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[Display omitted] • Synthesized MnTP@ZnAdCOF was characterized and its use as a catalyst in ODS was studied. • Desulphurizing ability of MnTP@ZnAdCOF was above than 98% for thiobenzoic acid. • RP-HPLC chromatograms for thiobenzoic acid represented the catalytic effect of MnTP@ZnAdCOF. • Effect of different temperatures and H 2 O 2 /TB molar ratio on ODS process was observed. • Kinetic study was done in order to determine the percentage desulfurization for TB. Sulfur compounds cause substantial environmental pollution problems, and their immediate removal is urgently needed to keep the environment clean. Fuel desulfurization is necessary due to the severe impacts of sulfur on humans, wildlife, and crops when emitted into the atmosphere during fuel combustion. Fuels with high sulfur contents used in automobiles and factories are the primary source of atmospheric sulfur. A new covalent organic framework (COF) MnTP@ZnAdCOF [(N(C 4 H 9) 4 ] 12 [{NHC(CH 2 O) 3 } 4 (CO) 4 C 44 H 24 N 4 Mn(OCOCH 3)][ZnMo 6 O 18 ] 4 is synthesized and characterized thoroughly using FT-IR, UV/visible, 1HNMR, TGA, PXRD, SEM-EDX, cyclic voltammetry and fluorescence spectroscopy. Herein, an environmentally safe and cost-effective approach for the ODS of thiobenzoic acid is reported using H 2 O 2 as an oxidant and MnTP@ZnAdCOF as a heterogenous catalyst under mild reaction conditions. Desulphurization results of the catalyst are confirmed by the RP-HPLC technique using acetonitrile and water in a 50:50 M ratio as a mobile phase. Active intermediates [(Por)(OAc)Mn-OOH]−, [(Por)(OAc)MnIV O] and Mo(O 2) are formed due to oxidation of Mn and Mo metal in the presence of H 2 O 2 considered responsible for the excellent catalytic efficiency of MnTP@ZnAdCOF catalyst up to 98% desulphurization efficiency was observed. Incredible catalytic conversion of dibenzothiophene, thiobenzoic acid and the mixture of different Sulphur containing compounds to sulfoxide is observed at 25 ℃ temperature. The H 2 O 2 /S molar ratio of 5:1 is an outstanding achievement that can be utilized for the oxidation of sulfur compounds present in diesel to reduce the sulfur contents of fuel. [ABSTRACT FROM AUTHOR]

[Display omitted] • Porphyrin molecules electronically decoupled on a passivated surface. • Photoemission orbital tomography detects saddle-shape of metalloporphyrins. • Geometric distortions change electronic structure of porphyrins. • Planar non-distorted configuration in porphyrin multilayer. • Conformation depends on molecule–substrate interaction. On-surface metal porphyrins can undergo electronic and conformational changes that play a crucial role in determining the chemical reactivity of the molecular layer. Therefore, accessing those properties is pivotal for their implementation in organic-based devices. Here, by means of photoemission orbital tomography supported by density functional theory calculations, we investigate the electronic and geometrical structure of two metallated tetraphenyl porphyrins (MTPPs), namely ZnTPP and NiTPP, adsorbed on the oxygen-passivated Fe(100)- p (1 × 1)O surface. Both molecules weakly interact with the surface as no charge transfer is observed. In the case of ZnTPP, our data correspond to those of moderately distorted molecules whereas NiTPP exhibits a severe saddle-shape deformation. From additional experiments on NiTPP multilayer films, we conclude that this distortion is a consequence of the interaction with the substrate, as the NiTPP macrocycle of the second layer turns out to be flat. We further find that distortions in the MTPP macrocycle are accompanied by an increasing energy gap between the highest occupied molecular orbitals (HOMO and HOMO-1). Our results demonstrate that photoemission orbital tomography can simultaneously probe the energy level alignment, the azimuthal orientation, and the adsorption geometry of complex aromatic molecules even in the multilayer regime. [ABSTRACT FROM AUTHOR]

