Reduction of C,O-chelated organotin(IV) dichlorides and dihydrides leading to protected polystannanes

Synthesis and Characterization of Readily Modified Poly(aryl)(alkoxy)stannanes by use of Hypercoordinated Sn Monomers

“…If the electron withdrawing substituents are replaced with one or two equally electron‐deficient Sn atoms, such as those present in hypercoordinated polystannanes, the opportunity to deploy additional electron density to the Sn backbone could result in stronger Sn−Sn bonds. This would, in turn, possibly make the metal–metal bonds less susceptible to undergo cleavage in the presence of nucleophiles such as H 2 O …”

“…This would, in turn, possibly make the metal-metal bonds less susceptible to undergo cleavage in the presence of nucleophiles such as H 2 O. [5,33,34] Here, we describe the preparation of asemi-crystalline, moderate molecular weighth ypercoordinated polystannane ( 10). This asymmetricalp olystannanea lso possesses exceptional light and moistures tability over several months of exposure to ambient atmosphere, with no observed changes in molecular weighto rN MR spectroscopic data.…”

Proof of Concept Studies Directed Towards Designed Molecular Wires: Property‐Driven Synthesis of Air and Moisture‐Stable Polystannanes

“…[12] After 5days, the Sn resonancea tÀ215 ppm hadc ompletely vanished with only the resonance at À196 ppm remaining. AC 6 D 6 solutiono f6 in aT eflonsealed NMR tube protected from ambient light sourcesw as monitored initially by NMR ( 1 Ha nd 119 Sn) spectroscopy.P hysical changes (colourc hange, trace precipitate formation < 10 %) were observed and thesec hanges thus characterized (NMR).…”

“…This characteristic is also observed for the alternating polymer.Polymers such as 10,with similarflexible propyloxy ligands capable of datively bondingt oS na toms, typically display 119 Sn resonances between À190 and À197 ppm. [12] Similarly,i ti se xpected that as peciess uch as dihydride 6 likely adopts as imilar distorted tetrahedral geometry because of the electronic environment of Sn;t his is assumed to be more Lewis basic due to the attached hydrides. Furthermore, exposure to ambient light sources, even for a short time, may also cause E/Z isomerization in the azobenzene moiety,a nd the additional crowding of this organic fragment in the Z-conformer could facilitate its release from dative interactions.…”

“…The incorporation of aromatic groups onto the Group 14 element, most notably in the case of tin, provides additional s-p delocalization, typi-cally resultingin ar edshift of the visible absorption. [12] This change in coordination number from four to five is surmised to decrease the Lewis acidity at tin;t his in turn leads to an increase in light stability (> 90 days) [12] and a modest improvementw ith respect to hydrolysis. [9,10] Althoughs table to oxidation,p olystannanes are readily hydrolysed to linear and cyclic oligostannoxanes when exposed to moist air.…”