Supramolecular Phosphorescent Trinuclear Copper(I) Pyrazolate Complexes for Vapochromic Chemosensors of Ethanol

Hendrik Oktendy Lintang(1*), Nur Fatiha Ghazalli(2), Leny Yuliati(3)

(1) Ma Chung University, Malang, Indonesia
(2) Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor
(3) Ma Chung Research Center for Photosynthetic Pigments, Universitas Ma Chung, Malang 65151, East Java
(*) Corresponding Author


We highlight that by using supramolecular single crystals of phosphorescent trinuclear copper(I) pyrazolate complexes with different molecular structures (2A-E), vapochromic chemosensors were successfully designed for sensing ethanol with high sensing capability. These complexes 2A-E were synthesized from non-side chain, 3,5-dimethyl, 3,5-bis(trifluoromethyl), 3,5-diphenyl and 4-(3,5-dimethoxybenzyl)-3,5-dimethyl pyrazole ligands (1A-E) in 83, 97, 99, 88 and 85% yields, respectively. All complexes showed emission bands centered at 553, 584, 570 and 616 nm upon an excitation at 280 nm for complexes 2A-C,E, respectively and 642 nm upon an excitation at 321 nm for complex 2D with lifetime in microseconds, indicating a large Stoke shift for phosphorescent compounds. These emission spectra were in good agreement with their colors from green to red upon exposure to a UV lamp with an excitation at 254 nm in dark room. Upon exposure to ethanol in 5 min, quenching, photoinduced energy transfer and shifting of emission intensities were observed for chemosensors 2A-C, 2D and 2E, respectively. Interestingly, chemosensor 2E only showed completely and autonomously recovery of its original emission intensity. Such novel finding in sensing capability might be caused by a weak intermolecular hydrogen bonding interaction of ethanol to oxygen atoms at dimethoxybenzyl side-chains of the pyrazole ring.


ethanol; phosphorescent properties; trinuclear copper(I) pyrazolate complexes; vapochromic chemosensor

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[1] Elosua, C., Bariain, C., Matias, I.R., Rodriguez, A., Colacio, E., Salinas-Castillo, A., Segura-Carretero, A., and Fernandez-Gutiérrez, A., 2008, Pyridine vapors detection by an optical fibre sensor, Sensors, 8 (2), 847–859.

[2] Mikov, I., Mikov, A., Siriski, J., Mikov, M., and Milovanov, V., 2000, Effect of simultaneous exposure to benzene and ethanol on urinary phenol excretion in mice, J. Occup. Health, 42 (5), 258–259.

[3] Prodi, L., Bolletta, F., Montalti, M., and Zaccheroni, N., 2000, Luminescent chemosensors for transition metal ions, Coord. Chem. Rev., 205 (1), 59–83.

[4] Zhang, X., Li, B., Chen, Z.H., and Chen, Z.N., 2012, Luminescence vapochromism in solid materials based on metal complexes for detection of volatile organic compounds (VOCs), J. Mater. Chem., 22 (23), 11427–11441.

[5] Krytchankou, I.S., Koshevoy, I.O., Gurzhiy, V.V., Pomogaev, V.A., and Tunik, S.P., 2015, Luminescence solvato-and vapochromism of alkynyl-phosphine copper clusters, Inorg. Chem., 54 (17), 8288–8297.

[6] Pu, S., Ma, L., Liu, G., Ding, H., and Chen, B., 2015, A multiple switching diarylethene with a phenyl-linked rhodamine B unit and its application as chemosensor for Cu2+, Dyes Pigm., 113, 70–77.

[7] Peng, H., Stich, M.I.J., Yu, J., Sun, L.N., Fischer, L.H., and Wolfbeis, O.S., 2010, Luminescent europium(III) nanoparticles for sensing and imaging of temperature in the physiological range, Adv. Mater., 22, 716–719.

[8] Elosúa, C., Bariáin, C., Matías, I.R., Arregui, F.J., Luquin, A., and Laguna, M., 2006, Volatile alcoholic compounds fibre optic nanosensors, Sens. Actuators, B, 115, 444–449.

[9] Macagnano, A., Perri, V., Zampetti, E., Bearzotti, A., and De Cesare, F., 2016, Humidity effects on a novel eco-friendly chemosensor based on electrospun PANi/PHB nanofibres, Sens. Actuators, B, 232, 16–27.

[10] Endres, H.E., Hartinger, R., Schwaiger, M., Gmelch, G., and Roth, M., 1999, A capacitive CO2 sensor system with suppression of the humidity interference, Sens. Actuators, B, 57 (1-3), 83–87.

[11] Xu, Z., Chen, X., Kim, H.N., and Yoon, J., 2010, Sensors for the optical detection of cyanide ion, Chem. Soc. Rev., 39 (1), 127–137.

[12] Kobayashi, A., and Kato, M., 2014, Vapochromic platinum(II) complexes: Crystal engineering toward intelligent sensing devices, Eur. J. Inorg. Chem., 2014 (27), 4469–4483.

[13] Bell, T.W., and Hext, N.M., 2004, Supramolecular optical chemosensors for organic analytes, Chem. Soc. Rev., 33 (9), 589–598.

[14] Mancin, F., Rampazzo, E., Tecilla, P., and Tonellato, U., 2006, Self‐assembled fluorescent chemosensors, Chem. Eur. J., 12 (7), 1844–1854.

[15] Nagel, C.C., 1998, Preparation of vapochromic double complex salts, Eur. Pat. Appl. EP, 277003.

[16] Lancaster, G.D., Moore, G.A., Stone, M.L., and Reagen, W.K., 1995, Volatile organic compound sensing devices, U.S. Patent 5, 445795.

