First π-linker featuring mercapto and isocyano anchoring groups within the same molecule: Synthesis, heterobimetallic complexation and self-assembly on Au(111).
First π-linker featuring mercapto and isocyano anchoring groups within the same molecule: Synthesis, heterobimetallic complexation and self-assembly on Au(111).
复制标题
第一个π链接在同一分子中具有墨托和异糖锚固组：合成，异金属金属络合和自组装Au（111）。
DOI：
10.1039/c5sc04017e
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发表时间：
2016-02-01
期刊：
影响因子：
8.4
通讯作者：
Barybin MV
中科院分区：
文献类型：
--
作者：
Applegate JC;Okeowo MK;Erickson NR;Neal BM;Berrie CL;Gerasimchukand NN;Barybin MV
Azulene is a convenient platform for accessing heterobimetallic complexes and self-assembled monolayers of a π-linker with asymmetric junctions. Mercapto (–SH) and isocyano (–NC) 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-NC 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)5Cr(η1-2-isocyano-1,3-diethoxycarbonyl-6-mercaptoazulene)] (7) with Ph3PAuCl, under basic conditions, afforded X-ray structurally characterized heterobimetallic Cr0/AuI ensemble [(OC)5Cr(μ-η1:η1-2-isocyano-1,3-diethoxycarbonyl-6-azulenylthiolate)AuPPh3] (8). Analysis of the 13C NMR chemical shifts for the [(NC)Cr(CO)5] core in a series of the related complexes [(OC)5Cr(2-isocyano-6-X-1,3-diethoxy-carbonylazulene)] (X = –NC, Br, H, SH, SCH2CH2CO2CH2CH3, SAuPPh3) unveiled remarkably consistent inverse-linear correlations δ(13COtrans) vs. δ(13CN) and δ(13COcis) vs. δ(13CN) that appear to hold well beyond the above 2-isocyanoazulenic series to include complexes [(OC)5Cr(CNR)] containing strongly electron-withdrawing substituents R, such as CF3, CFClCF2Cl, C2F3, and C6F5. In addition to functioning as a sensitive 13C NMR handle, the essentially C4v-symmetric [(–NC)Cr(CO)5] moiety proved to be an informative, remote, νNC/νCO infrared reporter in probing chemisorption of 7 on the Au(111) surface.