[Display omitted] • Porphyrins attached to SAMs can be metalated with Zn2+ and Cu2+ ions from solution. • Transmetalation occurs when Zn-porphyrins attached to SAMs contact Cu2+ solutions. • Cu-porphyrin/SAMs are more stable against demetalation than Zn-porphyrin/SAMs. In this work we studied the metalation, transmetalation and demetalation reactions of protoporphyrin (PPIX) molecules attached to self-assembled monolayers (SAM) grown over Au(1 1 1) surfaces at the solid/liquid interface. Using X-ray photoelectron spectroscopy we found that when the molecules attached to the SAM are immersed in Cu2+ or Zn2+ containing solutions, the degree of metalation is larger for Cu2+ than for Zn2+. Furthermore, when ZnPPIX molecules attached to the SAM are placed in contact with a Cu2+ solution the partial exchange of Zn ions with Cu ions at the porphyrin central cavity is observed. This suggests that insertion of Cu2+ to form CuPPIX is both kinetically and thermodynamically favored over the insertion of Zn2+ in agreement with the solution chemistry of the molecules. Finally, unlike the behavior in solution, Zn and CuPPIX molecules attached to the amino terminated SAMs are more stable against demetalation in acidic conditions. We attribute this difference to the competing protonation of the amine terminal groups. Our results could be useful for the design of molecular devices based on porphyrins that are exposed to liquid interfaces. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new paradigm in organic film engineering foresees exploiting axial coordination. • In-situ monitoring is required to assess the quality of the film growth. • Optical probes such as RAS reduce to minimum organic film damage. • We propose a strategy to apply RAS to these novel supramolecular structures. Ensuring the highest accuracy in determining the molecular assembling and the preservation of the chemical and physical properties of the molecules during the growth of organic layers requires a real-time monitoring of film formation. In this respect, optical techniques are preferred since they result in minimum organic film damage. Among these techniques, Reflectance Anisotropy Spectroscopy (RAS) proved to be the one with the highest sensitivity due to the development of intrinsic anisotropies in the optical response of molecular films, where molecular packing is driven by Van der Waals interactions. Recently, we proposed an original strategy to enable the growth of organic films via molecular self-assembly through highly directional coordination bonds. Herein, we consider a straightforward supramolecular structure employing axial bonds, based on the 1:1 assembly of a CoII porphyrin (CoTPP) and a linear ligand (DPNDI). This system is characterized by a rather isotropic structure that might, in principle, result in a weak RAS signal. Therefore, in the present work, we critically assess the range of applicability of such a spectroscopy. A number of other surface science techniques, including Low Energy Electron Diffraction (LEED), photoemission spectroscopies (PES and IPES) and Atomic Force Microscopy (AFM) is employed to fully characterize the axially coordinated molecular film. [ABSTRACT FROM AUTHOR]

[Display omitted] Synthesis of new asymmetric AB 3 type free-base-(3), Zn(II)-(4) and Pd(II)-(5) porphyrin derivatives conjugated with a cyclotriphosphazene ring bearing 2-naphtoxy groups in para position were described. Also, photophysical-photochemical properties of these porphyrin derivatives were studied. • Novel asymmetric metal free, Zn(II) and Pd(II) porphyrin derivatives were synthesized. • Photophysico-chemical properties of these porphyrin derivatives were studied. • Compound 5 has the highest singlet oxygen quantum yield due to the heavy metal effect of Pd(II). In this work, new asymmetric H 2 -(3), Zn(II)-(4) and Pd(II)-(5) porphyrin derivatives conjugated with a cyclotriphosphazene ring bearing 2‑naphtoxy groups in para position were synthesized and fully characterized. For investigation of photophysical and photochemical properties of these compounds; their ground state absorption, fluorescence emission, fluorescence lifetime, fluorescence quantum yield and singlet oxygen quantum yield measurements were studied in THF. The singlet oxygen quantum yields were determined as 0.62 for 3 , 0.49 for 4 and 0.64 for 5 in THF, respectively. As a result, conjugation of the porphyrin macrocycle with the cyclotriphosphazene ring have improved the singlet oxygen generation except compound 4 when compared to tetraphenylporphyrin (TPP) (0.58) and ZnTPP (0.61) in THF. Especially, compound 5 has the highest singlet oxygen quantum yield (0.64) due to the heavy metal effect of Pd(II). [ABSTRACT FROM AUTHOR]

The structure-property relationships were compared for the iron and iron-copper complexes of two functional cytochrome c oxidase models, 1 and 2 , both constructed upon a phenanthroline-strapped porphyrin bearing respectively pyridyl or picolinyl built-in proximal and distal ligands. The behavior of these heme models in the absence and in the presence of copper was studied by 1 H NMR, UV–visible absorption, EPR, Raman and FTIR spectroscopies, electrochemistry in solution and deposited on a rotating ring-disk graphite electrode. The distal binding site within the phenanthroline pocket of both 1 and 2 is available for the coordination of exogenic ligands, yet the oxygen binding affinity is higher for all complexes of 2 than for 1 . Despite this difference, [ 1Fe II Cu I ] more efficiently reproduced the electrocatalyzed reduction of oxygen to water than [ 2Fe II Cu I ]. The oxygenated complexes of both iron(II)-copper(I) species mimic the ability of cytochrome c oxidase to reversibly bind O 2 , as shown by competitive binding studies in the presence of CO. Differences in the binding and electrocatalytic properties of these models stem from difference in rigidity of scaffolds upon binding of both the proximal and distal ligands, as well as from the bulkiness of the distal ligand. [ABSTRACT FROM AUTHOR]

