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First π-linker featuring mercapto and isocyano anchoring groups within the same molecule: synthesis, heterobimetallic complexation and self-assembly on Au(111)
Mercapto (–SH) and isocyano (–N[triple bond, length as m-dash]C) terminated conducting π-linkers are often employed in the ever-growing quest for organoelectronic materials. While such systems typically involve symmetric dimercapto or diisocyano anchoring of the organic bridge, this article introduc...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Royal Society of Chemistry
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4748958/ https://www.ncbi.nlm.nih.gov/pubmed/26877864 http://dx.doi.org/10.1039/c5sc04017e |
Sumario: | Mercapto (–SH) and isocyano (–N[triple bond, length as m-dash]C) terminated conducting π-linkers are often employed in the ever-growing quest for organoelectronic materials. While such systems typically involve symmetric dimercapto or diisocyano anchoring of the organic bridge, this article introduces the chemistry of a linear azulenic π-linker equipped with one mercapto and one isocyano terminus. The 2-isocyano-6-mercaptoazulene platform was efficiently accessed from 2-amino-6-bromo-1,3-diethoxycarbonylazulene in four steps. The 2-N[triple bond, length as m-dash]C end of this 2,6-azulenic motif was anchrored to the [Cr(CO)(5)] fragment prior to formation of its 6-SH terminus. Metalation of the 6-SH end of [(OC)(5)Cr(η(1)-2-isocyano-1,3-diethoxycarbonyl-6-mercaptoazulene)] (7) with Ph(3)PAuCl, under basic conditions, afforded X-ray structurally characterized heterobimetallic Cr(0)/Au(I) ensemble [(OC)(5)Cr(μ-η(1):η(1)-2-isocyano-1,3-diethoxycarbonyl-6-azulenylthiolate)AuPPh(3)] (8). Analysis of the (13)C NMR chemical shifts for the [(NC)Cr(CO)(5)] core in a series of the related complexes [(OC)(5)Cr(2-isocyano-6-X-1,3-diethoxy-carbonylazulene)] (X = –N[triple bond, length as m-dash]C, Br, H, SH, SCH(2)CH(2)CO(2)CH(2)CH(3), SAuPPh(3)) unveiled remarkably consistent inverse-linear correlations δ((13)CO(trans)) vs. δ((13)CN) and δ((13)CO(cis)) vs. δ((13)CN) that appear to hold well beyond the above 2-isocyanoazulenic series to include complexes [(OC)(5)Cr(CNR)] containing strongly electron-withdrawing substituents R, such as CF(3), CFClCF(2)Cl, C(2)F(3), and C(6)F(5). In addition to functioning as a sensitive (13)C NMR handle, the essentially C(4v)-symmetric [(–NC)Cr(CO)(5)] moiety proved to be an informative, remote, ν(N[triple bond, length as m-dash]C)/ν(C[triple bond, length as m-dash]O) infrared reporter in probing chemisorption of 7 on the Au(111) surface. |
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