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DOI: 10.1039/C7CC06374A
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occurred on the molecular level, where the 1-E isomer combination of porosity and novel photoactive moieties opens
transforms into the 1-Z configuration accompany with the up intriguing perspectives in the field of photoresponsive
intramolecular H-bond broken; (2) the slightly slipped materials.
molecular stacking with large rotation angle of about 121.6° in
This work was supported by National Natural Science
each dimer changes into the face-to-face π-π stacking without Foundation of China (grant no. 21477047, 21371109),
rotation; (3) four dimers in the on-top “Zigzag” mode as one Shandong Province Science Foundation (ZR2013BL002), Doctor
structure repeating unit of the 1-E crystal rearrange into an on- Foundation of University of Jinan (160070104, XB1302), and
top “line” mode serving as two building blocks to the 1-Z Natural Science Foundation of University of Jinan (XKY1502,
crystal, and (4) the on-top “line” mode building blocks arrange XKY1201).
along a and c axis to form into the herringbone structure of 1-Z
crystal. The phase transition from 1-Z to 1-E crystal promoted
by heating occurs by the reverse process.
There are no conflicts to declare.
Notes and references
The efficient photoisomerization was realized in hydrazones
crystals, relying on the solely weak intermolecular interactions
and loose packing between the molecules in the porous 1-E
‡ Details of the synthesis and structural characterization are
provided in ESI† (Scheme S1 and Figure S1). CCDC numbers of
crystal, beyond the inherent good single-molecular the single crystals: 1486572 for 1-E , 1486571 for 1-Z
.
photoreactivity of the molecules. To the best of our knowledge,
substantial E→Z photoisomerization of hydrazone between
two crystalline phases is described for the first time, and on
consideration of such crystalline structure transformation,
effective enthalpy change desired for the energy storage is
1
2
S. Kobatake, M. Irie, et al. Nature 2007, 446, 778-781.
a) Y. Yang, I. Aprahamian, et al. J. Am. Chem. Soc. 2012, 134
15221−15224; c) X. Yao, H. Tian, et al. Adv. Opt. Mater. 2016,
, 1322-1349.
a) H. M. D. Bandara, S. C. Burdette, Chem. Soc. Rev. 2012, 41
,
4
3
,
1809-1825; b) S. M. Landge, E. Tkatchouk, W. A. Goddard, I.
Aprahamian, J. Am. Chem. Soc. 2011, 133, 9812-9823.
a) H-C. J. Zhou, S. Kitagawa, Chem. Soc. Rev. 2014, 43, 5415-
5418; b) F. X. Coudert, Chem. Mater. 2015, 27, 1905–1916.
a) T. J. Kucharski, R. Boulatov, et al. Energy Environ. Sci.,
2011, 4, 4449; b) G. D. Han, J. C. Grossman, et al. J. Mater.
Chem. A 2016, 4, 16157-16165; c) K. Ishiba, C. Chikara, N.
Kimizuka, et al. Angew. Chem. Int. Ed., 2015, 54, 1532–1536.
a) A. C. Pratt, Chem. Soc. Rev. 1977, 6, 63-81; b) L. A. Tatum,
I. Aprahamian, Acc. Chem. Res. 2014, 47, 2141-2149.
a) D. G. Belov, S. M. Aldoshin, et al. Russ. Chem. Bull. 2000,
49, 666-668; b) M. N. Chaur, D. Collado, J. M. Lehn, Chem.
Eur. J. 2011, 17, 248-258.
expected. Accordingly, the enthalpy change (ꢀH) from the
metastable 1-Z to thermodynamically stable 1-E in solid states
was checked by differential scanning calorimetry and
thermogravimetric analysis (DSC-TG) on the 1-Z polycrystalline
powders. The DSC-TG curves (Fig. S4) indicate the 1-Z to 1-E
thermal isomerization occurs during the melting of the 1-Z
polycrystalline powders with a enthalpy change of 32.3 kJ/mol,
which is comparable to the azobenzene in condensed
phase,5b,c showing potential application in energy harvesting
and storage. This value is much higher than the
photoisomerizatin induced enthalpy change from 1-Z to 1-E at
4
5
6
7
moleluar level (18.4 kcal/mol) as estimited by the density
Table S3),
21
8
9
a) X. Su, T. F. Robbins, I. Aprahamian. Angew. Chem. Int. Ed.
