π‑Conjugation between a SiSi Double Bond and Thiophene Rings: Synthesis, Structural Characteristics, and Photophysical Properties of 1,2-Bis(thiophen-2-yl)disilene and 1,2-Bis(2,2′-bithiophen-5-yl)disilene

The two new disilene compounds, 1,2-bis­(thiophen-2-yl)­disilene (1) and 1,2-bis­(2,2′-bithiophen-5-yl)­disilene (2), supported by the fused-ring bulky Eind groups (Eind = 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl) have been obtained as orange and purple crystals, respectively, by the reduction of the corresponding dibromosilanes. Their X-ray structures and spectroscopic properties demonstrate the effective π-conjugation between a SiSi double bond and thiophene units. Notably, the π-extended 2 exhibits a distinct emission both in solution and in the solid state at room temperature based on the essentially coplanar 1,2-bis­(bithienyl)­disilene skeleton. The structural features and electronic properties of 1 and 2 have been thoroughly characterized both experimentally and computationally.