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Effective systems for the catalytic oxygenation of hydrocarbons have been developed based on metalloporphyrins containing iron, manganese and ruthenium. These metalloporphyrin catalysts were inspired by studies of the mechanism of the heme oxygenase cytochrome P450 and related enzymes. Oxometalloporphyrins, which have now been spectroscopically characterized, have very high reactivity as oxygen transfer agents. A combination of experimental and computational methods has begun to provide an understanding of the structure and reactivity of these oxometalloporphyrin complexes and the mechanisms of oxygen transfer reactions they catalyze.

The crystal structure of (carbonyl)(1-methylimidazole)(5,10,15,20-tetraphenylporphyrinato)ruthenium(II)·2chloroform, Ru(TPP)(CO)(MeIm)·2CHCl₃, an R-state model of the hemoglobin active site, has been determined. The material crystallizes in space group P2₁/c of the monoclinic system with four formula units in a cell of dimensions a = 12.733(2) Å, b = 14.535(2) Å, c = 24.921(2) Å, β = 91.15(1) ° at T = 110 K. The structure has been refined to R(F) = 0.038 for 588 variables and 7458 data. The Ru–C(O) distance is 1.835(3) Å and the Ru–N_(imidazole) distance is 2.163(2) Å. This is the third reported crystal structure of a solvated Ru(TPP)(CO)(MeIm) compound. It differs from the other two in a larger displacement of 0.079(1) Å of the Ru atom from the mean porphyrin plane toward the CO ligand, a shorter Ru–N_(imidazole) bond, a smaller average deviation, 0.06 Å, of atoms from the porphyrin plane, and the absence of a small ≤60 ° dihedral angle between the porphyrin plane and phenyl rings.

Four diads consisting of a free-base or zinc aryl-porphyrin associated with two ruthenium(II) bis(terdentate) complexes (non-cyclometallated Ru(N6) or cylometallated Ru(N5C)) have been synthesized. The strong electron-withdrawing properties of the Ru(N6) as compared to the Ru(N5C) complex have been illustrated by their electrochemical and spectroscopic properties. Emission spectra of the diads and the reference compounds have shown that very efficient fluorescence quenching occurs, probably by energy transfer processes from the porphyrin to the ³MLCT excited state of the ruthenium unit.

Para-aminosubstituted nitrosoarenes react with Ru(CO)(OEP) or [Co(TPP)(THF)₂]SbF₆ (OEP^2- = 2,3,7,8,12,13,17,18-octaethylporphyrinato dianion, TPP^2- = 5,10,15,20-tetraphenylporphyrinato dianion) to generate Ru(OEP)(ONC₆H₄NMe₂)₂ and [Co(TPP)(ONC₆H₄NR₂)₂]SbF₆ (R = Me, Et), respectively, in fair to high yields. These N-bound nitrosoarene complexes have been characterized by spectroscopic methods. The complexes Ru(OEP)(ONC₆H₄NMe₂)₂ and [Co(TPP)(ONC₆H₄NMe₂)₂]ClO₄ have also been characterized by single-crystal X-ray crystallography. Their structures represent the first reported solid-state structures of Ru and Co porphyrins containing C-nitroso ligands.

The powerful RHEED technique has been demonstrated for the structural determination of the nano-crystals grown on metal and oxide substrate surfaces. Pt was electrochemically deposited onto a electrode, while Pb and cobalt were vapor deposited onto Ag(111) and oxide film/NiAl(100), respectively under UHV conditions. At any Pt coverage, 3D-clusters develop for which the Pt clusters grow in (311) orientation on the substrate surface, where the atomic rows of the (311) facet are parallel to the atomic rows of the surface. Due to the strong bonding at Pb/Ag(111) interface, the Pb deposit grows in 2D-islands with a phase (Θ < 1 ML). On the other hand, the β-crystallites of ≈ 1 nm in diameter with inclusion of smaller-sized particles (D < 1 nm) are observed on Θ-Al₂O₃ after Co deposition at room temperature. Annealing at 900 K Co clusters (≈ 3 nm) grow larger at expense of small particles on thin oxide film on NiAl(100) and become better ordered, where the [110] axis of the Co(001) facet is parallel to the [100] direction of the (001)-oxide surface. The in-plane lattice constant of Co clusters is ca. 4 larger than that of bulk Co, yielding less strain at the (001)-oxide surface. These results demonstrate that both orientation and phase of metal nano-clusters are governed by surface structure of the substrate.

