Heterosilacyclopentane Double-Click Chemistry

Heterosilacyclopentane Double-Click Chemistry Barry Arkles, Jonathan Goff, Taewoo Min, Youlin Pan, Alison Phillips, Kerry DeMella, Chad Brick ISOS-19 July 6, 2021 Enabling Your Technology 1 Silanes and Surface Modification 2 As the dimensions of structures decrease, the surface to volume ratios increase. Control of surface properties becomes critical. Organic phase R Interphase Si Inorganic substrate O Silanes remain the most versatile bridge between organic and inorganic systems and are meeting new surface modification challenges. Challenge: How do we make this chemistry faster and more effective? © 2021 by Gelest Inc. All rights reserved. Why Silicon? 3 • Which elements form stable oxane bonds (M-O-M’)? • Which metal elements form oxidatively stable C-M bonds? • Which elements form liquid, volatile, or soluble M-OR bonds • Group 4B are only stable as metallocenes • Ge and Sn are not practical for economics © 2021 by Gelest Inc. All rights reserved. Why Silicon? 4 C—M—X(OR) ORGANIC INORGANIC © 2021 by Gelest Inc. All rights reserved. Background: Silanes and Surface Modification 5 Typical hydrolyzable groups: • halogen • alkoxy (methoxy & ethoxy) • acetoxy Hydrolysis Condensation Hydrogen bonding Bond formation with substrate B. Arkles, CHEMTECH, 7(12), 766, 1977 © 2021 by Gelest Inc. All rights reserved. Background: Traditional Applications High-Aspect Ratio Fiberglass Manufacture Size components: film-formers, binders, lubricants, anti-stats, coupling agents © 2021 by Gelest Inc. All rights reserved. 6 Motivation: Reducing Cracks and Crack Propagation in Optical Fibers Moisture-induced stress corrosion attack of silica optical fibers is a significant problem associated with the drawing process and mechanical failure and long-term loss of reliability. Draw speed is 50 meters/second – a fast reaction is required to address crack propagation! Glass optical fiber O H O H O H H H H H O H H O H O In this process, glass fibers can crack upon cooling from 1650°C as the Si-O-Si bond becomes strained. The strained bonds adsorb moisture from the air which reacts on the surface to form exposed hydroxyl groups. The hydroxyl groups adsorb more water via hydrogen bonding which creates more stress, causing the crack to propagate at ~1 µ/s with failure in ~0.7s. © 2021 by Gelest Inc. All rights reserved. 7 Heterocyclic Silanes: Silanes That Click 8 Conventional silanes • • Silanes that click Byproducts produced during reaction can adsorb to substrates or create issues such as VOCs Require water for practical reaction with surface • Condensation requires time and heat • Tens of minutes reaction scale • • • • • Rapid reaction in high yield • • Anhydrous environment Low thermal budget No byproducts Catalyst free React with a greater range of –OH species Vapor phase (preferred) *B. Sharpless criteria for “click chemistry” © 2021 by Gelest Inc. All rights reserved. Outline Heterocyclic Silanes: Silanes That Click 9 Single Click Chemistry Double Click Chemistry O C C R N Si Si N CLICK 1 O C C R CLICK 1 Si R OH C C Si CLICK 2 N Si • Synthesis • Reactivity • Reactivity • New materials • Kinetics • Orthogonal double click • Applications • Applications © 2021 by Gelest Inc. All rights reserved. Heterocyclic Silanes: Silanes That Click Cyclic azasilane reactivity – model study + 10 Energetically Favorable No reaction Me3Si-SMe2 70 > 99% + Relief of ring-strain is a minor contribution Arkles, B., Pan, Y., Berry, D. H. & Larson, G. L. Cyclic azasilanes: Volatile coupling agents for nanotechnology. Silanes and Other Coupling Agents Vol. 3. (ed. Mittal, K.)