Voltage- and temperature-dependent spontaneous polarization behaviors of H-bonded bent-core dimeric and main-chain polymeric complexes

In theory, the spontaneous polarization behaviors were demonstrated in H-bonded bent-shaped dimers and main-chain polymers if the suitable electric field, frequency, and temperature were given. In order to identify the influence of H-bonds as well as the applied electric fields and temperatures on spontaneous polarization behaviors, two series of complexes V-N and II-N (not including complex II-B) with SmCP phases (represented the H-bonded bent-core dimers and MCP polymers, respectively) were examined in various electric fields and temperatures, and their correlative data were shown in Figures 3.13 and 3.14.

To consider the temperature-dependent spontaneous polarization studies of series of complexes V-N, their Ps values were raised gradually and diminished substantially

crystalline states, respectively (see Figure 3.13a). The observations of Ps value vs.

temperature were corresponded with DSC measurements to indicate that the Ps behavior is certainly contributed from polar smectic arrangement. The similar results in series of complexes II-N were also accomplished as shown in Figure 3.13b.

Figure 3.13. Ps values of (a) dimeric complexes V-N (N = A, B, C, D and E) and (b) MCP complexes II-N

To inspect the voltage-dependent effect of spontaneous polarization behaviors, the tendencies of Ps value vs. applied electric field were surveyed in the SmCP phases of complexes V-N and II-N (not including complex II-B) as shown in Figure 3.14.

Regarding the series of dimeric complexes V-N (N = A, B, D, and E), Ps values were increased and saturated via the increasing of applied voltage, where the maximum applied voltages were Vpp = 325 V and the saturated Ps values were reached at voltages above Vpp = 125 – 260 V. With respect to series of MCP complexes II-N (N

= C, D, and E), their saturated Ps values of complexes II-C, II-D and II-E were attained in voltages above 120 Vpp, 195 Vpp and 246 Vpp, respectively (see Figure 3.14b). Higher voltages were necessary to switch the relatively spontaneous polarization behaviors of complexes with higher isotropization temperatures duo to the tighter molecular stacking. This phenomenon was also revealed obviously in series of dimeric complex V-N, where the minimum required voltage of dimeric complex V-B (above Vpp = 260 V) were higher than those of other dimeric complexes V-A, V-C, V-D and V-E duo to its high isotropization temperature.

Almost H-bonded bent-core dimeric and MCP complexes would exhibit the stable spontaneous polarization behaviors under high applied electric fields, but not completely. For instance, as shown in Figure 3.14a, the Ps values of complex V-C were decreased when applied voltage was higher than 230 Vpp cause of the broken hydrogen bond force. In order to demonstrate this condition, the further clear apparent case of complex II-A was inspected by POM observations, which its Ps vs. Voltage data was lose collected imprecisely because that non-clear current response peak and very less Ps value were demonstrated under lower (Vpp ＜ 240 V) and higher (Vpp

＜ 270 V) voltage applying duo to the voltage sensitive effect. In general, the SmC_AP_A ground state would be transformed to polar switching domain (SmC_SP_F, as

contribute Ps property by the increasing of applied electric field. Nevertheless, the polar circular domain was disappeared and changed gradually to gray grainy domain to form the non polar switching domain as shown in Figure 3.15b and 3.15c.

Afterwards, the fan-like domain indicative the SmCAPA state (see Figure 3.15d) would return by the removing of electric field. It was indicated that the H-bond of complex II-A would become weak and unstable easily under large electric field applied to restrain the arising of spontaneous polarization behavior. Consequently, a voltage applied dependent material is established.

Figure 3.15. POM textures of MCP complex II-A under the applied triangular wave electric field as (a) Vpp = 264 V, (b) Vpp = 276 V, (c) vpp = 300 V and (d) Vpp = 0 V (electric field removing).

a b

c d

264 Vpp 276 Vpp

300 Vpp 0 Vpp

Figure 3.16. POM textures of dimeric complex IV-C under the applied triangular wave electric field as (a) Vpp = 230 V, (b) Vpp = 263 V, (c) Vpp = 296 V and (d) Vpp

= 0 V (voltage removing and heating and cooling again); (e) Ps values of dimeric complex IV-C as a function of applied voltage (as f = 200Hz and (Tc - T) = 10 ^oC).

