Remarkable difference in fluorescence lifetimes of the crystalline states of dibenzoylmethanatoboron difluoride and its diisopropyl derivative

New Fluorescence Domain “Excited Multimer” Formed upon Photoexcitation of Continuously Stacked Diaroylmethanatoboron Difluoride Molecules with Fused π‐Orbitals in Crystals

“…www.chemeurj.org 1c-eBF 2 are stacked in am anner that allows overlap of the benzene ring p-orbitals ( Figure 1, B-on-B overlap). [44] Molecules of 1fBF 2 and 1gBF 2 ,w ith bulky substituents, are stacked more closely still (Table 1, D C = 5.41 f or 1fBF 2 and 5.62 f or 1gBF 2 ), whicha voidsi ntermolecular overlap of the parentu nit and bulky substituents of adjacentm olecules. Thus, molecules in the crystalline states of 1fBF 2 and 1gBF 2 are stacked in am anner that enables overlap of the benzene groups with the 1,2-dihydro-2,6-dioxaborinine moietiesi nt he neighboring molecules (Figure 1, B-on-D overlap).…”

Room‐Temperature Phosphorescence of Crystalline Metal‐Free Organoboron Complex

“…X‐ray crystallographic analysis was carried out on a single crystal of 1BF 2 . The results show that an arbitrarily chosen molecule of this substance, M 0 , has a planar geometry and possesses 14 neighbors, that is two sets of seven kinds of pairs, M 0 /M 1 , M 0 /M 2 , M 0 /M 3 , M 0 /M 4 , M 0 /M 5 , M 0 /M 6 , and M 0 /M 7 (Figure a. Molecules in the M 0 /M 1 pair appear to be π‐stacked between a benzene (B, Figure a) ring on one and the 1,2‐dihydro‐2,6‐dioxaborinine (D) ring of the other ( B‐on‐D overlap), with a face‐to‐face distance of 3.74 Å (Figure b). In addition, a short distance of 2.57 Å exists between an H atom in the 4‐iodophenyl group of M 0 and the F atom in M 2 .…”

Remarkable Solvatofluorochromism of a [2.2]Paracyclophane‐Containing Organoboron Complex: A Large Stokes Shift Promoted by Excited State Intramolecular Charge Transfer

“…Earlier, we conducted studies designed to probe the relationships between the FL properties and intermolecular interactions in 1 BF 2 and its alkyl derivatives . The results show that upon increasing the concentration of 1 BF 2 in solution, its FL color changes from blue to yellow through white as a consequence of changes of the FL domain from an excited monomer to an excimer .…”

“…[24,25] Earlier,w ec onducted studies designed to probe the relationships between the FL properties and intermolecular interactions in 1BF 2 and its alkyl derivatives. [24][25][26][27] The results show that upon increasing the concentration of 1BF 2 in solution, its FL color changes from blue to yellow through white as aconsequenceo fc hanges of the FL domain from an excited mono-An organoboron complex containing a [ 2.2]paracyclophanyl group (2BF 2 )e xhibits remarkable solvatofluorochromism associated with al arge Stokes shift. With increased solventp olarity, the fluorescence( FL) color of 2BF 2 changes from sky blue (l FL = 485 nm in cyclohexane (c-C 6 H 12 )) to orange (l FL = 576 nm in CH 3 CN).…”

“…[24] These FL changes are not affected by the presenceo fa lkyl substituents in 1BF 2 .O nt he other hand, in the crystalline state FL properties of 1BF 2 are controlled by interactions associatedw ith intermolecular p-orbital overlap, which is controlled by the shape of attached alkyl substituents. [25,26] Moreover,w er ecently reported room-temperature phosphorescence from the 1BF 2 derivativei nt he crystalline state by introducing iodine as heavy atoms as substituents on phenylgroups. [27] To gain further insight into the FL properties of 1BF 2 ,w ed esigned 2BF 2 in which orbital overlap is fixed by the presence of the [2.2]paracyclophane moiety.…”