[RSiO 1.5 ] n Nanobuilding Blocks for Photonic and Electronic Applications

Transcription

1 [ 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

2 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

3 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 " "

4 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

5 Cross coupling allows mix and match functional groups J. Mater. Chem Web published 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

6 Photophysics indicates 3-D conjugation in the excited state nm 405 nm 353 nm 310 nm vs Normalized Intensity p-mestilbene Abs. p-mestilbene Em. o-mestyr8ps Abs. o-mestyr8ps Em. p-mestyr8ps Abs. p-mestyr8ps Em. o-mestyrps Wavelength (nm) ed shift of 50 nm: 3-D conjugation in excited state oll Sulaiman et al J. Am. Chem. Soc. 2010, Compound Φ PL (%) p-mestilbene 9 o-mestyr 8 PS 4 p-mestyr 8 PS 4 6

7 Bonding in SQs HM LUM oll, Sulaiman, J. Am. Chem. Soc. 2010,

8 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 (2008). 8

9 [StilbeneVinyl 1.5 ] 8 GEN = 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 (2008). 9

10 Photonic Motivation GEN2 (CH 2 Cl 2 ) 335 nm 387 nm H H H H H H H H 10

11 Solvent polarity affects emission λ max Proof of CT behavior 45-nm red-shift with increasing solvent polarity 507 nm NHnm 2 VinylStilbeneS 460 nm Normalized intensity Abs. in CH2Cl2 Em. in CH2Cl2 Abs. in CH3CN Em. in CH3CN H 2 N H 2 N H 2 N NH 2 NH Wavelength (nm) H 2 N 11 NH 2 NH 2

12 Two Photon Absorption Cross-sections Thus, excellent charge separation and long lifetime oll, Sulaiman, J. Am. Chem. Soc. 2010, 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 Me 2 NStil-corner Me 2 NStil-half Me 2 NStil 8 S StilbenevinylS p-mestilvinyls p-nh 2 StilvinylS

13 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 Phillips, et. al. Curr. pin. Solid State & Matl. Sci cx-linking groups complete network Laine et. al, JACS 2001, 123, Chem. Mater. 2003, 15, 793. Macromol. 2004, 37, 99 13

14 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

15 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, (2006). Kawakami et al Polysiloxanes with Periodically Distributed Isomeric Double-Decker lsesquioxane in the Main Chain Macromolecules, (2009).

16 F - ion inside SQ Bassindale ' ' TBAF F - N ' TBAF + ' F - F - N + ' ' ' = vinyl, p-tolyl eaction conditions: Bassindale, et.al., rganomet., mmol TBAF for 6.52 mmol ( ) 3 3 mmol F- for 1 mmol SQ Solvent: toluene Yield: 55% (p-tolyl), 60% (vinyl) 16

17 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

18 F - ion inside SQ Mabry, Bowers 29 -NM data Not stable in solution F and F form new structures in solution (e) Non-F cages also form mixed systems (f) Indicates scrambling of cage structures 18

19 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

20 Equilibrating Phenyl 8 T 8 + Vinyl 8 T 8 MALDI-ToF T 10 T 12 T 10 T 12 T 20 - T m/z (Ag + ) m/z (Ag+) 20

21 Metathesis eaction Scheme Metathesis w/styrene -> -Ph for further functionalization

22 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 m/z Ag +

23 Beads on a Chain, BCs? Cages linked by conjugated tethers Photoluminescent Soluble Asuncion et al JACS. 2010,

24 Synthesis of Model Compound Compare UV/PL absorption/emission spectra to Heck oligomer Asuncion et al JACS. 2010,

25 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 Wavelength (nm) Asuncion et al JACS. 2010,

26 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

27 Gen 2 Vinyl 10 and Vinyl 12 1st generation Grubbs catalyst 40 / CH 2 Cl x X = 10, 12 Me NH x X = 10, 12 = H, Me, Me, NH 2 Jae Hwan Jung

28 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) Time (min) Jae Hwan Jung

29 Gen 2 Vinyl 10 and Vinyl 12 MALDI G202A_5D G202A_5D 12 (0.438) TF LD+ 4.13e3 1.5 T 12 = Me x T 10 % T m/z

30 TGA Weight (%) H Me Me NH Temperature ( o C) x Ceramic Yield (%) (Experimental) Ceramic Yield (%) (Theoretical) Td (5%) ( o C) H Me Me NH

31 Gen 2 Vinyl 10 and Vinyl 12 Jae Hwan Jung/Joe Furgal

32 Solvent Effects 465 nm 517 nm

33 Gen 2 C6F5 Vinyl10 and Vinyl12

34 TPA Data for T10/T12 SQ s 1.5 x

35 Gen 2 Vinyl 10 and Vinyl 12 Cyclic Voltammetry Studies LUM E (ev) P3HT PCBM -6 H Me Me NH F -6.2 HM => To replace PCBM, GEN 2 LUM should be < -3.2 ev

36 Uv Vis of Gen 2 and with addition of Cyanophenyl (GEN 3) 5F Pd/t-Bu 3 5F_CN Me Me_CN

37 Gen 2 and 3 Vinyl 10 and Vinyl 12 + Ph-CN First efforts to modify LUM brings it half-way to target LUM E (ev) P3HT PCBM F (A) F-CN (A-A) -6.0 Me (D) Me-CN (D-A) => To replace PCBM, GEN 2 LUM should be < -3.2 ev HM D : Donor A : Accepter

38 Gen 3