Chennai Apr 11, 2018, (Research Matters):
A team of scientists from Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research-National Chemical Laboratory (CSIR-NCL) and Indian Institute of Science, Education and Research Kolkata (IISER Kolkata) have studied the formation of 2 Dimensional Covalent Organic Frameworks (COF)- organic solids bound together by covalent bonding, to understand the science behind the underlying structure.
COFs are porous and crystalline solid structures made of light, organic solids like Hydrogen, Boron, Nitrogen and Oxygen. Due to their lightweight nature, COFs are employed in engineering lightweight materials and their porous nature makes them useful in applications like gas storage. With wide ranging applications, economical and bulk synthesis of COFs is a challenge for material science. Several process like solvothermal synthesis have given rise to several variations of COFs, enriching the COF library. However, to manufacture on a large scale, scientist have to first, understand the processes that lead to the formation of such a structure.
According to the authors “the fundamental understanding of the integral processes of 2D COF assembly, including their growth from nucleating sites and the origin of periodicity, is an intriguing chemical question that needs to be answered”
To answer this question, the scientists, in their study, came up with a “green and easy to perform” approach of COF formation using an acid-diamine (organic compound with two amino groups) mixture. Using the new approach, the scientist were able to explore the role of hydrogen bonding in improving the crystallinity and porosity of the COFs that were formed. They did this by studying the average distance of the Hydrogen atom in the amines to the Oxygen atom in the acid. Thorough crystallographic analyses of the salt molecules provided accurate measurement of the role of hydrogen bonding.
Further, the scientists used their knowledge of hydrogen bonding distance in the acid-diamine salts and the relationship between product quality and reactant-structure to synthesize highly porous and crystalline COF, which, according to the authors “are unattainable by other synthetic means”.