Covalent Surface Modification of Silicon Oxides with Alcohols in Polar Aprotic Solvents

Abstract

Alcohol-based monolayers were successfully formed on the surfaces of silicon oxides through reactions performed in polar aprotic solvents. Monolayers prepared from alcohol-based reagents have been previously introduced as an alternative approach to covalently modify the surfaces of silicon oxides. These reagents are readily available, widely distributed, and are minimally susceptible to side reactions with ambient moisture. A limitation of using alcohol-based compounds is that previous reactions required relatively high temperatures in neat solutions, which can degrade some alcohol compounds or could lead to other unwanted side reactions during the formation of the monolayers. To overcome these challenges, we investigate the condensation reaction of alcohols on silicon oxides carried out in polar aprotic solvents. In particular, propylene carbonate has been identified as a polar aprotic solvent that is relatively nontoxic, readily accessible, and can facilitate the formation of alcohol-based monolayers. We have successfully demonstrated this approach for tuning the surface chemistry of silicon oxide surfaces with a variety of alcohol containing compounds. The strategy introduced in this research can be utilized to create silicon oxide surfaces with hydrophobic, oleophobic, or charged functionalities.

Immobilising molecular Ru complexes on a protective ultrathin oxide layer of p-Si electrodes towards photoelectrochemical CO2 reduction

“…The presence of (1) on p-Si/SiO x /CH 3 might be due to the interaction between the hydroxyl function of (1) and residual Si-O-R (R = Me or H, if hydrolysed) bonds that did not react with the oxide surface. 61,63 In addition, the decreased N:Ru ratio of 5:1 may suggest different anchorage modes of (1) on p-Si/SiO x /CH 3 than on p-Si/SiO x /Br, and in some cases, a ligand may be replaced by Si-O-R of the supportive layer. The control experiment shows that the bromide function does not play an essential role for the immobilization of (1).…”

“…57,58 It is well known that the formation of robust monodentate alcohol monolayers on SiO x requires a thermal activation. 61,63 Therefore, to favour the S N 2 coupling and limit a potential direct interaction of (1) with SiO x , we chose to perform the coupling at room temperature in the presence of an activating base. The poorly nucleophilic and sterically hindered base DIPEA was chosen for the S N 2 reaction to avoid the potential formation of an ammonium layer on the Br-terminated layer p-Si/SiO x /Br.…”

Versatile post-functionalisation strategy for the formation of modular organic–inorganic polyoxometalate hybrids

“…Ideally, this strategy could also be extended to functional surfaces or nanoparticles and even to the non-covalent self-assembly of species via the free triol groups. [21][22][23][24][25][26]64,65 Author Contributions D.E.S.M., M.A.M., A.V.A., and S.L. performed the synthesis and characterisation of the novel compounds.…”

“…16 All these HPOM structures are highly versatile since they can be easily postfunctionalised with a wide variety of organic moities. [17][18][19][20] However, the use of polyols for the functionalisation of POMs with other species aside from organic molecules -such as functional surfaces, [21][22][23][24] nanoparticles 25,26 and even other POMs -is challenging and remains scarcely explored.…”

Versatile Post-functionalisation Strategy for the Formation of Modular Organic-Inorganic Polyoxometalate Hybrids

“…Moreover, this strategy could ideally also be extended to functional surfaces or nanoparticles and even to the non-covalent self-assembly of species via the free triol groups. [21][22][23][24][25][26]64,65 Author Contributions D.E.S.M., M.A.M., A.V.A., and S.L. performed the synthesis and characterisation of the novel compounds.…”