50 100 150 200 250 300 350

10 20 30 40 50 60 70 80 90

(e)

Ps Values (nC/cm2 )

Applied Voltage (Vpp)

230 Vpp

a

263 Vpp

b

296 Vpp

c d

0 Vpp

In addition, the voltage-dependent condition was also demonstrated in complex IV-C to record its tendency of Ps value completely in Figure 3.16e. The saturated Ps values were obtained by the increasing of electric field up to V = 102 Vpp, and Ps values were decreased when the applied electric field was more than 246 Vpp. The circular and broken-fan domains indicative the polar switching behavior was shown in Figure 3.16a at 230 Vpp. However when the voltage was higher than 246 Vpp, the circular and broken-fan domains were dispersed into the dark grainy domain as shown in Figure 3.16b and 3.16c. Finally, the circular and fan-like domains (Figure 3.16d) were reversible by voltage removing, heating and cooling again. It was a typical case to show the voltage-sensitive polar switching behavior of bent-core material duo to the collapsible and reversible weak H-bonded force.

3.3.9. Chirality investigation

In principle, the chirality of SmCP phase was depended on molecular polar direction and molecular tilt direction in neighboring layers. The polar direction was determined based on the current response under triangular wave electric field applying to show opposite or identical directions between neighboring layers. In addition, a switching process of molecular tilt direction could be determined through the rotation and retention of the extinction crosses. In order to understand the chirality of all H-bonded bent-core dimeric and MCP complexes with SmCP phases, their optical investigations were observed by applying (or after removing) triangular wave (TAW), square wave (SW) and opposite direct current (d.c.) electric fields in H-bonded bent-core complexes with polar smectic phase.

In investigation the antiferroelectric characteristic of the H-bonded bent-core complexes with H-donors A and B (owning di-siloxyl unit), circular domains were formed in the SmCP phase, where the smectic layers are circularly arranged around the centers of the domains. The layer structure arrangement corresponds to the

Figure 3.17. The POM textures of chiral domain switching in MCP complex II-A between (a) SmCAPA groundstate with 0 V (without electric field) and (b) SmCSPF state with ±30 V of applied d.c. electric field in a parallel rubbing cell with a cell gap of 4.25 μm. (White arrows are the directions of polarizers and analyzers.)

domain models was proposed by Link et al.^[8,24] As shown in Figure 3.17, the rotation of the extinction crosses during the switched on and off states in complex II-A demonstrated the chiral domain behavior.^[7] Without the electric fields (off state), the extinction crosses were reoriented to the crossed polarizer directions (see Figure 3.17a), indicating an anticlinic tilt in the antiferroelectric ground state (SmCAPA). In view of Figure 3.17b, by applying d.c. electric fields (with reverse polarities), the extinction crosses rotated either counterclockwise or clockwise (i.e., rotated oppositely with positive and negative fields), indicating a synclinic tilt in the

b

SmCSPF

Siloxyl unit

Field on Field

direction

Field direction a

SmCAPA

Field on Field off

S

SmmCCAAPPAA

SmSmCC_SSPP_FF

SmC_AP_A states was also observed by triangular wave method as shown in Figure 3.8 and Figure 3.12b. Meanwhile, all H-bonded bent-core complexes with SmCP phase bearing H-donors A and B (owning di-siloxyl unit) like IV-A, V-A and V-B exhibited the similar chirlity investigation with complex II-A to show the chiral domain of anticlinic tilt in the antiferroelectric ground state (SmC_AP_A).

Figure 3.18. The co-existence of chiral (SmCSPF) and racemic (SmCAPF) domains under (a) the first time of the d.c. electric field applying and (b) second time of d.c.

electric field applying (opposite polarities). (White arrows are the directions of polarizers and analyzers.)

In chirality investigation of H-bonded bent-core dimeric complexes with H-donors C, D and E (owning tri-siloxyl unit), the chirality switching processes were determined in the complex V-C by applying the triangular wave, square wave and direction current (d.c.) electric fields. When the first time of d.c electric field was applied, two different circular domains were exhibited. As shown in Figure 3.18a, the extinction crosses of circular domain oriented to crossed polarizer directions was indicated the SmCAPF state, and the rotated extinction crosses of circular domains (orange region) was meant the SmC_SP_F state (see the red arrows in Figure 3.18a). This phenomenon was described the co-existence of chiral (SmCSPF) and racemic (SmC_AP_F) domains under the first time of the d.c. electric field applying. The similar

SmCSPF

SmCAPF

(a) (b)

^SmCSPF

SmCAPF

observation was obtained in the applied triangular wave field as well. However, the SmCSPF domains became smaller or disappeared to switch into the SmCAPF domains under the second time of opposite d.c. electric field applying as shown in Figure 3.18b.

In order to understand chirality switching processes, the optical investigation of the switching behavior of complex V-C were performed by the processes of applied SW (±35 V, 0.05 Hz) and TAW (140 Vpp, 100Hz) electric fields as shown in Figure 3.19.

When the SW electric field started to apply, The retented extension crosses of racemic domain (SmCAPF state) and few rotating extension crosses of chiral domain (SmCSPF

state), which were pointed out by the red arrows as shown in Figures 3.19b and 3.20b, were received form the ground states (SmCSPA and SmCAPA, see Figures 3.19a and 3.20a). The area of rotating extension cross were diminished obviously and oriented to crossed polarizer directions with the applied times of SW electric field (Figures 19c, 3.19d and 3.20c) to mean the changing chirality from chiral (SmC_SP_F) to racemic (SmCAPF) domains. When the SW electric field was removed, the SmCAPF state was switched into SmC_SP_A ground state as shown in Figures 3.19e and 3.20d, and then, even if the TAW or SW fields were applied, only the transfer of racemic domain (SmC_SP_A  SmC_AP_F) could be examined under switched off- (Figures 3.19f and 3.20d) and on-states (Figure 3.19g and 3.20c) of electric fields, suggesting the racemic behavior with no reversible of chiral behavior under electric field applying.

However, the co-existence of chiral (SmCSPF) and racemic (SmCAPF) domains could be achieved by heating to isotropic state and cooling to mesophasic state again.

Regarding the chirality of H-bonded bent-core MCP complexes with H-donors C, D and E (owning tri-siloxyl unit), the racemic domain of SmCAP_F ground state was identified. In optical inspection of MCP complex II-D, the extension crosses were oriented to the crossed polarizer directions with no d.c. electric field applying to mean

extension crosses were retained without rotating phenomenon under d.c. (Figure 3.21b) and TAW (Figure 3.21c) electric fields applying simultaneously, suggesting the opposite racemic domain of SmC_AP_F state.^[25c] This kind of characteristic was performed in H-bonded bent-core MCP complexes II-C, II-D and II-E with H-donors C, D and E to reveal the racemic behavior.

The chiral domain behavior could also be proven by the method of rotating the polarizer without applying electric fields.^[2,4] For example, the polarizer was rotated clockwise by a small angle of 10^o from the crossed position in complex II-B, and then the dark and bright domains become clearly distinguishable (see Figure 3.22a). On rotating the polarizer counterclockwise by the same angle (10^o) from the crossed position, the previously observed dark domains turned to bright domains, and vice versa (see Figure 3.22b). This observation was also indicative of the occurrence of chiral domains with opposite handednesses. The phenomenon could also be displayed in complexes IV-B and V-B. It means even if the complexes II-B, IV-B and V-B (with H-donor B) exhibited no spontaneous polarization behaviors, the opposite handednesses of chiral domain were still maintained (see Figure 3.22c to 3.22f).

Overall, the chirality of H-bonded bent-core dimeric complexes were depended on the siloxyl unit of H-donors, where the chiral domain of SmCAPA ground state and opposite handednesses was revealed in dimeric complexes with di-siloxyl H-donors A and B, and racemic domain of SmCSPA ground state was demonstrated in the dimeric complexes with tri-siloxyl H-donors C, D and E, respectively. However, the chiral domain was demonstrated in MCP complexes, in which SmCAPA ground state and opposite handednesses were displayed in MCP complexes with di-siloxyl H-donors A and B, and SmCSPF ground state was exhibited in MCP complexes with tri-siloxyl H-donors C, D and E, respectively.