A new solid-state synthesis method has been developed for rhenium(V) porphyrin. The electrochemical behavior and theoretical calculations like geometry optimization, electronic energy, frequency, and frontier molecular orbital (FMO) energy level have been studied for the first time for oxorhenium(V) porphyrins. [Display omitted] • A new synthesis method has been developed for oxo -rhenium(V) porphyrins. • On treatment with mild bases like pyridine, imidazole, dil. NH 4 OH oxo -rhenium(V) porphyrin instantly gets converted to µ -oxo bridged dimeric oxorhenium(V) complex. • The electrochemical behaviour of oxo -rhenium(V)porphyrin was examined and reported for the first time. • Theoretical investigations like geometry optimization, frequency, electronic spectra, and FMO energy level study have been performed by the DFT method which has never been executed earlier. • The experimental HOMO-LUMO energy gap matches the theoretical values. A new synthesis procedure has been developed for the preparation of oxo -rhenium(V) porphyrins using melted benzoic acid. Here we have demonstrated this method using three representative compounds namely O=ReV(TPP)(OOCPh) (1), O=ReV(TMP)(OOCPh) (2), and O=ReV(TCP)(OOCPh) (3) [where TPP = 5,10,15,20- meso -tetraphenylporphyrin, TMP = 5, 10, 15, 20 -meso- tetra(p -methoxy)phenylporphyrin and TCP = 5, 10, 15, 20- meso -tetra(p -chloro)phenylporphyrin]. The yield percentage is higher than any other method reported earlier. All the compounds were well characterized by C, H and N microanalysis, ESI-MS, IR, UV–vis and 1H NMR spectroscopic techniques. On treating with mild bases like pyridine, imidazole, dil. NH 4 OH compound 1 instantly gets converted to µ -oxo bridged dimeric oxorhenium(V) complex µ -O-[ReO(TPP)] 2 (4). The electrochemical behavior of the synthesized compounds has been examined by the cyclic voltammetric method. Theoretical calculations like geometry optimization, electronic energy, frequency, and frontier molecular orbital (FMO) energy level diagram for compound 1 have been investigated by Density Functional Theory (DFT) method. The experimentally calculated HOMO-LUMO energy gap and the experimental electronic spectrum were found to agree well with the value obtained from DFT studies. [ABSTRACT FROM AUTHOR]

Two series of metalated cationic porphyrins were evaluated for their capacity to bind G-quadruplex DNA as well as for their specificity with respect to duplex DNA as a function of the metal ion inserted in the core of the porphyrin. Various metal ions (Ni 2+ , Co 3+ , Mn 3+ ) afforded variation of the charge and axial coordination in the center of the porphyrin. The binding affinity of the metalated porphyrins toward DNA (G-quadruplex DNA and duplex DNA) was evaluated by Surface Plasmon Resonance and the influence of the metal was compared with that reported for TMPyP4. The second generation porphyrins were better G-quadruplex ligands than TMPyP4 porphyrins and, on the contrary to the TMPyP4 series, the metal had no influence on the K D values. [ABSTRACT FROM AUTHOR]

A unique magnesium diporphyrinate crystal structure due to the presence of two moieties [MgTClPP(pyz) 2 ] and [MgTClPP(H 2 O) 2 ] is presented. The plane of one porphyrin moiety is perpendicular with the plane of the other porphyrin moiety resulting in H-bonding interactions between axial ligand pyrazine of one magnesium porphyrin and water (H 2 O) molecule of another adjacent magnesium porphyrin. The H-bonding interactions between axial pyrazine and axial water of two porphyrin molecules stabilize this unique crystal structure. [Display omitted] • A unique magnesium porphyrinate crystal structure due to the presence of two moieties [MgTClPP(pyz) 2 ] and [MgTClPP(H 2 O) 2 ] is presented. • The plane of one porphyrin moiety is perpendicular to the plane of the other porphyrin moiety resulting in H-bonding interactions between axial ligands. • This is the first example of co-crystals of magnesium porphyrin with a unique structure. • Charge transfer from the lone pair of the pyrazine nitrogen atom to the lone pair of metal Mg (lpN (ax) → lpMg) has the highest E(2) value (9.93 Kcal/mol) and has a significant role in the stabilization of the complex. A new pyrazine coordinated magnesium porphyrin, [MgTClPP(pyz) 2 ], (TClPP = meso -tetra(4-chlorophenyl)porphyrin) was synthesized and characterized using different spectroscopic techniques. A single-crystal X-ray diffraction study shows a unique magnesium porphyrinate structure with the formation of a 1D polymeric chain due to the presence of two moieties [MgTClPP(pyz) 2 ] and [MgTClPP(H 2 O) 2 ]. The plane of one porphyrin moiety is perpendicular to the plane of the other porphyrin moiety resulting in H-bonding interactions between axial ligand pyrazine of one magnesium porphyrin and water (H 2 O) molecule of another adjacent magnesium porphyrin. This weak intermolecular H-bonding is present between the axial ligands [-O H....N] influencing to stabilize of the polymeric chain. UV–vis spectrum of the compound shows redshift of Soret band and Q-bands on axial ligand binding. Theoretical analysis like optimization of the geometry, calculation of single-point energy, natural bond analysis, and simulation of infrared spectra was carried out using the DFT (Density Functional Theory) method. Short-range interactions such as H-bonding are quantified by the Hirshfeld surface analysis and 2D fingerprint plots. This work suggests the role of non-covalent interactions in the case of stability of coordination compounds of bridging ligands when coordinates through only one donor atom. [ABSTRACT FROM AUTHOR]

Supramolecular species combining ruthenium(II) polypyridines and tetrapyridylporphyrins (TPyP) have been employed in electrochemical and molecular sensing devices, because of their unique synergistic properties. In this work, a new tetraruthenated porphyrin, 4-TRoxPyP has been synthesised, encompassing four pyridine bridged [Ru(Cl-tpy)(ox)] complexes (Cl-tpy = chloroterpyridine, ox = oxalate ion). Such species exhibit characteristic electronic transitions of porphyrin and ruthenium polypyridine complexes, such as a Soret band at 414 nm, Q bands at 514 nm, 557 nm and 588 nm and a ruthenium-to-terpy charge-transfer band at 643 nm. A typical tetraruthenated porphyrin redox process has been observed at 0.72 V versus NHE, associated with the peripheral Ru 3+/2+ complexes. Their thin films have been prepared by drop casting onto a glassy carbon electrode, and successfully employed in nitrite analysis, by monitoring the chronoamperometric response at the Ru 3+/2+ redox gate. A linear relationship between the anodic peak current and concentration of the analyte has been observed from 0 to 0.10 mmol L −1 , with a nitrite detection limit of 7.60 μmol L −1 . [ABSTRACT FROM AUTHOR]