The growth process of platinum on Ru(0001) near room temperature was characterized using photoelectron spectroscopy of high resolution. The binding energy position and intensity of the Pt 4f_7/2 and Ru 3d_5/2 core levels as well as the shape and structure of the valence band spectra corresponding to the different stages of the deposition were analyzed. Up to ca. two adsorbate monolayers, the intensity changes of the peaks indicated layer-by-layer growth mode. The surface core level shifts of Ru and Pt levels were evaluated as -0.33 and -0.476 eV, respectively. The valence band spectra show a rather weak interaction between the d-bands of Pt and Ru.

Scanning tunneling microscopy is used to study intercalation of cobalt underneath a graphene layer on Ru(0001). Deposition of cobalt on graphene/Ru(0001) at 873 K leads to the intercalation of cobalt between the graphene layer and the Ru(0001) substrate, and the intercalation is associated with Co diffusion at steps and defects. The morphology of graphene/Co/Ru(0001) shows moiré pattern, as same as that of graphene/Ru(0001). The bright areas where Co islands exist are hcp regions of graphene/Ru(0001). The intercalated Co islands have a pseudomorphic structure superimposed on Ru(0001).

Nitrogen and ruthenium co-doped titania films synthesized by sol–gel technique exhibit high photocatalytic activity under both UV and visible light. Incorporation of nitrogen and ruthenium ions in titania lattice is proven by XPS. Both doping agents affected the structural properties of the films.

The synthesis of novel bis-axially coordinated ruthenium(II) complexes with tetra-15-crown-5-phthalocyanine and N-donor ligands (R₄Pc)Ru(L₂) (R₄Pc^2- = 4,5,4',5',4'',5'', 4''',5'''- tetrakis(1,4,7,10,13-pentaoxotridecamethylene)phthalocyaninate-ion, L = pyridine (py), isoquino-line (iqnl), triethylamine (Et₃N)) is reported. The preparation technique involves the interaction of (R₄Pc)Ru(CO)(CH₃OH) with trimethylamine oxide in an N-donor solvent. The advantage of this method consists in selective carbonyl ejection from (R₄Pc)Ru(CO)X with simultaneous substi-tution by N-donor ligands. The application of this procedure allowed us to decrease essentially the reaction time, as compared with photochemical methods, as well as to increase substantially the yield of reaction products. UV-visible, ¹H NMR, FT-IR and mass-spectrometry were used for characterization of the obtained compounds.

Novel chiral systems for the catalytic asymmetric oxidation and cyclopropanation of olefins based on metalloporphyrins containing iron, ruthenium and manganese, have been recently introduced. High catalyst turnover numbers and sometimes high enantiomeric excess were observed. New catalytic reactions with metalloporphyrins have recently been reported; these are the olefination of aldehydes and cyclotrimerization of terminal alkynes. Dendrimers and polymers containing metalloporphyrins, have also been found to be efficient catalysts for oxidation and carbene transfer.

The (bpy)₂Ru^II and (phen)₂Ru^II moieties were linked to [Ni(OBTTAP)]1, periphery through coordinate bonds in order to synthesize cationic di- and pentanuclear complexes 2-5 that were obtained as PF₆⁻ salts. They were characterized by IR, ¹H NMR, UV-vis, and mass spectral data. The electronic absorption, emission and redox data of these bichromophoric systems indicate the presence of a high degree of intercomponent electronic interaction. The position and relative intensities of the Soret and Q bands in these complexes is altered due to peripheral binding of the metal units. The compounds were non-emissive for the Q band excitation but, Soret excitation led to a strong S₂ emission, observed between 400-450 nm. In cyclic voltammetry, the compounds exhibited one Ru centered oxidation together with one or two OBTTAP centered oxidations. The Ru^II/Ru^III oxidations were observed at significantly lower potentials as compared to the corresponding simple maleonitrile-benzylthioether complexes and has been interpretted in terms of weaker dπ(S)–dπ(Ru) interactions.

