Gelest - Enabling Your Technology Cyclic Azasilanes: Click Chemistry for licones Barry Arkles, Youlin Pan, Annalese Maddox Gelest, Inc. Morrisville, PA (US) 215-547-1015 executiveoffice@gelest.com licon Symposium
Click Chemistry Defined "Click Chemistry u A term introduced by Barry Sharpless in 2001 to describe reactions that proceed in: u high yield u wide in scope u do not create byproducts or only byproducts that can be removed without chromatography u simple to perform u can be conducted without solvent or in easily removable or benign solvents.
lane Surface Modification at anodimensions bjectives: React with a greater range of - species Anhydrous Environment Rapid Reaction (Spin-n, CVD or ALD) Vapor Phase (preferred) Low Thermal Budget o Byproducts
Coupling to a anoparticle simplified calculation for a 20 nm 2 sphere 10 nm! Surface area(4πr 2 ) - 10 2 nm 2 Step and repeat area for 2 = 4x10-2 nm 2 # of silicon atoms on surface= 12x10-2 = 30,000 For ordered 2 only 1/2 available = 15,000
Coupling to a anoparticle: simplified calculation for surface hydroxyls Theoretical maximum, -: 15,000 Experimentally only 60% have -: 9,000 ther forms: -- 4 types of -, but only hydrogen bonded react: 3,000 (25-35% for particles >20nm) nly ~10% of surface silicon atoms provide reactive sites
lylation Reagents Donor Effectiveness Enthalpy for - bond formation
Cyclic Azasilanes R' R'' R R R Azasilacyclopentanes Diazasilacyclooctanes
Substrate Reactivity 3 C 3 C Substrate Substrate
Cyclic Azasilanes - Previous Synthetic Work 3 C Cl C ( ) 2 Cl + 3 2 + 2 C32 + Cl - Aminative ring-closure with narrow utility John Speir, US Pat. 3,146,250, 1964 2 2 3 + Cl - Driven by formation of pentacoordinate silicon! 3 C W. Ziche, B. Ziemer, P. John, J. Weiss,. Auner, J. rganomet. Chem., 521, 29, 1996 +
Cyclic Azasilanes General Synthetic Method ( 4 ) 2 S 4 ( ) 3 + 120-140 equilibration 3 C 3 C ( ) 3 dimeric and polymerization products B. Arkles et al, lanes and ther Coupling Agents, Vol. 4, 179, 2004!
Azasilacyclopentanes yield b.p. Me Me nbu 47% 69-71 /3mm Me Me tbu 42% 58-60 /3mm Me Me C 40% 52-54 /3mm Me Me Me 19% 48-49/3mm 5-7% not isolated Et Et Me Me no cyclic compound observed B. Arkles et al, lanes and ther Coupling Agents, Vol. 4, 179, 2004!
Diazasilacyclooctanes Me Me yield b.p. 92% 70-72 /3mm Me Me SID3543.0 42% m.p. 61-2 SID3543.0 X-ray structure!
Reactivity of Cyclic Azasilanes Model Study C 2 5 C 2 5 + ( ) 3 no reaction C 2 5 C 2 5 C 2 5 + C 2 5 >99% C 2 5 C 2 5 C 2 5
ow Quick is the Click? 130 120 110 nc 4 9 100 90 %Reflectance 80 70 60 50 40 30 20 3800 3600 3400 3200 3000 Wavenumbers (cm-1) 0.5% cyclic azasilane in Cl 2 treatment of fumed silica
Substrate Reactivity of Cyclic Azasilanes - anoparticles CS = cyclic azasilane SIM6501.4 APDMMS = aminopropyldimethylmethoxysilane MDS = hexamethyldisilazane!
Monolayer Stability 3 C 3 C Substrate ngle bond to substrate Substrate
Substrate Reactivity of Cyclic Azasilanes Enhancing hydrolytic stability of the monolayer 2a 2 2 C + Substrate Substrate
Substrate Reactivity of Cyclic Azasilanes Enhancing hydrolytic stability of the monolayer 2b Substrate + 2 - Substrate
Comparative Deposition of lanes on 200m 2 /g fumed silica n-butyltrimethoxysilane 6.4 wgt% -n-butylaminopropyltrimethoxysilane 22.5 wgt% -n-butyl-aza-dimethoxysilacyclopentane 38.0 wgt%
Commercial Cyclic Azasilanes 3 C C 2 5 Me Me SIB1932.4 3 C SIM6501.4 C 2 5 C 2 5 nbu SIT8187.2! C 2 5 C25 3 C Me SIE4891.0 Me SIA0415.0 C 2 3 C SIA0604.0 3 C SIA0592.0 2 SID3546.93 Me Me SID3543.0
Cyclic Azasilanes: Click Chemistry for ydroxyl Groups Cyclic Azasilanes have greater reactivity than conventional alkoxysilanes Cyclic Azasilanes react with substrates without byproduct formation Cyclic Azasilanes provide effective surface modification at nanodimensions
lanol Terminated PDMS- Amine Reactivity n + 2 C C C C n 3 3
lanol Terminated PDMS C3 C3 C3 C4 9 C2 C2 C2 C3 C3 C3 C3 C3 C3 C3 C3 n C3 C3 C3 C3 C3 C3 + 2 C3 n C4 9 C 3 C3 C3 C3 C4 9 C2 C2 C2 n C3 C3 C3 < 5 minutes, >99% yield
lanol Terminated PDMS- Allylamine Functionality n + 2 C C C n
lanol Terminated PDMS- Moisture-Cure n + 2 nc 4 9 C 4 9 C 4 9 n + 2 - C 4 9 C 4 9 n
Moisture Initiated Reaction with Epoxides: Chain-extension 2 C C C + 2 2 C C C C n
Moisture-Cure Epoxies 2 C C Fast- 2 diffusion limited (time scale: minutes) C C 2 + 2 nc 4 9 C 4 9 C 4 9 ( ) 3 C ( ) 3 Slow- hydrolysis/condensation limited (time scale: hours) + 2 - catalyst accelerated (dibutyltindilaurate) C 4 9 C 4 9 ( ) 3 C ( ) 3
Moisture-Cure Isocyanate rmosils C2 5 C C2 5 C2 5 Fast- 2 diffusion limited (time scale: minutes) Me nbu Me 2 C4 9 C2 5 C Slow- hydrolysis/condensation limited (time scale: hours) + 2 C2 5 - C4 9 C C2 5
lanes Undergoing Ring-pening Reactions R' R'' R 3 C 3 C S 3 C C 2 5 C 2 5 C 2 5 C 2 5 C 2 5 SIT8567.0! SID3545.0 SIT8187.2
Cyclic Azasilane Applications Click Chemistry anoparticle vapor-phase functionalization Click Chemistry Capping of silanol functional siloxanes Introduction of reactive groups for further reaction including moisture cure Moisture activated reaction and cure of epoxy and isocyanate derived systems.
Cyclic Azasilanes: Click Chemistry for licones Gelest - Enabling Your Technology Barry Arkles, Youlin Pan, Annalese Maddox Gelest, Inc. Morrisville, PA licon Symposium