Implementing novel metal-free and strongly absorbing donor–acceptorsensitizers without carboxylic acid anchoring groups are still a frontier in dye-sensitized solar cells (DSSCs). Herein, the facile synthesis of a strongly absorbingsensitizer combining three 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) anchoringmoieties with a borazine core instead of the classical cyano anchoring groups,such as tetracyanoquinodimethane (TCNQ) and tetracyanoethylene (TCNE), andthe dimethyl-phenyl amino donor group, is disclosed. This results in a 1.6-foldincrease in solar energy conversion efficiency compared to DSSCs with thereference sensitizers (TCBD-dimethyl-amino-phenyl core) and the prior art cyano-sensitizers with TCNE and TCNG anchors. The advantages of the TCBD-borazinedesign are twofold: 1) threefold increase in absorption extinction coefficient aswell as 2) a reduction in back electron transfer and aggregation behavior upon dyeadsorption onto the semiconducting electrode, resulting in 45% and 23%improvement in open-circuit voltage (V oc) and short-circuit current density (J sc ),respectively, compared to those of the prior art. Overall, this work highlights aneasy-to-design of cyano-sensitizer that results in a significant improvement ofsolar energy conversion when using borazine frameworks for the first time.

Since its inception, organic synthesis has played a fundamental role in the development of society, as its efficiency is essential for the preparation of materials in several strategic sectors such as pharmaceuticals, transportation and energy. In this context, organic borazines have emerged as promising molecules useful both as doping units and organic semiconductors, particularly in the production of photovoltaics and organic transistors. However, like most “fine chemical” products, their engineering is generally complex and harmful to the environment due to the need for dangerous reagents, solvents, and harsh reaction conditions. Recent adopted advancements in the manufacturing process, including continuous-flow synthesis and the use of safer, biomass-derived solvents, have been confirmed through a comprehensive cradle-to-gate life cycle assessment (LCA). The study, compared to four batch processes from the literature, identified electricity consumption as the primary contributor to environmental and human health impacts. Additionally, it was demonstrated that adopting a continuous-flow approach, which reduces electricity consumption and leverages safer reaction media such as 2-MeTHF, characterized by an exceptional recovery rate (90%), proved to be an effective strategy, resulting in a notable 11% reduction in emissions. Furthermore, an uncertainty analysis using the Monte Carlo method revealed that energy mixes reliant on fossil fuels increase the impacts across all categories related to human health damage.

This paper discusses hyperconjugative stereoelectronic effects in borazines. A series of alkyl-substituted borazines were synthesized and analysed by NMR spectroscopy and X-ray diffraction. Supported by NBO analyses, the significant decreases in 1JCH coupling constant for the CH groups adjacent to the boron atoms are consistent with the presence of and interactions. These interactions lower the electrophilicity of boron atoms, enhancing moisture stability and establishing these molecules as valuable scaffolds in synthetic chemistry and materials science.

Borazine and its derivatives can be considered critical doping units for engineering hybrid C(sp2)-based molecules with tailored optoelectronic properties. Herein, we report the first synthesis of hexaarylborazines that, bearing ortho-substituted aryl moieties, extend three-dimensionally. Using a one-pot protocol, we first form an electrophilic chloroborazole and then react it with an aryl lithium (ArLi). By selecting the appropriate ortho-substituent, we can guide the ArLi to add to the BN-core in a specific way, ultimately controlling the stereochemical outcome of the three-substitution reaction. Rationalization of the stereochemical model through computational analysis allowed us to show that when aryl lithium nucleophiles bearing rigid long-range ortho-substituents are used, i.e., stiff substituents. The ortho-substituent shields its side of the electrophilic B3N3 core, biasing the incoming ArLi to add anti at each addition step, forming the final tri-aryl borazine exclusively as cc-isomer. Leveraging this stereoselective approach, prototypical multichromophoric borazine derivatives were prepared, and we showcased how the stereochemical arrangement of these chromophores distinctly influences their redox behavior. This methodology paves the way for previously inaccessible borazines to serve as privileged precursors to transcend the conventional bidimensionality associated with graphenoid systems and pioneer the construction of new forms of three-dimensional C(sp2)-based architectures.