be expected to differ substantially between ‘Ru(L)Ru’ and e.g. its
ether analogue these results suggest that L is not only an efficient
mediator for resonance exchange but also for inductive effects.
In summary, the non-linear amine-linked bis-tpy ligand de-
scribed herein can be employed as a bridging ligand in dinuclear
or polynuclear complexes. Compared to similar bis-tpy bridging
ligands ‘Ru(L)Ru’ features substantially stronger metal–metal
interaction in the mixed-valence state. From the ∼120◦ angle ob-
served in the X-ray crystal structure, it is intriguing to consider its
potential use in the self-assembly of hexagonal metallomacrocycles
with pronounced metal–metal interactions.
3 (a) E. C. Constable, R. W. Handel, C. E. Housecroft, A. Fa`rran,
Morales, B. Ventura, L. Flamigni and F. Barigelletti, Chem.–Eur. J.,
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4 (a) S.-H. Hwang, C. N. Moorefield, P. Wang, J.-Y. Kim, S.-W. Lee
and G. R. Newkome, Inorg. Chim. Acta, 2007, 360, 1780; (b) S.-H.
Hwang, C. N. Moorefield, P. Wang, F. R. Fronczek, B. H. Courtney
and G. R. Newkome, Dalton Trans., 2006, 3518; (c) E. C. Constable,
B. A. Hermann, C. E. Housecroft, M. Neuburger, S. Schaffner and
L. J. Scherer, New J. Chem., 2005, 29, 1475; (d) M. Ruben, J. Rojo, F. J.
Romero-Salguero, L. H. Uppadine and J.-M. Lehn, Angew. Chem., Int.
Ed., 2004, 43, 3644; (e) G. R. Newkome, T. Joon, Cho, C. N. Moorefield,
R. Cush, P. S. Russo, L. A. God´ınez, M. J. Saunders and P. Mohapatra,
Chem.–Eur. J., 2002, 8, 2946.
5 E. C. Constable, A. M. W. Cargill Thompson, P. Harveson, L. Macko
and M. Zehnder, Chem.–Eur. J., 1995, 1, 360.
This work was financially supported by the Swedish Energy
Agency, the Knut and Alice Wallenberg Foundation, the Carl
Trygger Foundation and NEST-STRP, SOLAR-H (EU Contract
516510).
6 (a) For recent reviews dealing with 2,2ꢀ:6ꢀ,2ꢀꢀ-terpyridine synthesis,
see: U. S. Schubert, H. Hofmeier and G. R. Newkome, in Modern
Terpyridine Chemistry, WILEY-VCH, Weinheim, 2006, ch. 2, pp. 7–
35; (b) M. Heller and U. S. Schubert, Eur. J. Org. Chem., 2003, 947;
(c) R.-A. Fallahpour, Synthesis, 2003, 155.
7 (a) A. Winter, A. M. J. van den Berg, R. Hoogenboom, G. Kickelbick
and U. S. Schubert, Synthesis, 2006, 2873; (b) S. Vaduvescu and P. G.
Potvin, Inorg. Chem., 2002, 41, 4081; (c) E. C. Constable and A. M. W.
Cargill Thompson, J. Chem. Soc., Dalton Trans., 1992, 3467; (d) F.
Kro¨hnke, Synthesis, 1976, 1.
8 (a) F. She Han, M. Higuchi and D. G. Kurth, Org. Lett., 2007, 9, 559;
(b) S.-C. Yuan, H.-B. Chen, Y. Zhang and J. Pei, Org. Lett., 2006, 8,
5701; (c) A. Khatyr and R. Ziessel, J. Org. Chem., 2000, 65, 3126.
9 (a) P. R. Andres and U. S. Schubert, Synthesis, 2004, 1229; (b) U. S.
Schubert, S. Schmatloch and A. A. Precup, Des. Monomers Polym.,
2002, 5, 211; (c) G. R. Newkome and E. He, J. Mater. Chem., 1997, 7,
1237.
Notes and references
‡ The reaction was typically performed in a sealed vial on a 0.4 mmol
scale (Cl-tpy) in 3 mL argon-degassed toluene. Analytical data for bis(4ꢀ-
(2,2ꢀ:6ꢀ,2ꢀꢀ-terpyridyl))phenylamine (L): 1H NMR (CDCl3): d 7.22–7.28 (m,
5H), 7.33 (m, 2H), 7.42 (m, 2H), 7.81 (dt, J = 7.7, 1.5 Hz, 4H), 8.20 (s,
4H), 8.55 (m, 4H), 8.59 (d, J = 8.0 Hz, 4H). 13C (CDCl3): d 114.9, 121.4,
123.8, 126.2, 127.1, 130.3, 136.8, 144.9, 149.1, 155.4, 156.1, 157.1. ESI-
MS: m/z = 556.7 (M + H+), 1133.2 (2M + Na+). X-Ray crystallography
experimental data for L: C36H25N7, monoclinic, space group C2/c (no.
