C. Mügge

1H, 13C, 15N and 119Sn NMR investigations on stannatranes

Abstract 1H, 13C, 15N and 119Sn NMR data for alkyl- and phenyl-stannatranes are reported. A trimeric structure and an intramolecular dynamic process are proposed.

Synthesis, molecular structure and stereoisomerization of 2-phosphinyl and 2-phosphonylethyl diorganotin halides

Abstract Functionally substituted triorganotin halides V–IX of type R 2 Sn(X)(CH 2 ) 2 P(O)PhR′ (R = Me, t-Bu; Rt = OEt, t-Bu; X = Cl, Br) have been synthesized by halogen cleavage of the corresponding tetraorganotin compounds R 2 R 2 Sn(CH 2 ) 2 P(O)PhR′ (R 2 = Me or Ph), I–IV. The solid state structure of Me 2 Sn (Br) (CH 2 ) 2 P(O)PhBu-t (IX), determined by X-ray diffraction, shows a distorted trigonal-bipyramidal structure at the tin atom, with intramolecular coordination of the Pue5fbO group. Spectroscopic data are in agreement with such a structure in solution for compounds V–IX. Upon varying the temperature, concentration or solvent in solutions of compounds V–IX a stereoisomerization is observed. On the basis of NMR 1 H, 13 C, 31 P, 119 Sn), IR and conductivity studies, it is suggested that this stereoisomerization involves a hexacoordinated transition state at the tin atom.

N-Alkyl-5,5-diorganodiptychoxazstannolidone, intramolekular pentakoordinierte stannylester der N-methylminodiessigsäure

The reaction of dialkyltin oxides or dialkyltin dialkoxides with N-methyliminodiacetic acid in dimethylformamide/toluene gives the title compounds in 80–90% yields. The structure of these compounds was investigated by NMR, IR and mass spectroscopy. The temperature dependent 1H and 13C NMR spectra are interpreted by a dissociation—inversion mechanism.

The structure of 5-aza-2,8-dioxa-1-stanna(II)bicyclo[3.3.0]octane

From the1H,13C, and119Sn NMR spectra at different temperatures, it is concluded that the 5-alkyl-5-aza-2,8-dioxa-1-stanna(II)bicyclo[3.3.0]octanes dimerize in nonpolar solvents. The barrier for dimerization is lower (ΔG‡=40 kJ/mol) than the barrier for simultaneous dissociation-inversion (ΔG‡=70 kJ/mol). The dimers studied are sterically uniform.

1,5,5-trimethyl-1-aza-5-silabicyclo[3.3.01,5]octan- und 1-aza-5-sila-5-methyltricyclo[3.3.3.01,5] undecanpentakoordinierte tetraorganosiliziumverbindungen

Abstract The synthesis of Me 2 Si(CH 2 CH 2 CH 2 ) 2 NMe and RSi(CH 2 CH 2 CH 2 ) 3 N (R = Cl, Me) is reported. Their structure is investigated by means of 1 H, 13 C and 29 Si NMR spectroscopy and mass spectrometry.

2,8-dithia-1,5-diphosphabicyclo[3,3,0]octan- und 2,8-dithia-1-phospha-5-arsabicyclo[3,3,0]octane-derivate

Abstract The reaction of dimercaptoethylphosphane HP(CH 2 CH 2 SH) 2 with tris (diethylamino)phosphane or tris(diethylamino)arsane leads in high yields to the title compounds.

Konfigurationsumkehr am tetrakoordinierten phosphor in 1,1-dialkyl-3-phenyl-3-thio-1,2,3-stannathiaphospholanen

Abstract A configuration inversion at the phosphorus atom in 1,1-dialkyl-3-phenyl-3-thio-1,2,3-stannathiaphospholanes (I—III) is indicated by the temperature dependence of the 1H NMR spectra. Solvent molecules, however, interact preferably with the tin atom. The activation parameters of this inversion process are consistent with a bicyclic transition state with pentacoordinated tin.

1,3,2,5-Dioxadiphosphorinanes. Six-membered ring compounds containing two different phosphorus atoms

The reaction of bis(hydroxymethyl)phenylphosphane withtert-butyldichlorophosphane leads to the formation ofcis-2-tert-butyl-5-phenyl-1,3,2,5-dioxadiphosphorinane (1). Thecis configuration was definitively proven by the X-ray diffraction study of the 2, 5-dithioxo derivative (2), which was obtained from (1) by a stereoselective reaction. The diselenoxo compound (3) was also prepared. These three new compounds were subjected to a complete NMR study (1H,13C,31P, and77Se).