Circularly Polarized Luminescence Designed from Molecular Orbitals: A Figure-Eight-Shaped [5]Helicene Dimer with D2Symmetry

Hiromu Kubo, Daiki Shimizu, Takashi Hirose,* and Kenji Matsuda*

Letter

Circularly Polarized Luminescence Designed from Molecular

Orbitals: A Figure-Eight-Shaped [5]Helicene Dimer with D₂

Symmetry

Cite This: https://dx.doi.org/10.1021/acs.orglett.0c03506

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sı Supporting Information

ABSTRACT: Although many chiral molecules exhibiting circularly polarized luminescence

CPL) have been reported recently, few molecular design guidelines are known for

(

increasing the dissymmetry factor for CPL (g_l_u_m). We demonstrate that a ﬁgure-eight-shaped

molecule with D symmetry has excellent chiroptical properties (Φ = 0.08, |g_l_u_m| = 1.5 ×

−

0 ), which are attributed to the parallel arrangement of μ and m as well as a good |μ|/|m|

ratio.

ircularly polarized luminescence (CPL) has been

attracting attention because of its potential applications

point group where the directions of μ and m vectors are always

parallel for all electronic transitions; therefore, it is preferable

for high g_l_u_mvalues (Table S1 ). Mori et al. reported that an X-

2−4

for quantum teleportation, probes,

and optoelectronic

−12

devices.

To improve device performance, CPL materials

shaped double helicene with the D symmetry is a potential

are desired to have high dissymmetry factor g and strong

candidate as an excellent CPL emitter because of its parallel

lum

13−21

luminescence intensity.

In the design of CPL molecules,

arrangement of μ and m (cos θ = ± 1), though its CPL

−

the relationship between the molecular orbitals and transition

dipole moments is of primary importance because it is directly

related to the magnitude of g_l_u_m. Recently, Isobe et al. reported

a cylindrical molecule with D₄symmetry that exhibits

properties were modest (|g_l_u_m| = 2.5 × 10 , Φ = 0.018) likely

because the |μ|/|m| ratio was away from 1. Besides the X-

shaped molecules, ﬁgure-eight-shaped molecules are also D₂

symmetric. Several researchers have reported D -symmetric

25−30

outstanding CPL properties (i.e., emission quantum yield Φ

ﬁgure-eight-shaped molecules such as 1−3 (Figure 1).

0.8 and g

= −0.152), which are the highest CPL

To rationalize the CPL properties of the ﬁgure-eight-shaped

molecules, we calculated the g_l_u_mvalues of 1a−6 at the TD-

B3LYP/6-31G(d) (Table 1). All geometries were optimized in

lum

properties of organic molecules ever reported. However, it

remains diﬃcult to ﬁnd general guidelines for designing

organic molecules that exhibit strong CPL.

the lowest energy singlet excited state (S ), which were used

According to the theory of optical activity, the g_l_u_mis

represented as follows

for the following excited state calculations. The μ and m are

arranged in parallel for 1a and 2, which is consistent with their

D -symmetric geometries. It is noted that the |μ| values of 1a

I_L− I_R

4|μ||m|cos θ

|μ| + |m|

g_l_u_m= ₁

and 2 are more than 50 times larger than those of |m| (i.e., |μ|/

(

I + I )

(1)

|m| > 50), which is the main reason for the small g values

lum

−

(

|g_l_u_m_,_c_a_l_c_d| < 8 × 10 ) according to eq 1. Compound 3, where

where I is the intensity of luminescence, subscripts L and R

represent the properties corresponding to the left and right

circularly polarized lights, respectively, μ is the transition

electric dipole moment (TEDM), m is the transition magnetic

dipole moment (TMDM), and θ is the angle between μ and

m. According to this equation, the maximum g_l_u_m(i.e., g_l_u_m

2) is obtained when μ and m are parallel (cos θ = ± 1) and

have the same magnitude (|μ|/|m| = 1).

