نتایج جستجو برای: porphyrin

تعداد نتایج: 6995  

2008
Suk Joong Lee Rebecca A. Jensen Christos D. Malliakas Mercouri G. Kanatzidis Joseph T. Hupp SonBinh T. Nguyen

The enormous potential that metalloporphyrins possess in catalysis, photochemistry, sensing, and as optical devices has made them favorite building blocks in the emerging field of molecular materials. With attractive structural features such as large bulk, rigid planarity, and a highly conjugated framework that can be readily modified with a variety of functional groups, porphyrins can be assem...

Journal: :Environmental Health Perspectives 2002
Dolores Ozalla Carmen Herrero Núria Ribas-Fitó Jordi To-Figueras Agustí Toll Maria Sala Joan Grimalt Xavier Basagaña Màrius Lecha Jordi Sunyer

The existence of a link between hexachlorobenzene (HCB) and porphyria cutanea tarda has been known for a long time. However, the epidemiologic data on effects on health caused by prenatal exposure have not provided convincing evidence that HCB alters porphyrin metabolism. Our objectives were to analyze urinary porphyrin excretion and HCB in maternal serum and fetal cord blood in neonates born i...

2015
Claudia E. Tait Patrik Neuhaus Harry L. Anderson Christiane R. Timmel

The delocalization of the photoexcited triplet state in a linear butadiyne-linked porphyrin dimer is investigated by time-resolved and pulse electron paramagnetic resonance (EPR) with laser excitation. The transient EPR spectra of the photoexcited triplet states of the porphyrin monomer and dimer are characterized by significantly different spin polarizations and an increase of the zero-field s...

Journal: :Journal of computer-aided molecular design 1998
Marcel J. de Groot Remco W. A. Havenith H. Maarten Vinkers Renate Zwaans Nico P. E. Vermeulen Joop H. van Lenthe

Geometry optimizations for several spin states of the iron(III)-S-methyl- porphyrin complex, the iron (III)-oxo-S-methyl-porphyrin complex and the respective anions were performed in order to examine models for intermediates in the oxidative cycle of cytochrome P450. The aim of this study was to obtain insights into the ground states of the intermediates of this catalytic cycle and to use the a...

Journal: :Organic & biomolecular chemistry 2006
Freek J M Hoeben Maarten J Pouderoijen Albertus P H J Schenning E W Meijer

Pi-pi stacking of hydrogen-bonded porphyrin and oligo(p-phenylene vinylene)s (OPVs) yields helical co-assemblies which exhibit energy transfer from OPV to porphyrin.

2015
M. Mar Bernal Emilio M. Pérez John George Hardy Max von Delius

A simple one-pot process to exfoliate graphite and synthesize nanographene-dimesitylporphyrin hybrids has been developed. Despite the bulky mesityl groups, which are expected to hinder the efficient π-π stacking between the porphyrin core and graphene, the liquid-phase exfoliation of graphite is significantly favored by the presence of the porphyrins. Metallation of the porphyrin further enhanc...

Journal: :Clinical chemistry 1977
J M Lamon

Measurement of porphyrins and porphyrin precursors has clinical significance beyond the detection or confirmation of lead poisoning. The porphyric diseases of man are characterized by the presence of a specific clinical syndrome and demonstration of abnormal porphyrin excretion or accumulation in the tissues. In addition, porphyrins accumulate in other disorders that are unrelated to lead poiso...

Journal: :Molecules 2009
Mohamad Mehdi Kashani-Motlagh Rahmatollah Rahimi Marziye Javaheri Kachousangi

We report the synthesis and optical properties of organic porphyrin nanoparticles with narrow size distribution and good dispersibility. Nanoparticles were produced by a combination of precipitation and sonication, termed the "ultrasonic method". The resulting [tetrakis(para-chlorophenyl)porphyrin]TClPP nanoparticles were stable in solution without precipitation for at least 30 days. No self ag...

Journal: :Chemical communications 2014
Theodore Lazarides Milan Delor Igor V Sazanovich Theresa M McCormick Irene Georgakaki Georgios Charalambidis Julia A Weinstein Athanassios G Coutsolelos

A combination of noble-metal free components, a water soluble porphyrin photosensitizer zinc meso-tetrakis(1-methylpyridinium-4-yl)porphyrin chloride [ZnTMPyP(4+)]Cl4 (1) with cobaloxime complex [Co(III)(dmgH)2(py)Cl] (2) as a catalyst, creates an efficient system for photochemical hydrogen production acting under visible light with 280 TONs. This is the first example of a water soluble porphyr...

Journal: :Organic & biomolecular chemistry 2013
Bin Liu Xiaofang Li Jie Zhang Piotr J Chmielewski

Active methylene compounds such as acetone, butanone, cyclopentanone, nitromethane, malononitrile, ethyl 2-cyanoacetate, diethyl malonate, and ethyl acetylacetate react with the C3 position of N-confused porphyrin in the presence of L-proline in refluxing THF-EtOH affording a variety of N-confused porphyrin derivatives in moderate yield. L-Proline catalyzes the reaction facilitating the formati...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید