Synthesis and Characterization of Tris(catecholato)Silicates, [(C6H4O2)3Si]2− with Different Counter Cations – First Pyrolysis Study and X-ray Structure of [{(CH3)2CH}2NH2]2[(C6H4O2)3Si] · 2CH3CN · H2O

TLDR: The synthesis of hypervalent tris(catecholato)silicate ion, [(C6H4O2)3Si]2- with six different counter cations has been achieved by the reaction of catechol and tetraethoxysilane in presence of the corresponding amine as mentioned in this paper.

Abstract: The synthesis of hypervalent tris(catecholato)silicate ion, [(C6H4O2)3Si]2- with six different counter cations: (i) diethylammonium (I), (ii) triethylammonium (II), (iii) diisopropylammonium (III), (iv) morpholinium (IV), (v) piperazinium (V) and (vi) N-methylpiperazinium (VI) has been achieved (yield: ca95%) by the reaction of catechol and tetraethoxysilane in presence of the corresponding amine Single crystal X-ray structure of compound (III) has been determined It crystallizes in orthorhombic system [space group P212121; a = 11735(2), b = 13708(3), c = 23283(5) A; α = 90°, β = 90°, γ = 90°; Volume = 37454(11) A3; Density = 1165 gcm−3; Z = 4; R = 00585; wR2(I) = 01610 and 3677 reflections] and the structure shows slightly distorted octahedral geometry around silicon Results of TG, DT and EG analysis of compounds (I)–(VI) reveal the influence of the counter cation on thermal stability Bench scale pyrolysis of (I) and (II) convert them to [(C6H4O2)2Si] n by the quantitative expulsion of ammoni