Halogen versus Hydrogen Bonding in Binary Cocrystals: Novel Conformation a Coformer with [2+2] Photoreactivity of Criss‐Crossed C=C Bonds

Abstract

This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record.

Halogen-Bond Mediated [2+2] Photodimerizations: À la Carte Access to Unsymmetrical Cyclobutanes in the Solid State

“…Adjacent sheets interact via offset, face-to-face π -stacks between the 2-pyr and 4-pyr rings of neighboring molecules of 2,4-bpe ( d (pyr N1 ∙∙∙pyr N2 ) ~ 5.10 Å). Nearest-neighbor molecules of 2,4-bpe stack head-to-head ( hh ) with alkene C=C bonds separated by 4.22 Å and with closest alkene C=C bonds stacked in a combination of parallel and crisscrossed geometries ( Figure 3 d) [ 18 , 19 ].…”

Supramolecular Sandwiches: Halogen-Bonded Coformers Direct [2+2] Photoreactivity in Two-Component Cocrystals

“…The C=C bonds of the two cocrystals also exhibited a criss-crossed geometry that, in contrast to (catechol)•(3,3 -bpe), also lie disordered. A disordered geometry is typically associated with pedal motion that supports reactivity [11,[13][14][15][16][17][18][19][20][21][22].…”

“…In the context of systematic, geometry-based design, such donors are attractive owing to their planar and rigid structure as well as the well-established enhancement of X-bond donor capability by polyfluorosubstitution [10]. We very recently described [11] that the cocrystallization of 1,2diiodotetrafluorobenzene (1,2-di-I-tFb) with trans-1,2-bis(n-pyridyl)ethylene (n,n'-bpe, where: n = n' = 2, 3, 4) affords cocrystals sustained by N•••I X-bonds that make up one-dimensional (1D) and twodimensional (2D) assemblies. For 2,2′-bpe, the components generated a discrete aggregate packed as a photostable 1D assembly.…”

X-ray crystal structure of trans-bis(pyridin-3-yl)ethylene: comparing the supramolecular structural features among the symmetrical bis(n-pyridyl)ethylenes (n = 2, 3, or 4) constitutional isomers

“…The alkene 3,3 0 0 0 -bpe was prepared as described (Quentin et al, 2020;Gordillo et al, 2007Gordillo et al, , 2013) via a one-pot, aqueous Pdcatalyzed Hiyama-Heck cross-coupling between 3-bromopyridine and triethoxyvinylsilane (2:1 molar ratio) (Fig. 7).…”