Photochemistry of Trimethyltin Iodide in Polar Media:  Orbital Parentage and Observed Reactivity

Abstract

(CH(3))(3)SnI exists as individual tetrahedral molecules in hexane but reacts with the silanol moieties present on the surface of porous glass and with the hydroxyl group of ethanol and hexanol to form five-coordinate adducts. With the exception of slight shifts to higher energy, formation of the adduct has little effect on the electronic spectrum of the complex, and the wavelength and O(2) dependencies of the quantum yield of (CH(3))(3)SnI disappearance indicate that the photochemistry of the complex initiates from the ligand-to-metal charge-transfer (LMCT) state populated on absorption in each medium. Nevertheless, 254 nm excitation in hexane leads to I(2) and ((CH(3))(3)Sn)(2), whereas excitation of the five-coordinate adduct on the glass surface leads to I(2), I(3)(-), ((CH(3))(3)Sn)(2), and (CH(3))(3)Sn-OSi[triple bond](OSi[triple bond]represents a surface siloxyl), while in ethanol, I(3)(-) is the only detectable product. Regardless of the medium, the ground state is polarized and population of the LMCT state creates a more uniform charge distribution from which homolytic cleavage of the (CH(3))(3)Sn-I bond is the dominant reaction pathway in each medium. In hexane, the (CH(3))(3)Sn(*) and I(*) radicals couple to form ((CH(3))(3)Sn)(2) and I(2), whereas adsorbed onto the glass, a fraction of the radical pairs thermalize via electron transfer to form I(3)(-) and a surface-bound (CH(3))(3)Sn-OSi[triple bond] species. In ethanol, excitation of the solvent adduct (CH(3))(3)Sn-OHC(2)H(5) leads to homolytic cleavage and I(2) formation, which reacts thermally with (CH(3))(3)Sn-OHC(2)H(5) to form an [(CH(3))(3)Sn(+), I(3)(-)] ion pair.

Synthesis of Crown Ether End-Capped PM6 Copolymers with Tunable Molecular Weight for Organic Solar Cells

“…The spectrum should exhibit typical polymer characters that the peak with an m / z value of x + 1222 N ( N is a positive integer) corresponded to a structure with N repeating units more than the peak at x . It should be noted that many of these chemical structures were methyl end-capped or formed by homocoupling between two Me 3 Sn-containing molecules in these curves, which had already been reported in other reports. ,− Interestingly, homocoupling of Me 3 SnDSnMe 3 were found in both PM6E1 and PM61. Compared with PM61, PM6E1 exhibited a lower homocoupling ratio, a smaller full-width at half maximum, and fewer peaks, especially when the m / z value was below 1200.…”

Low-Coordinate Cobalt Fluoride Complexes: Synthesis, Reactions, and Production from C–F Activation Reactions

“…The one-electron reduction of the Sn–F reagent by cobalt(I) produces the cobalt(II) fluoride complex and an unstable trimethyltin radical. Trimethyltin radicals dimerize to give hexamethylditin and also form dimethylstannylene and methyl radicals under heating or photolytic conditions . These known byproducts from Me 3 Sn • account for the species that we observed by 119 Sn{ 1 H} NMR spectroscopy (Scheme above).…”