| Autor: |
Ebeler F; Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany., Vishnevskiy YV; Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany., Neumann B; Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany., Stammler HG; Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany., Szczepanik DW; Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland., Ghadwal RS; Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany. |
| Abstrakt: |
The isolation of silicon analogues of phenyl anions such as (C 6 H 5 ) - and (C 6 H 4 ) 2- is challenging owing to their extremely high reactivity associated with their silylene character and weak C-Si π-interaction. Herein, we report the first annulated 1,4-disilabenzene-1,4-diide compound [(ADC)Si] 2 ( 5 ) based on anionic dicarbene (ADC) scaffolds (ADC = PhC{N(Dipp)C} 2 ; Dipp = 2,6- i Pr 2 C 6 H 3 ) as a green-yellow crystalline solid. Compound 5 is prepared by KC 8 reduction of the Si(IV) chloride [(ADC)SiCl 3 ] 2 ( 3 ) or the cyclic bis-chlorosilylene [(ADC)SiCl] 2 ( 4 ), which are also prepared for the first time. 5 is a neutral molecule, and each of the two-coordinated Si(I) atoms has a lone pair and an unpaired electron. Experimental and theoretical data indicate delocalization of the silicon unpaired electrons, resulting in a 6π-electron C 4 Si 2 ring in 5 . The diradical character ( y ) for 5 amounts to 15%. At room temperature, 5 readily reacts with dihydrogen (H 2 ) to form the elusive bis-hydridosilylenes [(ADC)SiH] 2 ( Z )- 6 and ( E )- 6 . The [4 + 2]-cycloaddition of 5 and PhC≡CPh in yielding the barrelene-type bis-silylene [(ADC)SiCPh] 2 ( 7 ) emphasizes the diradical reactivity of 5 . With elemental sulfur, 5 results in the S 2 - and S 3 -bridged silathione derivatives [(ADC)Si(S)] 2 (μ-S 2 ) ( 8a ) and [(ADC)Si(S)] 2 (μ-S 3 ) ( 8b ). Moreover, the treatment of 5 with Fe 2 (CO) 9 affords the Fe(0) complex [(ADC)Si(Fe(CO) 4 )] 2 (μ-CO) ( 9 ), in which each silicon atom serves as a two-electron σ-donor ligand and shares one electron with the bridging CO unit to form two Si-C bonds. The molecular structures of all compounds have been established by X-ray diffraction, and representative compounds have been analyzed by quantum chemical calculations. |
