Mini-Reviews in Organic Chemistry - Volume 16, Issue 3, 2019

Electron deficient compounds are extensively studied in the field of molecular materials. Compared to the simplest electron acceptors, multi-cyano heterocyclics performed excellent properties in electron-withdrawing ability, thermal stability, etc. This review provides a survey of the synthesis and modifications of two kinds of multi-cyano heterocyclics and their applications.

Benzodithiophene based conjugated small molecules (SMBDTs) are usually used in organic photovoltaic (OPV), Organic Filed Effection Transistor (OFET), Organic Phototransistor (OPT) and Non-Linear Optical (NLO) chromophores. Band-gap engineering is one of the key design principles for π-conjugated materials and this can be done by altering the structures of SMBDTs with sidechain and backbone reactions. In this way, scientists develop several kinds of SMBDTs with different electron donors and acceptors. The alkoxyl and aromatic substituted BDT units are mostly used as the donors, while the alkyl cyanoacetate, dicyano, rhodamine, indenedione, thieno[3,4-c]pyrrole-4,6(5H)-dione, benzothiadiazole and diketopyrrolopyrrole groups are used as the acceptors. The electronic characters of SMBDTs including the HOMO and LUMO energy level are listed and discussed. The synthesis methods of SMBDTs are mostly in common, especially with the backbone reaction. There are about four coupling methods for the backbone reaction, mostly used is the Stille coupling methods. In this review paper, the common synthesis methods and the electronic characters by several samples are summarized to provide researchers an overview of SMBDTs’ synthesis, structures and applications.

Conversion efficiency between electrical and optical signals is very important for the development of modern information technologies. Due to their advantages in half-wave voltage, bandwidth, cost and integration, as well as organic electro-optic (EO) parameters, these materials are widely studied and used in microwave photonic devices. Second order nonlinear optical (NLO) chromophores, as the core of organic EO materials have an increasing interest in this branch. Auxiliary donors present a new direction for the design and improvement of organic NLO chromophores. In this short review, the advantages, theoretical calculations and experimental results of auxiliary donors are reviewed and discussed in detail.

In this review, small-molecule donors for application in organic solar cells reported in the last three years are highlighted. Especially, the effect of donor molecular structure on power conversion efficiency of organic solar cells is reported in detail. Furthermore, the mechanism is proposed and discussed for explaining the relationship between structure and power conversion efficiency. These results and discussions draw some rules for rational donor molecular design, which is very important for further improving the power conversion efficiency of organic solar cells based on the small-molecule donor.

One dimensional (1-D) micro-/nanostructures provide a good system to investigate the dependence of various properties on dimensionality and size reduction, especially in optoelectronic field. Organic conjugates including small molecules and polymers exhibit good optoelectronic properties and are apt to assemble into ordered nanostructures with well-defined shapes, tunable sizes and defect-free structures. In this review, we focus on recent progress of 1-D organic semiconductors for waveguide applications. Fabrication methods and materials of 1-D organic semiconductors are introduced. The morphology influence on the properties is also summarized.

Organic conjugated materials have shown attractive applications due to their good optoelectronic properties, which enable them solution processing techniques in organic optoelectronic devices. Many conjugated materials have been investigated in polymer solar cells and organic field-effect transistors. Among those conjugated materials, Benzo[1,2-b:4,5-b′]dithiophene (BDT) is one of the most employed fused-ring building groups for the synthesis of conjugated materials. The symmetric and planar conjugated structure, tight and regular stacking of BDT can be expected to exhibit the excellent carrier transfer for optoelectronics. In this review, we summarize the recent progress of BDT-based conjugated polymers in optoelectronic devices. BDT-based conjugated materials are classified into onedimensional (1D) and two-dimensional (2D) BDT-based conjugated polymers. Firstly, we introduce the fundamental information of BDT-based conjugated materials and their application in optoelectronic devices. Secondly, the design and synthesis of alkyl, alkoxy and aryl-substituted BDT-based conjugated polymers are discussed, which enables the construction of one-dimensional and two-dimensional BDTbased conjugated system. In the third part, the structure modification, energy level tuning and morphology control and their influences on optoelectronic properties are discussed in detail to reveal the structure- property relationship. Overall, we hope this review can be a good reference for the molecular design of BDT-based semiconductor materials in optoelectronic devices.

In recent years, the production, processing and exportation of maqui and murta Chilean berries have increased due to their high Total Polyphenols Content (TPC) and high Antioxidant Capacity (AC). However, the leaves of these berries are agroindustrial discards that present even higher TPC and AC values. Extracts of leaves and berries of maqui and murta with water, methanol and ethanol as solvents showed significant bioactivity, like inhibition of alpha-glucosidase (an enzyme involved in the metabolism of carbohydrates), as well as anti-inflammatory and antidiabetic effects. They are also excellent sources of polyphenols such as oligomers and polymers of delphinidin, pelargonidin, resveratrol, among others that have shown health-promoting bioactivity and good bioavailability. Purified extracts may be useful as supplements for foods and cosmetics, and even as pharmaceutical products. However, it is necessary to control the variability of their TPC, AC and polyphenols profiles caused by genotype, environment, processing, storage and stage of harvesting.

Microalgae are a viable alternative for biofuel production to replace the world dependency on fossil fuel. It has a wide range of application for the sustainable production of biomaterials. Microalgae can convert solar energy into important natural components by utilizing marginal nutrients, wastewater and exhaust CO2 without sharing expensive crop field. Microalgae also have the potentiality to generate several promising components such as Polyunsaturated Fatty Acids (PUFAs), organic pigments and pharmaceutically important hydrocarbons. Cultivation and production of microalgae biomass have multifaceted challenges due to the requirement of large volume of water for the algae growth, high processing cost and contamination by pathogens. Genetic improvement and modifications are essential to construct superior microalgae for manufacturing industries using various methods such as selection of novel strain, stress tolerance, resistance to pathogens, product development and metabolic pathways and cellular contents. In addition, technologies related to cultivation, harvesting, extraction and processing are essential to develop for the growth of novel microalgae strains.

Tuberculosis (TB) is a global health disaster and is a wide-reaching hitch. The improper use of antibiotics in chemotherapy of TB patients led to the current problem of tuberculosis therapy which gives rise to Multi-Drug Resistant (MDR) strains. Nitrogen heterocycles including azole compounds are an important class of therapeutic agent with electron-rich property. Azole-based derivatives easily bind with the enzymes and receptors in organisms through noncovalent interactions, thereby possessing various applications in medicinal chemistry. Research on azoles derivatives have been expansively carried out and have become one of the extremely active area in recent years and the progress is quite rapid. A genuine attempt to review chemistry of azoles and to describe various azole-based compounds synthesized in the last two decades having promising antitubercular potential is described in the present article. It is hopeful that azole compounds may continue to serve as an important direction for the exploitation of azole-based antitubercular drugs with better curative effect, lower toxicity, less side effects, especially fewer resistances and so on.