., 2004, 179-1910 © 2021 by Gelest Inc. All rights reserved. Substrate Reactivity: Model of Fumed Silica Particle 11 Coupling to a nanoparticle: simplified calculation for a 20 nm SiO2 sphere 10 nm Nanoparticle surface area: SiO2 surface area: 0.2 nm (4Pr2) = 4*P*(10)2 = 12 x 102 nm2 # of Si atoms on surface: L x W = 0.2*0.2 = 4 x 10-2 nm2 12 x 102 4 x 10-2 = 30,000 For ordered SiO2, only 1/2 available = 15,000 Theoretical maximum of Si atoms on surface = 15,000 © 2021 by Gelest Inc. All rights reserved. Single Click Chemistry: Substrate Reactivity 12 Coupling to a nanoparticle: comparative deposition of silanes on 200 m2/g fumed silica OH H O H O H O H H O HO Four types of Si-OH, but only hydrogen bonded react with conventional alkoxy silane 25-35% for particles > 20 nm = ~3,000 reactive sites HO Silane reacted on silica particles Weight percent loading n-butyltrimethoxysilane 6.4% (not catalyzed) N-n-butylaminopropyltrimethoxysilane 22.5% (amine-catalyzed) N-n-butyl-aza-dimethoxysilacyclopentane 38.0% (click chemistry) © 2021 by Gelest Inc. All rights reserved. Increased reactivity and loading using heterocyclic silanes Heterocyclic Silanes: Synthesis 13 Method 1 – Aminative Ring-Closure John Speir, US Pat. 3,146,250, 1964. Method 2 – Dealkoxylative Ring-Closure Arkles, B., Pan, Y., Berry, D. H. & Larson, G. L. Cyclic azasilanes: Volatile coupling agents for nanotechnology. in Silanes and Other Coupling Agents Vol. 3. (ed. Mittal, K.)., 2004, 179-191. Method 3 – Silylation-Driven Ring-Closure Salikhov, T. R.; Kopylov, V. M.; Shragin, D. I. Russ. J. Gen. Chem. 2014, 84, 782. © 2021 by Gelest Inc. All rights reserved. Heterocyclic Silanes: Synthesis 14 Most practical and economical synthetic method Dimeric and polymerization products Arkles, B., Pan, Y., Berry, D. H. & Larson, G. L. Cyclic azasilanes: Volatile coupling agents for nanotechnology. in Silanes and Other Coupling Agents Vol. 3. (ed. Mittal, K.)., 2004, 179-191 © 2021 by Gelest Inc. All rights reserved. Heterocyclic Silanes: Synthesis 15 Cyclic reduction reaction B Arkles, Y Pan, F Jove US Patent 10,081,642, 2018 Cyclic reaction with Grignard reagents C. Piskoti US Patent 8,450,512, 2013 © 2021 by Gelest Inc. All rights reserved. Heterocyclic Silanes: New Materials Azasilacyclopentanes 16 Diazasilacyclooctanes Alkyl Alkoxy Hydrido © 2021 by Gelest Inc. All rights reserved. Heterocyclic Silanes: New Materials 17 Heterocyclic silacyclopentanes can be used as area specific reactive initiators for ALD B Arkles, RJ Liberatore, Y Pan US Patent App. 16/826,589, 2020 © 2021 by Gelest Inc. All rights reserved. Outline Heterocyclic Silanes: Silanes That Click 18 Single Click Chemistry Double Click Chemistry O C C R N Si Si N CLICK 1 O C C R CLICK 1 Si R OH C C Si CLICK 2 N Si • Synthesis • Reactivity • Reactivity • New materials • Kinetics • Orthogonal double click • Applications • Applications © 2021 by Gelest Inc. All rights reserved. Single Click Chemistry: Kinetics 20 Cyclic azasilane kinetic study: How quick is the click? 