Figure 3.19. The spherulite domains of dimeric complex V-C: (a) the co-existence of chiral (SmC_AP_A) and racemic (SmC_SP_A) domains without electric field applying; (b) the co-existence of chiral (SmC_SP_F) and racemic (SmC_AP_F) domains under the first time of square wave electric field applying; (c) The decreasing of chiral (SmC_SP_F) domains, which transferred to racemic (SmC_AP_F) domains partially under third time of square wave electric field applying; (d) The racemic (SmC_AP_F) domains with the disappearance of chiral (SmC_SP_F) domains under fifth time of square wave electric field applying; (e) the racemic (SmC_SP_A) domains without electric field applying; (f) the racemic (SmC_AP_F) domains under triangular wave electric field applying; (g) the racemic (SmC_AP_F) domains after the removing of triangular wave electric field applying. (White arrows are the directions of polarizers and analyzers, and red arrows

a b

c d

e f

g

Figure 20. The layer structural models of chirality switching behavior in dimeric complex V-C by five executed switching processes: (a) the initial state with co-existence of SmC_SP_A and SmC_AP_A mixed domains was transferred into (b) the field-on state of SmC_AP_F and SmC_SP_F mixed domains, where the SmC_SP_F domains were retained under triangular wave electric fields (i.e., steps i) but decreased gradually under square wave electric fields (i.e., steps ii). (c) The fully SmC_AP_F domains (field-on state) were achieved by applying square wave electric field several times (i.e., steps ii), and switched into (d) SmC_SP_A domains (field-off state) were transferred after the electric field removing (i.e., steps iii). Afterwards, the inconvertibly chirality switching of racemic behavior (SmC_SP_A and SmC_AP_F) was established even if the triangular or square wave electric fields were applied (i.e., steps iv). However, the co-existence of SmC_SP_A and SmC_AP_A mixed domains were occurred by heating to isotropic state and cooling to mesophasic state again (i.e., steps v).

(iv) TAW or SW Applied (ii) SW Applied

a b c d

(iii) SW removing

(v) Heating to isotropic state and cooling to mesophasic state (i) TAW Applied

Figure 3.21. The POM textures of racemic domain switching in MCP complex II-D:

(a) SmCAPF groundstate under 0 V d.c. electric field; (b) SmCAPF state under ±50 V d.c. electric field; (c) SmCAPF state under triangular wave electric field as Vpp = 140 V in a parallel rubbing cell with a cell gap of 4.25 μm. (White arrows are the directions of polarizers and analyzers.)

Field on Field off

Field on Field

direction

Field direction

a

b

c

SmC_SP_A

SmSmCC_AAPP_FF SmC_AP_F

SmCAPF

SmSmCCA_APPF_F

Figure 3.22. Chiral domain textures of exchange of dark and bright areas in (a) and (b) complex II-B; (c) and (d) complex IV-B; (e) and (f) complex V-B. (White arrows are the directions of polarizers and analyzers.)

3.4. Conclusion

In conclusion, the novel example of H-bonded bent-core main-chain polymers and their corresponding dimers with polar switching behaviors were developed by self-assembling via H-bonded force of bent-core pyridyl H-accepters and siloxane diacid H-donors. Their mesoporphism, polar switching behaviors and chirality

a b

c d

e f

II-B

IV-B

V-B

influenced by molecular configuration effects such as H-bonded injection, siloxyl units and rigid cores were reported. Almost H-bonded bent-core dimeric and MCP supramolecules exhibited the SmCP phases expect for the series of five-ring main-chain polymers and some complexes with diacid H-donors B. In addiction, the most extensive SmCP phase ranges and highest Ps values were achieved in H-bonded bent-core complexes composited with the biphenyl and naphthyl diacid H-donors E and D, respectively duo to the rigid terminal core designs as well as the bulky siloxane spacer. The SmCAPA ground state was observed in H-bonded bent-core dimeric and MCP complexes with di-siloxyl linking spacer of H-donor A to identify the chiral domain behavior, and SmCSPA ground state were investigated in H-bonded bent-core MCP complexes with tri-siloxyl linking spacer of H-donors to recognize the racemic domain behavior. However, a co-existence of SmCAPA and SmCSPA ground states were examined in H-bonded bent-core dimers with tri-siloxyl linking spacer of H-donors, and the unstable SmCAPA state would retain under triangular wave electric field, but exchange inconvertibly to the SmC_SP_A state under applying then removing the d.c. or square wave electric fields. Simultaneously, the voltage-dependent switching behavior of spontaneous polarization in H-bonded bent-core supramolecules were established by reorganized H-bonded design to be the voltage sensitive removable and reassemble (anti)ferroelectric materials.

