[ 1.5 ] n Nanobuilding Blocks for Photonic and Electronic Applications. M. Laine, J.H. Jung, J. Furgal, S. Sulaiman, J. Zhang JS. Clark, T. Goodson, T. Mizuno Materials Sci. & Eng., Macromolecular Sci. & Eng.; Chemistry Supported by: DE, ffice of Naval esearch, U.S. Army Natick, Mayaterials, Canon, Boeing, Intel Mayaterials.com = commercial source of silsesquioxanes
utline Why silsesquioxanes (SQs)? Vinyl 8 T 8 SQs 2 nd Generation Syntheses Photophysics Mixed functional SQs Beads on a Chain Polymers - [Ph 1.5 ] x Vinyl 1.5 ] 10/12-x - [Vinyl 1.5 ] 10/12 - Photophysics - More BCs Conclusions 2
Why lsesquioxanes (SQs)?" obust, typically stable to > 300 C" Also UV stable" Easily purified because their 3-D nature" imbues high solubility" GEN1 T 8 High symmetry allows well" ordered 3-D assembly via multiple" bonding modes." GEN1 T 10 pportunity to functionalize 8, 10, 12, 16, 24 times" 3-D conjugation in excited state via cage center" offers potential to assemble rigid 3-D hybrid structures" with semiconducting behavior. " GEN1 T 12 This is unique for organic and/or hybrid materials! " Already a review on use of SQs as LED components " Where their use can greatly enhance electron and hole transport " "
Why lsesquioxanes (SQs)? o- 8 PS 2,5-16 PS 8, 16 or 24 functional groups in 1.5 nm sphere Higher than any Gen 1-3 Dendrimer J. Mater. Chem. Web Published 24 PS
Cross coupling allows mix and match functional groups J. Mater. Chem Web published + 8 + 16 Pd catalyst Heck coupling = Ac, NH 2, NHBC, CH 3,CH 3, Cl, Ph, Pd catalyst Heck coupling 8 Functional groups 16 Functional groups + 24 Pd catalyst Heck coupling 24 Functional groups
Photophysics indicates 3-D conjugation in the excited state 1 300 nm 405 nm 353 nm 310 nm vs Normalized Intensity 0.8 0.6 0.4 0.2 p-mestilbene Abs. p-mestilbene Em. o-mestyr8ps Abs. o-mestyr8ps Em. p-mestyr8ps Abs. p-mestyr8ps Em. o-mestyrps 0 250 300 350 400 450 500 550 600 650 Wavelength (nm) ed shift of 50 nm: 3-D conjugation in excited state oll Sulaiman et al J. Am. Chem. Soc. 2010, 132 3708 Compound Φ PL (%) p-mestilbene 9 o-mestyr 8 PS 4 p-mestyr 8 PS 4 6
Bonding in SQs HM LUM oll, Sulaiman, J. Am. Chem. Soc. 2010, 132 3708 3722. 7
ctastyrylsq, GEN1 Cl Cl Cl H 2 /EtH -HCl Yield 40 % Grubbs 1 st Gen. Catalyst = H, p-me,-me, -Cl, m-n 2 See also Feher et al, Sellinger et al, Marciniec et al Yield 100 % Sulaiman et al Chem Mater. 20 5563 (2008). 8
[StilbeneVinyl 1.5 ] 8 GEN2 1 1 1 1 1 1 = H, Me, Me Pd catalyst 1 1 Heck rxns Yield 100 % 1 3-D Styrenyl SQ 1 = H, Me, Me, NH 2 Sulaiman et al Chem Mater. 20 5563 (2008). 9
Photonic Motivation GEN2 (CH 2 Cl 2 ) 335 nm 387 nm H H H H H H H H 10
Solvent polarity affects emission λ max Proof of CT behavior 45-nm red-shift with increasing solvent polarity 507 nm 1 360 NHnm 2 VinylStilbeneS 460 nm Normalized intensity 0.8 0.6 0.4 0.2 Abs. in CH2Cl2 Em. in CH2Cl2 Abs. in CH3CN Em. in CH3CN H 2 N H 2 N H 2 N NH 2 NH 2 0 250 300 350 400 450 500 550 600 650 Wavelength (nm) H 2 N 11 NH 2 NH 2
