Origins of Selectivity for the [2+2] Cycloaddition of α,β-unsaturated Ketones within a Porous Self-assembled Organic Framework

Abstract

X-Ray Structure Determination, C 12 H 16 O 2 X-ray diffraction intensity data from a colorless plate crystal were measured at 150(1) K using a Bruker SMART APEX diffractometer (Mo K radiation, = 0.71073 Å). 1 Raw area detector data frame integration was performed with SAINT+. 1 Final unit cell parameters were determined by least-squares refinement of 2964 strong reflections from the data set. Direct methods structure solution, difference Fourier calculations and full-matrix least-squares refinement against F 2 were performed with SHELXTL. 2 The compound crystallizes in the space group P2 1 /n as determined uniquely by the pattern of systematic absences in the intensity data. The asymmetric unit consists of half of one molecule located on a crystallographic inversion center. All non-hydrogen atoms were refined with anisotropic displacement parameters. Hydrogen atoms were located in difference maps

Manipulating the cavity of a porous material changes the photoreactivity of included guests

“…4 We synthesized benzophenone macrocycle 2 in which the ether oxygen of host 1 was replaced with a carbonyl group. Host 2 was synthesized in two steps from the dibromide and masked urea (triazinanone).…”

“…4 The new solid inclusion crystals (host 2Áenone) were UV-irradiated using a 450 W Hannovia high pressure mercury vapour lamp at B30 1C for 24 h. Next, each of the host-guest complexes was directly dissolved in d 6 -DMSO and monitored by 1 H NMR spectrometry. Only peaks that corresponded to the host macrocycle 2 and the starting enones were observed.…”

“…(3)(4)(5)(6) and photoisomerization of trans-b-methylstyrene (7) in the presence of host 1 and host 2…”

Design, Synthesis, Photophysics, and Anion‐Binding Studies of Bis(dicyclohexylphosphino)methane‐Containing Dinuclear Gold(I) Thiolate Complexes with Urea Receptors

“…Self-assembly through inter-or intramolecular urea-urea hydrogen-bonding interactions has proved to be an important and predictable secondary noncovalent bond, similar to the hydrophobic interactions, p-p interactions, and van der Waals forces that have commonly been exploited in the design of self-assembled supramolecular architectures, such as sol-gels, [30] supramolecular capsules, [31] fibers, [32] and columnar structures with guest-accessible channels. [33] It is likely that, in the solid state, complex 3 could form intramolecular urea-urea hydrogen bonds that could force the two gold atoms into close proximity, whereas in solution the Au···Au interactions would no longer exist. Such a cooperative aurophilic interaction and hydrogen-bonding interaction to afford supramolecular entities has also been reported previously.…”

Photocyclodimerization of 5‐Methyl‐2H‐pyran‐3(6H)‐one

“…-The ratio of regioisomeric products in photocyclodimerization of cyclohexenones is known to be sensitive to the reaction environment, in general, and to the solvent polarity, in particular, i.e., the ratio of HH-to HT-photocyclodimers increases in going from apolar (cyclohexane, benzene) solvents to more polar ones (MeCN, MeOH, H 2 O) [8]. As can be seen from the ratio of regioisomeric products summarized in Table 1, both dihydropyranones 2 and 3 follow this behavior, 2 exhibiting a very similar behavior to that of -the carbocyclic analogue -3-methylcyclohex-2-enone [9].…”