84
L. Mishra et al. / Spectrochimica Acta Part A 70 (2008) 79–85
complex 2 from 292 to 290 nm occurs on binding with Na+
ion.
Caution! Although no problems were encountered in this
work, perchlorate salts are potentially explosive. They should
be prepared in small quantities and handled with care.
To look into the binding pattern of Na+ ion with complexes
1 and 2, changes in peak positions of a representative complex
2 (10−4 M in DMSO) at λmax (294 nm) has been monitored by
adding different concentrations of NaClO4 and spectral varia-
tion is shown in Fig. 3. Binding constant as calculated using
Benesi–Hilde Brand equation [35] has been found to be 5 × 105
and shows substantial binding for Na+ ion. To show the direct
and clear view of binding of Na+ ion, space filling model of the
Na+ bound and unbound complexes 4 and 2 as shown in Fig. 4
Acknowledgements
AuthorswishtothankProf. RajeevJain, SchoolofChemistry,
Jiwaji University, Gwalior, India for providing electrochemical
data. Financial assistance received from UGC, New Delhi, India
to one of the authors (RP) is gratefully acknowledged.
˚
indicate the formation of the cavity of ∼1 A radii clearly (as cal-
References
culated tentatively using reported parameters of bond lengths
[1] N. Kameta, K. Hiratani, Chem. Commun. 725 (2005), and references
therein.
[2] L. Mishra, K. Bindu, L.C. Nathan, Ind. J. Chem. 41A (2002) 2533.
[3] N. Hoshimo, T. Iambe, J. Mitani, Y. Maruyama, Bull. Chem. Soc. Jpn. 61
(1988) 4207.
gets closed upon sitting of Na+ ion in the cavity as the radii of
+
˚
Na ion (0.9–1 A) is closer to the size of cavity. To check the
selective fitting of Na+ ion in the cavity, the space filling models
[36] of the complex 2 in presence of K+ and Li+ ions were also
looked upon but binding of K+ ion lead breaking of the system
whereas Li+ ion came out of the cavity. This behaviour suggests
that the cavity of the complexes is found selective for binding
of Na+ ion.
[4] P.G. Cozzi, Chem. Soc. Rev. 33 (2004) 410.
[5] T. Katsuki, Chem. Soc. Rev. 33 (2004) 437.
[6] X. Yang, R.A. Jones, J. Am. Chem. Soc. 127 (2005) 7686.
[7] M. Adelt, M.J. Devenney, J. Meyer, D.W. Thompson, J.A. Treadway, Inorg.
Chem. 37 (1998) 2616.
[8] A.P. De Silva, B. Mc Caugham, B.O. Mc Kinney, M. Querol, Dalton Trans.
(2003) 1902.
[9] L. Mishra, A.K. Yadaw, S. Srivastava, A.B. Patel, N. J. Chem. 24 (2000)
505.
[10] B.P. Sullivam, T.J. Meyer, Inorg. Chem. 17 (1978) 3334.
[11] L. Mishra, K. Bindu, S. Bhattacharya, Inorg. Chem. Commun. 7 (2004)
777.
[12] J.C. Rodriguez, B. Alpha, D. Plancherel, J.M. Lehn, Helv. Chim. Acta 67
(1984) 2264.
[13] W.J. Geary, Coord. Chem. Rev. 7 (1971) 81.
[14] K.C. Zheng, J.P. Wang, W.L. Peng, Y. Shen, F.C. Yun, Inorg. Chim. Acta
328 (2002) 247.
[15] K.C. Zheng, J.P. Wang, Y. Shen, W.L. Peng, F.C. Yun, J. Chem. Soc., Dalton
Trans. (2002) 111.
[16] H. Xu, K.-C. Zheng, H. Deng, L.-J. Lin, Q.-L. Zhang, L.-N. Ji, N. J. Chem.
27 (2003) 1255.
[17] H. Xu, K.-C. Zheng, Y. Chen, Y.-Z. Li, L.J. Lin, H. Li, P.-X. Zhang, L.-N.
Ji, Dalton Trans. (2003) 2260.