Co(III) complexes of DPP (DPP = ( Z )-2-(2-((5-(2-hydroxyphenyl)-1H-pyrrol-2-yl)(phenyl)methylene)-2H-pyrrol-5-yl)phenol) and two fluorinated DPP variants are prepared, structurally characterized, and their reactivity explored in the catalytic ring-opening of 1,2-epoxyhexane with alcohols. While the related Co(III) salen and porphyrin complexes are highly active for this catalytic transformation, the Co(III) DPP complexes are shown to be catalytically inert under the conditions studied. Computational characterization of the electronic structure of all the complexes shows that the Co(III) complexes ligated by the DPP ligands (tetradentate X 3 L type) do not have sufficient Lewis acidity to activate the epoxide, whereas the Co(III) porphyrin and salen (tetradentate X 2 L 2 type) incorporate a counter-ion that draws electron density away from the metal center, creating a more Lewis acidic Co species that is catalytically active for alcohol ring-opening of epoxides. The work thus gives insight into the requirements for effective Lewis acidic epoxide ring-opening catalysts based on cobalt. [ABSTRACT FROM AUTHOR]

When the new porphyrin 5,15-(4-pyridyl)-10,20-(4-trifluoromehtylphenyl)porphyrin is reacted with two equivalents of Ru(bipy) 2 Cl 2 (where bipy = 2,2′-bipyridine) formation of the target ruthenated porphyrin is achieved with 57% yield. Strong electronic transitions are observed in the visible region of the spectrum associated with the porphyrins Soret and four Q-bands. A shoulder at slightly higher energy than the Soret band is attributed to the Ru(dπ) to bipy(π ∗ ) metal to ligand charge transfer (MLCT) band. The bipyridyl π to π ∗ transition occurs at 295 nm. Cyclic voltammetry experiments of the porphyrin indicate porphyrin centered reductions in the cathodic direction with no noticeable oxidation process within the window scanned. The ruthenated porphyrin shows the characteristic quasireversible redox couple in the anodic region indicative of oxidation of Ru(II) to Ru(III). A single redox couple for Ru(III/II) indicates no electronic interaction between the ruthenium moieties. DNA titrations using calf thymus (CT) DNA and the ruthenium porphyrin give an unusually large binding constant K b = (1.1 ± 0.7) × 10 6 M −1 indicating a strong interaction between complex and DNA. When aqueous solutions of supercoiled DNA and ruthenium porphyrin are irradiated with visible light (energy lower than 550 nm) complete nicking of the DNA is observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrophilic Co-porphyrins self-assembly with bidentate ligands in water were studied. • Encapsulation of the supramolecular assembles into micelles were investigated. • Supramolecular porphyrin based assembles with preprogrammed lifetime were designed. The processes of hydrophilic Co(III)-tetra(4-sulfonatophenyl)porphyrin supramolecular assembly with 4,4-bipyridyl in aqueous buffer media have been studied by UV–vis, 1D and 2D 1H NMR-spectroscopy. In the case of 1,4-diazabicyclo[2.2.2]octane, pyrazine and piperazine in aqueous solutions, no assembly was observed. Interactions of the hydrophilic Co(III)-tetraarylporphyrin with ionic micelles (cationic surfactants with different alkyl tail lengths) in buffer media were investigated. These studies were performed by the UV–vis, 1D NOESY-spectroscopy and dynamic lightscattering (DLS) methods. The metalloporphyrins were incorporated into the hydrophobic part of micelles, which led to Co(III) reduction to Co(II) in the Co-porphyrinate composition. The rate of Co(III) reduction accompanied by detachment of additional ligands coordinated on Co(III)-porphyrins or disruption of supramolecular dimers and depends on the surfactant concentration and nature. The results obtained indicate the possibility of creating of supramolecular porphyrin-based assembles with the preprogrammed lifetime (from several hours to several days) and could be used in the creation of host – guest systems for recognition, selective binding and prolonged release of bioactive substrates as the means in the designing of biomimetic systems with effective binding affinities to heterocycles, DNA base pairs and RNA. [ABSTRACT FROM AUTHOR]

( S )-Enantiomer of an optically active metal free porphyrin bearing four chiral binaphthyl units, namely ( S )-meso-5,10,15,20-tetra-[(11,12:13,14-di(6′-octyl-1′,2′-naphtho)-4,7,10,15,18,21-hexaoxacycloeicosa-phenyl]-porphyrin ( 1 ), was designed, synthesized, and characterized. Comparative studies of the circular dichroism (CD) spectra of ( S )- 1 in chloroform solution and LB film have been carried out, indicating the effective chiral information transfer from the optically active binaphthyl moieties to the porphyrin chromophore at the molecular level. In particular, obvious bisignate Cotton effect is observed in the CD spectrum of the LB film of ( S )- 1 , revealing the right-handed chirality formed in the LB film. In addition, current–voltage ( I – V ) measurement result indicates good semiconductor feature of the LB film formed from ( S )- 1 with conductivity of 1.22 × 10 − 5 S m − 1 . [ABSTRACT FROM AUTHOR]

