DNA structural changes (photo)induced by tricarbonyl (pterin)rhenium(I) complex

We report on interactions of different types of DNA molecules including double-stranded and plasmid DNA as well as polynucleotides (poly[dGdC]2 and poly[dAdT]2) with fac-[ReI(CO)3(pterin)(H2O)] (or Reptr) complex. The interaction was characterized spectroscopically and changes in the plasmid structure were verified by both electrophoresis and AFM microscopy. For comparative reasons, two others related tricarbonyl rhenium(I) complexes, fac-[(4,4'-bpy)ReI(CO)3(dppz)]+ (or Redppz) and fac-[(CF3SO3)ReI(CO)3(2,2'-bpy)] (or Rebpy) were also studied to further explore the influence of the different co-ligands on the interaction and DNA (photo)damage. Data reported herein suggests that DNA molecules can be structurally modified either by direct interaction with Re(I) complexes in their ground states inducing DNA relaxation, and/or through photoinduced cross-linking processes. The chemical nature of the co-ligands modulates the extent of the damage observed.

Photofunctional multinuclear rhenium(i) diimine carbonyl complexes

In this review, we summarize the synthesis, photophysical properties and applications of a wide variety of multinuclear complexes consisting of Re(i)-diimine-carbonyl units.

Photocatalytic reactions of a nickel(ii) annulene complex incorporated in polymeric structures

A study of the structural and chemical processes of a new polymeric photocatalyst containing a Ni(ii) macrocyclic complex and its application to the solar reduction of CO₂ in aqueous homogeneous solution.

Intercalation of Re(phen)(CO)3Cl into zirconium phosphate: a water insoluble inorganic complex immobilized in a highly polar rigid matrix

The intercalation of fac-tricarbonylchloro-1,10-phenanthrolinerhenium(i) (Re(phen)(CO)(3)Cl) within zirconium phosphate (ZrP) has been achieved using a hydrated ZrP phase that possesses six water molecules per formula unit. This intercalation occurs only at high solution molar ratios (Re : ZrP, 3 : 1) and is characterized by the emergence of a new phase in the X-ray powder diffraction (XRPD) pattern with an interlayer distance of 15.6 A. The XRPD patterns show a decrease in the crystallinity upon intercalation of the inorganic complex. The MLCT absorption bands of Re(phen)(CO)(3)Cl-containing ZrP materials are red shifted in comparison with the complex in acetonitrile whilst the luminescence spectra at different loading levels are blue shifted up to 30 nm in comparison with the complex in acetonitrile. This blue shift is consistent with the rigidochromic effect. The luminescence lifetime of Re(phen)(CO)(3)Cl within ZrP was increased in comparison with its lifetime in acetonitrile solution but is shorter than that of Re(phen)(CO)(3)Cl in frozen glass and polyesther resins. To our knowledge, this is the first example of a water insoluble metal complex intercalated within the layers of ZrP, which opens up new possibilities in the intercalation chemistry of this lamellar material and in the study of host-guest interactions.

Aggregation in Nanobundles and the Effect of Diverse Environments on the Solution-Phase Photochemistry and Photophysics of −Re(CO)3L+ (L = 1,10-Phenanthroline, 2,2‘-Bipyridine) Pendants Bonded to Poly(4-vinylpyridine)

The UV-vis spectroscopy and photochemical properties of {(vpy-[Re(CO)3(2,2'-bpy)])m(vpy-[Re(CO)3(phen)])n(vpy)p}(CF3SO3)(m+n)}, vpy = 4-vinylpyridine, m = 131, n = 131 or m = 200, n = 150, and m + n + p = 600, were investigated in solution phase. The polymers exist in solution as aggregates of polymer strands with radii as large as approximately 10(2) nm. Given the size of the poly-vpy backbone, the aggregates must contain a large number of strands. The luminescence spectrum exhibits a strong resemblance to the emission spectrum of {(vpy-[Re(CO)3(phen)])200(vpy)400}(CF3SO3)200. The existence of Re(I) chromophores in diverse environments was shown by the intrinsic kinetics of the luminescence, the decay kinetics of the MLCT excited states observed by time resolved-absorption spectroscopy, and the quenching of the luminescence by various quenchers. Redox reactions of the MLCT excited states with the quenchers were responsible for the luminescence quenching. While static quenching resulted when Cu(II) and Fe(III) EDTA complexes were the quenchers, a dynamic quenching resulted with Fe(CN)6(4-) or 2,2',2' '-triethanolamine, TEOA. The photochemical and photophysical properties of the mixed-pendant polymers have been discussed in terms of arrays of MLCT excited states whose energies are determined by the diverse environments of the Re(I) chromophores. Conversions (with and without radiation) of the upper-energy MLCT excited states to the ground state and lower-energy MLCT excited states and the latter excited state to the ground state account for the experimental results.

On the Quenching of MLCTRe→bpy Luminescence by Cu(II) Species in Re(I) Polymer Micelles

Transmission electron microscopy (TEM) and dynamic light scattering (DLS) studies on acetonitrile solutions of the polymer {[(vpy)2-vpyRe(CO)3bpy] CF3SO3}200 demonstrated that the Re(I) polymer molecules aggregate to form spherical micelles of radius R = 156 nm. Coordination of Cu(II) species to the Re (I) polymer causes a decrease in the micelle radius and a distortion from the spherical shape. Besides, the coordination of Cu(II) species to the {[(vpy)2-vpyRe(CO)3bpy] CF3SO3}200 polymer produces the quenching of the metal to ligand charge transfer (MLCT) excited state by energy transfer processes that are more efficient than those in the quenching of the monomer pyRe(CO)3bpy+ luminescence by Cu(II). Moreover, the kinetics of the quenching by Cu(II) do not follow a Stern-Volmer behavior. Conversely, the quenching of the MLCT luminescence of the Re(I) polymer by the sacrificial electron donor 2,2',2' '-nitrilotriethanol, TEOA, follows a Stern-Volmer kinetics. A comparison is made between the quenching by CuX2 (X = Cl or CF3SO3) and TEOA.