3.5. Electronic Supplementary Information 3.5.1. Synthesis

The synthetic procedures of all diacid H-donors and pyridyl H-accepters were proceeded according to scheme S1 and S2, respectively.

3.5.1.1. Synthesis of NP0 and BP0. In preparation of compound NP0, 6-hydroxy-2-naphthoic acid (1 eq.), benzyl bromide (1.2 eq.) and potassium

for 8 hours (h) under reflux temperature. After that, reacted solution was extracted with water and Ethyl acetate (EA), and organic liquid layer was dried over anhydrous magnesium sulphate. After removal of the solvent, the residue was purified by column chromatography by EA and hexane to give a white solid. Identically, compound BP0 were reacted according to the similar protecting procedure of compound NP0 to get a white solid. Yield of NP0: 88%. ¹H NMR (300 MHz, CDCl3) δ (ppm) : 8.56 (s, 1H, Ar-H), 8.06 (d, 1H, J = 9.3 Hz, Ar-H), 7.86 (d, 1H, J = 6.0 Hz, Ar-H), 7.71 (d, 1H, J = 9.0 Hz, Ar-H), 7.51-7.32 (m, 5H, Ar-H), 7.16 (d, 1H, J = 9.0 Hz, Ar-H), 7.13 (s, 1H, Ar-H), 5.41 (s, 2H, -OCH₂-). Yield of BP0: 90%. ¹H NMR (300 MHz, CDCl3) δ (ppm) : 8.12 (d, 2H, J = 6.0 Hz, Ar-H), 7.62 (d, 2H, J = 6.0 Hz, Ar-H), 7.53 (d, 2H, J = 6.0 Hz, Ar-H), 7.49-7.35 (m, 5H, Ar-H), 6.94 (d, 2H, J = 6.0 Hz, Ar-H), 5.38 (s, 2H, -OCH2-).

3.5.1.2. Synthesis of PH1, BP1 and NP1. In preparation of compound PH1, Benzyl-4-hydroxy benzoate (1 eq.), w-undecylenyl alcohol (1.1 eq.) and triphenyl phosphine (1.1 eq.) were mixed in THF solvent under nitrogen for 10 min at room temperature (RT), and DEAD (40 % in toluene) (1.1 eq.) was added into solution for 24 h. After that, reacted solution was extracted with water and DCM, and organic liquid layer was dried over anhydrous magnesium sulphate. After removal of the solvent, the residue was purified by column chromatography by DCM and hexane to give a liquid product. Identically, compounds BP1 and NP1 were reacted according to the similar procedure of compound PH1 to get products. Yield of PH1: 92%. ¹H NMR (300 MHz, CDCl3) δ (ppm) : 8.02 (d, 2H, J = 9.0 Hz, Ar-H), 7.45-7.29 (m, 5H, Ar-H), 6.92 (d, 2H, J = 9.0 Hz, Ar-H), 5.88-5.74 (m, 1H, -CH=CH₂-), 5.33(s, 2H, Ar-CH2-), 5.03-4.91(m, 2H, -CH=CH2-), 3.98 (t, J = 6.3 Hz, 2H, OCH2), 2.08-2.01 (m, 2H, CH₂), 1.83-1.71 (m, 2H, CH₂), 1.47-1.27 (m, 12H, CH₂-CH₃). Yield of NP1:

85%. ¹H NMR (300 MHz, CDCl3) δ (ppm) : 8.47 (s, 1H, Ar-H), 8.02 (d, 2H, J = 9.0

Hz, Ar-H), 7.66 (d, 2H, J = 9.0 Hz, Ar-H), 7.60 (d, 2H, J = 9.0 Hz, Ar-H), 7.41-7.24 (m, 5H, Ar-H), 7.10 (d, 1H, J = 9.0 Hz, Ar-H), 6.97 (s, 1H, Ar-H), 5.82-5.70 (m, 1H, -CH=CH₂-), 5.32 (s, 2H, Ar-CH₂-), 5.02-4.90 (m, 2H, -CH=CH₂), 3.86 (t, J = 6.0 Hz, 2H, OCH2), 2.03-1.96 (m, 2H, CH2), 1.73-1.66 (m, 2H, CH2), 1.39-1.23 (m, 12H, CH₂-CH₃). Yield of BP1: 82%. ¹H NMR (300 MHz, CDCl₃) δ (ppm) : 8.13 (d, 2H, J

= 9.0 Hz, Ar-H), 7.62 (d, 2H, J = 9.0 Hz, Ar-H), 7.56 (d, 2H, J = 9.0 Hz, Ar-H), 7.48-7.32 (m, 5H, Ar-H), 7.00 (d, 2H, J = 9.0 Hz, Ar-H), 5.88-5.74 (m, 1H, CH=CH2-), 5.39 (s, 2H, Ar-CH2-), 5.03-4.91 (m, 2H, -CH=CH2-), 4.01 (t, J = 6.0 Hz, 2H, OCH₂), 2.05-2.00 (m, 2H, CH₂), 1.85-1.75 (m, 2H, CH₂), 1.51-1.25 (m, 12H, CH2-CH3).

3.5.1.3. Synthesis of PH2-1, PH2-2, BP2 and NP2. In preparation of compound PH2-1, reactant PH2 (2 eq.), 1,1,3,3-tetramethyldisiloxane (1 eq.) and Platinum(0)- 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, solution in xylenes,(~2% Pt) (0.03 eq.) were mixed in toluene for 24 h at RT. The reacted solution was extracted with water and DCM, and organic liquid layer was dried over anhydrous magnesium sulphate. After removal of the solvent, the residue was purified by column chromatography by DCM and hexane to give a white solid. Identically, compounds PH2-2, BP2 and NP2 were reacted according to the similar procedure of compound PH2-1 to get products. Yield of PH2-1: 87%. ¹H NMR (300 MHz, CDCl₃) δ (ppm) : 8.01 (d, 4H, J = 9.0 Hz, Ar-H), 7.43-7.31 (m, 10H, Ar-H), 6.89 (d, 4H, J = 9.0 Hz, Ar-H), 5.32 (s, 4H, Ar-CH₂-), 3.97 (t, 4H, J = 6.3 Hz, OCH₂), 1.83-1.71 (m, 4H, CH₂), 1.47-1.26 (m, 36H, CH2-CH3), 0.04-0.02 (s, 12H, Si-OCH3). Yield of PH2-2: 90%.

1H NMR (300 MHz, CDCl₃) δ (ppm) : 8.04 (d, 4H, J = 9.0 Hz, Ar-H), 7.46-7.33 (m, 10H, Ar-H), 6.90 (d, 4H, J = 9.0 Hz, Ar-H), 5.34 (s, 4H, Ar-CH2-), 3.99 (t, 4H, J = 6.3 Hz, OCH₂), 1.83-1.75 (m, 4H, CH₂), 1.67-1.28 (m, 36H, CH₂-CH₃), 0.06 (s, 12H,

(ppm) : 8.56 (s, 2H, Ar-H), 8.08 (d, 2H, J = 9.0 Hz, Ar-H), 7.84 (d, 2H, J = 9.0 Hz, Ar-H), 7.74 (d, 2H, J = 9.0 Hz, Ar-H), 7.52-7.33 (m, 10H, Ar-H), 7.21 (d, 2H, J = 9.0 Hz, Ar-H), 7.13(s, 2H, Ar-H), 5.42 (s, 4H, Ar-CH₂-), 4.07 (t, 4H, J = 6.0 Hz, OCH₂), 1.90-1.81 (m, 4H, CH2), 1.51- 1.27 (m, 36H, CH2-CH3), 0.08 (s, 12H, Si-OCH3), 0.05 (s, 6H, Si-OCH₃). Yield of BP2: 83%. ¹H NMR (300 MHz, CDCl₃) δ (ppm) : 8.12 (d, 4H, J = 8.4 Hz, Ar-H), 7.65 (d, 4H, J = 8.4 Hz, Ar-H), 7.60 (d, 4H, J = 9.0 Hz, Ar-H), 7.48-7.26 (m, 10H, Ar-H), 6.98 (d, 4H, J = 9.0 Hz, Ar-H), 5.40 (s, 4H, Ar-CH₂-), 3.99 (t, 4H, J = 6.0 Hz, OCH2), 1.84-1.75 (m, 4H, CH2), 1.51-1.28 (m, 36H, CH2-CH3), 0.056 (s, 12H, Si-OCH₃), 0.026 (s, 6H, Si-OCH₃).