Highlights: [•] The covalently linked hexamolybdate/porphyrin hybrid was synthesized and characterized. [•] Langmuir–Blodgett films of two kinds of hybrids were prepared and characterized. [•] The two films displayed interesting electrical conductivity. [ABSTRACT FROM AUTHOR]

Highlights: [•] Solid phase synthesis of oxo-tungsten(V) porphyrins. [•] Methodology developed gives almost quantitative yield of the desired complex. [•] On chromatographic purification hydrolyzed to monomeric species. [•] Structural characterization of the hydrolyzed products. [•] Spectral, electrochemical and DFT studies. [ABSTRACT FROM AUTHOR]

Abstract: Sawhorse-type diruthenium tetracarbonyl complexes incorporating carboxyphenyl porphyrin bridges and pyridine axial ligands have been prepared, characterized and evaluated as potential photosensitizing and chemotherapeutic agents in several human cancer cells (A2780, A549, Me300, HeLa). The mono carboxyphenyl porphyrin derivatives, 5-(4-carboxyphenyl)-10,15,20-triphenyl-21,23H-porphyrin (HOOCR1-H2) and 5-(4-carboxyphenyl)-10,15,20-triphenylporphyrin-Zn (HOOCR1-Zn), after reaction with Ru3(CO)12 and pyridine, give the dinuclear complexes [Ru2(CO)4(OOCR1-H2)2(NC5H5)2] (1) and [Ru2(CO)4(OOCR1-Zn)2(NC5H5)2] (2), respectively. Under the same reaction conditions, the di-carboxyphenyl porphyrin derivatives, 5,10-di(4-carboxyphenyl)-15,20-diphenyl-21,23H-porphyrin (HOOCR2-H2COOH) and 5,10-di(4-carboxyphenyl)-15,20-diphenylporphyrin-Zn (HOOCR2-ZnCOOH), give rise to the tetranuclear complexes, [{Ru2(CO)4(NC5H5)2}2(OOCR2-H2COO)2] (3) and [{Ru2(CO)4(NC5H5)2}2(OOCR2-ZnCOO)2] (4), in which two sawhorse diruthenium tetracarbonyl units are linked by the di-carboxyphenyl porphyrin ligands. When tested in human cancer cell lines, both Zn(II) metallo-porphyrin derivatives 2 and 4 and the tetranuclear derivative 3 show some degree of cytotoxicity in the dark, but seem to present no phototoxicity upon irradiation at 652nm. These results demonstrate the effect of the Zn(II) ion insertion into the porphyrin core, resulting in increased cytotoxicity and decreased phototoxicity. On the other hand, complex 1, the less cytotoxic derivative with IC50 >170μM in HeLa cervix and A2780 ovarian cancer cell lines, shows an excellent phototoxicity toward these cancer cell lines with LD50 comprised between 4.5 and 7.5J/cm2 (irradiance 30mW/cm2) at 5μM concentration (incubation time: 24h). Overall, an excellent ratio between photo- and cytotoxicity has been found for the metal-free porphyrin derivative [Ru2(CO)4(OOCR1-H2)2(NC5H5)2] (1). [Copyright &y& Elsevier]

Abstract: Two sandwich-type mixed (phthalocyaninato)(porphyrinato) rare earth double-decker complexes, M(Pc)(TPP) [H2Pc=phthalocyanine; H2TPP=meso-tetra(phenyl)porphyrin] (M=Eu, Lu) (1, 2) were synthesized and the structure of Lu(Pc)(TPP) was characterized by X-ray single-crystal diffraction method. Crystal data: triclinic, space group , Z =2, C77H45Cl3LuN12, Mr =1419.57, a =12.573(5), b =12.911(5), c =22.935(5)Å, α =103.793(5)°, β =101.363(5)°, γ =93.682(5)°, V =3521(2)Å3, μ(Mo Kα)=1.196mm−1, F(000)=1426, R =0.0590, and wR =0.1639 for 9745 observed reflections with I > 2σ(I). X-ray analysis reveals that the coordination polyhedron adopts a slightly distorted square-antiprismatic structure around the metal center. Both phthalocyanine and porphyrin ligands are saucer-shaped, with the skew angle of the two ligand planes approximately 45°. The self-assembled nano-structures of both complexes 1 and 2 were systematically investigated by electronic absorption and Fourier transform infrared (FT-IR) spectroscopy, transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), and X-ray diffraction (XRD) techniques, revealing the effect of molecular structure on the dimension of self-assembled nano-structures. [Copyright &y& Elsevier]

Abstract: NOBF4 reacts with para-substituted meso-tetraarylporphyrins, H2t(4-Xp)p, at room temperature for formation of green molecular complexes, [H2t(4-Xp)p(NO)]BF4. Mole ratio for the porphyrins and nitrosonium ion in the molecular complexes was 1:1, [H2T(4-X)PP(NO)]BF4. FT-IR, UV–Vis, (1H and 13C) NMR spectral data, elemental analysis and molar conductivity indicated that NO+ (as electron acceptor) is bound to the lone electron pairs of the two pyrrolenine nitrogens in a side of the porphyrin plane. In these molecular complexes, two pyrrolic nitrogen atoms of the porphyrin core coordinate to the acceptor and two protons of the pyrrolic nitrogen atoms have been remained on the porphyrin macrocycles. Molecular complexation of meso-tetraarylporphyrins with NO+ produces a large downfield shift for the NH signal. [Copyright &y& Elsevier]