[18] N. Iordanova, S.H. Schiffer, J. Am. Chem. Soc. 124 (2002) 4848.
[19] S. Fantacci, F.D. Angelis, J. Wang, S. Bernhard, A. Selloni, J. Am. Chem.
Soc. 126 (2004) 9715.
[20] S. Shi, J. Liu, J. Li, K.C. Zheng, C.P. Tan, T.M. Chen, L.N. Ji, Dalton Trans.
(2005) 2038.
To look into the effect of anions on the binding of
Na+, similar experiments have been performed by the addi-
tion of different concentration of NaCl, NaBr and NaI to a
fixed concentration (10−4 M) of the complex 2 again mon-
itored at λmax = 294 nm. Binding constants thus evaluated
are KNaCl (2.94 × 105 M−1) > KNaBr (2.08 × 105 M−1) > KNaI
(1.63 × 105 M−1). Whencomparedwiththebindingconstantfor
KNaClO (5 × 105 M−1), one concludes that non-coordinating
4
anion like ClO4− supported the stabilization of the system. Pos-
itive test by anions (Cl−, Br− and I−) with aqueous solution of
AgNO3 support that anions are present out of the coordination
sphere.
Since Ru(II)bipyridyl appended systems have intentionally
been constructed owing to its luminescent nature, therefore
emission spectra of Na+ unbound (1 and 2) and bound (3
and 4) complexes have been recorded. To get a visible sup-
port, the fluorescent intensity of representative complexes 2
and 4 has been compared using a NIKON-ECLIPSE TS
100-F model fluorescence microscope. It was found that
(Fig. 5). This finding goes parallel to K+-induced enhance-
ment in fluorescence of anthracene appended macrocycle
in alkaline medium as reported earlier by de Silva et al.
[37].
[21] K. Karidi, A. Garou, A. Tsipis, N. Hadjiliadis, H.D. Dulk, J. Reedijk, Dalton
Trans. (2005) 1176.
[22] M.J. Frish, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R.
Cheeseman, V.G. Zakrzewski, J.A. Montgomery Jr., R.E. Stratmann, J.C.
Burant, S. Dapprich, J.M. Millam, A.D. Daniels, K.N. Kudin, M.C. Strain,
O. Farkas, J. Tomasi, V. Barone, M. Cossi, R. Cammi, B. Mennucci, I.C.
Pomell, C. Adamo, S. Clifford, J. Ochterski, G.A. Petersson, P.Y. Ayala,
Q. Cui, K. Morokuma, D.K. Malick, A.D. Rabuck, K. Raghavachari, J.B.
Foresman, J. Cioslowski, J.V. Ortiz, B.B. Stefanov, G. Liu, A. Liashenko, P.
Piskorz, I. Komaromi, R. Gomperts, R.L. Martin, D.J. Fox, T. Keith, M.A.
Al-Laham, C.Y. Peng, A. Nanayakkara, C. Gonzalez, M. Challacombe,
P.M.W. Gill, B. Johnson, W. Chen, M.W. Wong, J.L. Andres, C. Gonzalez,
M. Head-Gordon, E.S. Replogle, J.A. Pople, GAUSSIAN’98 (Revision
A.11), Gaussian, Inc., Pittsburgh, PA, 2001.
4. Conclusion
Simple
metallomacrocycles
bearing
luminescent
[Ru(bpy)2]2+ unit in the structural framework of salen
and salophen have been synthesized and characterized.
Their binding with Na+ ion has been monitored by UV/vis
and emission spectra. The enhanced luminescence inten-
sity of complex 2 upon binding with Na+ ion has also
been monitored by luminescence microscopic measur-
ements.
[23] A.D. Becke, J. Chem. Phys. 98 (1993) 5648.
[24] C. Lee, W. Yang, R.G. Parr, Phys. Rev. B17 (1988) 785.
[25] R. Krishnan, J.S. Binkley, R. Seeger, J.A. Pople, J. Chem. Phys. 72 (1980)
650.
[26] A.D. McClean, G.S. Chandler, J. Chem. Phys. 72 (1980) 5639.