Solvent effects on oxygen atom transfer reaction between manganese(V)-oxo corrole and alkene

Pseudo-first order reaction rate constants of 5,10,15-tris（pentafluorophenyl）corrole Mn（V）-oxo (F₁₅CMn（V）-oxo),5,15-bis（pentafluorophenyl）-10-（phenyl）corrole Mn（V）-oxo(F₁₀CMn（V）-oxo),5,15- bis（phenyl）-10-（pentafluorophenyl）corrole Mn（V）-oxo（F₅CMn（V）-oxo） and 5,10,15-tris（phenyl）corrole Mn（V）-oxo（F₀CMn（V）-oxo） with a series of alkene substrates in different solvents were determined by UV-vis spectroscopy.The results indicated that the oxygen atom transfer pathway between Mn（V）-oxo corrole and alkene is solvent-dependent.     

First example of a palladium catalyzed coupling reaction between cationic porphyrins and alkynyls in aqueous medium

The first example of the palladium catalyzed (Sonogashira) carbon-carbon coupling reaction in aqueous medium between 5,10,15-tri-(4-N-methylpyridyl)-20-(4-bromophenyl)-porphyrin and a variety of terminal alkynyls is reported.     

Palladium catalyzed coupling reactions of cationic porphyrins with organoboranes (Suzuki) and alkenes (Heck)

The carbon-carbon coupling reaction in aqueous medium between 5,10,15-tri-(4-N-methylpyridyl)-20-(4-bromophenyl)-porphyrin and a variety of organoboranes, fluoroorganoboranes and alkenes using palladium catalyst (Suzuki and Heck) is explored.     

Synthesis of flexible dimeric meso-tetrakis-porphyrins

Monofunctionalisation of meso-tetrakis-porphyrins through introduction of a carboxylic group in the meso position of the phenyl group confers the necessary characteristics to anchor them through stable amide bonds to functionalised supports or to molecules. In this Letter we describe the synthesis, characterisation and photophysical evaluation of such a functionalised flexible dimeric porphyrin, bis-(meso-tetrakis-5,10,15-triphenyl-20-(p-carboxyphenyl)-porphyrinyl)-1,6-hexanediamide.     

Low energy light-triggered oxidative cleavage of olefins

A series of substituted olefins were tested for their reactivity with singlet oxygen as a singlet oxygen-mediated cleavable linker. Low intensity light of 200 mW/cm² was irradiated to the solution of an olefin and 5,10,15-triphenyl-20-(4-hydroxyphenyl)-21H,23H-porphyrin under atmospheric condition. Among the tested olefins, 1,2-cis-diphenoxyethylene reacted fast with singlet oxygen, >80% within 15 min yielding a stoichiometric conversion to aldehyde product without any side reactions.     

Synthesis of Peripherally Nitrated,Aminated, and Arylaminated Subporphyrins

2‐Nitro‐5,10,15‐tri(4‐tert‐butylphenyl)subporphyrin 2 was prepared by the nitration of 5,10,15‐tri(4‐tert‐ butylphenyl)subporphyrin 1a with five equivalents of Cu(NO₃)₂ ? 5 H₂O in a mixed EtOAc/Ac₂O solution and was reduced into 2‐amino‐5,10,15‐tri(4‐tert‐butylphenyl)subporphyrin 3 . Bromination of 5,10,15‐triphenylsubporphyrin 1b with 1.5 equivalents of N‐bromosuccinimide (NBS) gave 2‐bromo‐5,10,15‐triphenylsubporphyrin, which was converted into various 2‐arylamino‐5,10,15‐triphenylsubporphyrins ( 4a , 4b , 4c , 4d ) and 2‐benzamido‐5,10,15‐triphenylsubporphyrin 5 through Pd‐catalyzed cross‐coupling reactions. These molecules constitute the first examples of mono‐β‐substituted subporphyrins. These subporphyrins exhibit significantly perturbed optical and electrochemical properties, which reflect a large influence of the peripherally attached substituents on the electronic networks of subporphyrins.     

