: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Bromination is one of the most important transformations in organic synthesis and can be carried out using bromine and many other bromo compounds. Use of molecular bromine in organic synthesis is well-known. However, due to the hazardous nature of bromine, enormous growth has been witnessed in the past several decades for the development of solid bromine carriers. This review outlines the use of bromine and different bromo-organic compounds in organic synthesis. The applications of bromine, a total of 107 bromo-organic compounds, 11 other brominating agents, and a few natural bromine sources were incorporated. The scope of these reagents for various organic transformations such as bromination, cohalogenation, oxidation, cyclization, ring-opening reactions, substitution, rearrangement, hydrolysis, catalysis, etc. has been described briefly to highlight important aspects of the bromo-organic compounds in organic synthesis.

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

The main synthetic approaches for the preparation of porphyrazines are outlined. In addition, some structural and spectroscopic properties, especially the UV-vis absorption profiles emanating from their peripheral functionalization, the modification of the tetraazaporphyrin skeleton or the arrangement of macrocycles in a supramolecular manner, are discussed. Cyclotetramerization of appropriate dinitrile derivatives or modification of peripheral substituents on porphyrazines constitute the main synthetic routes. Moreover, the use of special templates, as well as different intermediates or nonpyrrolic precursors, are tools for the attainment of azaporphyrin analogues of distinct nature and unusual characteristics.

The chemistry of porphyrazines: an overview

Mechanisms of Inorganic Reactions. A Study of Metal Complexes in Solution.

Magnesium(II), zinc(II), and metal-free phthalocyanines (Pcs) and azaphthalocyanines (AzaPcs) containing alkylsulfanyl, aryloxy, and dialkylamino peripheral substituents have been synthesized. The complexation of magnesium(II) by metal-free Pcs and AzaPcs has been studied in detail to determine the optimal reaction conditions necessary to ensure a complete conversion. Photophysical and photochemical measurements in tetrahydrofuran showed that magnesium(II) AzaPcs with aryloxy and alkylsulfanyl substituents have excellent fluorescent properties (Φ(F) up to 0.73) and that the corresponding zinc(II) Pcs are efficient singlet oxygen producers (Φ(Δ) up to 0.68). The presence of dialkylamino substituents causes intramolecular charge transfer within the molecule that competes with fluorescence and singlet oxygen formation. Alkylsulfanyl MgAzaPc and ZnAzaPc were the most photostable compounds among the series of studied derivatives. In addition, high molar absorption coefficients (e ∼ 300,000 M(-1) cm(-1)), absorption (λ(max) ∼ 650 nm), and emission (λ(em) ∼ 660 nm, high Φ(F)) in the red region suggest that these molecules are potential fluorescent probes that are superior to the commercial red cyanine dye Cy5. MgAzaPc, when incorporated into lipidic bilayers of liposomes, maintains excellent fluorescence properties (Φ(F) = 0.64). Water-soluble MgAzaPc with quaternary ammonium peripheral substituents retained a high fluorescence quantum yield even in water (Φ(F) = 0.25). The described properties show that magnesium(II) AzaPcs are excellent red-emitting fluorophores with potential applications as fluorescent probes in sensing or in vitro imaging applications.

Magnesium azaphthalocyanines: an emerging family of excellent red-emitting fluorophores.

Effect of halogenation of ortho-positions of tetraphenylporphyrin and its Cd(II) complex on their complexing ability towards d-metal salts in dimethylformamide

Complexation of Halogen-Substituted Tetraphenylporphyrins and Cadmium(II) Tetraphenylporphyrins with MnCl2 in DMF

Study of the Metal Exchange Reaction of Cadmium(II) 5,15-Dinitro-2,3,7,8,12,13,17,18-octaethylporphyrinate with d-Metal Salts in Organic Solvents

2,3,7,8,12,13,17,18-Ocatbromo-5,10,15,20-tetra-(4-chloroprienyl)porphyrin and 2,3,7,8,12,13,17,18-octachloro-5,10,15,20-tetra-(4-bromophenyl)porphyrin have been synthesized. The obtained compounds have been identified by electronic absorption and 1H NMR spectroscopy as well as mass spectrometry. The complex-forming properties of the synthesized porphyrins in the zinc acetate (II)-acetonitrile system at 278–298 K have been studied. Kinetic parameters of the formation of the corresponding zinc complexes in acetonitrile have been determined.

Synthesis, Spectral, and Coordination Properties of Halogen-Substituted Tetraarylporphyrins

Complexation reactions of 5,10,15,20-tetraphenyltetrabenzoporphyrin and transmetallation of its cadmium complex with nickel(II) acetate, Ni(II), Pd(II), and Pt(II) chlorides in dimethylformamide and phenol have been studied. The corresponding Ni(II), Pd(II), and Pt(II) porphyrinates have been synthesized. PtIVBr2 porphyrinate has been obtained by the treatment of Pt(II) 5,10,15,20-tetraphenyltetrabenzoporphyrinate with bromine in chloroform. The obtained compounds have been characterized by elemental analysis, electronic absorption and 1H NMR spectroscopy and mass spectrometry.

Natalya V. Chizhova

Papers

Effect of halogenation of ortho-positions of tetraphenylporphyrin and its Cd(II) complex on their complexing ability towards d-metal salts in dimethylformamide

Complexation of Halogen-Substituted Tetraphenylporphyrins and Cadmium(II) Tetraphenylporphyrins with MnCl2 in DMF

Study of the Metal Exchange Reaction of Cadmium(II) 5,15-Dinitro-2,3,7,8,12,13,17,18-octaethylporphyrinate with d-Metal Salts in Organic Solvents

Synthesis, Spectral, and Coordination Properties of Halogen-Substituted Tetraarylporphyrins

Synthesis and Spectral Properties of Ni(II), Pd(II), Pt(II), and Pt(IV) Tetraphenyltetrabenzoporphyrinates