The shape and symmetry of molecular orbitals determine

the photophysical properties of molecules. In this work, we

designed a CPL active molecule in terms of the shape and

symmetry of π-conjugated molecules. The molecular symmetry

is closely related to the angle θ between μ and m. On the basis

two BODIPY subunits are linked by oxygen atoms and

therefore not conjugated each other, has a small TMDM

−20

−1

value|m| = 0.13 × 10 erg·G that is less than 1/20 of that

of 1asuggesting a magnetically forbidden nature of the S →

S transition for 3. The small TMDM is not suitable for

achieving large g_l_u_mwith retaining strong luminescence

Received: October 21, 2020

of the group theory, we noticed that D symmetry is the only

XXXX American Chemical Society

Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters

Letter

intensity. Interestingly, we noticed during the TD-DFT

calculations that the D -symmetric molecules do not always

retain their D symmetry in the excited state; for example, a

charge-transfer-type transition from one to the other BODIPY

fragments was suggested for 3, indicating a loss of D₂

symmetry in the S state, which is likely responsible for the

decrease of the cos θ value (Table 1). Thus, the small g_l_u_mof 3

was explained by both small |m| and small cos θ values. A

related result on the symmetry breaking in the excited state has

been reported by Crassous and co-workers on a naphthal-

imide−[6]helicene partially conjugated molecule.

We envisioned that designing D -symmetric molecules

which retain the D symmetry in the S state and have a |μ|/

m| ratio close to 1 is a key strategy to achieve an excellent g_l_u_m

To demonstrate this concept, we designed a D -symmetric

[

5]helicene dimer1,3(2,13)-dipentahelicena-2,4(1,4)-diben-

zenacyclotetraphane (4)as a new CPL-active molecule. The

molecular structure of 4 consists of two [5]helicene frame-

works covalently linked by p-phenylene linkers at the 2- and

Figure 1. Chemical structures and the |g_l_u_m| values of ﬁgure-eight-

shaped molecules 1−4.

³^-^p^o^sⁱ^tⁱ^oⁿ^s^.^T^D^-^D^F^T^c^a^l^c^u^l^a^tⁱ^oⁿ^s^s^u^g^g^e^s^t^e^d^t^h^a^t^t^h^e^glum

Table 1. Electric Transition Properties of 1−6

value for the (P)-isomer of 4 was estimated as high as g

small |μ| with retaining the relatively large |m| (i.e., |μ| = 50 ×

lum,calcd

compd

|μ|

|m|

3.0

2.3

4.3

cos θ

g_l_u_m_,_c_a_l_c_d

g_l_u_m_,_e_x_p

−1

−2.4 × 10 , which was attributed to (i) the signiﬁcantly

−2

−3

−1

−3

160

220

340

−1.00

−0.783

−1.00

−0.48

−0.94

−1.00

−7.4 × 10

−3.3 × 10

−5.1 × 10

−6.9 × 10

−2.4 × 10

−9.5 × 10

−3.7 × 10

−3

−20

−1

−5 × 10

esu·cm and |m| = 3.1 × 10 erg·G ; therefore, the ratio

−3

+3.7 × 10

μ|/|m| = 16) as well as (ii) the almost parallel μ and m (cos θ

−3

0.13

3.1

0.086

0.032

+9 × 10

−0.94) in the S state.

−2

−1.5 × 10

To investigate the origin of the expected large g

value

lum,calcd

of 4, the excited states of [5]helicene (5) and 2,13-

diphenyl[5]helicene (6)that are partial structures of 4

Calculated for the (P)-isomers at the TD-B3LYP/6-31G(d) level

were calculated for the optimized structures in the S state

using geometries optimized in the S state. Transition electric dipole

(Figure 2). Frontier orbitals of 5 and 6, especially the LUMO

and LUMO+1, were pseudodegenerated, and their S → S

transitions consist of two of one-electron transitions by

conﬁguration interaction. Signiﬁcant orbital coeﬃcients were

found on the phenyl substituents of 6 in the HOMO and

moment in the CGS unit (10⁻esu·cm). Transition magnetic dipole

−

−1

moment in the CGS unit (10 erg·G ) θ represents the angle of μ

and m. Dissymmetry factor calculated as follows: g = 4|μ||m|cos θ/

lum

(

|μ| + |m| ). Experimentally reported g values. Not reported.

lum

Figure 2. (a) Orbital correlation diagram and transition conﬁgurations of propellicene (1a), [5]helicene (5), 2,13-diphenyl[5]helicene (6), and 4

from left to right) calculated at the B3LYP/6-31G(d) level of theory for the optimized structures in the S state. Blue and red frameworks

(

represent the C -symmetric and C -antisymmetric molecular orbitals, respectively, regarding the [5]helicene subunit. (b) Twisted structures of 1a

and 4 optimized in the S states. Red and blue planes represent least-squares mean planes, each deﬁned by 22 carbon atoms in the [5]helicene

subunits.

Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters

Letter

LUMO, but not in the HOMO−1 and LUMO+1. As a

consequence, the frontier orbitals of 4 are not degenerated,

and the S → S transition almost solely consists of the LUMO

respectively, which were well consistent with the calculated

values (vide supra) (Figure S4).

UV−vis absorption and emission spectra of 4 were measured

in chloroform at room temperature (Figure 3 b), and

→

HOMO transition (96%). In terms of the shape and

symmetry, the LUMO → HOMO transition of 4 corresponds

to the LUMO+1 → HOMO transition of 5 or the LUMO →

HOMO transition of 6. Thus, TD-DFT calculations revealed

that dimerization of [5]helicenes has a signiﬁcant inﬂuence on

the frontier orbitals; the electronic state of 4 in the S state was

largely diﬀerent from those of 5 and 6. Considering that the |m|

value of 4 (|m| = 3.1 × 10⁻erg·G ) is comparable to a

−1

higher energy transition of unsubstituted [5]helicene 5 (|m| =

.9 × 10 erg·G for the S → S transition that is partly

0 3

−

−1

consisting of the HOMO → LUMO+1 transition, Table S14),

the magnitude of TMDM of 4 can be assignable as a

magnetically allowed electronic transition.

It is noted that the shape and the symmetry of the LUMO

→

HOMO transition of 4 was consistent with that of 1a. A

prominent diﬀerence between 4 and 1a was found in the twist

angle (ϕ ) of the two [5]helicene subunits; the ϕ was 54.3°

for 4, which is signiﬁcantly smaller than that of the highly

^t^wⁱ^s^t^e^d¹^a⁽^ϕTA = 82.0°) (Figure 2b and Figure S3 ). The

diﬀerence in the twist angles likely aﬀects the π-conjugation

between the two [5]helicene subunits.

Figure 3. (a) CD (solid line) and CPL (dashed line) spectra of 4 in

chloroform at room temperature. (b) UV−vis absorption (left, black

line) and ﬂuorescence spectra (right, red line) of 4 in chloroform. The

inset is a photograph of a solution of 4 in chloroform under UV

irradiation.

[

5]Helicene dimer 4 was synthesized according to Scheme

. 4,4″-Diformyl-p-terphenyl (7) was prepared by a Suzuki−

photophysical properties of 4 and unsubstituted [5]helicene

2,34

(

were summarized in Table 2. [5]Helicene dimer 4

Scheme 1. (a) Synthesis and (b) X-ray Single-Crystal

showed a strong absorption band at 339 nm (ε = 6.5 × 10

−

−1

Structure of 4

M ·cm ) and a small absorption band around 390 nm (ε =

−1

.0 × 10 M ·cm ). The lowest energy absorption band at

90 nm was assigned to the S → S transition, whose

absorption coeﬃcient was about 40 times larger than that of 5

−1

−1 32

(

ε = 2.0 × 10 M ·cm ). The ﬂuorescence maximum of 4

λ_m_a_x_,_F_L= 442 nm, Figure 3b, Table 2) was red-shifted by 18

nm compared to that of 5 (λ_m_a_x_,_F_L= 424 nm). The ﬂuorescence

quantum yield of 4 (Φ = 0.08) was twice of that of 5 (Φ =

.04), which was attributed to the increase in the radiative rate

−1

constant (k = 7 × 10 s ). It is noted that the experimentally

determined k value for 4 was 7 times larger than the calculated

one (k_f_,_c_a_l_c_d= 1.0 × 10 s ), suggesting that the TD-DFT

calculation underestimates the magnitude of |μ| for 4 at the

B3LYP/6-31G(d) level.

−1

The enantiomers of 4 were separated by HPLC equipped

with a chiral column (Figure S11). No racemization was

detected in toluene at 80 °C for 24 h (Figure S12a), indicating

One of the two independent molecules is shown. Hydrogen atoms

a greater racemization barrier of 4 than 5. The large

racemization barrier of ﬁgure-of-eight geometries is consistent

with the concept of persistent chirality of 1a and 1b reported

are omitted for clarity. Thermal ellipsoids are drawn at the 50%

probability level.

by Durola et al_.CD spectra of (P)-4 showed the ﬁrst negative

−

−1

Cotton eﬀect at 350 nm or more (Δε = −87 M ·cm at 374

−

Miyaura coupling of 4-formylphenylboronic acid with 1,4-

dibromobenzene in 68% yield (see the Supporting Information

for details). A 4-fold Wittig reaction of 7 with p-xylene

bis(triphenylphosphonium bromide) aﬀorded the macrocyclic

precursor 8 in 4% yield. [5]Helicene dimer 4 was then

obtained in 44% yield by a 4-fold photocyclodehydrogenation

of 8 in the presence of iodine and propylene oxide. The

ﬁgure-eight structure of 4 was determined by single-crystal X-

ray diﬀraction analysis (Scheme 1, Figure S1, Table S3). Two

independent molecules of 4 were found in an asymmetric unit

nm, g = −1.9 × 10 at 403 nm, which was assigned to the

S → S transition) and positive Cotton eﬀects between 290

and 350 nm, as well as another negative Cotton eﬀect at 290

nm or less (Figure 3a). The CD spectrum of (M)-4 showed

the mirror image of that of (P)-4. The chirality of 4 was

assigned based on TD-DFT calculations as follows: (P)-4 and

(M)-4 show the ﬁrst negative and positive CD signals,

respectively, for the longest wavelength absorption region

(Figure S13 ). It is noted that the assignment of chirality is

opposite to that of conventional carbo[n]helicenes. Both

(P)-4 and (M)-4 showed clear and mirror-image CPL spectra

(Figure 3a). The g_l_u_mof both (P)-4 and (M)-4 were

in the achiral P1 space group. According to the X-ray crystal

structures of 4 and 1b, the mean twist angles of the two

independent structures were ⟨ϕ ⟩ = 54.2° and 86.3°,

−

−2

experimentally determined as −1.5 × 10 and +1.5 × 10

Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters

Letter

Table 2. Absorption and Fluorescence Properties of 4 and 5

experimental

theoretical

compd

λ_m_a_x_,_a_b_s(nm)

λ_m_a_x_,_F_L(nm)

Φ_f

⟨τ ⟩ (nm)

k_f(s⁻¹)

k_n_r(s⁻¹

)

|g_C_D

|g_l_u_m

k_f_,_c_a_l_c_d(s⁻¹

)

390

393

442

424

0.08

0.04

7 × 10⁶

2 × 10⁶

8 × 10⁷

4 × 10⁷

1.9 × 10⁻²

1.5 × 10⁻²

1.0 × 10⁶

7.0 × 10⁵

In chloroform at room temperature. λ_m_a_x_,_a_b_s: longest wavelength absorption maximum. λ

: ﬂuorescence maximum. Φ : ﬂuorescence quantum

max,FL

yield. ⟨τ ⟩: area-weighted mean ﬂuorescence lifetime. ⟨τ ⟩ = Σ(A τ )/Σ(A τ ), where A is the coeﬃcient of the exponential functions for the nth

component. k : ﬂuorescence emission rate constant, k = Φ /⟨τ ⟩. k : nonradiative decay rate constant, k = (1 − Φ )/⟨τ ⟩. Calculated at the

B3LYP/6-31G(d) level (also see the Supporting Information for details). Reported values in chloroform, ref 32. Reported values in 1,4-dioxane,

ref 34. Not reported.