◦
˚
˚
˚
15), a = 30.670(3) A, b = 8.4665(12) A, c = 22.428(2) A, a = 90 , b =
◦
◦
94.063(12) , c = 90 , V = 5809.4(11) A , Dcalc = 1.271 g cm−3, T = 293(2)
3
˚
10 (a) E. C. Constable, C. E. Housecroft and Y. Tao, Synthesis, 2004, 869;
(b) 4ꢀ-Bromo-2,2ꢀ:6ꢀ,2ꢀꢀ-terpyridine as an electrophile: B. Whittle, S. R.
Batten, J. C. Jeffery, L. H. Rees and M. D. Ward, J. Chem. Soc., Dalton
Trans., 1996, 4249.
K, Z = 8, Rint = 0.0623, R = 0.0430 for 2998 observed unique reflections.
1
§ Analytical data for Ru(L)Ru: H NMR (CD3CN): d 2.54 (s, 6H), 7.16
(m, 4H), 7.32 (m, 4H), 7.44 (m, 4H), 7.59 (d, J = 8.0 Hz, 4H), 7.63 (m,
1H), 7.69 (m, 4H), 7.79 (t, J = 7.7 Hz, 2H), 7.85 (dt, J = 7.7, 1.5 Hz, 4H),
7.91 (m, 2H), 7.99 (dt, J = 7.7, 1.5 Hz, 4H), 8.12 (d, J = 8.1 Hz, 4H),
8.39 (d, J = 7.7 Hz, 4H), 8.67 (d, J = 7.7 Hz, 4H), 8.68 (s, 4H), 9.01 (s,
4H). ESI-MS m/z = 1840.3 (M − PF6)+, 847.5 (M − 2PF6)2+, 516.7 (M −
3PF6)3+, 351.3 (M − 4PF6)4+. Anal. Calcd for C80H59N13Ru2P4F24: C 48.42,
H 3.00, N 9.18. Found: C 48.19, H 3.22, N 9.17%.
11 O. Johansson, Synthesis, 2006, 2585.
12 (a) K. W. Anderson, R. E. Tundel, T. Ikawa, R. A. Altman and S. L.
Buchwald, Angew. Chem., Int. Ed., 2006, 45, 6523; (b) X. Huang, K. W.
Anderson, D. Zim, L. Jiang, A. Klapars and S. L. Buchwald, J. Am.
Chem. Soc., 2003, 125, 6653.
13 A similar amine-linked bis-tpy ligand, bis(4ꢀ-(2,2ꢀ:6ꢀ,2ꢀꢀ-terpyridyl))-
amine was described by R.-A. Fallahpour, in a recent review (see
ref. 6(c)).
1 (a) A. C. Benniston, A. Harriman, P. Li, P. V. Patel and C. A. Sams,
J. Org. Chem., 2006, 71, 3481; (b) A. C. Benniston, A. Harriman,
P. Li, C. A. Sams and M. D. Ward, J. Am. Chem. Soc., 2004, 126,
13630; (c) J.-P. Collin, P. Laine´, J.-P. Launay, J.-P. Sauvage and A.
Sour, J. Chem. Soc., Chem. Commun., 1993, 434; (d) E. C. Constable,
A. M. W. Cargill Thompson and S. Greulich, J. Chem. Soc., Chem.
Commun., 1993, 1444.
14 The factor 4 accounts for a purely statistical contribution to the
comproportionation constant, i.e. Kc = 4 for a completely non-
interacting mixed-valence system.
15 K. Onitsuka, N. Ohara, F. Takei and S. Takahashi, Dalton Tans., 2006,
3693.
2 (a) J.-P. Launay, Chem. Soc. Rev., 2001, 30, 386; (b) M. D. Ward, Chem.
Soc. Rev., 1995, 24, 121.
16 J. E. Sutton and H. Taube, Inorg. Chem., 1981, 20, 3125.
17 N. S. Hush, Prog. Inorg. Chem., 1967, 8, 391.
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