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Dalton Transactions
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Journal Name
138.29 (ArC), 137.92 (ImC), 131.75 (ArC), 123.73 (ArC), 122.60
ARTICLE
(ArC), 122.19 (ImC), 59.50 (CH2) ppm. FT‐IR (neat): ῡ = lead nitrate and different organic ligandDsOysI:t1e0m.10s3b9a/Cse5DdTo04n4t0h9eJ
3356(w), 3103(w), 3030(w), 1696(s), 1647(w), 1607(m), imidazolium carboxylate along with variable structural
1549(m), 1422(m), 1394(s), 1343(m), 1321(s), 1304(s), 1214(s), freedom at organic spacer. We have also shown that a novel
1121(m), 1069(m), 1037(w), 1014(w), 990(w), 954(w), 862(m), structural topologies and versatile coordination properties
826(w), 798(w), 768(s), 685(m), 649(w), 615(m) cm‐1.
could be achieved by changing the number of flexible node at
organic spacer and employing judicious synthetic strategies.
The first catalytic application of imidazolium carboxylate
Synthesis of [Pb4(L2)2(NO3)8(H2O)4]nxH2O (3)
A suspension of L2H2Br2 (0.05 g, 0.09 mmol) and Pb(NO3)2 spacers supported lead assemblies has been explored. The
(0.06 g, 0.18 mmol) in water (3 ml) and DMF (2 ml) was present catalytic demonstration evidence that the catalysts 1‐5
o
maintained at 100 C for 12 h then slowly brought to room shows the high nucleophilic activity, facilitating a proton
temperature. The colourless crystals of was obtained within transfer, ability to stabilize negative charge in active aldehyde
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12 h. Yield: 45% (based on Pb(NO3)2). M.p., 279‐282 C. FT‐IR intermediate and ability to depart finally. Their catalytic
(neat): ῡ = 3080(w), 1601(w), 1531(m), 1386(s), 1298(s), applications in benzoin condensation reactions have been
1214(m), 1114(w), 1067(w), 1013(w), 849(s), 778(m), 722(w), promising with different aldehydes. Structural insight into
675(w), 636(m), 598(w) cm‐1.
these compounds provides explanations for the diverse
catalytic behaviours of these compounds. Future studies on
the reactivity of these ligands and their heavier main‐group
Synthesis of [Pb(L3)(Cl)]n (4)
A mixture of L3H2Cl (0.05 g, 0.15 mmol) and Pb(NO3)2 (0.10 metal complexes toward organic transformations are
g, 0.29 mmol) in DMF (3 mL) was heated at 120 °C for 12 h underway in our laboratory.
under solvothermal condition. Yield: 54% (based on Pb(NO3)2).
M.p., 290‐292 oC (decomp.). FT‐IR (neat): ῡ = 3067(w),
1598(m), 1538(s), 1374(s), 1306(s), 1246(m), 1171(m),
Acknowledgements
We gratefully acknowledge the DST‐FT (SR/FT/CS‐94/2010) for
1092(m), 1058(w), 1034(w), 1011(w), 950(w), 874(m), 845(s),
800(s), 741(m), 715(m), 696(s), 660(m), 617(m) cm‐1.
financial support. CNB thank UGC for the fellowship.
Synthesis of [Pb(L3)(NO3)]n (5)
L3HCl (0.05 g, 0.15 mmol), Pb(NO3)2 (0.10 g, 0.29 mmol)
and DMF (5 ml) were loaded in a schlenk tube. Subsequently,
the schlenk tube temperature was maintained at 120 C for
Notes and references
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two days then slowly allowed to reach at room temperature.
The colourless crystals of were obtained within 12 h. Yield:
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S. Sen, N. N. Nair, T. Yamada, H. Kitagawa and P. K.
Bharadwaj, J. Am. Chem. Soc., 2012, 134, 19432.
