Cocrystals with tunable luminescence colour self-assembled by a predictable method

Abstract

Organic light-emitting materials play an essential role in the field of luminescent materials because they are easily prepared and they have controllable luminescent properties. Here it is shown that intermolecular interactions and luminescent properties of cocrystals can be predicted using the molecular surface electrostatic potential of selected -hole/-holeÁ Á Á bonding donor haloperfluorobenzenes and acceptor acenaphthene (AC). Single-crystal X-ray diffraction data reveal that actual bonding patterns in five cocrystals assembled from haloperfluorobenzenes and AC are in accordance with predictable patterns of intermolecular interactions; that is -holeÁ Á Á bond is the major interaction in AC-octafluoronaphthalene, AC-1,4-dibromotetrafluorobenzene and AC-1,3,5-tribromo-2,4,6-trifluorobenzene cocrystals, whereas -holeÁ Á Á bond is the major interaction in AC-1,4-diiodotetrafluorobenzene and AC-1,3,5-trifluoro-2,4,6-triiodobenzene cocrystals. The luminescent properties of the cocrystals are affected by the bonding patterns between AC and haloperfluorobenzenes; the -holeÁ Á Á bond leads to weak phosphorescence, whereas the -holeÁ Á Á bond results in weak delayed fluorescence and relatively strong phosphorescence. research papers Acta Cryst. (2018). B74, 610-617 Lili Li et al. Cocrystals with tunable luminescence colour 611 research papers Acta Cryst. (2018). B74, 610-617 Lili Li et al. Cocrystals with tunable luminescence colour 617

Influence of methyl-substitution on the dynamics of the C–H⋯F–C interaction in binary adducts

“…in the stabilization of graphene sheets, 34 and in the selfassembly of bespoke cocrystals with tuneable luminescence colour. 35…”

New Crystal Forms for Biologically Active Compounds. Part 2: Anastrozole as N-Substituted 1,2,4-Triazole in Halogen Bonding and Lp-π Interactions with 1,4-Diiodotetrafluorobenzene

“…In accordance with their geometrical parameters (Table 1), the theoretically estimated energies of these contacts are 4.6-5.3 kcal/mol (I3S•••N2) and 4.8-6.0 kcal/mol (I1S•••N3), which is comparable with a lower limit for strength of "moderate" hydrogen bonding according to Jeffrey's classification ("strong": 40−15 kcal/mol; "moderate": 15−4 kcal/mol; "weak": <4 kcal/mol) [36]. For 1,4-FIB, the molecular electrostatic potential calculations were reported [37][38][39], which confirm the σ-hole electrophilicity [40,41] of iodine atoms in this molecule. Previously, the C-I• • • N XBs including 1,2,4-triazole moiety was mentioned only in two metal-organic frameworks (FALNEN [43] and UMOTOG [44]) and one free 4H-1,2,4-triazole (FARCIN01 [45]).…”

Four strategies towards customized rainbow/white light emission from a series of organic charge-transfer cocrystals and their heterostructures

“…The polymorphs usually display completely distinct optical properties because the luminescence is greatly sensitive to the molecular packing in p-conjugate systems. 22,25,[46][47][48][49][50][51] It is noteworthy that the light in these compounds mainly originated from the charge transfer between the donors and acceptors. Charge-transfer complexes form firstly, then further assemble and evolve into different polymorphs; [52][53][54][55] thus, the similar charge-transfer state in different polymorphs ensures that the luminescence will not change too much due to different supramolecular packings (Fig.…”