3.5.1.4. Synthesis of A, C, D and E. Diacid structure of A was synthesized by de-protecting procedure. PH2-1 (1 eq.) and Pd/C powder (3 wt%) were mixed in THF under hydrogen gas for 24 h at RT. The catalyst powder was filtered, and the organic solvent was removed to form white powder. The purification was recrystallized by THF and hexane to give a white solid, and compounds C, D and E were reacted according to the similar procedure of compound A. Yield of A: 85%. ¹H NMR (300 MHz, D-THF) δ (ppm): 7.93 (d, 4H, J = 9.0 Hz, Ar-H), 6.91 (d, 4H, J = 9.0 Hz, Ar-H), 4.00(t, 4H, J = 6.0 Hz, OCH₂), 1.83-1.71 (m, 4H, CH₂), 1.47-1.31 (m, 36H, CH2-CH3), 0.03 (s, 12H, Si-OCH3). ¹³C NMR (300 MHz, D-THF) δ (ppm): 167.197, 163.57, 132.18, 123.82, 114.42, 68.59, 34.24, 30.43, 30.38, 30.18, 30.16, 29.94, 26.77, 24.05, 18.99, 0.24. EA: Calcd for C40H66O7Si2: C, 67.18, H, 9.30; Found: C, 66.74; H, 9.33. Yield of C: 86%. ¹H NMR (300 MHz, DMSO) δ (ppm) : 7.87 (d, 4H, J = 9.0 Hz, Ar-H), 6.98 (d, 4H, J = 9.0 Hz, Ar-H), 3.99 (t, 4H, J = 6.3 Hz, OCH2), 1.73-1.64 (m, 4H, CH₂), 1.37-1.22 (m, 36H, CH₂-CH₃), 0.02 (s, 12H, Si-OCH₃), -0.02 (s, 6H, Si-OCH3). ¹³C NMR (300 MHz, DMSO) δ (ppm) : 166.74, 162.17, 131.23, 122.91, 113.83, 67.57, 32.95, 29.27, 29.18, 29.03, 28.98, 28.71, 25.57, 22.76, 17.75, 0.99, -0.06. EA: Calcd for C42H72O8Si3: C, 63.91, H, 9.19; Found: C, 63.83; H, 9.34. Yield

of D: 78%. ¹H NMR (300 MHz, CDCl₃) δ (ppm) : 8.57(s, 2H, Ar-H), 8.05 (d, 2H, J = 8.7 Hz, Ar-H), 7.84 (d, 2H, J = 8.7 Hz, Ar-H), 7.73 (d, 2H, J = 8.7 Hz, Ar-H), 7.16 (d, 2H, J = 8.7 Hz, Ar-H), 7.10 (s, 2H, Ar-H), 4.05 (t, 4H, J = 6.6 Hz, OCH₂), 1.86-1.79 (m, 4H, CH2), 1.49-1.29 (m, 36H, CH2-CH3), 0.06 (s, 12H, Si-OCH3), 0.02 (s, 6H, Si-OCH₃). ¹³C NMR (300 MHz, CDCl₃) δ (ppm) : 172.43, 159.37, 137.69, 131.87, 130.99, 127.68, 126.83, 126.02, 124.10, 119.97, 106.31, 68.16, 33.49, 29.67, 29.62, 29.43, 29.17, 26.09, 23.24, 18.30, 1.30, 0.21. EA: Calcd for C₅₀H₇₆O₈Si₃: C, 67.52, H, 8.61; Found: C, 67.81; H, 8.72. Yield of E: 88%. ¹H NMR (300 MHz, D-THF) δ (ppm) : 8.04 (d, 4H, J = 9.0 Hz, Ar-H), 7.67 (d, 4H, J = 9.0 Hz, Ar-H), 7.62 (d, 4H, J

