Organotin Compounds

Schumann, Herbert; Schumann, Ingeborg; Krüerke, Ulrich

doi:10.1007/978-3-662-06612-6_1

Cited by 2 publications

(2 citation statements)

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“…Photolysis with a Zn resonance lamp (214 nm) of a deoxygenated 0.02 M solution of 4b in cyclohexane- d 12 containing 0.5 M methanol (MeOH), with periodic monitoring of the photolyzate by (600 MHz) 1 H NMR spectroscopy, resulted in the formation of 2,3-dimethyl-1,3-butadiene (DMB) and a colorless precipitate that deposited on the walls of the NMR tube. A collection of very weak peaks was also present in the 0.5−0.8 ppm range of the spectrum (including a singlet at δ 0.53 ppm), consistent with (SnMe 2 ) n oligomers, but no new signals were detectable in the δ 3.5−5.5 ppm region, where those due to Sn−H and Sn−OMe protons would be expected …”

Section: Resultsmentioning

confidence: 71%

“…The magnitude of this barrier could explain why the methoxystannane is in fact not formed in detectable amounts in steady-state trapping experiments (vide supra); the ultimate fate of SnMe 2 in the latter experiments, even in the presence of relatively high concentrations of alcohol, is oligomerization. Few examples of stable alkoxydialkylhydridostannanes are known, ,, but water and MeOH are known to undergo oxidative addition to Lappert's stannylene {Sn[CH(SiMe 3 ) 2 ] 2 } to afford the corresponding (stable) O−H insertion products . The reaction was proposed to proceed via initial formation of the corresponding stannylene−alcohol (water) complex, but if this complex can rearrange readily to product, then the required H migration must either have a lower barrier than that calculated by Su for the SnMe 2 −MeOH complex ( 6 ) 40 or proceed catalytically.…”

Section: Discussionmentioning

confidence: 99%

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Direct Detection of Dimethylstannylene and Tetramethyldistannene in Solution and the Gas Phase by Laser Flash Photolysis of 1,1-Dimethylstannacyclopent-3-enes

et al. 2005

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The photochemistry of 1,1-dimethyl- and 1,1,3,4-tetramethylstannacyclopent-3-ene (4a and 4b, respectively) has been studied in the gas phase and in hexane solution by steady-state and 193-nm laser flash photolysis methods. Photolysis of the two compounds results in the formation of 1,3-butadiene (from 4a) and 2,3-dimethyl-1,3-butadiene (from 4b) as the major products, suggesting that cycloreversion to yield dimethylstannylene (SnMe2) is the main photodecomposition pathway of these molecules. Indeed, the stannylene has been trapped as the Sn-H insertion product upon photolysis of 4a in hexane containing trimethylstannane. Flash photolysis of 4a in the gas phase affords a transient absorbing in the 450-520-nm range that is assigned to SnMe2 by comparison of its spectrum and reactivity to those previously reported from other precursors. Flash photolysis of 4b in hexane solution affords results consistent with the initial formation of SnMe2 (lambda(max) approximately 500 nm), which decays over approximately 10 micros to form tetramethyldistannene (5b; lambda(max) approximately 470 nm). The distannene decays over the next ca. 50 micros to form at least two other longer-lived species, which are assigned to higher SnMe2 oligomers. Time-dependent DFT calculations support the spectral assignments for SnMe2 and Sn2Me4, and calculations examining the variation in bond dissociation energy with substituent (H, Me, and Ph) in disilenes, digermenes, and distannenes rule out the possibility that dimerization of SnMe2 proceeds reversibly. Addition of methanol leads to reversible reaction with SnMe2 to form a transient absorbing at lambda(max) approximately 360 nm, which is assigned to the Lewis acid-base complex between SnMe2 and the alcohol.

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Section: Resultsmentioning

confidence: 71%