Abstract: A heteroleptic porphyrinate phthalocyaninate donor–acceptor europium double-decker complex was synthesized. The UV–Vis spectral properties and cyclic voltammetry of the compound were investigated and compared to model compounds. [Copyright &y& Elsevier]

Abstract: N-Heterocyclic carbene (NHC) coordination to a cobalt(III) center embedded in a porphyrin scaffold has been accomplished by decarboxylation from N,N′-dimethylimidazolium-2-carboxylate in the presence of Co(TPP)Cl (TPP=5,10,15,20-tetraphenylporphyrin). The distal chloride ligand in the resulting complex Co(NHC)(TPP)Cl was successfully substituted with imidazoles and alcohols. Single crystal X-ray diffraction of the latter complexes Co(NHC)(TPP)(ROH) (R=Me, Et) revealed a pronounced ruffling of the porphyrin macrocycle due to the two ortho methyl groups in the carbene ligand and because of the relatively short distance between the cobalt center and the carbene ligand. Spectroscopic investigations support a substantial porphyrin dearomatization upon NHC bonding. [Copyright &y& Elsevier]

Abstract: Two dodecachlorinated porphyrins, 2,3,7,8,12,13,17,18-octachloro-5,10,15,20-tetra(4-chlorophenyl)porphyrin free base (TCl12PPH2) and its nickel compound (TCl12PPNi), have been synthesized. Single-crystal X-ray diffraction analysis shows that porphyrin rings are heavily distorted and exhibit saddled conformations. The Soret and Q bands of two compounds are red-shifted compared to their non-chlorinated counterparts. Theoretical calculations reveal that the optical band gap of TCl12PPH2 is reduced, whereas that of TCl12PPNi remains almost the same as to its non-chlorinated nickel compound due to the concurrent lowering of HOMO and LUMO energy levels. The frontier molecular orbitals are degenerated due to the decrease of symmetry of the molecules. [Copyright &y& Elsevier]

The thermal reaction of Ru3(CO)12 with various carboxylic acids (benzoic, 4-hydroxyphenylacetic, ferrocenic, stearic, oleic, 4-(octadecyloxy)benzoic) in refluxing tetrahydrofuran, followed by addition of 5-(4-pyridyl)-10,15,20-triphenylporphyrin (L), gives the dinuclear complexes Ru2(CO)4(OOCR)2L2 (1: R = –C6H5, 2: R = –CH2-p-C6H4OH, 3: R = –C5H4FeC5H5, 4: R = –(CH2)16CH3, 5: R = –(CH2)7CH=CH(CH2)7CH3, 6: R = –p-C6H4O(CH2)17CH3). Complexes 1–6 were characterised by IR, NMR, and ESI-MS as well as by elemental analysis. The UV–Vis spectra show the Soret band centred at 417 nm and the Q bands at 515, 550, 590 and 645 nm, respectively. [Copyright &y& Elsevier]

Abstract: Condensation of tetraphenylporphyrin-2,3-dione with 1,10-phenanthroline-5,6-diamine provided porphyrinphenanthroline (2) as the desired ligand. Metallation of the porphyrinic site of 2 with CoCl2, NiCl2, ZnCl2 and CuCl2 afforded the corresponding metal complexes [Co(2)] (8a), [Ni(2)] (8b), [Zn(2)] (8c) and [Cu(2)] (8d), respectively. Subsequent reactions of these metalloporphyrins with [(COD)PdCl2] yielded the corresponding bimetallic complexes [Co/Pd (9a), Ni/Pd (9b), Zn/Pd (9c) and Cu/Pd (9d)] in high yields. The bimetallic complex 9e (Mg/Pd) was prepared directly by complexation of 2 with MgBr2 and [(COD)PdCl2]. All complexes were characterized by both spectroscopic and elemental analyses. In addition, crystal structure of 9c was determined to confirm its formulation. The use of these bimetallic complexes as pre-catalysts for Mizoroki–Heck coupling reaction has been examined. [ABSTRACT FROM AUTHOR]

Abstract: New complexes based on a coordination interaction between a pyridyl-porphyrin (namely 5,10,15-tritolyl-20-(4-pyridyl)porphyrin, 5,10,15-tritolyl-20-(3-pyridyl)porphyrin or 5,10,15-triphenyl-20-(4-pyridyl)porphyrin) and a Keggin-type polyoxometalate (α-[MSiW11O39]6−, M=Co2+ or Ni2+) are formed in solution. The formation of these complexes is clearly evidenced by steady-state and time-resolved luminescence measurements. A strong quenching of the porphyrin fluorescence, accompanied by an important shortening of the fluorescence lifetime, is observed upon addition of the POM and formation of the complexes. Using a variant of the Job’s method from the luminescence spectra, the association constants of the complexes have been estimated to be around 106 Lmol−1. Paramagnetic 1H NMR experiments confirm the formation of the complexes. Indeed, in addition to broadenings of the signals, the coordination binding of the POM to the porphyrin induces large high-frequency shifts for the protons of the pyridyl group coordinated to theparamagnetic metal, and low-frequency shifts for all the other resonances. [Copyright &y& Elsevier]

