Three-dimensional structure analysis and percolation properties of a barrier marine coating.

Artificially structured coatings are widely employed to minimize materials deterioration and corrosion, the annual direct cost of which is over 3% of the gross domestic product (GDP) for industrial countries. Manufacturing higher performance anticorrosive coatings is one of the most efficient approaches to reduce this loss. However, three-dimensional (3D) structure of coatings, which determines their performance, has not been investigated in detail.

Energy transfer by a hopping mechanism in dinuclear Ir(III)/Ru(II) complexes: a molecular wire?

The synthesis and electrochemical and photophysical properties of a series of heterodinuclear ruthenium-iridium complexes linked by a modular para-phenylene bridge [Ir-ph(n)-Ru]3+ (Ir=Ir(ppyFF)2bpy, Ru=Ru(bpy)3, ppyFF=2-(2,4-difluorophenyl)pyridine), bpy=2,2'-bipyridine, ph=phenylene, n=2, 3, 4, 5) are reported. The use of a high-energy iridium complex, which can act as an energy donor when coupled to the lower energy ruthenium-based component, allows the investigation of photoinduced energy transfer from the excited iridium-centre to the ruthenium fragment (energy acceptor). The rate constants of the energy-transfer processes are determined by time-resolved emission and sub-picosecond transient absorption spectroscopy.

Redox control of light-induced charge separation in a transition metal cluster: photochemistry of a methyl viologen-substituted [Os3(CO)10(alpha-diimine)] cluster.

(Sub)picosecond transient absorption (TA) and time-resolved infrared (TRIR) spectra of the cluster [Os3(CO)10-(AcPy-MV)]2+ (the dication AcPy-MV = AcPy-MV2+ = [2-pyridylacetimine-N-(2-(1'-methyl-4,4'-bipyridine-1,1'-diium-1-yl)ethyl)](PF6)2) (1(2+)) reveal that photoinduced electron transfer to the electron-accepting 4,4'-bipyridine-1,1'-diium (MV2+) moiety competes with the fast relaxation of the initially populated sigmapi excited state of the cluster to the ground state and/or cleavage of an Os-Os bond. The TA spectra of cluster 1(2+) in acetone, obtained by irradiation into its lowest-energy absorption band, show the characteristic absorptions of the one-electron-reduced MV*+ unit at 400 and 615 nm, in accordance with population of a charge-separated (CS) state in which a cluster-core electron has been transferred to the lowest pi orbital of the remote MV2+ unit. This assignment is confirmed by picosecond TRIR spectra that show a large shift of the pilot highest-frequency nu(CO) band of 1(2+) by ca.

Low-lying excited states and primary photoproducts of [Os3(CO)10(s-cis-L)] (L=cyclohexa-1,3-diene, buta-1,3-diene)] clusters studied by picosecond time-resolved UV/Vis and IR spectroscopy and by density functional theory.

Combined picosecond transient absorption and time-resolved infrared studies were performed, aimed at characterising low-lying excited states of the cluster [Os(3)(CO)(10)(s-cis-L)] (L=cyclohexa-1,3-diene, 1) and monitoring the formation of its photoproducts. Theoretical (DFT and TD-DFT) calculations on the closely related cluster with L=buta-1,3-diene (2') have revealed that the low-lying electronic transitions of these [Os(3)(CO)(10)(s-cis-1,3-diene)] clusters have a predominant sigma(core)pi*(CO) character. From the lowest sigmapi* excited state, cluster 1 undergoes fast Os-Os(1,3-diene) bond cleavage (tau=3.

First direct observation of a CO-bridged primary photoproduct of [Ru3(CO)12] by picosecond time-resolved IR spectroscopy.

For the first time, a CO-bridged primary photoproduct was observed for [Ru3(CO)12] by using picosecond time-resolved IR spectroscopy (ps-TRIR).

Bonding and redox properties of [Os(3)(CO)(9)(tmbp)(L)] (tmbp=4,4',5,5'-tetramethyl-2,2'-biphosphinine; L=CO, PPh(3)) clusters with an unprecedented electron-deficient metallic core and doubly bridging biphosphinine dianion.

Herein we describe in detail the bonding properties and electrochemical behavior of the first known triosmium carbonyl clusters with a coordinated redox-active ligand 4,4',5,5'-tetramethyl-2,2'-biphosphinine (tmbp), the phosphorus derivative of 2,2'-bipyridine. The clusters investigated were [Os(3)(CO)(10)(tmbp)] (1) and its derivative [Os(3)(CO)(9)(PPh(3))(tmbp)] (2). The crystal structures of both clusters are compared with those of relevant compounds; they served as the basis for density functional theory (DFT and time-dependent DFT) calculations.