Lattice-Directed Selective Synthesis of Acetylenic and Diacetylenic Organometallic Polyynes

Abstract

As a bottom-up strategy, on-surface synthesis shows great potential in constructing novel carbon-based nanostructures. Herein, on-surface reactions of 1,1,2,2-tetraiodoethylene and 1,1,4,4-tetrabromo-1,2,3-butatriene were systematically explored. A combination of scanning tunneling microscopy and noncontact atomic force microscopy demonstrates that it is feasible to achieve acetylenic and diacetylenic organometallic polyyne (i.e., acetylenic Ag−carbyne and diacetylenic Cu−carbyne) on Ag(110) and Cu(110) surfaces, respectively. Interestingly, after annealing the sample, the acetylenic Ag−carbyne was transformed to diacetylenic Ag−carbyne on Ag(110), while an opposite transformation process occurred between diacetylenic and acetylenic Cu−carbyne on Cu(110). The DFT calculations indicate that such a lattice dependence of skeleton reconstruction originates from the thermodynamic stability of diacetylenic Ag−carbyne/acetylenic Cu−carbyne on the corresponding surfaces.

Bottom-Up Synthesis of Metalated Carbyne Ribbons via Elimination Reactions

“…CBr 4 monomers (as sketched in Figure 1a) were deposited on the clean Cu(110) single-crystal surface held at 300 K by thermal sublimation (with a typical sublimation temperature of 300 K) under ultra-high vacuum conditions, resulting in the formation of isolated 1D chain structures along the closepacked [11̅ 0] direction of the substrate (Figure 1b). Based on our previous studies, 20,24 these chain structures with a periodicity of 5.2 ± 0.2 Å (Figure 1b) could be naturally attributed to Cu-incorporated metalated carbyne (−Cu−C� C−), and the protrusions within the chain result from the electronic density of states of Cu atoms. Notably, organometallic species are often formed in dehalogenative coupling reactions.…”

“…Intriguingly, the asymmetric DOS for spin-up and spindown components indicates a spin polarization of the CuCRs, although the incorporated Cu atoms in the chains are not magnetically active, which is similar to our previous studies. 24 More interestingly, the CuCRs exhibit a width-dependent band gap modulation. The calculated band gap decreases from 4.02 to 2.38 eV with an increasing width (N) from 1 to 5 (Figure 3a).…”

“…More interestingly, the MCRs exhibit a width-dependent band gap modulation, which could serve as another strategy for engineering the band gap of metalated carbynes compared to the previous study. 24 These results present the availability of elimination reactions in generating new low-dimensional carbyne-like nanostructures, which should enrich the toolbox for the on-surface synthesis of carbon nanostructures and carbon-rich nanomaterials and also contribute to the development of on-surface chemistry.…”

Hexa-peri-hexabenzocoronene derivatives carrying dovetailed alkyl and diacetylenic side chains: a synthesis, characterization, and polymerization study

“…1(a)), where m and n represent the spacer group and the terminal alkyl chain around the DA units, respectively. We showed that the columnar packing of HBC cores can help align the DA-containing side chains along the column and get polymerized [26][27][28][29][30] to give conjugated poly(eneyne) chains as conducting channels for transistor application. The position of the DA unit along the alkyl chain nevertheless appeared to affect the polymerization profoundly.…”

On-surface synthesis of a polyynic carbon chain with ~40 alkyne units

“…On-surface synthesis is emerging as a promising approach for atomically precise fabrication of highly reactive 1D nanostructures with sp-hybridization that could be hardly synthesized via conventional solution synthetic chemistry [19][20][21][22] . Developments in scanning tunneling microscopy (STM) and atomic force microscopy (AFM) have enabled the designing and in-situ characterization of low-dimensional carbon nanostructures with unprecedented resolution on the atomic scale and chemical-bond level [23][24][25] .…”