Tipping the Balance with the Aid of Stoichiometry: Room Temperature Phosphorescence versus Fluorescence in Organic Cocrystals

D’Agostino, Simone; Grepioni, Fabrizia; Braga, Dario; Ventura, Barbara

doi:10.1021/acs.cgd.5b00226

Cited by 83 publications

(73 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These data confirm the nature of the emission that results from the low‐lying singlet excited state of the cis ‐keto tautomer . A general trend in lifetime decrease is observed upon moving from simple compounds to co‐crystals (Table ); this is likely to be due to an external heavy‐atom effect induced by the halogenated co‐former …”

Section: Resultssupporting

confidence: 71%

Halogen‐Bond Effects on the Thermo‐ and Photochromic Behaviour of Anil‐Based Molecular Co‐crystals

Carletta

Spinelli

D’Agostino

et al. 2017

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

N-Salicilideneanilines are among the most studied thermo- and photochromic systems in the solid state. Although thermochromism is a general property of crystalline N-salicilideneanilines, photochromism is known in a limited number of cases. As a method for the construction of thermo- and photo-responsive molecular architectures, the co-crystallisation of 1,2,4,5-tetrafluoro-3,6-diiodobenzene (I2F4) with three selected imines of o-vanillin, named 1, 2 and 3, obtained through a condensation reaction with 3-aminopyridine, 4-bromoaniline and 4-iodoaniline, respectively, is reported herein. All crystals and co-crystals have been characterised by means of solid-state complementary techniques (X-ray diffraction, solid-state NMR spectroscopy, absorption and emission spectroscopy). The role of halogen bonding and crystal packing in the optical and chromic properties of all solid materials is discussed. All solids exhibit thermochromic behaviour, and three of them (2, 2 ⋅I2F4 and 3 ⋅I2F4) are also photochromic. Imine derivative 3 crystallises in two different polymorphic forms (3 A and 3 B) and a solvate (3 ). The bromo and iodo derivatives, 2 and 3 B, are isomorphous and form isomorphous co-crystals with I2F4, but behave differently when exposed to UV light because only crystalline 2 is photochromic. Interestingly, the replacement of bromine with iodine seems to turn off the photochromism because crystalline 3 A and 3 , and even the 2 3 solid solution, do not manifest photochromic behaviour.

show abstract

Section: Resultssupporting

confidence: 71%

Halogen‐Bond Effects on the Thermo‐ and Photochromic Behaviour of Anil‐Based Molecular Co‐crystals

Carletta

Spinelli

D’Agostino

et al. 2017

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is considered that the EHE is executed through the orbital interactions between the heavy-atom perturber and the luminophore. 3 Although the EHE has been routinely used to boost molecular phosphorescence 4,5,6,7,8,9,10,11,12 for various applications, 13,14,15 very few reports are focused on the mechanistic perspective. 16 Here, we synthesized two types of organic aromatic molecules, carbazole and quinolinium derivatives (Chart 1), based on the relative energy-level of the HOMO (or basicity) / LUMO (or acidity) and combine them with heavy-atom perturbers to generate room-temperature phosphorescence (RTP) 17,18 in the solid state.…”

Section: Introductionmentioning

confidence: 99%

External Heavy-Atom Effect via Orbital Interactions Revealed by Single-Crystal X-ray Diffraction

Sun¹,

Zhang²,

Li³

et al. 2016

J. Phys. Chem. A

View full text Add to dashboard Cite

Enhanced spin-orbit coupling through external heavy-atom effect (EHE) has been routinely used to induce room-temperature phosphorescence (RTP) for purely organic molecular materials. Therefore, understanding the nature of EHE, i.e., the specific orbital interactions between the external heavy atom and the luminophore, is of essential importance in molecular design. For organic systems, halogens (e.g., Cl, Br, and I) are the most commonly seen heavy atoms serving to realize the EHE-related RTP. In this report, we conduct an investigation on how heavy-atom perturbers and aromatic luminophores interact on the basis of data obtained from crystallography. We synthesized two classes of molecular systems including N-haloalkyl-substituted carbazoles and quinolinium halides, where the luminescent molecules are considered as "base" or "acid" relative to the heavy-atom perturbers, respectively. We propose that electron donation from a π molecular orbital (MO) of the carbazole to the σ* MO of the C-X bond (π/σ*) and n electron donation to a π* MO of the quinolinium moiety (n/π*) are responsible for the EHE (RTP) in the solid state, respectively.

show abstract

“…The pyrene/1,4-DITFB 162 cocrystal displayed strong RTP with an average lifetime of 0.574 ms 163 [22]. Subsequently, RTP cocrystals built with 1,4-DITFB were 164 extended to polycyclic aromatic hydrocarbons, such as biphenyl 165 (BP), naphthalene (Nap) and phenanthrene (Phe) [23], fluorene 166 analogues [24], as well as conjugated hydrocarbons (diphenylace-167 tylene (DPA), trans-stilbene(tS)) [25] (Fig. 5a).…”

mentioning

confidence: 99%

Room-temperature phosphorescence from purely organic materials

Liu

Zhan

Liu

et al. 2016

Chinese Chemical Letters

View full text Add to dashboard Cite

Tipping the Balance with the Aid of Stoichiometry: Room Temperature Phosphorescence versus Fluorescence in Organic Cocrystals

Cited by 83 publications

References 56 publications

Halogen‐Bond Effects on the Thermo‐ and Photochromic Behaviour of Anil‐Based Molecular Co‐crystals

Halogen‐Bond Effects on the Thermo‐ and Photochromic Behaviour of Anil‐Based Molecular Co‐crystals

External Heavy-Atom Effect via Orbital Interactions Revealed by Single-Crystal X-ray Diffraction

Room-temperature phosphorescence from purely organic materials

Contact Info

Product

Resources

About