= 9.0 Hz, Ar-H), 6.99 (d, 4H, J = 9.0 Hz, Ar-H), 3.99 (t, 4H, J = 6.0 Hz, OCH2), 1.80-1.74 (m, 4H, CH₂), 1.48-1.27 (m, 36H, CH₂-CH₃), 0.07 (s, 12H, Si-OCH₃), 0.02 (s, 6H, Si-OCH3). ¹³C NMR (300 MHz, D-THF) δ (ppm) : 167.35, 160.34, 145.51, 132.73, 130.80, 129.73, 128.70, 126.62, 115.55, 115.25, 68.43, 33.49, 30.43, 30.20, 18.91, 0.515, -0.099. EA: Calcd for C54H80O8Si3: C, 68.89, H, 8.56; Found: C, 68.56;

H, 8.37.

3.5.1.5. Synthesis of PH3. compound A (1 eq.), N,N-dicyclohexylcarbodiimide (DCC) (1.2 eq) and a catalytic amount of 4-(N,Ndimethylamino) Pyridine (DMAP) was dissolved in dry dichloromethane (DCM) under nitrogen for 15 h at room temperature. The precipitated dicyclohexylurea (DCU) was filtered off and washed with an excess of DCM (20 ml). The filtrate was extracted with water/DCM and organic liquid layer was dried over anhydrous magnesium sulphate. After removal of the solvent by evaporation under reduced pressure, the residue was recrystallized from ethanol to give a white solid. Yield of PH3: 80%. ¹H NMR (300 MHz, CDCl₃) δ (ppm) : 8.16 (q,8H, Ar-H), 7.47-7.31 (m, 10H, Ar-H), 7.29 (d, 4H, J = 9.0 Hz, Ar-H), 6.95 (d, 4H, J = 9.0 Hz, Ar-H), 5.37 (s, 4H, Ar-CH₂-), 4.03 (t, 4H, J = 6.6 Hz, OCH₂),

3.5.1.6. Synthesis of B. By following the similar deprotecting procedure of compound A, compound PH3 (1 eq.) and Pd/C powder (3 wt%) were reacted to obtain a white solid. Yield of B: 75%. ¹H NMR (300 MHz, D-THF) δ (ppm) : 8.11 (m, 8H, Ar-H), 7.32 (d, 4H, J = 9.0 Hz, Ar-H), 7.04 (d, 4H, J = 9.0 Hz, Ar-H), 4.06 (t, 4H, 6.3Hz, OCH₂), 1.83-1.71 (m, 4H, CH₂), 1.47-1.26 (m, 36H, CH₂-CH₃), 0.04 (s, 12H, Si-OCH3). ¹³C NMR (300 MHz, D-THF) δ (ppm) : 166.757, 164.560, 164.219, 155.612, 132.71, 131.65, 128.977, 122.30, 122.106, 114.955, 68.863, 34.255, 30.442, 30.38, 30.17, 29.90, 26.75, 24.065, 18.998, 0.335. EA: Calcd for C54H74O11Si2: C, 67.89, H, 7.81; Found: C, 67.75; H, 8.09.

O

60 80 100 120 140 160 180 200 220 240 260 280

A

Temp. (o C)

SmC K

A B B C C D D E E

H C H C H C H C H C

Figure S3.1. Phase diagram of diacid H-donors A, B, C, D and E.

Figure S3.2. The POM patterns under various direct current (D.C.) electric field applying: (a) ＋100 V; (b) 0 V (voltage removing); (c) －100 V for complex IV-C with antiferroelectric switching property to show racemic domain (exchanging between SmC_SP_A and SmC_AP_F).

a b c

SmSmCCAAPPFF SmSmCCSSPPAA SSmmCCAAPPFF

Field on Field direction

Siloxyl unit Field on

Field direction

Chapter 4

Novel Supramolecular Side-Chain Banana-Shaped Liquid

在文檔中 含氫鍵之香蕉型液晶超分子之研究 (頁 134-156)