in chloroform, respectively, which is large among small organic

and z-axis components of TMDM were fully canceled out. The

−

13,14

compounds reported so far (g_l_u_m∼ 10 ).

experimental g_l_u_mvalue of (P)-4 (g_l_u_m_,_e_x_p= −1.5 × 10 ) was

signiﬁcantly smaller than the calculated one (g = −2.4 ×

The

x-axis component of the TMDM density (ρ ) distributes over

−

the whole molecular framework, suggesting that the p-

phenylene linker moiety as well as the two [5]helicene

subunits of 4 signiﬁcantly contribute to the magnitude of |m|

(Figure 4). The large |m| can be explained by the contributions

of both the p-phenylene linker moiety as well as the two

[5]helicene subunits. Thus, the signiﬁcantly small |μ| with

retaining the large |m| is a key factor in the large g_l_u_mvalue of 4.

In conclusion, we reported good chiroptical properties of

ﬁgure-eight-shaped helicene dimer 4 (Φ = 0.08, g = 1.5 ×

lum,calc

−

0 ), which may be related to the fact that the TD-DFT

calculation underestimated the |μ| value (vide supra); we

conﬁrmed by TD-DFT calculation that the |μ| of 4 signiﬁcantly

increased upon the rotation of p-phenylene linker group

Figure 4 ). The transition dipole moment density reveals

Table S7 ).

To gain detailed insights into the chiroptical properties of 4,

we conducted transition dipole moment density analysis

lum

−

The Supporting Information is available free of charge at

10 ). The ﬁgure-eight-shaped dimer demonstrated a unique

molecular design concept as a CPL-active material: a

combination of D -symmetric (ﬁgure-eight) structure and

small transition electric dipole moment. By designing chiral

molecules with the D symmetry, the transition electric and

magnetic dipole moments (μ and m) are always parallel in

terms of the group theory, so the condition for maximum |cos

θ| is always satisﬁed. Covalent linkage of two [5]helicene

subunits with p-phenylene linker made the |μ| for the S → S

transition eﬀectively small. Furthermore, a large macrocyclic

ring formed by linking two [5]helicenes generated large |m|,

oﬀering a good |μ|/|m| ratio. Further exploration on rational

design of CPL materials is ongoing in our laboratories.

ASSOCIATED CONTENT

sı Supporting Information

■

Figure 4. (a) The spatial arrangement of μ and m of 4, (b) transition

electric dipole moment density, (c) transition magnetic dipole

moment density calculated at B3LYP/6-31G(d) level of theory,

displayed with an isosurface value of 0.001 au.

https://pubs.acs.org/doi/10.1021/acs.orglett.0c03506.

Experimental procedures, details of the ﬂuorescence

lifetime analyses, theoretical calculations, as well as H

and C NMR spectra (PDF )

which part of molecular orbitals contributes to the magnitudes

of TEDM and TMDM. The integrated values of the transition

Accession Codes

moment densities for TEDM (ρ_t_o_t_a_l) and TMDM (ρ^m

)

total

CCDC 2038896 contains the supplementary crystallographic

data for this paper. These data can be obtained free of charge

via www.ccdc.cam.ac.uk/data_request/cif , or by emailing

data_request@ccdc.cam.ac.uk , or by contacting The Cam-

bridge Crystallographic Data Centre, 12 Union Road,

Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

correspond to the magnitudes of transition dipole moments |μ|

and |m|, respectively (see the Supporting Information for

details). TD-DFT calculation suggested that 4 has only the x-

axis components both for TEDM and TMDM (Table S4 ).

According to the transition moment densities, the TEDM of 4

are fully canceled along the y- and z-axes (ρ and ρ ) due to

the symmetry of molecular orbitals (Figure 4b). Therefore, the

μ| of 4 can be interpreted solely as the integral of the x-axis

AUTHOR INFORMATION

Corresponding Authors

■

component of TEDM density (ρ ). In the plot of ρ , the

integration of blue lobes was similar in magnitude to that of

red lobes, which is the cause of the small |μ| of 4. It is noted

that the |μ| of 4 was less than 1/3 of the directly connected

dimers 1a and 1b (Table 1), which is likely related to the

diﬀerence in twist angle (ϕ_T_A).

