Silanization of quartz, silicon and mica surfaces with light-driven molecular motors: construction of surface-bound photo-active nanolayers

London, Gábor; Carroll, Gregory T.; Feringa, Bernard

doi:10.1039/c3ob40276b

Cited by 23 publications

(17 citation statements)

References 53 publications

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“…During this process the silyl groups of the silane reacted with the hydroxyl groups on the surface forming siloxane bonds ( Fig. 1; London et al [53]). As a result, alkyl (or aminoalkyl) groups were chemically bonded to the surface, which rendered the surface more oil-wet.…”

Section: Surface Modification With Silanesmentioning

confidence: 96%

Wettability alteration of oil-wet carbonate by silica nanofluid

Al-Anssari

Barifcani

Wang

et al. 2016

Journal of Colloid and Interface Science

363

243

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Changing oil-wet surfaces toward higher water wettability is of key importance in subsurface engineering applications. This includes petroleum recovery from fractured limestone reservoirs, which are typically mixed or oil-wet, resulting in poor productivity as conventional waterflooding techniques are inefficient. A wettability change toward more water-wet would significantly improve oil displacement efficiency, and thus productivity. Another area where such a wettability shift would be highly beneficial is carbon geo-sequestration, where compressed CO2 is pumped underground for storage. It has recently been identified that more water-wet formations can store more CO2. We thus examined how silica based nanofluids can induce such a wettability shift on oil-wet and mixed-wet calcite substrates. We found that silica nanoparticles have an ability to alter the wettability of such calcite surfaces. Nanoparticle concentration and brine salinity had a significant effect on the wettability alteration efficiency, and an optimum salinity was identified, analogous to that one found for surfactant formulations. Mechanistically, most nanoparticles irreversibly adhered to the oil-wet calcite surface (as substantiated by SEM-EDS and AFM measurements). We conclude that such nanofluid formulations can be very effective as enhanced hydrocarbon recovery agents and can potentially be used for improving the efficiency of CO2 geo-storage.

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Section: Surface Modification With Silanesmentioning

confidence: 96%

Wettability alteration of oil-wet carbonate by silica nanofluid

Al-Anssari

Barifcani

Wang

et al. 2016

Journal of Colloid and Interface Science

363

243

View full text Add to dashboard Cite

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“…In their functionalized forms, the lower-half "stator" is immobilized on a surface 32,[35][36][37][38] and the upper-half "rotator" rotates around the double-bond "axle". Due to steric overcrowding in the so-called fjord regions, the motor halves deviate from planarity to adopt helical structures, denoted P or M to indicate right-handed or left-handed helicity, respectively.…”

Section: Introductionmentioning

confidence: 99%

Computational design of faster rotating second-generation light-driven molecular motors by control of steric effects

Oruganti

Fang

Durbeej

2015

Phys. Chem. Chem. Phys.

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We report a systematic computational investigation of the possibility to accelerate the rate-limiting thermal isomerizations of the rotary cycles of synthetic light-driven overcrowded alkene-based molecular motors through modulation of steric interactions.Choosing as reference system a second-generation motor known to accomplish rotary motion in the MHz regime and using density functional theory methods, we propose a three-step mechanism for the thermal isomerizations of this motor and show that variation of the steric bulkiness of the substituent at the stereocenter can reduce the (already small) free-energy barrier of the rate-determining step by a further 15−17 kJ mol -1 . This finding holds promise for future motors of this kind to reach beyond the MHz regime. Furthermore, we demonstrate and explain why one particular step is kinetically favored by decreasing and another step is kinetically favored by increasing the steric bulkiness of this substituent, and identify a possible back reaction capable of impeding the rotary rate.3

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“…All these motors, whose 360° rotary cycles involve two photochemical steps and two thermal steps, have two identical or distinct halves. The “lower” half is known as the “stator”, as it is immobilized on a surface in the functionalized form of the motor [35, 38–41], and the “upper” half is known as the “rotator” that rotates around the central carbon-carbon double-bond (“axle”) connecting the two halves. An essential chiral feature of these motors is the helicity(ies) adopted by the motor half(ves) because of steric overcrowding in the so-called fjord regions, denoted P or M to indicate right-handed or left-handed helicity, respectively [18, 19].…”

Section: Introductionmentioning

confidence: 99%

On the possibility to accelerate the thermal isomerizations of overcrowded alkene-based rotary molecular motors with electron-donating or electron-withdrawing substituents

Oruganti

Durbeej

2016

J Mol Model

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We employ computational methods to investigate the possibility of using electron-donating or electron-withdrawing substituents to reduce the free-energy barriers of the thermal isomerizations that limit the rotational frequencies achievable by synthetic overcrowded alkene-based molecular motors. Choosing as reference systems one of the fastest motors known to date and two variants thereof, we consider six new motors obtained by introducing electron-donating methoxy and dimethylamino or electron-withdrawing nitro and cyano substituents in conjugation with the central olefinic bond connecting the two (stator and rotator) motor halves. Performing density functional theory calculations, we then show that electron-donating (but not electron-withdrawing) groups at the stator are able to reduce the already small barriers of the reference motors by up to 18 kJ mol−1. This result outlines a possible strategy for improving the rotational frequencies of motors of this kind. Furthermore, exploring the origin of the catalytic effect, it is found that electron-donating groups exert a favorable steric influence on the thermal isomerizations, which is not manifested by electron-withdrawing groups. This finding suggests a new mechanism for controlling the critical steric interactions of these motors.Graphical AbstractThe introduction of electron-donating groups in one of the fastest rotary molecular motors known to date is found to reduce the free-energy barriers of the thermal steps that limit the rotational frequencies by up to 18 kJ mol−1.Electronic supplementary materialThe online version of this article (doi:10.1007/s00894-016-3085-y) contains supplementary material, which is available to authorized users.

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Silanization of quartz, silicon and mica surfaces with light-driven molecular motors: construction of surface-bound photo-active nanolayers

Cited by 23 publications

References 53 publications

Wettability alteration of oil-wet carbonate by silica nanofluid

Wettability alteration of oil-wet carbonate by silica nanofluid

Computational design of faster rotating second-generation light-driven molecular motors by control of steric effects

On the possibility to accelerate the thermal isomerizations of overcrowded alkene-based rotary molecular motors with electron-donating or electron-withdrawing substituents

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