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The “majority-rule” and “sergeant-soldier” principle action containing either or both non-charged chiral helix of both Poly (n-hexyl-(S)-2-methylbutylsilane) (PSi-S) and poly (n-hexyl-(R)-2-methylbutylsilane) (PSi-R) were employed as scaffold to determine the polymer capability to amplified chiral shape to the achiral poly (9,9-di-n-octylfluorene) PF8 in a hetero-aggregate system. The majority-rule polysilane refers to the PSi-R-ran-PSi-S copolymers with excess copolymers of R or S in a copolymer system. Meanwhile, the “sergeant and soldier” polysilane was described as PSi-R(S)-ran-PSi-iBu copolymers when one chiral element imposes its screw sense on a large “platoon” of achiral copolymer fragments. For PSi-R-ran-PSi-S copolymers, the effect is rather small featuring PF8 small monotonic increase along with the percentage of back-bone chiral unit. In PSi-R(S)-ran-PSi-iBu copolymer systems, the helix inversion is more obvious in which the PF8 followed the PSi chiral screw preferences.

This paper reports the first magnetic circularly polarized luminescence (MCPL) characteristics of racemic helicenes, including four unsubstituted [n]helicenes (n=3,4,5,7) and two [4]helicene derivatives bearing methoxy substituents, in tetrahydrofuran (THF) and dimethyl sulfoxide (DMSO) solutions. The value of |gMCPL | was calculated to be of the order of 10-3 T-1 within 350-430 nm under the north-up (N-up) and south-up (S-up) Faraday geometries in an external magnetic field of 1.6 T. The [n]-dependent MCPL signs were altered by the N-up and S-up geometries.

Herein, magnetic circularly polarized luminescence (CPL) (MCPL) spectroscopy was conducted to analyze an EuIII (hfa)3 complex with three chiral PIII -ligands. Resultantly, (R)-chirality luminophores with S-up orientation and (S)-chirality luminophores with N-up orientation were observed to possess symmetrical mirror image spectra, i. e., they were enantiomers. Similarly, the (R)-chirality luminophores with N-up orientation and the (S)-chirality luminophores with S-up orientation were also enantiomers. Contrarily, (R)-S-up and (S)-S-up were diastereomers and did not possess a mirror-image relationship. Likewise, (R)-N-up and (S)-N-up were diastereomers. The J-dependency of gMCPL and gCPL datasets suggested that the N-up/S-up external magnetic field, with the aid of chiral PIII -ligands, increased the gMCPL values by two- to sixteen-fold and modulated the gMCPL signs at J=1-4. Additionally, the origins of the nonideal mirror-symmetric CPL and MCPL spectral characteristics of EuIII (hfa)3 with three chiral PIII -ligands were discussed in terms of parity (space-inversion, P)-symmetry, time-reversal (T)-symmetry, and PT-symmetry laws.

Herein, we report an example of red-green-blue full-color magnetic circularly polarized luminescence (MCPL) from three inorganic luminophores in their solid powder form and upon embedding in poly(m...

The magnetic circularly polarized luminescence (MCPL) and photoluminescence (PL) spectra of achiral (2,3,7,8,12,13,17,18-octaethylporphyrinato)platinum(II), PtOEP, and [2-(4',6'-difluorophenyl)pyridinato-N,C2' ]platinum(II) acetylacetonate-O,O, F2 -ppyPt(acac), in toluene and dichloromethane solutions were recorded under an external magnetic field of 1.6 T with N-up and S-up Faraday geometries. The MCPL signs of PtOEP and F2 -ppyPt(acac) were controlled solely by changing the N-up and S-up geometries. The MCPL/PL wavelengths of F2 -ppyPt(acac) in solutions were varied by the ratio of the monomeric and excimeric species.

Molecular pyrene, 1-hydroxylpyrene, and 2-hydroxypyrene in chloroform and embedded in poly(methyl methacrylate) film reveal mirror-image magnetic circularly polarized luminescence (MCPL) when south...

Five optically inactive EuIII(hfa)3, TbIII(hfa)3, EuIII(acac)3·Phen, TbIII(acac)3·Phen and EuIII(hfa)3·BDPB (hfa: hexafluoroacetylacetonate, acac: acetylacetonate, BDPB: 2,2′-bis(diphenylphosphino)biphenyl and Phen: phenanthroline) complexes showed clear mirror-image magnetic circularly polarised luminescence (MCPL) spectra in CHCl3, acetone, and DMF solutions, in a poly(methyl methacrylate) film, a KBr pellet and bulk powder at room temperature under 1.6 T as an external magnetic field with Faraday geometry. The signs of the MCPL signals were determined via N-up and S-up geometries. The gMCPL values of EuIII(hfa)3 and TbIII(hfa)3 were ±(0.046–2.0) × 10−2 T−1 at the 5D0 → 5FJ transitions (J = 1–4) in the range of 590 nm and 703 nm and ±(0.0081–1.0) × 10−2 T−1 at the 5D4 → 7FJ transitions (J = 3–6) in the range of 480 nm and 630 nm, respectively. Interestingly, the photoluminescence spectra of EuIII(hfa)3 and TbIII(hfa)3 in CHCl3 and acetone under 1.6 T considerably redshifted by 10–114 cm−1, while those of EuIII(acac)3·Phen and TbIII(acac)3·Phen did not reveal detectable redshifts.

Planar-chiral Phanephos, containing the coordinatable P(III), formed P(III)/Tb(III)(hfa)3 hybrid luminophores that successfully emitted characteristic circularly polarised luminescence (CPL) due to 5D4 → 7F5 transitions in solution. On the other hand, BINAP, containing P(III)O as axially chiral ligand, exhibited no detectable CPL with Tb(III)(hfa)3.

Optically active fullerenes, including C60 and C70 derivatives carrying organic substituents, are used in a range of applications because of their unique spectroscopic, catalytic, and chiral recognition properties. However, their inherent photoexcited chirality is yet to be elucidated because of their very poor fluorescence quantum yield (Φf). We synthesised a new chiral C70 derivative, X70A, with 20% yield, by reacting bis-borylated xanthene with C70 in a one-step double addition reaction, followed by a successful optical resolution. The isolation of two separate X70A enantiomers was confirmed by mirror-image circular dichroism spectroscopy in the range of 300–750 nm. In toluene, the enantiomeric pair of X70A clearly revealed mirror-image circularly polarised luminescence (CPL) spectra with a high |glum| value of 7.0 × 10−3 at 690 nm. The first fullerene-based deep-red CPL of X70A should provide a new guideline for the design of chiral nanocarbon materials.

Diamagnetic achiral pyrene and phenanthrene derivatives substituted with electron-donating hydroxyl/methoxy groups and electron-withdrawing carboxylic acid groups exhibited clear magnetic circularly polarised luminescence (MCPL) spectra at 360–460 nm in dilute solvents upon the application of N-up and S-up Faraday geometries under an external magnetic field of 1.6 T. Their MCPL signs were also susceptible upon application of the same Faraday geometry.

The magnetic circularly polarized luminescence (MCPL) and photoluminescence (PL) spectra of achiral (2,3,7,8,12,13,17,18-octaethylporphyrinato)platinum(II), PtOEP, and [2-(4',6'-difluorophenyl)pyridinato-N,C

Optically inactive, paramagnetic Ir(III)(ppy)3 and Ir(III)(ppy)2(acac) (ppy: 2-phenylpyridinate and acac: acetylacetonate) showed nearly mirror-symmetric magnetic circularly polarised luminescence (MCPL) spectra in dilute dichloromethane and dimethyl sulfoxide under N-up and S-up geometries in a 1.6-T magnetic field. However, the MCPL signs of Ir(III)(ppy)3 and Ir(III)(ppy)2(acac) under the same N-up (or S-up) Faraday geometry were opposite to each other when one ppy was replaced with an acac. This ligand exchange approach provides facile control of the MCPL sign, irrespective of the Faraday geometry.

Stereospecific synthesis of several cyclic sulfite esters containing three stereogenic centers from enantiopure 1,1,4,4-tetraarylbutanetetraols was achieved. Chiral sulfur centers were constructed stereospecifically via a diastereoselective reaction with the assistance of an intramolecular H-bonding interaction. The absolute configuration of the S atom was elucidated by using the corresponding single-crystal X-ray diffraction analysis of the synthesized monochloride cyclic sulfite esters. Furthermore, a crystallographic evidence of the specific intramolecular C(sp3)-H···CAr weak H-bondings was presented, and its dramatic effect on the 1H NMR spectral properties was revealed. This intriguing behavior was unambiguously rationalized by different shielding effects of the neighboring phenyl rings. Additionally, the theoretical results obtained on the basis of MP2 calculations fully supported the existence of intramolecular hydrogen bonding interactions being responsible for the observed unique chemical and spectral properties.

Although 12 diamagnetic fused aromatics with or without substituents exhibit mirror-symmetric magnetic circularly polarised luminescence (MCPL) through N-up and S-up Faraday geometries under a magnetic field intensity of 1.6 T, their signs (single and multiple) and magnitudes depend strongly on either the aromatic structures or the peripheral positions of the substituents.

Circularly polarized luminescence (CPL) reflects the chiroptical properties at the lowest excited state of the emitter. Thus, a wide range of applicability of these materials is in order, e.g. optical sensing. Polymeric systems possess complex vibronic states in ground states and excited states, which presents a challenge to carefully design and amplify the CPL signals from functional polymers. In this chapter, the fundamentals of CPL are briefly introduced followed by a review of several π-conjugated and coordination polymers exhibiting CPL signals. In addition, the chiroptical properties will be discussed based on the CPL signals of the polymer materials.

Optically active fullerenes (C76, C82, C84), including C60 and C70 derivatives carrying organic substituents, possess various potent applications because of unique spectroscopic, catalytic, and chiral recognition properties. However, their inherent photoexcited chirality has not yet been elucidated because of a very poor quantum yield of fluorescence (FL). With this background in mind, we synthesized new chiral C70 derivatives, X70A, solely by reacting bis-borylated xanthene with C70 in a one-step double addition reaction with 20% yield, followed by a successful optical resolution using a recyclable chiral-HPLC technique. The isolated X70A enantiomers were confirmed by their mirror-image circular dichroism spectra in the range of 300 nm and 700 nm. The enantiomeric pair of X70A in toluene revealed clearly mirror-image circularly polarized luminescence (CPL) spectra with a high |glum| value of 7.0 × 10–3 at 690 nm associated with FL lifetime of 0.99 ns. The deep-red CPL of X70A should provide new photofunctionality as chiral nanocarbon materials.