We also conducted transition dipole moment density

analysis for TMDM (Figure 4c). Similar to TEDM, the y-

Takashi Hirose − Institute for Chemical Research, Kyoto

University, Uji, Kyoto 611-0011, Japan; orcid.org/0000-

0002-5351-2101 ; Email: hirose@scl.kyoto-u.ac.jp

Kenji Matsuda − Department of Synthetic Chemistry and

Biological Chemistry, Graduate School of Engineering, Kyoto

University, Kyoto 615-8510, Japan; orcid.org/0000-

0002-2420-4214 ; Email: kmatsuda@sbchem.kyoto-u.ac.jp

Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters

Authors

(11) Han, J.; Guo, S.; Lu, H.; Liu, S.; Zhao, Q.; Huang, W. Recent

Letter

Progress on Circularly Polarized Luminescent Materials for Organic

Optoelectronic Devices. Adv. Opt. Mater. 2018, 6, 1800538.

Hiromu Kubo − Department of Synthetic Chemistry and

Biological Chemistry, Graduate School of Engineering, Kyoto

University, Kyoto 615-8510, Japan

Daiki Shimizu − Department of Synthetic Chemistry and

Biological Chemistry, Graduate School of Engineering, Kyoto

University, Kyoto 615-8510, Japan; orcid.org/0000-

(12) Li, M.; Li, S.-H.; Zhang, D.; Cai, M.; Duan, L.; Fung, M.-K.;

Chen, C.-F. Stable Enantiomers Displaying Thermally Activated

Delayed Fluorescence: Efficient OLEDs with Circularly Polarized

Electroluminescence. Angew. Chem., Int. Ed. 2018, 57, 2889−2893.

(13) Sanchez-Carnerero, E. M.; Agarrabeitia, A. R.; Moreno, F.;

002-2053-3483

Maroto, B. L.; Muller, G.; Ortiz, M. J.; de la Moya, S. Circularly

Polarized Luminescence from Simple Organic Molecules. Chem. - Eur.

J. 2015, 21, 13488−13500.

Complete contact information is available at:

https://pubs.acs.org/10.1021/acs.orglett.0c03506

(14) Chen, N.; Yan, B. Recent Theoretical and Experimental Pro-

gress in Circularly Polarized Luminescence of Small Organic Mole-

cules. Molecules 2018, 23, 3376−3407.

Notes

The authors declare no competing ﬁnancial interest.

(15) Zhao, W.-L.; Li, M.; Lu, H.-Y.; Chen, C.-F. Advances in

Helicene Derivatives with Circularly Polarized Luminescence. Chem.

Commun. 2019, 55, 13793−13803.

ACKNOWLEDGMENTS

■

(16) Kumar, J.; Nakashima, T.; Tsumatori, H.; Kawai, T. Circular-ly

This work was supported by a Grant-in-Aid for Scientiﬁc

Research on Innovative Areas “Photosynergetics” (JSPS

KAKENHI Grant Number JP26107008) and “Coordination

Asymmetry” (JSPS KAKENHI Grant Number JP19H04573)

from MEXT, Japan. This work was also supported by Fusion

Emergent Research from the Integrated Research Consortium

on Chemical Sciences (IRCCS). H.K. acknowledges JSPS for a

Grant-in-Aid for JSPS Research Fellow (JSPS KAKENHI

Grant Number JP18J21819). We thank Dr. Masayuki Gon and

Prof. Yoshiki Chujo (Department of Polymer Chemistry,

Graduate School of Engineering, Kyoto University) for

assistance with CPL spectroscopic measurements.

Polarized Luminescence in Chiral Aggregates: Dependence of

Morphology on Luminescence Dissymmetry. J. Phys. Chem. Lett.

(

014, 5, 316−321.

17) Jimenez, J.-R.; Doistau, B.; Cruz, C. M.; Besnard, C.; Cuerva, J.

M.; Campan

a, A. G.; Piguet, C. Chiral Molecular Ruby [Cr(dqp) ]

with Long-Lived Circularly Polarized Luminescence. J. Am. Chem. Soc.