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(a) J. Y. Lee, J. M. Roberts, O. K. Farha, A. A. Sarjeant, K. A.
Scheidt and J. T. Hupp, Inorg. Chem., 2009, 48, 9971; (b) G.
Nickerl, A. Notzon, M. Heitbaum, I. Senkovska, F. Glorius and
S. Kaskel, Cryst.Growth Des., 2012, 13, 198; (c) S. Wang, Q.
Yang, J. Zhang, X. Zhang, C. Zhao, L. Jiang and C.‐Y. Su, Inorg.
Chem., 2013, 52, 4198; (d) S. Sen, S. Neogi, A. Aijaz, Q. Xu
and P.K. Bharadwaj, Inorg. Chem., 2014, 53, 7591; (e) S. Sen,
T. Yamada, H. Kitagawa and P.K. Bharadwaj, Cryst. Growth
Des., 2014, 14, 1240.
(a) C. I. Ezugwu, N. A. Kabir, M. Yusubov and F. Verpoort,
Coord. Chem. Rev., 2015, in press and references therein; (b)
J. Lee, O. K. Farha, J. Roberts, K. A. Scheidt, S. T. Nguyen and
J. T. Hupp, Chem. Soc. Rev., 2009, 38, 1450.
G‐Q. Kong, X. Xu, C. Zou and C.‐D. Wu, Chem. Commun.,
2011, 47, 11005.
G.‐Q. Kong, S. Ou, C. Zou and C.‐D. Wu, J. Am. Chem. Soc.,
2012, 134, 19851.
A. Burgun, R. S. Crees, M. L. Cole, C. J. Doonan and C. J.
Sumby, Chem. Commun., 2014, 50, 11760.
50% (based on Pb(NO3)2). M.p., 280‐282 C (decomp.). FT‐IR
(neat): ῡ = 3093(w), 3057(w), 1608(m), 1579(m), 1545(s),
1512(m), 1430(w), 1353(s), 1312(s), 1252(s), 1156(m),
1133(m), 1062(m), 1008(m), 945(w), 862(m), 838(m), 774(s),
710(m), 685(m), 628(m) cm‐1.
Reaction condition of benzoin condensation reactions
Oven dried Schlenk was charged with catalysts (1 mol%),
benzaldehyde (0.94 mmol) then dried under vacuum for 5 min.
Solvent (5 mL) was added under nitrogen condition to the
reaction mixture, evacuated for few seconds, refilled with
nitrogen then KOt‐Bu (4 mol%) was added to the reaction
mixture under nitrogen condition at room temperature. The
reaction progress was monitored by TLC. The reaction mixture
was diluted with water (10 mL) and DCM (10 mL). The organic
phase was separated, washed with brine solution (7 mL), dried
over anhydrous sodium sulphate then the reaction mass was
concentrated under reduced pressure to get crude compound.
The crude compound was absorbed on silica gel (100‐200
mesh) for purification then petroleum ether and 10% ethyl
acetate/petroleum ether (200 mL) were poured on column to
separate the final product.
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M. B. Lalonde, O. K. Farha, K. A. Scheidt and J. T. Hupp, ACS
Catal., 2012, 2, 1550.
X. W. Wang, L. Han, T‐J. Cai, Y‐Q. Zheng, J‐Z. Chen and Q.
Deng, Crystal Growth & Design., 2007, , 1027.
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K. Nakamoto, Infrared and Raman Spectra of Inorganic and
Coordination Compounds, Part B: Applications in
Coordination, Organometallic and Bioinorganic Chemistry,
6th Ed.; John Wiley & Sons, Inc. New Jersey, 2009.
10 For selected examples of NHC mediated Benzoin
Condensation reaction: (a) D. Enders, O. Niemeier and A.
Henseler, Chem. Rev., 2007, 107, 5606; (b) I. Piel, M. D.
Conclusions
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J. Name., 2013, 00, 1‐3 | 9
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