Hybrid organic–inorganic, hexa-arm dendrimers based on an Mo₆Cl₈ core

Abstract

Dendrons with focal phenoxide groups were shown to substitute for triflate or methoxide ligands around an Mo₆Cl₈ core to form molecules of the form Mo₆(µ₃-Cl)₈(OR)₆ where R = dendrons with zero to two hyperbranches, respectively; these molecules represent a new type of metal cluster core dendrimer with six arms and high symmetry.

References

1. C. B. Gorman, Adv. Mater., 1998, 10, 295.
2. C. B. Gorman, B. L. Parkhurst, K.-Y. Chen and W. Y. Su, J. Am. Chem. Soc., 1997, 119, 1141.
3. C. B. Gorman, Adv. Mater., 1997, 9, 1117.
4. P. Bhyrappa, J. K. Young, J. S. Moore and K. S. Suslick, J. Am. Chem. Soc., 1996, 118, 5708.
5. J. P. Collman, L. Fu, A. Zingg and F. Diederich, Chem. Commun., 1997, 193.
6. P. J. Dandliker, F. Diederich, M. Gross, C. B. Knobler, A. Louati and E. M. Sanford, Angew. Chem., Int. Ed. Engl., 1994, 33, 1739.
7. P. J. Dandliker, F. Diederich, J.-P. Gisselbrecht, A. Louati and M. Gross, Angew. Chem. Int., Ed. Engl., 1995, 34, 2725.
8. D.-L. Jiang and T. Aida, Chem. Commun., 1996, 1523.
9. J. Issberner, F. Vögtle, L. De Cola and V. Balzani, Chem. Eur. J., 1997, 3, 706.
10. B. Hong, T. P. S. Thoms, H. J. Murfee and M. J. Lebrun, Inorg. Chem., 1997, 36, 6146.
11. F. J. Feher and K. D. Wyndham, Chem. Commun., 1998, 323.
12. Use of a Re₆Se₈ core has also recently been reported: Z. Zheng and R. Wang, 217th American Chemical Society Meeting, Anaheim, CA, March 1999, Paper INOR563.
13. N. Prokopuk and D. F. Shriver, Inorg. Chem., 1997, 36, 5609.
14. P. Nannelli and B. P. Block, Inorg. Chem., 1969, 8, 1767.
15. P. Nannelli and B. P. Block, Inorg. Chem., 1968, 7, 2423–2426.
16. N. Perchenek and A. Simon, Z. Anorg. Allg. Chem., 1993, 619, 103.
17. D. H. Johnston, D. C. Gaswick, M. C. Lonergan, C. L. Stern and D. F. Shriver, Inorg. Chem., 1992, 31, 1869.
18. J. H. Golden, H. Deng, F. J. DiSalvo, J. M. J. Fréchet and P. M. Thompson, Science, 1995, 268, 1463.
19. K.-Y. Chen and C. B. Gorman, J. Org. Chem., 1996, 61, 9229.
20. P. Nannelli and B. P. Block, Inorg. Synth., 1971, 13, 99.
21. For experimental details see http://www.rsc.org/suppdata/cc/1999/877/.
22. To a suspension of Na₂[Mo₆Cl₈(OMe)₆](80 mg, 0.073 mmol) in a solution of Lχ(χ= 1, 2)(0.47 mmol) in 1,2-dichlorobenzene (3 ml), 3 ml of anhydrous methanol was added with stirring. The resulting mixture became clear immediately, and was further stirred overnight under a partial vacuum of 100 mTorr. This allowed solvents and byproduct methanol to be removed slowly, and a yellow solid remained. The residue was dissolved into 4 ml of toluene, and filtered under nitrogen to remove the unreacted starting cluster, and then 10 ml of Et₂O was added to the filtrate. The precipitate was collected and washed with Et₂O. The product was further purified by precipitation from toluene–Et₂O several times (yield: 92% for G1). Molecule G0 was prepared similarly except that DMF was substituted for 1.2-dichlorobenzene.
23. Crystal data for Mo₆Cl₈C₆₀H₇₉O_16.5Na₂(NaG0·4THF·2Et₂O): M= 1969.50, monoclinic, space group C2/c, a= 22.9666(19), b= 18.1932(18), c= 18.1761(19)Å, U= 7509.8(12)ų, T= 148 K, Z= 4, µ= 1.33 mm^–1, 8106 reflections measured, 6108 of which had intensities > 1.0 σ(I) and were considered observed. The structure was refined using full matrix least squares based on F. The final R and R_w were 0.036 and 0.041 respectively. CCDC 182/1218. See: http://www.rsc.org/suppdata/cc/1999/877/ for crystallographic files in .cif format.
24. M. H. Chisholm, J. A. Heppert and J. C. Huffman, Polyhedron, 1984, 3, 475.
25. C. G. Enke, Anal. Chem., 1997, 69, 4885.