Effects Of Chloro Substitution Research Articles

Thin films of poly(oxyethylene)-substituted phthalocyaninato zinc(II) and oxotitanium(IV) complexes: synthesis, structure and sensor response to ammonia

In this work, the effect of chloro-substitution in poly(oxyethylene)-substituted phthalocyaninato zinc(II) and oxotitanium(IV) complexes on the ordering and sensor response of their thin films to ammonia was studied. Thin films of thia-bridged tetrapoly(oxyethylene)- and tetrachlorotetrapoly(oxyethylene)-substituted zinc and titanyl Pcs forming mesophases in wide temperature range were spun onto glass slides with interdigitated electrodes to test their chemiresistive sensor response to ammonia in the concentration range from 1 to 50 ppm. It was shown by the methods of UV–Vis, polarized Raman spectroscopy and polarized optical microscopy that these phthalocyanines formed thin films with different orientation and ordering in dependence on their molecular structure. The introduction of chloride substituents into the phthalocyanine ring was found to lead to the increase of the chemiresistive sensor response of both zinc and oxotitanium phthalocyanine films toward low concentrations of ammonia in air.

Chlorosubstituted Copper Phthalocyanines: Spectral Study and Structure of Thin Films.

In this work, the tetra-, octa- and hexadecachloro-substituted copper phthalocyanines CuPcClx (where x can equal 4, 8 or 16) were investigated by the methods of vibrational (IR and Raman) spectroscopy and X-ray diffraction. The assignment of the most intense bands, both in IR and Raman spectra, was carried out on the basis of DFT calculations. The structure of a CuPcCl4 single crystal grown by sublimation in vacuum was refined for the first time. The effect of chloro-substitution on the structure of CuPcClx thin films deposited in a vacuum onto a glass substrate at 50 and 200 °C was studied. It was shown that CuPcCl4 formed polycrystalline films with the preferential orientation of the (100) crystallographic plane of crystallites parallel to the substrate surface when deposited on a substrate at 50 °C. Introduction of more Cl-substituents into the phthalocyanine macrocycle leads to the formation of amorphous films on the substrates at 50 °C. At the elevated substrate temperature, the growth of polycrystalline disordered films was observed for all three copper phthalocyanines.

Barriers to Rotation in ortho-Substituted Tertiary Aromatic Amides: Effect of Chloro-Substitution on Resonance and Distortion.

Planarity of the amide bond represents one of the most widely recognized properties of amides. Herein, we report a combined structural and computational study on the effect of ortho-substitution on resonance and barriers to rotation in tertiary aromatic amides. We demonstrate that ortho-chloro substitution in a class of benzamides that are important from the reactivity and medicinal chemistry perspective results in increased barriers to rotation around both the N-C(O) and C-C(O) axes. The effect of steric hindrance on structures, resonance energies, barriers to rotation, and proton affinities is discussed. The present study strongly supports the use of ortho-substitution in common benzamides to strengthen amidic resonance.

Laser photoisomerization of methyl α-arylcinnamates; effect of chloro substitution

An investigation of the 308 nm laser photochemistry of methyl α-phenylcinnamate ( 1a) and a series of p-chloro-substituted derivatives is reported. Dilute solutions of ( E)- 1a or ( Z)- 1a undergo photoisomerization, but also form ring closure products analogous to those observed during the photolysis of cis-stilbene. The photostationary state (PSS) compositions ( E/Z) were determined by analytical high performance liquid chromatography (HPLC). The PSS values are not dependent on the laser power or the presence of oxygen. However, they are unusually rich in the E isomer compared with the PSS of alkyl cinnamates (over 70% E compared with about 50% E for alkyl cinnamates). p-Chloro substitution on the α ring causes a small increase in the E content of the PSS, whereas p-chloro substitution on the β ring leads to a dramatic reduction in the E content of the PSS (28% E). Possible explanations for these results are discussed.

ChemInform Abstract: The Effects of Chloro Substitution on the Electronic Structure of ClCr+, ClMn+, and ClFe+ and Their Reactivity with Small Alkanes.

AbstractThe exothermic reactions of ClCr+, ClMn+ and ClFe+ with small alkanes (propane, butane, 2‐methylpropane, 2,2‐dimethylpropane) in the gas phase are investigated in the ion trap of a mass spectrometer.