Characterization of the terminal iron(IV) imides [[PhBP(t)(Bu)2(pz')]Fe(IV)NAd]+

New hybrid bis(phosphine)(pyrazole)borate tripodal ligands ([PhBPtBu2(pz')]-) are reported that support pseudotetrahedral iron in the oxidation states +1, +2, +3, and +4. The higher oxidation states are stabilized by a terminal FeNR linkage. Of particular interest is the generation and thorough characterization of an S = 1 FeIVNR+ imide cation using this new ligand system. The latter species can be observed electrochemically and spectroscopically, and its solid-state crystal structure is reported.     

Analysis of thermal,oxidative and cold flow properties of methyl and ethyl esters prepared from soybean and mustard oils

Oilseed crop with high oil content and promising ecological adaptability are potential sources for competitive biodiesel production. This study investigates the scope of utilizing biodiesel development through the methyl and ethyl ester from soybean and mustard oil as an alternative fuel. Methyl and ethyl esters of oils having different fatty acids compositions such as soybean (SOME and SOEE) and mustard oil (MUME and MUEE) were prepared by transesterification with methanol and ethanol in the presence of an alkali-KOH catalyst. The gas chromatographic (GC) analysis of oil samples revealed that primary fatty acid composition in soybean oil was linoleic acid (C_18:2, 51.93%), followed by oleic acid (C_18:1, 22.82%), palmitic acid (C_16:0, 11.56%), linolenic acid (C_18:3, 5.95%) and stearic acid (C_18:0, 4.32%). Whereas, the main components in mustard oil were erucic acid (C_22:1, 32.81%), oleic acid (C_18:1, 24.98%), eicosenoic acid (C_20:1, 10.44%), linolenic acid (C_18:3, 8.61%) and palmitic acid (C_16:0, 2.80%). The physicochemical properties (acid value, iodine value, calorific value, flash point, pour point etc.) of methyl and ethyl ester samples were estimated and found to be within the acceptable range of ASTM D6751 standards specifications. The prepared esters and oil samples were examined for cold flow properties by differential scanning calorimetry (DSC). Results revealed better cold flow properties for MUME (−2.55 °C) and MUEE (−3.10 °C) than SOME (3.21 °C) and SOEE (1.83 °C) due to more unsaturated fatty acid content in MU. Thermal and oxidative stability of samples was determined by thermogravimetric analysis (TG) and differential thermal analysis (DTA). The thermal and oxidative stability ranking of the samples was in the order of oil > methyl esters > ethyl esters.

     

Reaction of β‐Lapachone with 1,2‐Diamines: Facile Synthesis of Novel Tetracyclic Pyrazines

The reactions of β‐lapachone (1) with 1,2‐diaminoethane (2) and 1,2‐diaminopropane (4) gave the tetracyclic pyrazine derivatives (3) and mixtures of (5) and (6), respectively, while reaction with o‐phenylene diamine (7) gave the quinoxaline derivative (8). The structure of pyrazine derivative (3) is confirmed by single‐crystal X‐ray diffraction study.     

CuPy2Cl2: A Novel and Efficient Catalyst for Synthesis of Propargylamines Under the Conventional Method and Microwave Irradiation

CuPy₂Cl₂ is an efficient catalyst for the preparation of propargylamines via three-component coupling reaction of aromatic aldehydes, amines, and aromatic alkynes stirred at 95 °C without using any solvent to afford the corresponding products in good yields. The reaction mixture was irradiated at 450 W in a microwave oven to furnish the expected products in excellent yields.     

Application of Fundamental Organometallic Chemistry to the Development of a Gold‐Catalyzed Synthesis of Sulfinate Derivatives

The development of a gold(I)‐catalyzed sulfination of aryl boronic acids is described. This transformation proceeds through an unprecedented mechanism which exploits the reactivity of gold(I)–heteroatom bonds to form sulfinate anions. Further in situ elaboration of the sulfinate intermediates leads to the corresponding sulfones and sulfonamides, two pharmacophores routinely encountered in drug discovery.     

Expeditious Synthesis of Thiadiazolo Benzodiazepines Under Conventional Method and Microwave Irradiation

This article explores the use of sulfamic acid as an efficient catalyst for the one-pot synthesis of thiadiazolo 1, 5 benzodiazepines by using benzo[c][1,2,5]thiadiazole-4,5-diamine and various types of ketones in the presence of chloroform as a solvent under conventional methods and microwave irradiation. Our method is more advantageous than current methods. The catalyst (sulfamic acid) is cost effective, readily available and gives excellent yields with high purity. In comparison, the microwave irradiation method is equally as effective with a shorter reaction time and still maintaining high yields.     

Identification of liquid crystalline phases in 7O.O9 compound based on structural similarity index measure

Textural analysis is done in the case of the thermotropic liquid crystal (LC), 4-heptyloxybenzylidene-4′-nonyloxyaniline, 7O.O9, using a polarising microscope attached with a hot stage with a high-resolution camera. Natural images are highly structured: their pixels exhibit strong dependencies and carry important information about the structure of the objects. In this article, we consider the structural similarity index measure parameter computed as a function of the temperature. The results exhibit abrupt changes with temperature showing different liquid crystalline phases. This statistical image analysis is compared with the differential scanning calorimeter data and good agreement was found. The proposed methodology is very sensitive and reliable technique to identify the LC phases.     

Splitting and storing excitons in strained coupled self-assembled quantum dots

We present a novel self-assembled quantum dot structure designed to spatially separate and store photo-generated electrons and holes in pairs of strain coupled quantum dots. The spatial separation of electron–hole pairs into quantum dots and strain-induced quantum dots has been investigated and verified by photoluminescence experiments. Results from time-resolved PL demonstrates that at low temperatures (3 K) the electron–hole pair can be stored for several seconds.