Competition Between Head-to-Head and Head-to-Tail Photocycloaddition Reaction in the Solid State: A Case Study

Sawant, V.A.; Wu, Jixuan; Vittal, Jagdese J.

doi:10.1021/acs.cgd.8b00442

“…In fact, two singlet peaks (4.78 and 4.38 ppm) were observed for the cyclobutaner ing in the 1 HNMR spectrum ( Figure S16), which are very similar to the chemical shifts observed for HHrctt-3F-ppcb (whereH H-rctt-3F-ppcb = 1,2-bis(4'-pyridyl)3,4bis(3'-fluoro-phenyl)cyclobutane) in [Zn 2 (1,3-bdc) 2 (rctt-3Fppcb) 2 ], 4-UV. [33] Hence, photoproduct 4-UV is likely to be a dimer.…”

Section: Solid-state Photoreactivitymentioning

confidence: 99%

Solid‐State Photochemical [2+2] Cycloaddition Reaction of Mn^II Complexes

Yadava

¹

,

Vittal

²

2019

Chemistry A European J

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Three Mn II complexes have been synthesized under similare xperimental conditions. Of these [Mn 2 (benzoate) 4 (L) 2 ]( whereL = 4-styrylpyridine or 4spy, 1 and 2-fluoro-4'-styrylpyridineo r2 F-4spy, 3)a re paddlewheel complexes, but crystallized in different space groups.W hereas [Mn 2 (benzoate) 4 (3F-4spy) 4 ]( 3F-4spy = 3-fluoro-4'-styrylpyridine), 4 is ad inuclearc omplex having different stoichiometry from 1 and 3 with two pairs of 3F-4spy ligandsalignedi n face-to-face manner.A ni rreversible phase transition occurs from the space group P2 1 /c to C2/c when 1 was heated up to 125 8Ct o2 in as ingle-crystal-to-single-crystal fashion or when ground 1 to powder. 2 is isomorphousa nd isostruc-tural to 3.C omplimentary p-p interactions in head-to-tail alignment of the styrylpyridine ligands furnishes 1D aggregates in 1-3 which are congenial to undergo [2+ +2] cycloaddition reaction under UV light. Whereas, face-to-facea lignment of the 4spy pairs in 4 is expected to provide ah eadto-head photoproduct. All theM n II complexes are indeed found to be photoreactive.T oo ur surprise, contrary to their Zn II analogues, 2 and 3 were not found to be photosalient. The percentage volumee xpansiond uring the photoreaction as determined from the density measurements, was found to be too low (3.2 and4 .6 %r espectively for 2 and 3)t o have this behavior.1 HNMR spectroscopy has also confirmed the ratios between the ligands in these complexes.

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Simultaneous Cycloadditions in the Solid State via Supramolecular Assembly

Juneja,

George,

Hutchins

2024

Angewandte Chemie

0

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Chemical reactions conducted in the solid phase (specifically, crystalline) are much less numerous than solution reactions, primarily due to reduced motion, flexibility, and reactivity. The main advantage of crystalline‐state transformations is that reactant molecules can be designed to self‐assemble into specific spatial arrangements, often leading to high control over product regiochemistry and/or stereochemistry. In crystalline‐phase transformations, typically only one type of reaction occurs, and a sacrificial template molecule is frequently used to facilitate self‐assembly, similar to a catalyst or enzyme. Here, we demonstrate the first system designed to undergo two chemically unique and orthogonal cycloaddition reactions simultaneously within a single crystalline solid. Well‐controlled supramolecular self‐assembly of two molecules containing different reactive moieties affords orthogonal reactivity without use of a sacrificial template. Using only UV light, the simultaneous [2+2] and [4+4] cycloadditions are achieved regiospecifically, stereospecifically, and products are obtained in high yield, whereas a simultaneous solution‐state reaction affords a mixture of isomers in low yield. Application of dually‐reactive systems toward (supra)molecular solar thermal storage materials is also discussed. This work demonstrates fundamental chemical approaches for orthogonal reactivity in the crystalline state and highlights the complexity and reversibility that can be achieved with supramolecular design.

show abstract

Simultaneous Cycloadditions in the Solid State via Supramolecular Assembly

Juneja,

George,

Hutchins

2024

Angew Chem Int Ed

0

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Chemical reactions conducted in the solid phase (specifically, crystalline) are much less numerous than solution reactions, primarily due to reduced motion, flexibility, and reactivity. The main advantage of crystalline‐state transformations is that reactant molecules can be designed to self‐assemble into specific spatial arrangements, often leading to high control over product regiochemistry and/or stereochemistry. In crystalline‐phase transformations, typically only one type of reaction occurs, and a sacrificial template molecule is frequently used to facilitate self‐assembly, similar to a catalyst or enzyme. Here, we demonstrate the first system designed to undergo two chemically unique and orthogonal cycloaddition reactions simultaneously within a single crystalline solid. Well‐controlled supramolecular self‐assembly of two molecules containing different reactive moieties affords orthogonal reactivity without use of a sacrificial template. Using only UV light, the simultaneous [2+2] and [4+4] cycloadditions are achieved regiospecifically, stereospecifically, and products are obtained in high yield, whereas a simultaneous solution‐state reaction affords a mixture of isomers in low yield. Application of dually‐reactive systems toward (supra)molecular solar thermal storage materials is also discussed. This work demonstrates fundamental chemical approaches for orthogonal reactivity in the crystalline state and highlights the complexity and reversibility that can be achieved with supramolecular design.

show abstract

Competition Between Head-to-Head and Head-to-Tail Photocycloaddition Reaction in the Solid State: A Case Study

Cited by 9 publications

References 60 publications

Solid‐State Photochemical [2+2] Cycloaddition Reaction of Mn^II Complexes

Solid‐State Photochemical [2+2] Cycloaddition Reaction of Mn^II Complexes

Simultaneous Cycloadditions in the Solid State via Supramolecular Assembly

Simultaneous Cycloadditions in the Solid State via Supramolecular Assembly

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Competition Between Head-to-Head and Head-to-Tail Photocycloaddition Reaction in the Solid State: A Case Study

Cited by 9 publications

References 60 publications

Solid‐State Photochemical [2+2] Cycloaddition Reaction of MnII Complexes

Solid‐State Photochemical [2+2] Cycloaddition Reaction of MnII Complexes

Simultaneous Cycloadditions in the Solid State via Supramolecular Assembly

Simultaneous Cycloadditions in the Solid State via Supramolecular Assembly

Contact Info

Product

Resources

About

Solid‐State Photochemical [2+2] Cycloaddition Reaction of Mn^II Complexes

Solid‐State Photochemical [2+2] Cycloaddition Reaction of Mn^II Complexes