Getting the right answer to a key question concerning molecular wires

Abstract

It is shown that the Cr₅(tpda)₄Cl₂ molecule has alternating long and short (Cr···Cr) contacts in three compounds, including one in which an evenly spaced chain was recently claimed.

References

1. (a) F. A. Cotton, L. M. Daniels and G. T. Jordan IV, Chem. Commun., 1997, 421; (b) F. A. Cotton, L. M. Daniels, C. A. Murillo and I. Pascual, J. Am. Chem. Soc., 1997, 119, 10 223; (c) F. A. Cotton, L. M. Daniels, G. T. Jordan IV and C. A. Murillo, J. Am. Chem. Soc., 1997, 119, 10 377; (d) F. A. Cotton, L. M. Daniels, C. A. Murillo and X. Wang, Chem. Commun., 1998, 39; (e) F. A. Cotton, L. M. Daniels, C. A. Murillo and I. Pascual, Inorg. Chem. Commun., 1998, 1, 1; (f) R. Clérac, F. A. Cotton, K. R. Dunbar, C. A. Murillo, I. Pascual and X. Wang, Inorg. Chem., 1999, 38, 2655.
2. (a) L.-P. Wu, P. Field, T. Morrissey, C. Murphy, P. Nagle, B. Hathaway, C. Simmons and P. Thornton, J. Chem. Soc., Dalton Trans., 1990, 3835; (b) G. J. Pyrka, M. El-Mekki and A. A. Pinkerton, J. Chem. Soc., Chem. Commun., 1991, 84; (c) S. Aduldecha and B. Hathaway, J. Chem. Soc., Dalton Trans., 1991, 993; (d) E.-C. Yang, M.-C. Cheng, M.-S. Tsai and S.-M. Peng, J. Chem. Soc., Chem. Commun., 1994, 2377; (e) J.-T. Sheu, C.-C. Lin, I. Chao, C.-C. Wang and S.-M. Peng, Chem. Commun., 1996, 315; (f) S.-J. Shieh, C.-C. Chou, G.-H. Lee, C.-C. Wang and S.-M. Peng, Angew. Chem., 1997, 109, 57; (g) C.-C. Wang, W.-C. Lo, C.-C. Chou, G.-H. Lee, J.-M. Chen and S.-M. Peng, Inorg. Chem., 1998, 37, 4059; (h) S.-Y. Lai, T.-W. Lin, Y.-H. Chen, C.-C. Wang, G.-H. Lee, M.-H. Yang, M.-K. Leung and S.-M. Peng, J. Am. Chem. Soc., 1999, 121, 250; (i) M.-M. Rohmer and M. Bénard, J. Am. Chem. Soc., 1998, 120, 9372.
3. The term molecular compounds is emphasized because it distinguishes the discrete molecules we are interested in from a host of previously known substances in which linear chains of metal atoms arise in the solid state only by stacking of flat molecules (e.g. K₂Pt(CN)₄Br_0.3 or Pt (NH₃)₄PtCl₄) or by formation of µ-X bridged chains of octahedra (e.g. NbCl₄).
4. F. A. Cotton and R. A. Walton, Multiple Bonds between Metal Atoms, Oxford University Press, Oxford, UK, 2nd edn., 1992.
5. F. A. Cotton, C. A. Murillo and X. Wang, J. Chem. Soc., Dalton Trans., 1999, 3327.
6. F. A. Cotton, C. A. Murillo and X. Wang, Inorg. Chem., in press.
7. R. Clérac, F. A. Cotton, L. M. Daniels, K. R. Dunbar, C. A. Murillo and I. Pascual, Inorg. Chem., submitted.
8. F. A. Cotton, L. M. Daniels, T. Lu, C. A. Murillo and X. Wang, J. Chem. Soc., Dalton Trans., 1999, 517.
9. H.-C. Chang, J.-T. Li, C.-C. Wang, T.-W. Lin, H.-C. Lee, G.-H. Lee and S.-M. Peng, Eur. J. Inorg. Chem., 1999, 1243.
10. Y. H.-Chen, C.-C. Lee, C.-C. Wang, G.-H. Lee, S. Y. Lai, F.-Y. Li, C.-Y. Mou and S.-M. Peng, Chem. Commun., 1999, 1667.