Abstract: In this paper the synthetic methods of three covalently linked porphyrin-phthalocyanine heteropentamers, containing four units of porphyrin linked to a central phthalocyanine (Mpor-LPc; M=2H, Fe, L=Zn, Fe), are described. The synthetic strategy is on the basis of nucleophilic substitution reactions between [1,8,15,22-tetra nitro phthalocyanines] and [5-(4-hydroxy phenyl)-10,15,20-triphenyl porphyrins] as the phenolic alcohols. Porphyrins are linked with oxygen as spacer through meso position of phenyl group to phthalocyanines. These macromolecules were characterized by 1H NMR, UV–Vis, IR, fluorescence and mass spectroscopy. The electronic absorption spectrums of the hetero-dyad systems changed significantly upon coupling and showed a great red shift in the phthalocyanine Q-bands. These changes confirm the electron-donating effects of the porphyrin units and the extension of conjugated п-systems. The emission spectra of the products supports intramolecular energy and charge transfer between the sub-units. [Copyright &y& Elsevier]

Abstract: The reaction of meso-tetraarylporphyrins with phosphorus oxychloride was studied. The reaction product is the so-called intermediate sitting-atop (i-SAT) complex where two pyrrolic nitrogen atoms of the porphyrin core coordinate to the phosphorus atom and two protons on the pyrrolic nitrogen atoms remain. Selection of solvent free conditions is caused that the reaction does not progress until deprotonation step of porphyrin and stopped in the intermediate step for formation of the sitting-atop complex, [POCl2(H2t(X)pp)]Cl. The sitting-atop complexes were characterized by (1H, 31P, 13C) NMR, FT-IR, UV–vis and photoluminescence spectroscopy (PL), elemental analysis and electrical conductometry. Photoluminescence study of the complexes indicates that their emission spectra are different from those of free base porphyrins. [Copyright &y& Elsevier]

Abstract: GeCl4 and meso-tetraarylporphyrins (H2TAPP) react in chloroform solvent for formation sandwich intermediate sitting-atop (i-SAT) complexes, [GeCl4(H2TAP)2]. The various spectral data (1H NMR, 13C NMR, UV–Vis, FT-IR and elemental analysis) were used for characterization of the i-SAT complexes. In the sandwich complexes, the pyrrole rings of two porphyrin macrocycles are tilted up and down and act as electron donors by lone pairs of pyrrolic nitrogens to germanium center of GeCl4. The spectral results of 1H NMR and FT-IR showed that in the i-SAT complexes, the hydrogen atoms of two pyrrolic nitrogens remained still on the porphyrin macrocycles. [Copyright &y& Elsevier]

Abstract: The electrocatalytic reduction of protons in 1.0M perchloric acid at glassy carbon electrodes anodically modified with a Co(II)/Pt(II) porphyrin show shifts of 400mV versus Ag/AgCl when compared to the same electrodes which have not been anodically modified. Anodic cycling of glassy carbon electrodes coated with the Co(II)/Pt(II) porphyrin in this study form stable electroactive films capable of improving both electroreduction of protons to hydrogen and oxygen to both peroxide and water. Electrooxidation of glassy carbon electrodes coated with the free base porphyrin show no improvement in catalytic ability for the reduction of protons in acidic solution or the reduction of molecular oxygen in basic solution. Glassy carbon electrodes coated with the Co(II)/Pt(II) porphyrin indicate, by rotating disk electrochemistry, that the electrocatalysis of oxygen is a two electron process leading to the formation of hydrogen peroxide. Koutecky–Levich plots of the data obtained from the reduction of oxygen at electrode surfaces coated with the Co(II)/Pt(II) porphyrin after oxidation of the surface indicate that 25% of the oxygen is reduced by four electrons directly to water while 75% of the oxygen is reduced by two electrons to hydrogen peroxide. [Copyright &y& Elsevier]

Abstract: The intermediate sitting-atop (i-SAT) complexes are metalloporphyrins in which the metal ion is bonded to fewer than four nitrogen atoms in the distorted porphyrin plane. The i-SAT complexes may be considered as models for the initial steps of the metallation of the macrocycles. The new ionic intermediate sitting-atop complexes of [PCl3(H2t(X)pp)]Cl2 containing phosphorus(V) was synthesized by reaction of PCl5 and meso-tetraarylporphyrins (H2t(X)pp) in solvent free conditions. The structure of the complexes was confirmed by (1H, 31P, 13C) NMR, FT-IR and UV–Vis spectroscopies, elemental analysis and electrical conductometry. These data proved that only two pyrrolenine nitrogen atoms of the porphyrin act as electron donors to one phosphorus(V) center and so two pyrrolic protons remained still on the macrocycle. [Copyright &y& Elsevier]

