Structural versatility of pyrene-2-(4,4,5,5-tetramethyl-[1,3,2] dioxaborolane) and pyrene-2,7-bis(4,4,5,5-tetramethyl-[1,3,2]dioxaborolane)

Abstract

Three polymorphs of pyrene-2,7-bis(Bpin) 2 (1) and two of pyrene-2-(Bpin) (2), where Bpin = 4,4,5,5-tetramethyl-[1,3,2]dioxaborolane, two different 1:1 co-crystals of 1 with toluene, and co-crystals of hexafluorobenzene (HFB) with 1 (of highly unusual 2:1 composition) and 2 (of usual 1:1 composition) were isolated, studied by X-ray diffraction and differential scanning calorimetry, and described using Hirshfeld surfaces and two-dimensional fingerprint plots. Centrosymmetric phases β- and γ-1 have densities respectively lower and higher than the chiral α-1; α- and β-2 have different packing modes, both with Z′ = 3. Compound 1 is prone to form channel host-guest structures, for example, α- and β-1•PhMe and 1•2HFB. The drastically different stabilities of α- and β-1•PhMe are discussed. The complex 2•HFB has a mixed-stack packing motif. The structural versatility of 1 and 2 is explained by synthon frustration between structurally incongruent pyrene and Bpin moieties. © 2012 American Chemical Society.