A new synthesis is reported for hexadecafluorophthalocyanineruthenium(II), F₁₆Pc(2-)Ru^II and hexadecachlorophthalocyanineruthenium(II), Cl₁₆Pc(2-)Ru^II, is reported for the first time. These paramagnetic species, which contain no axial ligand, are quite reasonably soluble in a range of common organic solvents. We report and discuss electronic and vibrational (infrared and resonance Raman) spectroscopic, MALDI-TOF and magnetic data. In addition we report electrochemical data and use spectroelectrochemical methods to obtain the electronic spectra of these species in the phthalocyanine(1-), (3-) and (4-) oxidation states.

The synthesis of novel ruthenium(II) meso-tetra-(benzo-15-crown-5)-porphyrinates, meso-[(B15C5)₄Por]Ru(CO)(MeOH) (1) and meso-[(B15C5)₄Por]Ru(L)₂ (2)-(4) (meso-[(B15C5)₄Por]₂-= 5,10,15,20-tetrakis-(benzo-15-crown-5)-porphyrinato-dianion; L = pyridine (py), pyrazine (pyz), 4,4′-bipyridyl (4,4′-bpy)), where CO and MeOH, or two N-donor ligands are axially coordinated to the central metal, are reported. The metalation of the free ligand performed by the reaction of Ru₃(CO)₁₂ with meso-[(B15C5)₄Por]H₂ in 1,2,4-trichlorobenzene (TCB, bp = 215°C), gives (1) in a high yield. The synthesis of (2)-(4) involves the decarbonylation of (1) with trimethylamine N-oxide ((CH₃)₃NO) in the presence of an excess of the N-donor ligand. The coordination of the axially bonded ligands is evidenced by different spectroscopic data.

The information concerning the architecture of supramolecular assemblies, which are composed of ruthenium(II) tetra-15-crown-5-phthalocyaninate with axially coordinated triethylenediamine molecules, has been obtained with the application of atomic force microscopy. The ensembles are formed in Ru(II) complex solutions in chloroform and tetrachloroethane. The number of molecules and their relative orientation in supramolecular assemblies were estimated in dependence of the solvent (chloroform, tetrachloroethane) and the heating temperature. Samples fabricated after heating of the Ru(II) complexes solution in tetrachloroethane formed stable supramolecular wires of 600 nm and more in length. The third-order non-linear optical characteristics of complexes in tetrachloroethane solution were studied by the z-scanning method. Molecular polarizability of the complex is about 4.5 × 10^-32 esu. The polarizability attributed to one molecule increases by a factor of 3.6 when the individual molecule assembles into a supramolecular aggregate.

Water-soluble, metal-tetrasubstituted phthalocyanines (-SO₃H, MPcS and -COOH, MPcC) of platinum and ruthenium were synthesized and their photostability to visible light irradiation was determined. For the ruthenium phthalocyanines, the characteristic visible Q band of the phthalocyanines was almost totally suppressed after five days of irradiation. The platinum derivatives were instead more resistant to photodegradation, and the Q band did not decrease by more than 25%. The addition of carbonyl compounds to the phthalocyanine solution in water (at concentrations at least 1400-fold those of the phthalocyanines) dramatically accelerated the photobleaching of these phthalocyanine complexes. PtPcS turned from blue to green and to colorless with one day of visible-light irradiation in the presence of acetone. This effect decreased with the increase in molecular weight of the ketones (from acetone to 2-pentanone). The addition of alcohols (i.e. 1-butanol) or other organics (i.e. phenylacetic acid) did not affect the photostability of these metal-tetrasubstituted phthalocyanines. Dioxygen also had an important role, as when the solutions of phthalocyanines were carefully deaerated before irradiation, the visible spectra were preserved. The platinum phthalocyanines, as with the palladium analogs, sensitize the photoproduction of ¹O₂, as shown by the formation of endoperoxide and its rearranged products in the presence of furfuryl alcohol (a singlet oxygen trapping agent).