Abstract: The reaction of free base para-substituted meso-tetraarylporphyrins (H2T(p-X)PP, X=H, OMe, Me, and Cl) with indium(III) chloride in CHCl3 and mild conditions produced intermediate sitting-atop (i-SAT) complexes, [InCl2(H2T(p-X)PP)]InCl4, as sole products. In the proposed structures of these complexes, four pyrrole rings are tilted alternatively up and down the porphyrin plane. This distortion makes suitable orientation of lone pairs of two pyrrolenine nitrogens for electron donation to an indium center of cation. The 1:2 (porphyrin:indium) formation constant of resulting i-SAT complexes were calculated by the computer fitting of the complexes absorbance versus mole ratio data based on appropriate equations. Thermodynamic parameters, ΔG 0, ΔH 0, and ΔS 0, have been determined and the influence of electron donation of the para-substituted aryl groups in the free base porphyrins on the stability of the complexes is discussed. [Copyright &y& Elsevier]

Abstract: New supramolecular hybrid assemblies have been selectively prepared starting off with stoichiometric mixtures of pyridine-tagged Zn(salphen) and non-metalated porphyrin ligands in the presence of suitable metal acetates. This one-pot procedure leads to in situ transmetalation of the salen unit, metalation of the porphyrin ligand by the released Zn(OAc)2 and subsequent heterometallic assembly formation between the metallosalen and metalloporphyrin components via Zn–Npyr coordination motifs. The reactions were followed by NMR spectroscopy and MALDI-TOF mass spectrometry, and for one of the Zn(salphen) building blocks the X-ray molecular structure is reported. [Copyright &y& Elsevier]

Abstract: The 5,10,15-tri-(p-dodecanoxyphenyl)-20-(p-hydroxyphenyl)- and 5,10,15,20-tetrakis-(p-dodecanoxyphenyl)-cobalt porphyrin complexes were synthesized, purified and characterized. Silica substrates were functionalized with a covalent 4-ClCH2C6H4SiCl3 monolayer. Additional covalent bonding of the 5,10,15-tri-(p-dodecanoxyphenyl)-20-(p-hydroxyphenyl)-cobalt porphyrin to the silylated substrates was further achieved. The monolayer surface chemical characterization was carried out by X-ray photoelectron measurements. Both the Co 2p and N 1s spectra are evident. The NO2 sensing capability of the present cobalt porphyrin systems, at ppm levels, has been demonstrated. [Copyright &y& Elsevier]

Treatment of meso(tetra-p-tolyl)porphryin, H2(TTP), or Li2(TTP) with OᆖSeCl2 or OᆖSe(NMe2)2 in toluene or THF resulted in the formation of the diprotonated porphyrin, [H4(TTP)]Cl2 and indicated the reluctance of selenium to insert into the porphyrin core. The molecular structure of [H4(TTP)]Cl2 was determined by single-crystal X-ray diffraction and exhibited the typical saddle-shape distortion of diprotonated porphyrins. The molecular structure of (p-MeO–Ph)2Te(salen) was reexamined by X-ray diffraction. The geometry of the Te(IV) center is strongly influenced by a stereochemically active lone pair and is best described as having an AX4E disphenoid structure in which the salen oxygen atoms occupy axial positions and the two anisyl ligands reside in equatorial sites. Distances between Te and the salen nitrogen atoms are 2.852(3) and 2.984(3) Å and are largely nonbonding. [Copyright &y& Elsevier]

Abstract: Amphiphilic ligands 4′-((4-(5-pyridin-4-yloxy)pentyloxy)styryl)-4-methyl-2,2′-bipyridine (L1), 4,4′-bis((E)-4-(5-(pyridin-4-yloxy)pentyloxy)styryl)-2,2′-bipyridine (L2), 4′-(4-(5-(4′-cyano-4-biphenoxy)pentyloxy)styryl)-4-methyl-2,2′-bipyridine (L3), and 4′-(4-(5-(zinc tetrakis-5,10,15-tritolyl-20-(4-hydroxyphenyl)porphyrin)pentyloxy)styryl)-4-methyl-2,2′-bipyridine (L4) and their heteroleptic ruthenium(II) complexes of the types [Ru(L1)(L)(NCS)2] (D20), [Ru(L2)(L)(NCS)2] (D21), [Ru(L3)(L)(NCS)2] (D22), and [Ru(L4)(L)(NCS)2] (D23) (where L=4,4′-bis(carboxylic acid)-2,2′-bipyridine) have been synthesized, as photosensitizers for nanocrystalline dye-sensitized solar cells. All complexes D20–D23 exhibit a broad MLCT band around 520–530nm in DMF and an emission band around 740–790nm in DMF. We have studied photovoltaic performances based on the newly synthesized dyes. Under standard AM 1.5 sunlight, the dye D20 gave a short-circuit photocurrent density of 13.31mA/cm2, an open-circuit voltage of 0.64V, and a fill factor of 0.68, corresponding to an overall conversion efficiency of 5.81%. [Copyright &y& Elsevier]

Reactions of photochemically or radiolytically generated radicals with tetrakis(x-aminophenyl)porphyrin, tapp2−, initiate the polymerization of the porphyrin complexes Mtapp, where M=Ni or Zn. In the photochemical process, the porphyrin-centered excited state of Mtapp reacts with the ground state to generate oxidized and reduced radical species. The cationic radical, M(tapp·+), appears to be the initiator of the porphyrin polymerization. An electron transfer reaction between the excited state of Mtapp and a Co(III) complex generates also the cation radical and initiates the polymerization process. Pulse radiolytically generated Cl2- and OH· radicals were also able to initiate the polymerization of the porphyrin complexes. [Copyright &y& Elsevier]