A series of neutral pyrithionato (OPTO) organosilicon compounds, R 3 Si(OPTO) [R = Me (1), Ph (2)], cis-R 2 Si(OPTO) 2 [R = Me (3), Et (4), i Pr (5), t Bu (6), mesityl (10), allyl (11), p-tolyl (13); R 2 = (CH 2 ) 3 ( 7), (CH 2 ) 4 ( 8), (CH 2 ) 5 (9), Me, allyl (12)], and cis-R 2 Si(OPTO)Cl [R = Me (14), i Pr (15), allyl ( 16), p-tolyl (17), mesityl (18), Ph (19)], have been prepared and characterized by 1 H, 13 C, and 29 Si NMR spectroscopy. X-ray crystallographic analysis reveals four-coordinate silicon atoms in 1, 2, 6, and 10, five-coordinate in 3, 9, 11, 12, and 14−19, six-coordinate in 7 and 8, and primarily six-coordinate with cocrystallized five-coordinate forms in 13. Collectively, a wide range of chelate strengths of the OPTO ligand is observed in these complexes characterized by the Si−S bond length and S−Si−O bite angle in the solid state, which correlates well with the solutionstate 13 C NMR C�S chemical shift. In TBP five-coordinate silicon complexes, the ambidentate potential of the OPTO ligand and πelectron delocalization (π-ED) that occurs within the ligand generally allows the chelate effect to be enhanced with sulfur occupying an equatorial vs axial position. For 8, 9, and 18, reversible chelation equilibria involving Si ← S bond formation and concurrent π-ED have been characterized by variable-temperature 13 C and 29 Si NMR spectroscopy. Solvents of varying dielectric constants were found to have pronounced effects on the 13 C NMR chemical shifts of 1, 15, and pyrithione.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.