Planar bismuth triamides: a tunable platform for main group Lewis acidity and polymerization catalysis.

Autor:	Hannah TJ; Chemistry Department, Dalhousie University 6274 Coburg Rd Halifax NS B3H 4R2 Canada saurabh.chitnis@dal.ca., McCarvell WM; Chemistry Department, Dalhousie University 6274 Coburg Rd Halifax NS B3H 4R2 Canada saurabh.chitnis@dal.ca., Kirsch T; Chemistry Department, Dalhousie University 6274 Coburg Rd Halifax NS B3H 4R2 Canada saurabh.chitnis@dal.ca., Bedard J; Chemistry Department, Dalhousie University 6274 Coburg Rd Halifax NS B3H 4R2 Canada saurabh.chitnis@dal.ca., Hynes T; Chemistry Department, Dalhousie University 6274 Coburg Rd Halifax NS B3H 4R2 Canada saurabh.chitnis@dal.ca., Mayho J; Chemistry Department, Dalhousie University 6274 Coburg Rd Halifax NS B3H 4R2 Canada saurabh.chitnis@dal.ca., Bamford KL; Chemistry Department, Dalhousie University 6274 Coburg Rd Halifax NS B3H 4R2 Canada saurabh.chitnis@dal.ca., Vos CW; Department of Chemistry, Memorial University of Newfoundland St. John's NL A1B 3X7 Canada., Kozak CM; Department of Chemistry, Memorial University of Newfoundland St. John's NL A1B 3X7 Canada., George T; Department of Chemistry, Saint Mary's University 923 Robie St. Halifax NS B3H 3C3 Canada., Masuda JD; Department of Chemistry, Saint Mary's University 923 Robie St. Halifax NS B3H 3C3 Canada., Chitnis SS; Chemistry Department, Dalhousie University 6274 Coburg Rd Halifax NS B3H 4R2 Canada saurabh.chitnis@dal.ca.
Jazyk:	angličtina
Zdroj:	Chemical science [Chem Sci] 2023 Apr 06; Vol. 14 (17), pp. 4549-4563. Date of Electronic Publication: 2023 Apr 06 (Print Publication: 2023).
DOI:	10.1039/d3sc00917c
Abstrakt:	Geometric deformation in main group compounds can be used to elicit unique properties including strong Lewis acidity. Here we report on a family of planar bismuth(iii) complexes ( cf. typically pyramidal structure for such compounds), which show a geometric Lewis acidity that can be further tuned by varying the steric and electronic features of the triamide ligand employed. The structural dynamism of the planar bismuth complexes was probed in both the solid and solution phase, revealing at least three distinct modes of intermolecular association. A modified Gutmann-Beckett method was used to assess their electrophilicity by employing trimethylphosphine sulfide in addition to triethylphosphine oxide as probes, providing insights into the preference for binding hard or soft substrates. Experimental binding studies were complemented by a computational assessment of the affinities and dissection of the latter into their intrinsic bond strength and deformation energy components. The results show comparable Lewis acidity to triarylboranes, with the added ability to bind two bases simultaneously, and reduced discrimination against soft substrates. We also study the catalytic efficacy of these complexes in the ring opening polymerization of cyclic esters ε-caprolactone and rac -lactide. The polymers obtained show excellent dispersity values and high molecular weights with low catalyst loadings used. The complexes retain their performance under industrially relevant conditions, suggesting they may be useful as less toxic alternatives to tin catalysts in the production of medical grade materials. Collectively, these results establish planar bismuth complexes as not only a novel neutral platform for main group Lewis acidity, but also a potentially valuable one for catalysis. Competing Interests: There are no conflicts to declare. (This journal is © The Royal Society of Chemistry.)
Databáze:	MEDLINE
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