, 50, 1841-1844; b) I. Aprahamian, Nat. Chem. 2016, 8,
functional theory
(
suggesting the large
2011
97-99.
contribution on the energy change from the multi-
intermolecular interections as mentioned above.
In conclusion, the reversible photoisomerization of
S. Yamamura, K. Ichimura, et al. Chem. Lett. 1992, 21, 543-
456.
phenylhydrazones
1 in solution and the crystalline state has
10 a) J. R. Holst, A. Trewin, A. I. Cooper, Nature Chem. 2010, 2
915–920; b) J. Li, R. Cao, Angew. Chem. Int. Ed. 2016, 55
,
,
been well demonstrated. Upon irradiation of 380 nm light or
stored in dark, the cyclic single-molecular photoisomerizations
between 1-E and 1-Z isomers in THF show good reversibility
and photochemical fatigue resistance. Above all, such
photoisomerization could proceed in crystalline state, which
induced identified crystalline structures of the 1-E and 1-Z
isomers. The intramolecular hydrogen bonds in the 1-E
molecules lead to the distortion and rigidity of the molecular
structures, which prevent a close-packed arrangement in the
crystals and promote low-density molecular self-assembly,
affording porous molecular crystals with fluctuated quasi-
hexagonal channels of about 7.07 Å in diameter and a porosity
9474-9480.
11 P. Cankař, J. Slouka, et al. J. Heterocycl. Chem., 2003, 40, 71-
76.
12 K. Stranius, K. Börjesson, Sci. Rep. 2017, DOI: 10.1038/
srep41145.
13 a) A. Isabelle, R. Odile, et al. J. Am. Chem. Soc. 2001, 123
,
8177–8188; b) S. Hong, K. Kim, et al. Angew. Chem. Int. Ed.
2015, 54, 13241-13244.
14 M. Baroncini, A. Credi, et al. Nat. Chem. 2015, 7, 634-640.
15 M. Mastalerz, I. M. Oppel, Angew. Chem. Int. Ed. 2012, 51
5252-5255.
,
16 a) P. Van der Sluis, A. L. Spek, Acta Crystallogr. Sect. A 1990,
46, 194; b) A. L. Spek, Acta Crystallogr. Sect. D 2009, 65, 148.
17 Y. Liu, W. Gan, et al. Liq. Cryst. 2011, 38, 995-1006.
18 L. Yuan, Z. Wei, et al. Adv. Mater. 2016, 28, 5980-5985.
of about 17%. This relatively loose stacking facilitates the E→Z
photoisomerization in the solid state. The efficient bulk
photoisomerization induces the disappearance of the pore
structure from the porous (1-E) to herringbone (1-Z) crystalline
19 a) K. Ariga, T. Kunitake, et al. J. Am. Chem. Soc. 1997, 119
,
2224-2231; b) F. Wang, K. Hashimoto , K. Tajima, Adv. Mater.
2015, 27, 6014-6020.
20 a) E. Moreno-Calvo, et al. Cryst. Growth Des., 2010, 10, 4262-
4271; b) V. Lloveras, J. et al. Chem. Eur. J. 2016, 22, 1805-
1815.
21 a) M. J. Frisch, et al. Gaussian 03, revision B.05, Gaussian,
Inc., 2003; b) C. T. Lee, R. G. Parr, Phys. Rev. B 1988, 37,
785–789; c) M. M. Francl, J. A. Pople, et al. J. Chem. Phys.
1982, 77, 3654–3665.
structure. The micropores can also be restored upon
isomerization promoted by heating with the enthalpy (
Z→E
H) of
ꢀ
32.3 kJ/mol in melting state following the reverse process. The
structural flexibility and photoswitchable performance make
this novel photoactive material interesting in energy
harvesting, storage and conversion. It also paves the way to a
better understanding of solid-state photochemical reactions
and photoinduced crystalline phase transitions. The special
4 | J. Name., 2012, 00, 1-3
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