2026-04-29T06:18:33Z https://www.eurjchem.com/index.php/eurjchem/oai

oai:ojs.www.eurjchem.com:article/2608 2025-03-31T05:36:21Z eurjchem:ART driver

Synthesis of an eight-membered 2,2,4,6,6,8-hexaphenyl-1,3,5,7,2,6,4,8-tetraoxadisiladiborocane and its reaction with 4,4-azo-pyridine leading to ring contraction to give a dimer and hydrogen bonded macrocyclic siloxane-azo-pyridine Bull, Okpara Sergeant Don-Lawson, Chioma Ahuchaogu, Ahamefula Anslem 4,4-Azo-pyridine Diphenylsilanediol Phenylboronic acid Cyclodiborasiloxane B-N dative-bonded-dimer Macrocyclic siloxane-azo-pyridine We hereby report the syntheses and characterization of a new dimer of azopyridine connected through the six-membered B-N dative-bonded-adduct Ph8B4Si2O6·L (4) and a hydrogen-bond-induced macrocyclic product 4(Ph2Si(OH)2)·3(C10H8N4) (5). The products were obtained after an eight-membered 2,2,4,6,6,8-hexaphenyl-1,3,5,7,2,6,4,8-tetraoxa disiladiborocane (Ph6B2Si2O4) (3), which is abundant in the literature, was successfully synthesized and characterized by standard analytical and spectroscopic methods such as single-crystal XRD, melting point, nuclear magnetic resonance and Fourier transform infrared spectroscopy. Subsequently, compound 3 and 4,4-azopyridine (L) were reacted in a mixture of diethyl ether and petroleum ether solvents at reflux. This reaction caused a contraction of the eight-membered compound 3 to give two products - a dimer compound 4 (Ph8B4Si2O6·L), and a macrocyclic product 4(Ph2Si(OH)2)·3(C10H8N4) (5). These two products have been characterized by single-crystal XRD, nuclear magnetic resonance, Fourier transform infrared spectroscopy, and melting point. Single crystal X-ray diffraction studies reveal that the dimer compound 4 compound crystalized in the monoclinic crystal system with a centrosymmetric space group of P21/c, a = 11.0879(4) Å, b = 14.3707(4) Å, c = 16.2697(5) Å, β = 98.759(3)°, V = 2562.20(13) Å3, Z = 2. On the other hand, the macrocyclic product 4(Ph2Si(OH)2)·3(C10H8N4) (5) is orange blocky needles that crystallized in the triclinic crystal system with a centrosymmetric space group of P-1, a = 12.2352(3) Å, b = 15.3274(6) Å, c = 20.0271(6) Å, α = 89.879(3)°, β = 89.988(2)° γ = 78.298(3)°, V = 3677.7(2) Å3, Z = 2. Furthermore, compounds 4 and 5 exhibit various noncovalent interactions in crystal packing, such as intermolecular and intramolecular π-π as well as hydrogen bonding. This study demonstrates the potential for making novel materials via the combination of cyclodiboradisiloxane (a Lewis acid) and nitrogen-containing ligand (a Lewis base). Atlanta Publishing House LLC 2025-03-31 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion application/pdf text/plain text/plain https://www.eurjchem.com/index.php/eurjchem/article/view/2608 10.5155/eurjchem.16.1.37-45.2608 European Journal of Chemistry; Vol. 16 No. 1 (2025): March 2025; 37-45 2153-2257 2153-2249 eng https://www.eurjchem.com/index.php/eurjchem/article/view/2608/2898 https://www.eurjchem.com/index.php/eurjchem/article/view/2608/2883 https://www.eurjchem.com/index.php/eurjchem/article/view/2608/2884 Copyright (c) 2025 Okpara Sergeant Bull, Chioma Don-Lawson, Ahamefula Anslem Ahuchaogu https://creativecommons.org/licenses/by-nc/4.0