Benzylic amines are synthesized in yield up to 90% by the Ru(TPP)CO-catalyzed amination of both exocyclic and endocyclic benzylic C-H bonds. The choice of arylazides as nitrogen sources confers to the methodology a good sustainability due to the formation of molecular nitrogen as the only stoichiometric by-product. A preliminary mechanistic investigation evidenced a critical role of the hydrocarbon concentration to drive the chemoselectivity of the reaction.

The preparation of two chiral porphyrin ligands 7 and 9 and of their ruthenium and cobalt complexes is reported. These new complexes have been used as catalysts in cyclopropanation reactions. Both 7-Ru and 9-Ru complexes showed a catalytic activity in the enantiomeric cyclopropanation of α-methylstyrene by ethyldiazoacetate whereas amination of ethylbenzene by arylazide in the presence of 7-Ru or 9-Ru did not stop at the corresponding benzylamine stage but instead afforded the corresponding benzylimine.

A number of novel carbonyl(1,4,8,11,15,18,22,25-octaalkylphthalocyaninato)-ruthenium(II) complexes were prepared by metal insertion with Ru₃(CO)₁₂. The new compounds have been characterized by ¹H NMR, ¹³C NMR, IR, UV-vis and mass spectroscopy. This study demonstrated that this type of complexes and specifically carbonyl(1,4,8,11,15,18,22,25-octahexylphthalo-cyaninato)ruthenium(II) and carbonyl[1,4,8,11,15,18,22,25-octa(2-cyclohexylethyl)phthalocyaninato]-ruthenium(II), exhibit high catalytic activity and stability in the epoxidation of stilbenes with 2,6-dichloropyridine N-oxide as oxidant.

Two novel donor-π-acceptor (D-π-A type) porphyrin dyes were successfully synthesized and use in a dye-sensitized solar cell (DSSC). The molecular structures of both porphyrins are composed of the same dialkyl-substituted diphenylamino unit acting as the donor part, and two bisalkoxyphenyl substituents at the 5,15-meso positions. The acceptor part is composed of different ethyne-linked π-extended bridges, and a cyanoacrylic acid (Dye I) or carboxyphenyl (Dye II) moiety acting as anchoring groups. In order to investigate the effects of including the π-extended bridge between the porphyrin and acceptor unit, two different π-extended bridges such as 2,2′-bithiophene and 2-(phenylethynyl)-thiophene, were employed. In particular, Dye II contains two triple bonds between donor substituted porphyrin and carboxylic acid group. These modifications could potentially reduce dye aggregation on the TiO₂ surface. The charge recombination resistance and diffusion length for the cells with Dye II were relatively higher for all the measured ranges of bias potentials, implying that electron recombination loss from injected electrons was highly suppressed when Dye II molecules were adsorbed on the TiO₂ surface. Eventually, Dye II containing a 2,2′-bithiophene π-spacer and anchored trough a carboxyphenyl group exhibited a superior power conversion efficiency of 6.7% under AM 1.5 illumination (100 mW.cm^-2) in a photoactive area of 0.46 cm² than Dye I with a 2-(phenylethynyl)thiophene (PCE = 3.5%) anchored through a cyanoacrylic group.

Non-peripherally alkyl substituted ruthenium phthalocyanines were demonstrated to be highly active epoxidation catalysts. It is compatible with pyridine N-oxides, and especially 2,6-dichloropyridine N-oxide. The catalytic activity towards a variety of alkenes was comparable to that published for other catalytic systems, but superior in the cases of 1,2-dihydronaphthalene and trans-stilbene. Linear substituents on the non-peripheral sites of the phthalocyanine were able to reduce aggregation and increase the solubility of the catalyst without compromising its activity by steric congestion as all substituted catalysts were more reactive than the unsubstituted phthalocyanine, whereas the bulky isopentyl and cyclohexyl substituted catalysts were less active than those with linear substituents. Although the epoxidation mechanism and the exact active intermediate is still ambigious, it likely involves the coordination of the N-oxide to ruthenium and subsequent transfer of the oxygen to the metal to form a high-valent oxo-ruthenium species. It is proposed that the alkene approaches this metal oxo moiety from the top and that oxygen transfer to the alkene is concerted with concomitant stereoretention.