Transmetallation of bis(6-diphenylphosphinoxy-acenapth-5-yl)mercury with tin tetrachloride, antimony trichloride and bismuth trichloride

Abstract

We recently communicated (Angew. Chem. Int. Ed., 2018, 57, 5917–5920) the transmetallation of [6-Ph₂P(O)-Ace-5-]₂Hg (1) with Pb(OAc)₄, which, after work-up with HCl in Et₂O, provided the first aryl lead trichloride, 6-Ph₂P(O)-Ace-5-PbCl₃ (2), and 6-Ph₂P(O)-Ace-5-HgCl (3). With LiCl, 1 forms a complex, [{[6-Ph₂P(O)-Ace-5]₂Hg}₂Li]Cl (1a), that shows no reactivity towards Pb(OAc)₄ anymore, which highlights the role of the intramolecularly coordinated P(O) functionality in transmetallation. In this work, we have broadened the scope of the transmetallation reagent by the reaction of 1 with SnCl₄, SbCl₃ and BiCl₃ giving rise to the formation of 6-Ph₂P(O)-Ace-5-SnCl₃ (4), 6-Ph₂P(O)-Ace-5-SbCl₂ (5) and 6-Ph₂P(O)-Ace-5-BiCl₂ (6), respectively. The high Lewis acidity permits 4 and 5 to undergo complexation with THF, whereas no such complexes were formed with 2 and 6. The molecular structures of 1a, 3, 4, 4·THF, 5, 5·THF and 6 were established by X-ray crystallography. The different P–O distances of 2, 4, 4·THF, 5, 5·THF and 6, reflecting the relative strength of the P(O)⋯E coordination (E = Pb, Sn, Sb, Bi), were discussed. The nature of the P(O)⋯E interactions of 2, 4, 4·THF, 5, 5·THF and 6 was studied using a set of real-space bond indicators (RSBIs).