The Use of Pinner Type Reaction for the Synthesis of New Indeno[2,1‐c]pyridine‐4‐carbonitrile Derivatives

An efficient and convenient route was developed for the synthesis of new pyridinecarbonitrile derivatives by using the Pinner type of reaction. The 2‐((E)‐2‐((dimethylamino)methylene)‐1,2‐dihydro‐5,6‐dimethoxyinden‐3‐ylidene) malononitrile 2 was reacted in the presence of dry HCl gas to yield 3‐chloro‐6,7‐dimethoxy‐9H‐indeno[2,1‐c]pyridine‐4‐carbonitrile ( 3 ) in good yield. The S_NAr reaction on compound 3 with various nucleophiles yielded 3‐substituted pyridinecarbonitriles 4 , 5 , 6 , 7 , 8 , 9 in moderate to good yield.     

Synthesis of Polysubstituted Pyrazolo[3,4‐b]pyridine‐3‐Carbohydrazide and Pyrazolo[3,4‐d]pyridazine Derivatives

5‐Amino‐4‐formyl pyrazole carboxylate gave facile reactions with malononitrile, hydrazine, and ketones in the presence of piperidine furnished substituted pyrazolo[3,4‐b]pyridines and pyrazolo[3,4‐b]quinolones. The pyridazine sulfonamides were obtained by the reaction of 5‐chloro 4‐formyl pyrazole carboxylate with sulfonamide derivatives.     

A computational investigation on the photochemistry of the popular spin-trap agent N-tert-butyl-α-phenylnitrone (PBN) and thermal isomerization pathways of its photoproduct oxaziridine

Computational investigation on the low-lying photo-excited states of N-tert-butyl-α-phenylnitrone (PBN), a well-known spin-trap agent, has revealed its photo-product (oxaziridine) formation channel. The S₀-S₂ vertical excitation in PBN is subsequently followed by a non-radiative decay pathway through S₂/S₁ and S₀/S₁ conical intersections (CIs) with CNO-kinked structures, situated around 23 kcal/mol and 45 kcal/mol below the vertically excited S₂ state, respectively. The reverse photo-process of PBN formation involves photo-excitation of oxaziridine to its S₂ and S₃ photo-excited states. The forward photo-isomerization leads to the trans-oxaziridine with a backside CNO kink (trans-OX_B) while the reverse path studied by us, connects its front-side CNO-kinked analogue (trans-OX_F) with the PBN. Our search for the reverse thermal reaction paths from these two oxazirdines has led to their corresponding transition states, one at 35 kcal/mol and the other at 27 kcal/mol above trans-OX_F and trans-OX_B geometries, respectively. They lead to two different isomers (E and Z) of PBN which supports the reported nature of products from the trans-oxaziridine in this thermal reaction. The inversion path of the chiral nitrogen atom of this N-tert-butyl-oxaziridine (barrier 21 kcal/mol) has also been tracked. This reaction path has been compared with that of the N-methyl (barrier 30 kcal/mol) and N-acyl (barrier 10.5 kcal/mol) oxaziridine analogues.     

Limiting Ionic Partial Molar Volumes of Cs+, Na+, (C4H9)4N+, Cl−, Br−, I−, BPh4 − in Aqueous Acetone at 298.15 K

Densities of CsX (X = Cl^–, Br^–, I^–), NaBr, (C₄H₉)₄NBr, and NaBPh₄ in (0, 20, 40, 60 and 80) mass % acetone + water have been measured over the entire composition range at 298.15 K. The apparent and limiting partial molar volumes of the electrolytes and ions in their mixtures have been evaluated from these densities.     

可见光下具有高光子效应和光催化活性的CuS-石墨烯氧化物/TiO2复合材料的制备（英文）

CuS-graphene oxide/TiO2 composites were prepared using a sol-gel method to improve the photocatalytic performance of the photocatalyst. The composites were characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, and transmission electron microscopy. The photocatalytic activities were examined by the degradation of methylene blue (MB) under visible-light irradiation. The photodegradation of MB under visible-light irradiation reached 90.1% after 120 min. The kinetics of MB degradation was plotted alongside the values calculated from the Langmuir-Hinshelwood equation. The CuS-graphene oxide/TiO2 sample prepared using 0.2 mol of TiO2 showed the best photocatalytic activity. This was attributed to a cooperative reaction as a result of increased photoabsorption by graphene oxide and an increased photocatalytic effect by CuS.     

Synthesis of nicotinonitrile derivatives and study of their photophysical properties

Abstract  

A convenient route was developed for the synthesis of novel nicotinonitrile derivatives by a three-component Dimroth reaction of chalcones, malononitrile, and secondary heterocyclic amines or sodium alcoholate. Nicotinonitrile derivatives are obtained in fair to good yields. The structures of all new compounds were established by spectroscopic characteristics and their photophysical properties were studied.