Novel Stannatranes of the Type N(CH₂CMe₂O)₃SnX (X = OR, SR, OC(O)R, SP(S)Ph₂, Halogen). Synthesis, Molecular Structures, and Electrochemical Properties

Abstract

The syntheses of the stannatrane derivatives of the type N(CH(2)CMe(2)O)(3)SnX (1, X = Ot-Bu; 2, X = Oi-Pr; 3, X = 2,6-Me(2)C(6)H(3)O; 4, X = p-t-BuC(6)H(4)O; 5, X = p-NO(2)C(6)H(4)O; 6, X = p-FC(6)H(4)O; 7, X = p-PPh(2)C(6)H(4)O; 8, X = p-MeC(6)H(4)S; 9, X = o-NH(2)C(6)H(4)O; 10, X = OCPh(2)CH(2)NMe(2); 11, X = Ph(2)P(S)S; 12, X = p-t-BuC(6)H(4)C(O)O; 13, X = Cl; 14, X = Br; 15, X = I; 16, X = p-N(CH(2)CMe(2)O)(3)SnOSiMe(2)C(6)H(4)SiMe(2)O) are reported. The compounds are characterized by X-ray diffraction analyses (3-8, 11-16), multinuclear NMR spectroscopy, (13)C CP MAS (14) and (119)Sn CP MAS NMR (13, 14) spectroscopy, mass spectrometry and osmometric molecular weight determination (13). Electrochemical measurements show that anodic oxidation of the stannatranes 4 and 8 occurs via electrochemically reversible electron transfer resulting in the corresponding cation radicals. The latter were detected by cyclic voltammetry (CV) and real-time electron paramagnetic resonance spectroscopy (EPR). DFT calculations were performed to compare the stannatranes 4, 8, and 13 with the corresponding cation radicals 4(+•), 8(+•), and 13(+•), respectively.

Theoretical study of the geometrical, energetic and NMR properties of atranes

“…Stannatranes have longer Sn$$$N distances, between 2.2 and 2.4 Å [17]. A recent paper reports the geometry of silatranes with Si$$$N distances between 2.1 and 2.2 Å [18].…”

Covalent Grafting of Silatranes to Carbon Interfaces

“…For producing Si‐centered radicals in the vicinity of the carbon‐based interface, we exploited one‐electron reduction of SiCl bonds. Although cathodic electrochemical investigations of chloro metallatranes is only reported for chlorido stannatrane,24 electroreduction of chlorosilanes is well documented25 and we expected that the SiCl bond in silatranes would follow a similar pathway. At a bare GC electrode, the reduction of chloro silatrane and that of its precursor, (EtO) 3 SiCl, just as for chlorosilanes in general, occurs at quite negative potentials in a one two‐electron step (Figure 1).…”

Carbastannatranes: a powerful coupling mediators in Stille coupling

“…[53][54][55][56][57] Amongst different organotin cyclic systems, stannatranes possess cage like structures with transannular donoracceptor interaction. 59,60,[62][63][64][65][66][67][68] Tin-atranes possessing heteroatoms like oxygen (stannatranes), nitrogen (azastannatranes) and sulphur (thiastannatranes) at the equatorial donor site have not been reported as coupling mediators. Depending upon the equatorial donor atoms (Y), they are categorized into stannatranes, carbastannatranes, azastannatranes and thiastannatranes (Chart 1).…”