Effect of the chemical modification of the tetrapyrrole macrocycle on the reactivity of porphyrins in complexation with Pt4+ and Pd2+ cations

The reactions of 5,10,15,20-tetraphenylporpine, 5,10,15-triphenyl-20-(4-hexadecanoxyphenyl)porphine, 5,10,15,20-tetra-(4-butoxyphenyl)porphine, and 2,3,7,8,12,13,17,18-ocaethylporphine with H₂PtCl₆ in boiling phenol and with PdCl₂ in boiling dimethylformamide are studied by spectrophotometry. Due to a strong electronic effect of the substituents, the reactivity of the tetrapyrrole macrocycle during porphyrinate formation changes by more than two orders of magnitude. Platinum(II) 5,10,15-triphenyl-20-(4-hexadecanoxyphenyl)porphinate and palladium(II) 5,10,15,20-tetra-(4-butoxyphenyl)porphinate have been synthesized and identified for the first time.     

Synthesis of biomimetic heme precursors

Three kinds of biomimetic heme precursors have been prepared. The first type is based on tetra-aminoporphyrins: either 5,10,15,20-tetrakis (o-aminophenyl)porphyrin (various atropoisomers), or 5,15-bis(2′,6′-diaminophenyl)porphyrin. The second type is based on octa-aminoporphyrins: 5,10,15,20-tetrakis (2′,6′-diamino-4′-tert-butylphenyl)porphyrin. One example of “basket handle” porphyrin demonstrates selective discrimination between O₂ and CO with an M value [M=p_1/2(O₂)/p_1/2(CO)] of 105. This is similar to values reported for various natural hemoproteins. The third type is based on aminoporphyrin templates [5, 5,10- or 5,15- and 5,10,15-(2′,6′-dinitro,4′-tert-butylphenyl)porphyrins] which have been tested in asymmetric epoxidation.     

Synthesis of highly substituted meso-tetraarylporphyrins

meso-Tetraphenylporphyrin (and its derivatives), in the reaction with fuming yellow nitric acid (d=1.53), form either 5-(4-nitroaryl)-10,15,20-triarylporphyrin, 5,10-bis(4-nitroaryl)-15,20-diarylporphyrin, or 5,10,15-tris(4-nitroaryl)-20-arylporphyrin, depending on the reaction temperature (0-20 °C), amounts of the acid used, and reaction time. The above nitroporphyrins react, in the presence of a base (t-BuOK) at 0 °C, with carbanions (which bear nucleophugal groups at the carbanionic center: ⁻CH(Cl)SO₂Tol, ⁻CH(Br)SO₂Tol, and ⁻CH(Cl)SO₂NMe₂), leading to the nucleophilic substitution of hydrogen in one or more of the meso-nitroaryl rings. By this route, the preparation of the highly substituted ‘synthetic’ porphyrins (bearing up to ten O-, N-, Cl-, or C-substituents) was demonstrated.     

Porphyrin–TiO2 nanoparticle heterostructure assembly by Langmuir–Blodgett method

Surface pressure–area (π–A) isotherm characteristics of 5,10,15-(4-hydroxyphenyl)-20-(4-hexadecyloxyphenyl) porphyrin monolayers on both the water and TiO₂ hydrosol subphases, the UV–vis absorption and fluorescence spectra of the monolayers deposited onto CaF₂ substrates are investigated. π–A isotherms find that the porphyrin ring extends to lie more flat on a TiO₂ hydrosol surface than on a water surface. The UV–vis absorption spectra of the deposited monolayers prove that the porphyrin TiO₂ nanoparticle heterostructure assembly is formed, in which the J-aggregated effect of porphyrin is weakened, comparing with that in the monolayer deposited from water subphase. The fluorescence spectra show that the fluorescent emission quenching by the photoinduced electron transfer from the excited porphyrin molecule to TiO₂ nanoparticle, occurs under excitation in the Soret band region of porphyrin.     

Synthesis and antitumor activity of DNA binding cationic porphyrin-platinum(II) complexes

A new series of DNA binding 5,10,15-tri(N-methyl-4-pyridiniumyl)porphyrin (TrisMPyP)-platinum(II) conjugates was synthesized, in which different spacer ligands were used for appropriate coordination to platinum(II) complexes. Compound 9b exhibited in vivo antitumor activity (T/C%, 294) superior to cisplatin (T/C%, 184) against the leukemia L1210 cell line.     

