6381-06-2Relevant academic research and scientific papers
Reaction products of dichlorodiorganostannanes with sodium in liquid ammonia: In-situ investigations with 119Sn NMR spectroscopy and usage as intermediates for the synthesis of tetraorganostannanes
Trummer, Markus,Zemp, Jerome,Sax, Cedric,Smith, Paul,Caseri, Walter
, p. 3041 - 3049 (2011)
Dichlorodibutylstannane, dichlorodioctylstannane and dichlorodiphenylstannane were reacted with different amounts of sodium in liquid ammonia. At a molar ratio of R2SnCl2/Na of 1:2, polystannanes precipitated, in some cases accompanied by cyclic oligostannanes. The products resulting from mixtures with R2SnCl2/Na ratios of 1:3 to 1:10 were soluble and, hence, could be studied in-situ in liquid ammonia with 119Sn NMR spectroscopy. The compounds obtained, tin hydrides of the type R2SnH- and in certain cases distannides of the composition R4Sn22-, formed essentially independent of the R2SnCl2/Na ratio; this, in contrast to views expressed in the literature. Our experiments showed that the chemical structure of the in-situ generated species did not permit to draw conclusions about the composition of the reaction products with bromoethane and vice versa - a practice commonly described. Furthermore, we observed migration of the butyl groups both in-situ during the reaction of dichlorodibutylstannane with sodium in liquid ammonia, as well as in the final reaction product. By contrast in the case of the phenyl substituent, migration was detected not during the chemical event in liquid ammonia, but only in the compounds formed. These observations imply a different mechanism for butyl and phenyl group migration.
Carbon-carbon bond formation on reaction of a copper(I) stannyl complex with carbon dioxide
Bhattacharyya, Koyel X.,Akana, Jennifer A.,Laitar, David S.,Berlin, Jacob M.,Sadighi, Joseph P.
, p. 2682 - 2684 (2008)
The reaction of (IPr)CuOt-Bu (IPr = 1, 3-bis(2, 6-diisopropylphenyl) imidazol-2-ylidene) with triphenylstannane forms a stannyl complex, (IPr)CuSnPh3, by deprotonation of the tin-hydrogen bond. This stannyl complex reacts with CO2 to afford (1Pr)CuO2CPh as the sole copper-containing species. A tin-carbon bond in (1Pr)CuSnPh3 also undergoes facile cleavage by mild acids such as 2,4-lutidinium chloride.
Direct Detection, Dimerization, and Chemical Trapping of Dimethyl- and Diphenylstannylene from Photolysis of Stannacyclopent-3-enes in Solution
Duffy, Ian R.,Leigh, William J.
, p. 5029 - 5044 (2015/11/09)
Dimethyl- and diphenylstannylene (SnMe2 and SnPh2, respectively) have been successfully detected and characterized in solution. The stannylenes were generated by photolysis of 1,1,3-trimethyl-4-phenyl- (2) and 3,4-dimethyl-1,1-diphenylstannacyclopent-3-ene (3), respectively, which have been shown to extrude the species cleanly and in high (0.6 2SnCl2) as the stannylene substrate. Laser flash photolysis of 2 and 3 in deoxygenated hexanes affords promptly formed transient absorptions assigned to SnMe2 (λmax = 500 nm; ε500 = 1800 ± 600 M-1 cm-1) and SnPh2 (λmax = 290, 505 nm; ε500 = 2500 ± 600 M-1 cm-1), respectively, which decay with absolute second-order rate constants within a factor of 2 of the diffusional limit in both cases. The decay of the stannylenes is accompanied by the growth of new transient absorptions ascribable to the corresponding dimers, the structures of which are assigned with the aid of DFT and time-dependent (TD) DFT calculations at the (TD)ωB97XD/6-31+G(d,p)C,H,O-LANL2DZdpSn level of theory. Dimerization of SnMe2 affords a species exhibiting λmax = 465 nm, which is assigned to the expected Sn=Sn doubly bonded dimer, tetramethyldistannene (Me2Sn=SnMe2, 16a), in agreement with earlier work. In contrast, the spectrum of the dimer formed from SnPh2 exhibits strong absorptions in the 280-380 nm range and a very weak absorption at 650 nm, on the basis of which it is assigned to phenyl(triphenylstannyl)stannylene (17b). The calculations suggest that 17b is formed via ultrafast rearrangement of a novel phenyl-bridged stannylidenestannylene intermediate (20), which can be formed either directly by "endo" dimerization of SnPh2 or by isomerization of the "exo" dimer, tetraphenyldistannene (16b); the predicted barriers for these rearrangements are consistent with the experimental finding that the observed product is formed at close to the diffusion-controlled rate. Absolute rate and equilibrium constants are reported for the reactions of SnMe2 and SnPh2 with Me2SnCl2 and methanol (MeOH), respectively, in hexanes at 25 °C.
Electrochemistry and infrared spectroelectrochemistry of MnSnPh4-n (M = CpMo(CO)3, Mn(CO)5, CpFe(CO)2; n = 1, 2)
Bullock, John P.,Palazzotto, Michael C.,Mann, Kent R.
, p. 4413 - 4421 (2008/10/08)
The electrochemistry and infrared spectroelectrochemistry of the series MnSnPh4-n (M = CpMo(CO)3, Mn(CO)5 and CpFe(CO)2; n = 1, 2) and the corresponding homobinuclear compounds (M2) were examined in CH3CN/TBAH solutions (TBAH = tetran-butylammonium hexafluorophosphate). Cyclic voltammetric and double-potential step chroncoulometric data indicate that all of these compounds undergo net two-electron oxidations, with concomitant metal-tin or, in the case of the homobinuclear species, metal-metal bond rupture. The oxidation products for the triphenyltin adducts are the solvent adducts of the transition-metal cation and the triphenyltin cation. For Mn(CO)5SnPh3, the oxidation process is chemically reversible. Oxidation of the diphenyltin-bridged compounds results in cleavage of only one metal-tin bond, to give the metal cation and a base-stabilized stannylene cation. An ECE mechanism is proposed for the oxidation of these species. [Mn(CO)5]3SnPh undergoes metal-tin bond cleavage reactions. The reductions of the compounds in this series and the homobinuclear compounds were also studied. Almost all of the reductions were net two-electron processes, which, like the oxidations, resulted in metal-tin or metal-metal bond cleavage. The reduction products for the homobinuclear species were the monomeric metal anions. The triphenyltin adducts yielded the metal anions and either the triphenylstannate anion or the triphenyltin dimer species, Sn2Ph6, upon reduction, depending on the transition-metal moiety. The diphenyltin-bridged compounds were reduced to the transition-metal anions and an unreduced tin product, possibly an oligomerization product of diphenyltin. Infrared spectral data imply that this reduction proceeds via a terminal diphenylstannate anion adduct of the transition-metal moiety.