100 90 Time 0 s % Reflectance 80 0.5% cyclic azasilane in CH2Cl2 treatment of fumed silica 70 Time 32 s 60 Time 56 s 50 40 3800 3600 3400 3200 3000 2800 2600 2400 Wavenumber (cm-1) Maddox, A. F.; Matisons, J. G.; Singh, M.; Zazyczny, J.; Arkles, B. Single Molecular Layer Adaption of Interfacial Surfaces by Cyclic Azasilane “Click-Chemistry. MRS Proc. 2015, 1793, 35−40. DOI:10.1557/opl © 2021 by Gelest Inc. All rights reserved. Single Click Chemistry: Kinetics – 21 90 Dimethylthiasilacyclopentane 80 Water contact angle Water contact angle of silacyclopentane-deposited films: How quick is the click? 70 60 50 40 0 1 2 3 4 5 6 5 6 Pulse length (seconds) 90 N-methyl-dimethylazasilacyclopentane Atomic Layer Deposition (ALD) Native oxide on silicon <100> wafer © 2021 by Gelest Inc. All rights reserved. Water contact angle Native oxide on PVD copper on silicon wafer 80 70 60 50 40 0 1 2 3 4 Pulse length (seconds) Single Click Chemistry: Applications 23 Facile surface modification of hydroxylated silicon nanostructures using heterocyclic click chemistry Kim, D.; Zuidema, J. M.; Kang, J.; Pan, Y.; Wu, L.; Warther, D.; Arkles, B.; Sailor, M. J. Facile Surface Modification of Hydroxylated Silicon Nanostructures Using Heterocyclic Silanes. J. Am. Chem. Soc. 2016, 138, 15106−15109. © 2021 by Gelest Inc. All rights reserved. Outline Heterocyclic Silanes: Silanes That Click 24 Single Click Chemistry Double Click Chemistry O C C R N Si Si N CLICK 1 O C C R CLICK 1 Si R OH C C Si CLICK 2 N Si • Synthesis • Reactivity • Reactivity • New materials • Kinetics • Orthogonal double click • Applications • Applications © 2021 by Gelest Inc. All rights reserved. Double Click Chemistry: Reactivity TOOLBOX CLICKS Silanes Ring-opening click Organic Inorganic Cryptic amine-reveal click Cryptic mercaptanreveal click Exocyclic click © 2021 by Gelest Inc. All rights reserved. Double Click Chemistry: Reactivity Ring-opening + cryptic mercaptan-reveal click Silane 1 Ring-opening click to react with inorganic substrate Organic Inorganic 2 Cryptic mercaptan-reveal click to react with organic © 2021 by Gelest Inc. All rights reserved. Double Click Chemistry: Reactivity Ring-opening + exocyclic click Silane 1 Ring-opening click to react with inorganic substrate Organic Inorganic 2 © 2021 by Gelest Inc. All rights reserved. Exocyclic click to react with organic Double Click Chemistry: Reactivity Exocyclic + ring-opening click 1 Silane 1 Exocyclic click to react with organic Organic 2 Inorganic 2 © 2021 by Gelest Inc. All rights reserved. Ring-opening click to react with inorganic substrate Double Click Chemistry: Reactivity 29 Azide-yne exocyclic click + 80-100 °C without catalyst t = 0 hour 1:2 molar ratio of heterocyclic silane to benzyl azide > 90% yield t = 8 hour t = 16 hour © 2021 by Gelest Inc. All rights reserved. Double Click Chemistry: Single-Molecule Orthogonal Double-Click Pathways Ring-opening and exocyclic clicks DOUBLE-CLICK REACTIONS Reagents A + + + Potential organic reagents Tfinal Ring-opening Ring-opening Exocyclic B Ring-opening + C Inorganic substrate Hydroxylated surface R1 = alkenyl or alkynyl substitution C C B Organic reactants Exocyclic + A Exocyclic functionality B T0 B + A Heterocyclic silanes A C © 2021 by Gelest Inc. All rights reserved. Exocyclic Product 30 Double Click Chemistry: Applications Bio-organic molecular anchoring • Tacrolimus is an immunosuppressive drug for organ transplant patients. • Immune-triggered foreign body response (FBR) is of concern for a wide range of implantable devices that rely on the structural properties of metals and ceramics (like pacemakers, stents, infusion ports, and drug-delivery systems) © 2021 by Gelest Inc. All rights reserved. 