2019, 141, 13244−13252.

(18) Sawada, Y.; Furumi, S.; Takai, A.; Takeuchi, M.; Noguchi, K.;

Tanaka, K. Rhodium-Catalyzed Enantioselective Synthesis, Crystal

Structures, and Photophysical Properties of Helically Chiral 1,1 ’-

Bitriphenylenes. J. Am. Chem. Soc. 2012, 134, 4080−4083.

(19) Oyama, H.; Akiyama, M.; Nakano, K.; Naito, M.; Nobusawa,

K.; Nozaki, K. Synthesis and Properties of [7]Helicene-like Com-

pounds Fused with a Fluorene Unit. Org. Lett. 2016, 18, 3654 −3657.

(20) Wang, Y.; Li, X.; Li, F.; Sun, W.-Y.; Zhu, C.; Cheng, Y. Strong

circularly polarized luminescence induced from chiral supramolecular

assembly of helical nanorods. Chem. Commun. 2017, 53, 7505−7508.

REFERENCES

■

(

1) Nielsen, M. A.; Chuang, I. L. Quantum Computation and

Quantum Information: 10th Anniversary ed.; Cambridge University

Press: Cambridge, 2010.

(21) Ma, K.; Chen, W.; Jiao, T.; Jin, X.; Sang, Y.; Yang, D.; Zhou, J.;

2) Tempelaar, R.; Stradomska, A.; Knoester, J.; Spano, F. C. Cir-

Liu, M.; Duan, P. Boosting the circularly polarized luminescence of

small organic molecules via multi-dimensional morphology control.

Chem. Sci. 2019, 10, 6821−6827.

cularly Polarized Luminescence as a Probe for Long-Range Interac-

tions in Molecular Aggregates. J. Phys. Chem. B 2011, 115, 10592−

0603.

3) Wu, T.; Bour,

cularly Polarized Luminescence Probe of DNA Structure. Sci. Rep.

019, 9, 1068−1072.

4) Carr, R.; Evans, N. H.; Parker, D. Lanthanide complexes as chiral

probes exploiting circularly polarized luminescence. Chem. Soc. Rev.

012, 41, 7673−7686.

5) Yang, Y.; da Costa, R. C.; Fuchter, M. J.; Campbell, A. J. Cir-

(22) Sato, S.; Yoshii, A.; Takahashi, S.; Furumi, S.; Takeuchi, M.;

P.; Andrushchenko, V. Europium (III) as a Cir-

Isobe, H. Chiral intertwined spirals and magnetic transition dipole

moments dictated by cylinder helicity. Proc. Natl. Acad. Sci. U. S. A.

24) Tanaka, H.; Ikenosako, M.; Kato, Y.; Fujiki, M.; Inoue, Y.;

017, 114, 13097−13101.

23) Schellman, J. A. Circular Dichroism and Optical Rotation.

Chem. Rev. 1975, 75, 323−331.

Mori, T. Symmetry-based rational design for boostingchiroptical

cularly polarized light detection by a chiral organic semiconductor

responses. Commun. Chem. 2018, 1, 1−8.

transistor. Nat. Photonics 2013, 7, 634−638.

W.; Jiang, L.; Duan, P. Hierarchically Chiral Lattice Self-Assembly

25) Thulin, B.; Wennerstrom, O. Propellicene or Bi-2,13-

(

6) Liang, J.; Guo, P.; Qin, X.; Gao, X.; Ma, K.; Zhu, X.; Jin, X.; Xu,

pentahelicenylene. Acta Chem. Scand. 1976, B 30, 688−690.

(

Induced Circularly Polarized Luminescence. ACS Nano 2020, 14,

26) Robert, A.; Naulet, G.; Bock, H.; Vanthuyne, N.; Jean, M.;

Giorgi, M.; Carissan, Y.; Aroulanda, C.; Scalabre, A.; Pouget, E.;

Durola, F.; Coquerel, Y. Cyclobishelicenes: Shape-Persistent Figure-

Eight Aromatic Molecules with Promising Chiroptical Properties.

Chem. - Eur. J. 2019, 25, 14364−14369.

