First Reaction of a Bare Silicon Surface with Acid Chlorides and a One-Step Preparation of Acid Chloride Terminated Monolayers on Scribed Silicon

Abstract

Methyl-terminated and acyl chloride terminated monolayers are produced when silicon is scribed under mono- and diacid chlorides, respectively. To the best of our knowledge, this is the first report of the reaction between a bare silicon surface and acid chlorides. This reaction takes place by wetting the silicon surface in the air with the acid chloride and scribing. Scribing activates the silicon surface by removing its passivation layer. We propose that scribed silicon abstracts chlorine from an acid chloride to form an Si-Cl bond and that the resulting acyl radical diffuses back to the surface to condense with the surface and form an alkyl monolayer. X-ray photoelectron spectroscopy (XPS) confirms the presence of chlorine and shows a steady increase in the amount of carbon with increasing alkyl chain lengths of the acid chlorides. Time-of-flight secondary ion mass spectrometry shows SiCl(+) species and a steady increase in representative hydrocarbon fragments with increasing alkyl chain lengths of the acid chlorides. XPS indicates that diacid chlorides react primarily at one of their ends to create acyl chloride terminated surfaces in a single step. The resulting surfaces are shown to react with various amines (piperazine, morpholine, and octylamine) and a protein. Calculations at Hartree-Fock and density functional theory levels are consistent with the proposed mechanism.

Chemical manipulation of multifunctional hydrocarbons on silicon surfaces

“…[442]. c 2007, American Chemical Society studies supported the assumptions made based on the experimental investigation [450]. Finally, the most recent work on scribed silicon surface modification using 1,9-decadiene suggested that the majority of reactions of this compound proceeds via addition of only one alkene group leaving the other to be available for further modification, as was supported by chemical verification with bromine, osmium tetroxide, dichlorocarbene, and ((cyclohexyl) 3 P) 2 Cl 2 Ru=CHPh (Grubbs' catalyst) [452].…”

“…The 1-alkenes [443][444][445], 1-alkynes [443,445], aldehydes [446], alcohols [444], alkyl halides [445,447,448], epoxides [449], and acid chlorides [450] all react with the scribed silicon surface in a manner similar to that expected for Si (100) and Si(111) substrates. According to the review [442], the examples of epoxides [449] and acid chlorides [450] were the first demonstration of the reactivity of this type of compounds with bare silicon. For the types of surface reactive sites available on Si(100) and Si (111) surfaces, the products of selected reactions are listed in Fig.…”

“…[442]. c 2007, American Chemical Society no current analogues on clean silicon single crystals, acid chlorides seem to favor C-Cl dissociation on scribed silicon rather than alternative [2 + 2] addition reactions [450]. The other example is 1-cholorobutanol.…”

“…The other example is 1-cholorobutanol. It also dissociates via C-Cl rather than O-H [450]. This work explored the use of DFT modeling with a cluster representing an ideal Si(100)-2×1 surface and the findings of the computational Fig.…”

Acyl Chloride-Modified Amorphous Carbon Substrates for the Attachment of Alcohol-, Thiol-, and Amine-Containing Molecules

“…Hussani et al reported a photochemical means of forming acyl chloride terminated silicon surfaces by adding gaseous oxalyl chloride to an evacuated quartz cell containing an alkyl-modified Si(111) surface and irradiating with 367nm light 16. Lua et al modified silicon surfaces with suberoyl chloride under dry conditions, in which one of the acyl chlorides reacted with the silicon surface while the second acyl chloride was reacted with amine-containing molecules 17. Duevel, et al have also fabricated acyl chloride-modified gold SAMs 18…”