Two Photon Absorption Cross-sections Thus, excellent charge separation and long lifetime oll, Sulaiman, J. Am. Chem. Soc. 2010, 132 3708 3722. N N N N N N N N N N N N N Sample δ (GM) δ/moiety (GM) λ max nm φ f MeStil 8 S 11 1.2 735 0.06 Me 2 NStil-corner 12 12 780 0.08 Me 2 NStil-half 30 7.5 790 0.09 Me 2 NStil 8 S 211 26 755 0.03 StilbenevinylS 25 3 705 0.36 p-mestilvinyls 110 14 705 0.12 p-nh 2 StilvinylS 810 101 720 0.05
Beads on a Chain Polymers Motivation Control no. of xlinks 1 x-linking group pendant or end-cap groups Li, et. al. J. Inorg. rganomet. Polym. 2002 Phillips, et. al. Curr. pin. Solid State & Matl. Sci. 2004 8 cx-linking groups complete network Laine et. al, JACS 2001, 123, 12416. Chem. Mater. 2003, 15, 793. Macromol. 2004, 37, 99 13
Control no. of xlinks 2 xlink groups linear polymer with SQs in backbone Target structure: Beads on a Chain polymers Few literature examples of difunctional silsesquioxanes Disilanol available in 15% yield after 12 weeks! Lichtenhan, et. al. Macromol. 1993 14
Control no. of xlinks 2 xlink groups linear polymer with SQs in backbone Double Decker Chemistry Higher yields, Variety of copolymers much work in progress Kakimoto et al Hydrosilylation Polymerization of Double-Decker-Shaped lsesquioxanes Macromolecules 39, 3473-5 (2006). Kawakami et al Polysiloxanes with Periodically Distributed Isomeric Double-Decker lsesquioxane in the Main Chain Macromolecules, 42 3309 331(2009).
F - ion inside SQ Bassindale ' ' TBAF F - N ' TBAF + ' F - F - N + ' ' ' = vinyl, p-tolyl eaction conditions: Bassindale, et.al., rganomet., 2004 2.5mmol TBAF for 6.52 mmol ( ) 3 3 mmol F- for 1 mmol SQ Solvent: toluene Yield: 55% (p-tolyl), 60% (vinyl) 16
F - ion inside SQ Mabry, Bowers TMAF T F - N + N + F- TMAF Mabry, Bowers et.al., Chem. Mater., 2008 equires stoichiometric F - Works for = e - withdrawing (vinyl, phenyl, styrenyl, f ) Not e - donating groups (alkyl) Not simple insertion of F - Complex rearrangement 17
F - ion inside SQ Mabry, Bowers 29 -NM data Not stable in solution F - @PS and F - @VS form new structures in solution (e) Non-F - @ cages also form mixed systems (f) Indicates scrambling of cage structures 18
Can we make mixed-functionality SQs? TBAF Phenyl 8 T 8 Vinyl 8 T 8 Target product eaction conditions: Equimolar Phenyl 8 T 8 and Vinyl 8 T 8 Solvent: THF 2 mol% TBAF (of total SQ cage) T/24 h 19
Equilibrating Phenyl 8 T 8 + Vinyl 8 T 8 MALDI-ToF T 10 T 12 T 10 T 12 T 20 - T 22 1000 1200 1400 1600 1800 2000 m/z (Ag + ) 2200 2400 2600 2800 m/z (Ag+) 20
Metathesis eaction Scheme Metathesis w/styrene -> -Ph for further functionalization
Metathesis with -styrene MALDI-ToF T 10 Ph 10 T 12 Styr 2 Ph 8 Styr 2 Ph 10 Styr 1 Ph 9 Styr 1 Ph 11 1200 1300 1400 1500 1600 1700 1800 1900 m/z Ag +
Beads on a Chain, BCs? Cages linked by conjugated tethers Photoluminescent Soluble Asuncion et al JACS. 2010, 132 3723 3736.
