Flash Communication: On the Bistabilities and Reactivities of ortho-Phenylene Compounds with ChO→B Interactions

Intramolecular Lewis adducts, especially those bearing a boron Lewis acid and a phosphine oxide Lewis base, have become attractive motifs for tunable luminescence properties in materials. However, intramolecular Lewis adducts with Ch(IV)O moieties (Ch = chalcogen) as Lewis bases are under-represented in the field. Here, we describe the syntheses of two chalcogen boranes of general formula o-(PhCh)(BMes2)C6H4 (Ch = S (1), Se (2)) and their conversions into the corresponding chalcogen-oxide boranes of general formula o-(PhChO)(BMes2)C6H4 (Ch = S (3), Se (4)). While both 3 and 4 form inner adducts held by ChO→B dative bonds in the solid state and in solution, we examine the bistabilities of these interactions computationally and experimentally. Interestingly, the reaction of 4 and HF·pyridine gives rise to o-(SePhMes)(BF3)C6H4 (5) which shows evidence for F→Se intramolecular chalcogen bonding.

分子内路易斯加合物（intramolecular Lewis adducts），尤其是兼具硼路易斯酸与氧化膦路易斯碱结构的这类加合物，已成为制备可调谐发光功能材料的热门结构基元。然而，以硫族(IV)氧代基团（Ch = 硫族元素，chalcogen）作为路易斯碱的分子内路易斯加合物，在该研究领域中尚未得到充分探索。本文报道了两种通式为o-(PhCh)(BMes₂)C₆H₄的硫族硼烷的合成方法（Ch = S (1)、Se (2)），以及它们向对应硫族氧化物硼烷的转化反应，对应产物通式为o-(PhCh=O)(BMes₂)C₆H₄（Ch = S (3)、Se (4)）。尽管3与4在固态与溶液中均通过Ch=O→B配位键形成内加合物，但我们从计算与实验两个维度考察了这类相互作用的双稳态特性。值得注意的是，化合物4与氟化氢-吡啶络合物的反应生成了通式为o-(SePhMes)(BF₃)C₆H₄的产物（5），该产物展现出分子内硫族键（intramolecular chalcogen bonding）的相关证据。