SSRG International Journal of Applied Chemistry Volume 10 Issue 2, 1-6, May-Aug 2023 ISSN: 2393 – 9133 / https://doi.org/10.14445/23939133/IJAC-V10I2P101 © 2023 Seventh Sense Research Group® This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Original Article Application of Green Chemistry for the One-pot Preparation of Tris (4-bromophenyl) Chlorosilane Okpara Sergeant Bull 1* , Eyu Okpa 1 1 Department of Chemistry, Rivers State University, Nkpolu-Oroworukwo, Port Harcourt, Nigeria. 1* Corresponding Author : bullistics4real@yahoo.com Received: 25 March 2023 Revised: 01 May 2023 Accepted: 12 May 2023 Published: 26 May 2023 Abstract - Among the twelve principles of green chemistry are the avoidance of waste, the use of benign chemicals, and the incorporation of the starting materials into the final product. To this end, a one-pot facile, more benign, less expensive and higher yield method has been used for the preparation of tris(4-bromophenyl)chlorosilane, which is a highly used precursor for the making of a rigid core carbosilane dendrimers. The reaction pathway for the synthesis of tris(4- bromophenyl)chlorosilane is similar to the procedure followed for synthesising similar compounds in the literature but with differences in starting materials and modifications in the workup processes. The tris(4-bromophenyl)chlorosilane in this work was prepared by the dissolution of 1,4-dibromobenzene in dry ether at -76 °C, followed by the slow addition/stirring of n-BuLi. After 1 h of stirring, tetrachlorosilane was slowly added at temperature range of -70 to -75 °C. The reaction setup was allowed to stir further to room temperature for 24 h. The reaction was stopped, followed by a workup to obtain a colourless powder product with an 82% yield. The colourless powder was characterised by melting point (123.4 °C) and elemental analysis (Anal. Calc for C18H12ClBr3Si: C, 40.67; H, 2.28; found: C, 40.80; H, 2.26; as well as 1 H NMR: δ (CDCl3 400 MHz) 7.44 (d, J = 8.4 Hz, 6H, Ar-H), 7.58 (d, J = 8.4 Hz, 6H, Ar-H); 13 C{ 1 H}, NMR: δ (CDCl3, 101 MHz) 126.46, 130.66, 131.61, 136.53 ppm; 29 Si{ 1 H}, NMR: δ (CDCl3, 79.5 MHz) 1.47 ppm. The results obtained from this one-pot synthetic method are in agreement with that reported in the literature for the multi-step pathway and more expensive starting materials. Keywords - Green chemistry, One-pot, Tris(4-bromophenyl)chlorosilane , n-BuLi, 1,4-dibromobenzene, Tetrachlorosilane. 1. Introduction The traditional ways in which many chemical reactions are conducted are changing, especially as it relates to the overall greenness and sustainability of chemical processes. Chemistry is a dynamic science for which research chemists continue asking questions and experimenting to refine or replace existing methods and theories. This is most glaring for reactions with a wide range of applications constantly revisited, refined or modified to arrive at better methods or more benign products. Bridging ligands are important building units in the construction of Metal-Organic Frameworks (MOFs) 1,2 and Covalent Organic Frameworks (COFs) 3 . Hence, to control the structure of a MOF and or a COF material, the selection of rigid, organic linkers is one of the most crucial decisions. For this reason, most of the organic linkers used in the construction of MOFs and COFs are usually molecules containing aromatic groups that give rigidity to MOF and COF networks. The functional groups in the aromatic organic ligand could be carboxylic acid (Davies et al., 2007, 2010; Guo et al., 2017; Li et al., 1999; Liu et al., 2017; Vlad et al., 2016; Wen et al., 2012) heterocyclic aromatic rings containing N atoms (pyridine) 10–15 or other coordinating functional groups such as phosphonates 16–20 and sulfonate 21,22 . In theory, the structure, as well as the properties of a MOF, can be pre-designed and systematically tuned using a suitable selection of the building blocks. Dipyridyl linkers have also been used in the literature for the synthesis of MOF materials. However, as they are neutral components, another anionic ligand or counterion is required to balance out the positive charge on the metal centres. For example, Bunz and co-workers constructed a series of MOFs using the tetrahedral pyridine linker [tetrakis(4-(pyridin-4-ylethynyl)phenyl)silane]. 23 This series of MOFs was reported to show a variety of topologies, interpentrations as well as porosities. Mandal and co- workers used a carboxylate silicon-based linker, 4,4’- bipyridine as a co-connector and Mn(II) paddle-wheel subunit to construct {[Mn2(O2CC6H4Si(CH3)2C6H4CO2)2(4,4'-bpy)]}n. 24 Mocanu et al. 15 used 1,3,5,7-tetrakis{4-(4- pyridyl)phenyl}adamantane) and copper (II) ions to construct a 3-D MOF [CuL 1 (H2O)2](BF4)2·8H2O. This MOF was reported to show a 4-fold interpenetration with a pts topology. A zinc(II) MOF [Zn2(l 4-o-pda)2(l -abpy)]n based on flexible o-phenylenediacetate and rigid 4,4'- azobis(pyridine) ligands were constructed by Tabak and co- workers 14 . This MOF was reported to be thermally stable up to 300 °C. Most of the carboxylate and N-heterocyclic linkers used for the construction of MOF and COF materials are based on carbon centres as well as commercially available connectors. Silicon-based connecting units are scarce