Self-Assembled Molecular Wires and Highly Ordered Monolayer: Thiazole on Ge(100)

Abstract

Adsorption of organic molecules on Ge(100) is important because of its potential applications in organic–semiconductor devices and semiconductor fabrication. On Ge(100), buckled Ge dimers composed of up-Ge and down-Ge atoms align to dimer rows separated by troughs. Adsorption of thiazole on Ge(100) surfaces was investigated using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. Two distinct features were observed when coverages were less than 0.25 monolayer (ML), including feature I on top of down-Ge atoms and feature II in dimer troughs. At 0.25 ML, feature II dominates and forms a highly ordered c(4 × 2) pattern. For coverage >0.25 ML, feature I self-assembles to one-dimensional molecular wires. DFT calculations reveal that feature I can be attributed to thiazole binding vertically to the down-Ge through N–Ge dative bonds, while feature II can be related to cross-dimer [4 + 2] cycloadducts through two C–Ge bonds. π–π interaction between T-shaped and parallel-displaced pairs of feature I facilitate the formation of the molecular wires. Our results indicate that thiazole may have application in both molecular electronics as well as Ge surface processing.

Harnessing Diazoketones for the Efficient Synthesis of 2,4-Disubstituted-(1,3)Thiazoles: Scalable and Versatile Approach to Important Heterocyclic Scaffolds

“…Their integration into bioactive peptides has highlighted their potential in drug development, where they contribute to enhanced stability and efficacy of peptide-based bioactive compounds and therapeutics 3-4, 10, 27-35 . Beyond their biomedical applications, these compounds have found roles in nanoelectronics [36][37] and material science [38][39][40][41] , where their chemical properties contribute to advancements in electronic devices and novel materials.…”

Autocatalytic Dissociative Adsorption of Imidazole on the Ge(100)-2 × 1 Surface

“…Aromaticity can be an important factor in determining product structure upon adsorption of organic molecules on solid surfaces, in that reaction pathways which break the aromaticity of the reactant are generally disfavored. 13 Adsorption of several N-containing aromatic heterocycles on the Ge(100)-2 × 1 surface, including pyrrole, 14,15 pyridine, 16−18 pyrimidine, 19 pyridazine, 20 thiazole, 21 hydroxypyridine and pyridone, 22 3-methyl-5-pyrazolone, 23 guanine, 24 and purine, 25 have been studied to date. As discussed above, the nitrogen moieties of these heterocycles show different reactivity upon adsorption; pyrrole undergoes N−H dissociation, 14,15 while molecules with pyridinic nitrogen form N−Ge dative bonds.…”

“…Adsorption of several N-containing aromatic heterocycles on the Ge(100)-2 × 1 surface, including pyrrole, , pyridine, − pyrimidine, pyridazine, thiazole, hydroxypyridine and pyridone, 3-methyl-5-pyrazolone, guanine, and purine, have been studied to date. As discussed above, the nitrogen moieties of these heterocycles show different reactivity upon adsorption; pyrrole undergoes N–H dissociation, , while molecules with pyridinic nitrogen form N–Ge dative bonds. − Imidazole is a rigid five-membered aromatic heterocycle that possesses both pyrrolic (N 1 ) and pyridinic (N 3 ) nitrogens. The adsorption chemistry of a few molecules that include imidazole as part of their structure, but not that of imidazole itself, has been investigated on Group 14 semiconductor surfaces.…”

A theoretical guide for fabricating a conductive molecular wire on a silicon surface via an in situ surface polymerization reaction

“…[8][9][10][11][12][13] Such STM control of single-molecule dynamics and molecular adsorption on surface has been attracting great attention. Meanwhile, many theoretical works are devoted to uncovering the mechanisms behind the formation of molecular wires [22][23][24][25][26][27][28][29][30][31][32][33][34][35] and proposing of new reaction pathways 36,37 . [16][17][18][19][20][21] However, all reported 1D nanostructures are actually the molecular arrays rather than molecular wires or surface polymers, since adsorbed molecules are separately standing on the surfaces and there is no direct bond between the molecules.…”

“…[16][17][18][19][20][21] However, all reported 1D nanostructures are actually the molecular arrays rather than molecular wires or surface polymers, since adsorbed molecules separately stand on the surfaces and there is no direct bond between the molecules. Meanwhile, many theoretical studies are devoted to uncovering the mechanisms behind the formation of molecular wires [22][23][24][25][26][27][28][29][30][31][32][33][34][35] and proposing of new reaction pathways. 36,37 For example, based on density functional theory (DFT) calculations, Choi and Cho proposed a self-assembly approach for the fabrication of heterogeneous pyridine-borine molecular arrays on a hydrogen passivated, H-Si(001)2 × 1 surface along the [110] direction.…”