One-pot reactions of diorganotin oxides, R(2)SnO, with dimethyl sulfite under reflux conditions (125-127 degrees C) proceed via the Arbuzov rearrangement at the sulfur center, yielding the corresponding methoxydiorganotin methanesulfonates, R(2)Sn(OMe)OS(O)(2)Me [R = n-Pr (1), n-Bu (2), i-Bu (3), c-Hx (4)], as white, hygroscopic solids. These compounds react with beta-diketones [acetylacetone (Hacac), benzoylacetone (Hbzac), and dibenzoylmethane (Hbzbz)] to afford mixed-ligand organotin derivatives, R(2)Sn(X)OS(O)(2)Me [X = acac, R = n-Pr (5), n-Bu (6); X = bzac, R = n-Pr (7), n-Bu (8); X = bzbz, R = n-Pr (9), n-Bu (10), i-Bu (11)]. Selective hydrolysis of the Sn-OMe bond in 1-3 occurs, resulting in the isolation of (&mgr;-hydroxo)diorganotin methanesulfonates, R(2)Sn(OH)OS(O)(2)Me [R = n-Pr (12), n-Bu (13), i-Bu (14)]. All the compounds are characterized by elemental analyses and IR, multinuclear ((1)H, (13)C, and (119)Sn) NMR, and mass spectra. Unequivocal evidence of the presence of the methanesulfonate group is provided by the X-ray crystal structures of 6, 10, and 13. [For 6: trigonal space group R&thremacr; (No. 148), a = 28.664(1) Å, c = 13.056(1)Å, Z = 18. For 10: triclinic space group P&onemacr; (No. 2), a = 13.056(3) Å, b = 14.062(3) Å, c = 16.282(3) Å, Z = 4. For 13: triclinic space group P&onemacr; (No. 2), a = 9.089(2) Å, b = 12.040(2) Å, c =13.894(2) Å, Z = 2]. For 6 and 10, the solid-state structural analyses reveal dimeric structures with a bridging bidentate methanesulfonate group forming a centrosymmetric eight-membered ring. Compound 13 possesses a polymeric sheet structure with repeating 20-membered macrocycles (including two four-membered [Sn(OH)](2) rings) by virtue of the bridging bidentate methanesulfonate groups. A search for a possible pathway to give Arbuzov-rearranged products 1-4 leads us to speculate that there is an initial catalytic transformation of dimethyl sulfite to methyl methanesulfonate via intermediate compounds, Bu(2)Sn(OMe)(2) (A) and [Bu(2)SnOMe](2)O (B). A and B subsequently react with methyl methanesulfonate to give 1-4.

No abstract

Some unique features of 1-isothiocyanatosilatrane, 1, include concomitant NMR couplings of quadrupolar 14N(NCS) nucleus with adjacent heteroatoms [J(13C−14N) = 26.17 Hz; J(29Si−14N) = 28.47 Hz] and the crystallographically determined shortest N→Si bond, 2.007(3) Å, as well as a nearly linear structure of the heteroatoms N(1)−Si−N(2)−C(7)−S(1). Contrary to the known reactivity of tetracoordinate isothiocyanatosilanes, 1 invariably shows retention of the Si−N(CS) bond under normal nucleophilic/electrophilic reaction conditions. These novel features also get support from semiemperical MO calculations on the compound.