Reactivity of mixed manganese complexes with porphyrins and anionic ligands. Effect of modification of the organic part of the molecule

Manganese(III) complexes with octaethyl-, 5-phenyloctaethyl-, 5,10-and 5,15-diphenyloctaethyl-, 5,10,15-triphenyloctaethyl-, and 5,10,15,20-tetraphenyloctaethylporphyrins were synthesized, and the kinetics and mechanism of their dissociation in mixed AcOH-H₂SO₄ system were studied. The complete stability series of octaethylporphyrin manganese(III) complexes with increasing number of phenyl substituents at the meso positions of the porphyrin ligand was obtained.     

Determination of acidity of di-, tri-, and tetraazaporphyrins in dimethyl sulfoxide-potassium cryptate medium

Acidic properties of 10,20-diaza-3,7,13,17-tetramethyl-2,8,12,18-tetra-n-hexylporphyrin, 2,7,12,17-tetra-t-butyltetrabenzo-5,10,15-triazaporphyrin and octa(n-amyloxy)phthalocyanine in the system of dimethyl sulfoxide-potassium cryptates (DMSO-K[222]OH) at ambient temperature was investigated by the method of spectrophotometric titration. The porphyrins in the DMSO-K[222]OH medium were shown to dissociate sequentially forming mono- and dianions in two steps. The concentration ranges of existence of the anionic forms and the acidity sequence of the studied meso-aza-substituted porphyrins were investigated.     

Polymeric optical sensors for selective and sensitive nitrite detection using cobalt(III) corrole and rhodium(III) porphyrin as ionophores

Cobalt(III) 5,10,15-tris(4-tert-butylphenyl) corrole with a triphenylphosphine axial ligand and rhodium(III) 5,10,15,20-tetra(p-tert-butylphenyl) porphyrin are incorporated into plasticized poly(vinyl chloride) films to fabricate nitrite-selective bulk optodes via absorbance measurements. The resulting films yield sensitive, fast and fully reversible response toward nitrite with significantly enhanced nitrite selectivity over other anions including lipophilic anions such as thiocyanate and perchlorate. The selectivity patterns differ greatly from the Hofmeister series based on anion lipophilicity and are consistent with selectivity obtained with potentiometric sensors based on the same ionophores. The optical nitrite sensors are shown to be useful for detecting rates of emission of nitric oxide (NO) from NO releasing polymers containing S-nitroso-N-acetyl-DL-penicillamine.     

Spectrophotometric study of the complexing properties of 2,3,7,8,12,13,17,18-Octaethyl-5,10,15-trinitroporphyrin and its dianion toward Zn(OAc)2 in acetonitrile

Complexing properties of 2,3,7,8,12,13,17,18-octaethyl-5,10,15-trinitroporphyrin and its dianionic form in the systems acetonitrile-Zn(OAc)₂ and 1,8-diazabicyclo[5.4.0]undec-7-ene-acetonitrile-Zn(OAc)₂ have been studied by spectrophotometric titration. Zinc complexes of 2,3,7,8,12,13,17,18-octaethyl-5,10,15-trinitroporphyrin have been characterized by spectral data, and kinetic parameters of the complex formation according to the molecular and ionic mechanisms have been analyzed.     

Synthesis, electrochemical and photophysical properties of β-carboxy triaryl corroles

An unswerving one-pot conversion of 3-formyl-5,10,15-triaryl substituted corroles and their copper(III) derivatives to the corresponding 3-carboxy-5,10,15-triaryl substituted corroles was achieved by adopting mild reaction conditions by using hydroxylamine hydrochloride and phthalic anhydride. All these substituted carboxy corroles were completely characterized by using Mass, CHN analysis, IR, ¹H NMR, UV-vis., Fluorescence spectroscopies, and cyclic voltammetry. Both the absorption maxima and emission maxima of carboxy corroles were red shifted by 5-13 nm. The LUMO level of these corroles is above the TiO₂ conduction band and HOMO level was below the redox electrolytes. These β-carboxy corroles confined with may find applications as sensitizers in dye-sensitized solar cells.     

