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A nano-scale barrel and cube: transition metal-mediated self-assembly of CpCoCb-derived ligand scaffolds.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Johannessen, Stig Brisbois, Ronald G. Fischer, Jan Paul Grieco, Paolo Counterman, Anne E. Clemmer, David E. |
| Copyright Year | 2001 |
| Abstract | Alternative topological motifs will continue to emerge as the SSA field evolves, providing more options for preparation of novel nanoscale architectures. In this regard, we wish to report the seminal results of our recent efforts to demonstrate the immediate utility of the CpCo-cyclobutadienyl (CpCoCb) metallocene in SSA, thereby identifying a readily accessible scaffold for which numerous synthetic modifications are conceivable. In particular, our work applies the CpCo-tetrakis(3and 4-pyridyl)cyclobutadiene scaffolds in SSA to illustrate a set of novel complements for selecting the directionality of nitrogen chelating vectors and easily controlling size and topology of our target assemblies. We detail below construction of a nanoscale barrel 1 and a nanoscale cube2.2 Synthesis of self-assembled barrel 1 requires only two steps from readily available starting materials (eq 1). Cobalt-mediated [2+2]3 dimerization of34 provided ligand-scaffold meta 4, which was treated subsequently with enPd(NO 3)2 in CH3OH-H2O to give a quantitative yield of 1. The exceedingly simple proton and carbon NMR spectra, each of which exhibits only a single set of resonances, are entirely consistent with a single entity possessing the indicated structure 1.5a Of particular note is the chemical shift observed for the Ha in 1. In the precursor ligand-scaffold 4, Ha appears at δ 8.65, whereas in the self-assembled “barrel” H a shifts upfield to δ 7.76. We attribute this upfield shift to anisotropic † Current address: Macalester College, Department of Chemistry, 1600 Grand Avenue, St. Paul, MN 55105-1899. § To whom questions regarding mass spectrometric analyses should be directed. (1) (a) Leininger, S.; Olenyuk, B.; Stang, P. J. Chem. Re V. 2000, 100, 853. (b) Fujita, M. Chem. Soc. Re V. 1998, 27, 417. (c) Jones, C. J. Chem. Soc. ReV. 1998, 27, 289. (2) Alternatively, self-assembly 2 can be construed as a truncated cube if one defines the solid shape derived by formally drawing lines between the Pd atoms. |
| File Format | PDF HTM / HTML |
| DOI | 10.1021/ja004007s |
| PubMed reference number | 11457114 |
| Journal | Medline |
| Volume Number | 123 |
| Issue Number | 16 |
| Alternate Webpage(s) | http://www.indiana.edu/~clemmer/Publications/pubs/pub%20065.pdf |
| Alternate Webpage(s) | https://doi.org/10.1021/ja004007s |
| Journal | Journal of the American Chemical Society |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
