Publisher SummaryThis chapter explores the biogenesis and metabolism of folic acid and vitamin B12. The biosynthesis of folic acid by microorganisms the aromatic ring of the p-aminobenzoic acid group is formed from carbohydrate via shikimic acid. Glutamic acid is possibly added after p-aminobenz...

Publisher SummaryThis chapter discusses the biosynthesis of purines and pyrimidines. The vitamin, folic acid, is converted to its coenzyme form, tetrahydrofolic acid, by a pyridine nucleotide-dependent enzyme, dihydrofolate reductase. In turn, tetrahydrofolate serves as the carrier of various on...

A large number of isomeric ring systems in which both fused heterocyclic five-membered rings contain one bridgehead nitrogen atom and one further heteroatom in each ring have received considerable attention over the past few years (more than 250 references cited here). Several heterocycles conta...

Small molecule inhibitors of adipocyte fatty acid binding protein 4 (FABP4) have attracted interest following the recent publications of beneficial pharmacological effects of these compounds. FABP4 is predominantly expressed in macrophages and adipose tissue where it regulates fatty acids (FAs) ...

SummaryAldose reductase (AKR1B1), the key enzyme of the polyol pathway, plays a crucial role in the development of long-term complications affecting diabetic patients. Nevertheless, the expedience of inhibiting this enzyme to treat diabetic complications has failed, due to the emergence of side ...

We performed comparative DFT study, including Natural Bond Orbitals (NBO) analysis, of the binding energies between all the first-row transition metals Mn+ (M = Sc–Zn) and two ligands of the similar type: porphine, P2−, and its completely P-substituted counterpart, P(P)42−. The main findings ar...

Thin films of 5,10,15,20-Tetraphenyl-21H,23H-porphine-nickel(II) were prepared by thermal evaporation technique onto clean quartz and glass substrates. Thermogravimetric analysis, X-Ray Diffraction, Scanning Electron Microscope, Transmission Electron Microscope and Fourier transforms infrared sp...

It has been demonstrated that the treatment of the magnesium polyporphine of type I, pMgP-I, by trifluoroacetic acid in acetonitrile may be used to replace initial central Mg(II) cations inside the monomeric macrocycle units by protons, to get a new electroactive polymer, “free-base polyporphin...

The coupling of benzyl protected dopamine with meso-tetra(4-carboxyphenyl)porphine (m-TCPP) and a simple deprotection by hydrogenation under catalyst (Pd/C) to remove the benzyl groups afforded the meso-tetra(4-carboxyphenyl)porphine-dopamine conjugate, m-TCPPD (1). Previously prepared superpara...

Organic molecules have been proposed as promising candidates for electrode protection in acidic electrolytes. The use of tetraphenyl-porphines (H2TPP) as graphite surface-protecting agents in sulphuric acid (H2SO4) is one of the newest. With the aim of unveiling the mechanism of such a protectiv...

A new purification method of magnesium(II) and zinc(II) porphine complexes (MgP and ZnP, respectively) by crystallization of their respective pyridine adducts is described. Pure MgP and ZnP can be regenerated by removal of the coordinated pyridine ligands by heating at 200 °C under vacuum. X-ra...

This paper presents an easy, efficient and reproducible way to obtain cobalt polyporphine films. A fast three step process (less than one hour) based on electrosynthesis of magnesium polyporphine of type I followed by a demetallation in acid medium and then cobalt insertion inside the porphine u...

Reaction energies have been calculated for the hexacarbonyl metal complexes of chromium, molybdenum, and tungsten using six different Density Functional Theory (DFT) methods. Two gas phase reactions have been utilized to benchmark the computed results. The reactions are the heat of formation of ...

The flash-photolysis of chromium hexacarbonyl in cyclohexane yields a transient species (A), whose half-life at room temperature is approximately 6 msec. It is converted into a second transient species (B) which recombines with carbon monoxide yielding chromium hexacarbonyl. It is assumed that (...

Infrared spectrometry was used to characterize the surface adducts formed on interaction of Cr(CO)6 and Mo(CO)6 with partially hydroxylated MgAl2O4 (spinel) prepared in a high-surface-area form. Cr(CO)6 is molecularly adsorbed and gives four characteristic IR absorption bands at 1890 cm-1 (O-bon...

Measurements of the enthalpy of thermal decomposition of chromium hexacarbonyl have been made using a “hot-zone” reaction calorimeter. Independent measurements of the energy of combustion of the hexacarbonyl in oxygen at 298 K by static bomb calorimetry lead to an enthalpy of formation in acco...

Chromium hexacarbonyl [Cr(CO)6] was physisorbed on the Pd(100) surface, and the molecular orientation was determined using reflection-absorption infrared spectroscopy (RAIRS). The thermal decomposition of the compound was observed, by the indirect observation of a modified surface morphology, wh...

We have developed high-pressure photoacoustic calorimetry to determine the volume of reaction for organometallic compounds. This allows the calculation of reaction enthalpies from the photoacoustic data. The photoacoustic signal for chromium hexacarbonyl with acetonitrile in heptane was examined...

Chromium oxide (Cr2O3) thin films have been deposited by plasma enhanced chemical vapor deposition on c-cut sapphire (Al2O3) and oxidized silicon substrates at temperatures between 250 and 400 °C using the precursor chromium hexacarbonyl (Cr(CO)6). The film growth rate ranges between 5 and 14 Å...

Cr(CO)6/Al2O3 samples were prepared in a fluidized bed reactor by vapour phase adsorption of chromium hexacarbonyl under nitrogen flow. The preparation of the samples were followed by diffuse reflectance IR spectroscopy and the chromium content was determined by EDXRF. Deposition and pulse techn...