Synthèses dans ka série des bis-indéno-fluorènes II. Le dihydro-10,15-5H-bis-indéno [1, 2-a;2′,1′-i] fluorène

The biangular bis-indeno-fluorene 10,15-dihydro-5H-diindeno [l, 2-a; 2′, 1′-i]-fluorene (XII) has been synthesised in 6 steps starting from 1-(o-carboxyphenyl)-fluorenone (overall yield 21%). As an intermediate the 5,10,15-trioxoderivative of XII and, accessorily, its 5,10-dioxoderivative were also obtained.     

Kinetics of the formation and dissociation of complexes of cobalt(II) with <Emphasis Type="Italic">meso</Emphasis>-Phenylocta(methyl)porphyrin derivatives in organic solvents

The influence of the deformation of the tetrapyrrole aromatic macrocycle and the electronic effects of substituents on the kinetic parameters in the formation and dissociation reactions of cobalt complexes of porphyrins are discussed on the basis of a study of the kinetics of the formation and dissociation of cobalt complexes with meso-phenyl octa(methyl)porphyrin derivatives: 5,10,15-triphehyl octa(methyl) porphyrin; 5,15-bis-(3′,5′-di-tert-butyl phenyl) octa(methyl)porphyrin; 5,10,15-tris-(3′,5′-di-tert-butyl phenyl) octa(methyl)porphyrin; and 5,10,15,20-tetrakis-(3′,5′-di-tert-butyl phenyl) octa(methyl)porphyrin in acetic acid and pyridine.     

Octupolar trisporphyrin conjugates exhibiting strong two-photon absorption

We report octupolar trisporphyrin conjugates, derived from the symmetrical functionalization of a triphenylamine core with three ethynylporphyrin wings, exhibiting largely enhanced two-photon absorption (TPA) compared to the porphyrin monomers. Octupolar trisporphyrin conjugate tris-H₂P was synthesized by the Pd(0)-catalyzed Sonogashira cross-coupling reaction of tris(4-iodophenyl)amine with 5,10,15-tri-(p-tolyl)-20-ethynylporphyrin, and fully characterized by various spectroscopic methods and elemental analysis. The optimized geometry of tris-H₂P obtained by semi-empirical AM1 calculations reveals that tris-H₂P adopts a propeller-shaped structure. Our photophysical studies strongly manifest that the trisporphyrin conjugates are promising octupolar fluorophores with effective π-conjugation over the porphyrin wings through the octupolar core. The trisporphyrin conjugates exhibit much larger TPA cross-section values in comparison with the monomers; the TPA cross-section σ⁽²⁾ value of tris-ZnP (11,800 GM) exceeds that of mono-ZnP (630 GM) by about 20 times.     

Mn(II), Co(II), Ni(II) and Cu(II) complexes of a tertraaza macrocyclic ligand: Synthesis, characterization and biological screening

Manganese(II), cobalt(II), nickel(II) and copper(II) complexes with 1,5,11,15-tetraaza-21,22-dioxo-tricyclo [19,3,1,I^6,10]-5,10,15-20-dicosatetraene (L), as a new macrocyclicligand, have been synthesized with and characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, electronic and EPR spectral studies. The molar conductance measurements of the complexes in DMF correspond to non-electrolytic nature of Mn(II), Co(II) and Cu(II) complexes, while showing a 1:2 electrolyte for thew Ni(II) complexe. Thus, these complexes may be formulated as [M(L)X₂] and [Ni(L)]X₂ (where M = Mn(II), Co(II) and Cu(II) and X = Cl^- and NO₃ ^-). On the basis of IR, electronic and EPR spectral studies, an octahedral geometry has been assigned for Mn(II) and Co(II), a square planar for Ni(II) and tetragonal for Cu(II) complexes. In vitro ligand and its metal complexes were also screened against the growth of some fungal and bacterial species in order to assess their antimicrobial properties.