New Hypercoordinating Organostannanes for the Modular Functionalization of Mono‐ and Polystannanes: Synthetic and Computational Studies

• Published in: European journal of inorganic chemistry 2022-03, Vol.2022 (7), p.n/a
• Main Authors: Pau, Jeffrey, Choi, Jung‐Won, Silverthorne, Kaitlyn, Ranne, Mokhamed, Wylie, R. Stephen, Gossage, Robert A., Lough, Alan J., Foucher, Daniel A.
• Format: Article
• Language: English
• Subjects: Chloroform; Crystal structure; DFT NMR calculations; Hypercoordinate; Inorganic chemistry; Macromolecular substitution; NMR; Nuclear magnetic resonance; Nucleophiles; Polystannanes; Single crystals; Stannanes; Tin compounds
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.202100937

A series of potentially hypercoordinate tin compounds derived from a substitutionally labile tosyl stannane (5) was produced to gain access to a library of propyloxybiphenyl (11), propylmethoxy (12, 14, 18, 22) or propylthioester (13, 15, 19, 23) stannanes for structure/property/polymerization investigations. Structural characterizations by single crystal X‐ray diffraction of 12, 14, 18 and 19 were also undertaken. The relative energies of hypercoordinate conformers for the propylmethoxystannanes 12, 14, 18, and 22 were determined with DFT methods and the fractional abundance of conformers in the gas and solution (CHCl3) phase were estimated. Relativistic DFT calculations of 119Sn NMR chemical shifts were carried out for a series of non‐hypercoordinate reference compounds and the conformers, allowing the estimation of Boltzmann‐averaged chemical shifts of the hypercoordinate propylmethoxystannanes. A semi‐crystalline homopolymer (25) was isolated from the dehydropolymerization of 22 using Wilkinson's catalyst. Conversion of the liable tosylated polystannane (24) to a new partially substituted polystannane (28) via nucleophile displacement reactions was achieved. A series of hypercoordinated triphenyl‐, dichlorido‐ and dihydrido‐stannanes were prepared from a single substitutionally liable tosyl containing tin species. Evidence of hypercoordination was confirmed by X‐ray crystallography for these species. Excellent correlation of relativistic DFT 119Sn NMR calculations vs. experimental data for propylmethoxy hypercoordinate tin species was demonstrated. Partial macromolecular substitution of a tosyl‐containing polystannane was also achieved.