31 Double Click Chemistry: Applications 32 Bio-organic molecular anchoring: using a double click reaction, we can adhere tacrolimus to silica particles as a model for drug and enzyme payload delivery systems. 1 Thiasilane clicks to silica surface 2 Exposed thiol attacks vinyl group on drug Silica particle Drug - tacrolimus 3 Drug chemically adhered to silica surface © 2021 by Gelest Inc. All rights reserved. hn Double Click Chemistry: Applications 33 Click-driven polymer cure: The moisture-induced stress-corrosion attack of silica optical fibers is a significant problem associated with the drawing process and results in the long-term loss of reliability. Glass optical fiber O H O H O H H H H H O H H O H O In this process, glass fibers can crack upon cooling as the Si-O-Si bond becomes strained The strained bonds adsorb moisture from the air which reacts on the surface to form exposed hydroxyl groups The hydroxyl groups adsorb more water via hydrogen bonding which creates more stress, causing the crack to propagate © 2021 by Gelest Inc. All rights reserved. Using click chemistry, we can quicky apply a cure to the surface to prevent and stop moisture-induced stress cracking on the surface of these glass fibers. Double Click Chemistry: Application to Optical Fiber 34 Click-driven polymer cure: using a double click reaction, we can use a click polymer cure to reduce induced surface microcracking. 1 Glass optical fiber S S S Si Si S Si Si Ring-opening click: cyclic thiasilanes react with exposed surface hydroxyls hn ~30% decrease in stress failure under deflection H H S S Si Si 2 H H 3 S 4 S S S Si Si Si Si S S Si Si S S S S Si Si Si Si Cryptic mercaptan-reveal click: unveiled Condensation: alkoxy groups condense to form Strengthened surface: Silane linked PDMS thiols react with vinyl-functional PDMS covalent linkages coating strengthens the glass fiber © 2021 by Gelest Inc. All rights reserved. Silanes and Surface Modification 35 As the dimensions of structures decrease, the surface to volume ratios increase. Control of surface properties becomes critical. Organic phase R Interphase Si Inorganic substrate O Silanes remain the most versatile bridge between organic and inorganic systems and are meeting new surface modification challenges. © 2021 by Gelest Inc. All rights reserved. 36 References References 1. Arkles, B., Goff, J., Min, T.,Pan, Y., Phillips, A., DeMella, K., Brick. C., ACS Appl. Mater. Interfaces, 2020, 12(24), 27737–27744. 2. Arkles, B., Pan, Y., Berry, D. H. & Larson, G. L. Cyclic azasilanes: Volatile coupling agents for nanotechnology. Silanes and Other Coupling Agents Vol. 3. (ed. Mittal, K.)., 2004, 179-191. 3. Arkles, B., Pan, Y., Jove, F., US Patent 10,081,642, 2018. 4. Piskoti, C., US Patent 8,450,512, 2013. 5. B Arkles, RJ Liberatore, Y Pan US Patent App. 16/826,589, 2020. 6. Kim, D.; Zuidema, J. M.; Kang, J.; Pan, Y.; Wu, L.; Warther, D.; Arkles, B.; Sailor, M. J. Facile Surface Modification of Hydroxylated Silicon Nanostructures Using Heterocyclic Silanes. J. Am. Chem. Soc. 2016, 138, 15106−15109. 7. Maddox, A. F.; Matisons, J. G.; Singh, M.; Zazyczny, J.; Arkles, B. Single Molecular Layer Adaption of Interfacial Surfaces by Cyclic Azasilane “Click-Chemistry. MRS Proc. 2015, 1793, 35−40. 8. Salikhov, T. R.; Kopylov, V. M.; Shragin, D. I. Russ. J. Gen. Chem. 2014, 84, 782. Note: Animations/ video clips have been removed from the original presentation. © 2021 by Gelest Inc. All rights reserved.