[17] Mann, K.R., Daws, C.A., Exstrom, C.L., Janzen, D.E., and Pomije, M., 1998, Vapochromic platinum-complexes and salts, U.S. Patent 5, 766952.

[18] Wenger, O.S., 2013, Vapochromism in organometallic and coordination complexes: chemical sensors for volatile organic compounds, Chem. Rev., 113 (5), 3686–3733.

[19] Enomoto, M., Kishimura, A., and Aida, T., 2001, Coordination metallacycles of an achiral dendron self-assemble via metal-metal interaction to form luminescent superhelical fibers, J. Am. Chem. Soc., 123 (23), 5608–5609.

[20] Ghazalli, N.F., Yuliati, L., Endud, S., Shamsuddin, M., and Lintang, H.O., 2014, Vapochromic copper(I) pyrazolate complex materials for phosphorescent chemosensors of ethanol, Adv. Mater. Res., 970, 44–47.

[21] Kishimura, A., Yamashita, T., and Aida, T., 2005, Phosphorescent organogels via “metallophilic” interactions for reversible RGB-color switching, J. Am. Chem. Soc., 127 (1), 179–183.

[22] Hu, B., Gahungu, G., and Zhang, J., 2007, Optical properties of the phosphorescent trinuclear copper(I) complexes of pyrazolates: Insights from theory, J. Phys. Chem. A, 111 (23), 4965–4973.

[23] Dias, H.R., Polach, S.A., and Wang, Z., 2000, Coinage metal complexes of 3,5-bis (trifluoromethyl) pyrazolate ligand: synthesis and characterization of {[3,5-(CF3)2Pz] Cu}3 and {[3,5-(CF3)2Pz] Ag}3, J. Fluorine Chem., 103 (2), 163–169.

[24] Kishimura, A., 2005, Novel luminescent materials based on the self–assembly via metal–metal interactions among group 11 metal ions, Thesis, University of Tokyo, GI1 – GI35 and III1-III27.

[25] Dias, H.R., Diyabalanage, H.V., Eldabaja, M.G., Elbjeirami, O., Rawashdeh-Omary, M.A., and Omary, M.A., 2005, Brightly phosphorescent trinuclear copper(I) complexes of pyrazolates: Substituent effects on the supramolecular structure and photophysics, J. Am. Chem. Soc., 127 (20), 7489–7501.

[26] Dias, H.R., Diyabalanage, H.V., Rawashdeh-Omary, M.A., Franzman, M.A., and Omary, M.A., 2003, Bright phosphorescence of a trinuclear copper(I) complex: Luminescence thermochromism, solvatochromism, and “concentration luminochro mism”, J. Am. Chem. Soc., 125 (40), 12072–12073.

[27] Kishimura, A., Yamashita, T., Yamaguchi, K., and Aida, T., 2005, Rewritable phosphorescent paper by the control of competing kinetic and thermodynamic self-assembling events, Nat. Mater., 4, 546–549.

[28] Lintang, H.O., Kinbara, K., Tanaka, K., Yamashita, T., and Aida, T., 2010, Self-repair of a one-dimensional molecular assembly in mesoporous silica by a nanoscopic template effect, Angew. Chem. Int. Ed., 49 (25), 4241–4245.

[29] Lintang, H.O., Kinbara, K., Yamashita, T., and Aida, T., 2010, Heating effect of a one-dimensional molecular assembly on self-repairing capability in the nanoscopic channels of mesoporous silica, Proceedings of International Conferences on Enabling Science and Nanotechnology (ESciNano), Article Number 5700970, ISBN: 978-1-4244-8853-7.

[30] Lintang, H.O., Kinbara, K., Tanaka, K., Yamashita, T., and Aida, T., 2012, Metal-ion permeation in congested nanochannels: The exposure effect of Ag+ ions on the phosphorescent properties of a gold(I)–pyrazolate complex that is confined in the nanoscopic channels of mesoporous silica, Chem. Asian J., 7 (9), 2068–2072.

[31] Lintang, H.O., Kinbara, K., and Aida, T., 2012, Thermally resistive phosphorescent molecular assembly in the channels of mesoporous silica nanocomposites, Proceedings of International Conferences on Enabling Science and Nanotechnology (ESciNano), Article Number 6149684, ISBN: 978-1-4577-0799-5.

[32] Lintang, H.O., Yuliati, L., and Endud, S., 2014, Phosphorescent sensing and imaging of temperature using mesoporous silica/gold nanocomposites, Mater. Res. Innovations, 18, S6-444–S6-448.

[33] Jalani, M.A., Yuliati, L., Endud, S., and Lintang, H.O., 2014, Synthesis of mesoporous silica nanocomposites for preparation of gold nanoparticles, Adv. Mater. Res., 925, 233–237.

[34] Jalani, M.A., Yuliati, L., Lintang, H.O., 2014, Thermal hydrogen reduction for synthesis of gold nanoparticles in the nanochannels of mesoporous silica composite, Jurnal Teknologi, 70 (1), 131–136.

[35] Zhao, Q., Li, F., and Huang, C., 2010, Phosphorescent chemosensors based on heavy-metal complexes, Chem. Soc. Rev., 39 (8), 3007–3030.

[36] Sathish, V., Ramdass, A., Thanasekaran, P., Lu, K.L., and Rajagopal, S., 2015, Aggregation-induced phosphorescence enhancement (AIPE) based on transition metal complexes–an overview, J. Photochem. Photobiol., C, 23, 25–44.

[37] Analytical Methods Committee, 1987, Recommendations for the definition, estimation, and use of detection limit, Analyst, 112, 199–204.


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