7) Zhao, B.; Yu, H.; Pan, K.; Tan, Z.; Deng, J. Multifarious Chiral

190−3198.

Nanoarchitectures Serving as Handed-Selective Fluorescence Filters

for Generating Full-Color Circularly Polarized Luminescence. ACS

Nano 2020, 14, 3208−3218.

(

27) Senthilkumar, K.; Kondratowicz, M.; Lis, T.; Chmielewski, P. J.;

Cybinska, J.; Zafra, J. L.; Casado, J.; Vives, T.; Crassous, J.; Favereau,

L.; Stepien, M. Lemniscular [16]Cycloparaphenylene: A Radially

Conjugated Figure-Eight Aromatic Molecule. J. Am. Chem. Soc. 2019,

41, 7421−7427.

28) Saikawa, M.; Nakamura, T.; Uchida, J.; Yamamura, M.; Na-

(

8) Shi, Y.; Zhou, Z.; Miao, X.; Liu, Y. J.; Fan, Q.; Wang, K.; Luo, D.;

Sun, X. W. Circularly polarized luminescence from semiconduc-tor

quantum rods templated by self-assembled cellulose nanocrystals. J.

Mater. Chem. C 2020, 8, 1048−1053.

(

9) Cerdan, L.; Moreno, F.; Johnson, M.; Muller, G.; de la Moya, S.;

beshima, T. Synthesis of figure-of-eight helical bisBODIPY macro-

cycles and their chiroptical properties. Chem. Commun. 2016, 52,

10727−10730.

(29) Kiel, G. R.; Bay, K. L.; Samkian, A. E.; Schuster, N. J.; Lin, J. B.;

Handford, R. C.; Nuckolls, C.; Houk, K. N.; Tilley, T. D. Expanded

Helicenes as Synthons for Chiral Macrocyclic Nanocarbons. J. Am.

Chem. Soc. 2020, 142, 11084−11091.

García-Moreno, I. Circularly polarized laser emission in optically

active organic dye solutions. Phys. Chem. Chem. Phys. 2017, 19,

10) Yang, L.; Huang, J.; Qin, M.; Ma, X.; Dou, X.; Feng, C. High-ly

2088−22093.

efficient full-color and white circularly polarized luminescent nano-

assemblies and their performance in light emitting devices. Nanoscale

2020, 12, 6233−6238.

Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters

Cabanetos, C.; Autschbach, J.; Crassous, J. Modulation of Circularly

Letter

(

30) We also conﬁrmed ground state D or pseudo D symmetry of

2 2

4a−6 by DFT calculations (Supporting Information).

(

31) Dhbaibi, K.; Favereau, L.; Srebro-Hooper, M.; Quinton, C.;

Vanthuyne, N.; Arrico, L.; Roisnel, T.; Jamoussi, B.; Poriel, C.;

Polarized Luminescence Through Excited-State Symmetry Breaking

and Interbranched Exciton Coupling in Helical Push −Pull Organic

Systems. Chem. Sci. 2020, 11, 567−576.

32) Kubo, H.; Hirose, T.; Matsuda, K. Control over the Emission

Properties of [5]Helicenes Based on the Symmetry and Energy Levels

of Their Molecular Orbitals. Org. Lett. 2017, 19, 1776−1779.

33) Liu, L.; Yang, B.; Katz, T. J.; Poindexter, M. K. Improved

methodology for photocyclization reactions. J. Org. Chem. 1991, 56,

769−3775.

34) Birks, J.B.; Birch, D.J.S.; Cordemans, E.; Vander Donckt, E.

Fluorescence of the higher helicenes. Chem. Phys. Lett. 1976, 43, 33−

35) Goedicke, C.; Stegemeyer, H. Resolution and Racemization of

Pentahelicene. Tetrahedron Lett. 1970, 11, 937−940.

36) Furche, F.; Ahlrichs, R.; Wachsmann, C.; Weber, E.; Sobanski,

A.; Vogtle, F.; Grimme, S. Circular Dichroism of Helicenes

Investigated by Time-Dependent Density Functional Theory. J. Am.

Chem. Soc. 2000, 122, 1717−1724.