Synthesis of Model Compound Compare UV/PL absorption/emission spectra to Heck oligomer Asuncion et al JACS. 2010, 132 3723 3736.
UV Absorb./PL Emission Absorption / Emission 60 nm red-shift from model cpd 120 nm red-shift from absorption Heck Cpd Absorption Heck Model Cpd Absorption Heck Cpd Emission Heck Model Cpd Emission Excitation Wavelength = 265 nm Solvent: THF 235 285 335 385 435 485 535 Wavelength (nm) Asuncion et al JACS. 2010, 132 3723 3736.
Cross-metathesis reaction Gen 1 Vinyl 10 and Vinyl 12 1st generation Grubbs catalyst 40 / CH 2 Cl 2 X = 10, 12 (Ph) (MePh) Me (MePh) (CH 2 ClPh) (Ph) (Np) (BiPh) Jae Hwan Jung
Gen 2 Vinyl 10 and Vinyl 12 1st generation Grubbs catalyst 40 / CH 2 Cl 2 1.5 x X = 10, 12 Me NH 2 1.5 x X = 10, 12 = H, Me, Me, NH 2 Jae Hwan Jung
Gen 2 Vinyl 10 and Vinyl 12 GPC 1.5 x X = 10, 12 X = 10, 12 = H, Me, Me, NH 2 Styrenyl SQ (GEN1) GEN2 (H) GEN2 (Me) GEN2 (me) GEN2 (NH2) 27 28 29 30 31 32 Time (min) Jae Hwan Jung
Gen 2 Vinyl 10 and Vinyl 12 MALDI G202A_5D G202A_5D 12 (0.438) 100 3361.8 TF LD+ 4.13e3 1.5 T 12 = Me 2820.2 2821.1 x T 10 % T 14 3902.9 0 2200 2400 2600 2800 3000 3200 3400 3600 3800 4000 4200 m/z
TGA Weight (%) 100 80 60 40 H Me Me NH 2 1.5 20 0 400 800 Temperature ( o C) x Ceramic Yield (%) (Experimental) Ceramic Yield (%) (Theoretical) Td (5%) ( o C) H 23.3 23.4 390 Me 21.5 22.1 385 Me 20.8 20.9 325 NH 2 22.1 22.1 390
Gen 2 Vinyl 10 and Vinyl 12 Jae Hwan Jung/Joe Furgal
Solvent Effects 465 nm 517 nm
Gen 2 C6F5 Vinyl10 and Vinyl12
TPA Data for T10/T12 SQ s 1.5 x
Gen 2 Vinyl 10 and Vinyl 12 Cyclic Voltammetry Studies -2-2.6-2.6-2.5-2.2-2.6 LUM -3-3.2 E (ev) -4-5 -6 P3HT -5.2-4.2 PCBM -6 H Me Me -5.7-5.6-5.5 NH 2-4.9 5F -6.2 HM => To replace PCBM, GEN 2 LUM should be < -3.2 ev
Uv Vis of Gen 2 and with addition of Cyanophenyl (GEN 3) 5F Pd/t-Bu 3 5F_CN Me Me_CN
Gen 2 and 3 Vinyl 10 and Vinyl 12 + Ph-CN First efforts to modify LUM brings it half-way to target -2-3 -2.6-2.9-3.2-2.5-2.8 LUM E (ev) -4-5 -6 P3HT -5.2-4.2 PCBM -6.0 5F (A) -6.2 5F-CN (A-A) -6.0 Me (D) Me-CN (D-A) -5.5-5.6 => To replace PCBM, GEN 2 LUM should be < -3.2 ev HM D : Donor A : Accepter
Gen 3