT excited state were found to be dependent on medium and laser power. MLCT excited states in the polymer undergo a more efficient annihilation and/or secondary photolysis than in the monomer. In the polymer, redox quenching of MLCT excited states by methyl viologen and by 2,2‘,2‘ ‘-nitrilotriethanol revealed the presence of intrastrand electron-transfer processes. These processes exhibited a complex kinetics. Mechanisms of the excited-state annihilation and electron-transfer processes in the polymer are proposed.

UV Photolysis of a Re(I) Macromolecule, [(4-vinylpyridine)2(4-vinylpyridineRe(C0)3(1,10-phenanthroline)+]200: Addition of C-centered Radicals to Coordinated CO

“…Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions INTRODUCTION Numerous studies have been concerned with thermal and photochemical reactions of inorganic polymers in solid-and solution-phase. Some interest in their photochemical and photophysical properties is driven by their potential technical applications to catalysis and optical devices [1][2][3][4][5][6][7]. Previous work has shown marked differences between the photochemical and photophysical properties of the monomer pyRe(COh(1,10-(Phen) phenanthroline)+ and a related polymer (A}, with nearly 200 pendant groups -Re(CO)J(l, 10-phen)+ bonded to vpy (vinylpyridine} 600 , [2].…”

“…The reductive quenching of the {(vpyh-vpyRe(COhphen+hoo excited states by TEOA is represented in Eq. (1) where the MLCT excited state is identified as -*Re(COh(l,lO-phen)+. Radicals (CH 2 0HCH 2 )N-cH·cH 2 0H are formed when TEOA is oxidized by TEOA •+ in Eq.…”

Review: Properties and chemical reactivity of metallo phthalocyanine and tetramethylbenzoannulene complexes grafted into a polymer backbone

“…If solutions of the polymer-free complexes were used instead of the polymer-grafted ones, the creation of similar conditions requires orders of magnitude larger concentrations of the complexes and/or light intensities. In addition to producing the simultaneous creation of two neighboring electronically excited pendent complexes by absorption of light, the experimental evidence has shown that migration of energy is possible, for example via a Forster energy transfer mechanism, from one electronically excited pendent complex to another in the ground state [31,32,42,43]. This energy hopping through the bundle has been observed in the photochemical processes of a number of polymers with grafted coordination complexes such as poly(HOAl III tspc) [31].…”

Shielding of Electron Acceptors Coordinated to Rhenium(I) by Carboxylato Groups. Intraligand and Charge-Transfer Excited-State Properties of fac-(‘Anthraquinone-2-carboxylato')(2,2′-bipyridine)tricarbonylrhenium (fac-[ReI(aq-2-CO2)(2,2′-bipy)(CO)3])

“…Interest in the properties that L S imposes on the ÀRe I L A (CO) 3 moiety is brought about by possible applications of the Re complexes to biochemical processes [8 ± 11] and to CO 2 reduction [12]. Also, the derivatization of polymers with chromophores, e.g., with pendant ÀRe I L A (CO) 3 groups [13] has prompted investigation of the role of L S in the reactivity of some Re I monomers [14]. Literature reports show, for example, that the function of L S is to exert small perturbations that alter the electronic structure of the chromophore and modify its photophysics [6].…”

“…IL 3 [Re I (aq-2-CO 2 )(2,2'-bipy)(CO) 3 ] hn'''; t 1 41 ns (12) MLCT bipy2Re 3 [Re I (aq-2-CO 2 )(2,2'-bipy)(CO) 3 ] hn'''; t 2 460 ns (13) [Re I ( T aq-2-CO ' spectrum calculated by extrapolation to the beginning of the laser flash is a convolution of two spectra (Fig. 6).…”