Five optically inactive EuIII(hfa)3, TbIII(hfa)3, EuIII(acac)3·Phen, TbIII(acac)3·Phen and EuIII(hfa)3·BDPB (hfa: hexafluoroacetylacetonate, acac: acetylacetonate, BDPB: 2,2'-bis(diphenylphosphino)biphenyl and Phen: phenanthroline) complexes showed clear mirror-image magnetic circularly polarised luminescence (MCPL) spectra in CHCl3, acetone, and DMF solutions, in a poly(methyl methacrylate) film, a KBr pellet and bulk powder at room temperature under 1.6 T as an external magnetic field with Faraday geometry. The signs of the MCPL signals were determined via N-up and S-up geometries. The gMCPL values of EuIII(hfa)3 and TbIII(hfa)3 were ±(0.046-2.0) × 10-2 T-1 at the 5D0 → 5FJ transitions (J = 1-4) in the range of 590 nm and 703 nm and ±(0.0081-1.0) × 10-2 T-1 at the 5D4 → 7FJ transitions (J = 3-6) in the range of 480 nm and 630 nm, respectively. Interestingly, the photoluminescence spectra of EuIII(hfa)3 and TbIII(hfa)3 in CHCl3 and acetone under 1.6 T considerably redshifted by 10-114 cm-1, while those of EuIII(acac)3·Phen and TbIII(acac)3·Phen did not reveal detectable redshifts.

Several poly(2,7-carbazole)s having a planar triazine at the carbazole N-position were synthesized. Their torsion angles between the carbazole donor and the triazine acceptor units were controlled by phenylene connectors to separate their electronic functions. The polymers showed delayed fluorescence characteristics at room temperature besides phosphorescence with two different triplet energies at a liquid N2 temperature. The effect of π-conjugation along the polycarbazole main chain on the luminescence behavior was investigated by controlling the torsion angle between the carbazole units using substituents at 3,6-positions. The limitation of π-conjugation caused the overlapping of a phosphorescence spectrum with the fluorescence. They also showed solvent-dependent orientation properties like lyotropic liquid crystals. These new functions could be derived from the anchored acceptor unit in the polycarbazole.

The left and right helicities of azobenzene (Azo)-containing main-chain polymer (PF8Azo) were successfully controlled with an enantiomeric pair of rigid rod-like helical polysilanes carrying (S)- and (R)-2-methylbutyl groups (PSi-S and PSi-R, respectively) as their hetero-aggregates in a mixture of chloroform and methanol solvents and in the solid state. Optimizing the good and poor cosolvents and their volume fractions showed that the molar ratio of PF8Azo to PSi-S/-R and the molecular weight of PF8Azo were crucial to boost the CD amplitudes of PF8Azo/PSi-S and PF8Azo/PSi-R hetero-aggregates. The photoresponsive trans–cis transformation caused noticeable changes in the sign and magnitude of the chiroptical behavior due to the hetero-aggregates. Moreover, the optically active PF8Azo homo-aggregates were produced by complete photoscissoring reactions at 313 nm, which could be assigned to the Siσ–Siσ* transitions of PSi-S and PSi-R.

Herein, photoluminescent poly(4-vinylpyridine)-based ionic liquids (PILs) bound with D- and L-histidine were synthesized for the first time and fully characterized by NMR, IR and UV-vis spectroscopy and TG analysis. The chiral PILs self-assembled into helical aggregates, which were isolated by two different methods, namely, by the addition of a poor solvent and by the slow evaporation of solvent. The isolated nanofibers, comprising helical aggregates, were observed to be thin in the case of the former and thick in the case of the latter method. Moreover, the helical nanofibers formed herein were several hundreds of micrometers long. The aggregation of the PIL chains in the helical nanofibers was further revealed by the significantly red-shifted photoluminescence spectra.

Pentahelicene (PH) exhibits the largest absorption (gabs) and luminescence (glum) dissymmetry factors among the helicene family but is configurationally and (photo)chemically labile, encumbering its application to chiroptical materials. To bypass the pitfalls, three PH units are merged in a single molecule to build D3-symmetric triple pentahelicene, hexabenzotriphenylene (HBT), which attains indeed the configurational and (photo)chemical robustness through equilibrium with a C2-symmetric conformer that interrupts the racemization and photocyclization. UV–vis, circular dichroism (CD), and circularly polarized luminescence (CPL) spectral examinations reveal the significantly larger gabs and glum values for HBT than for any of configurationally robust single [n]helicene (n ≥ 6) and C2-symmetric triple pentahelicene, trinaphthotriphenylene (TNT). Theoretical calculations precisely reproduce the main features of the experimental CD and CPL spectra of PH, HBT, and TNT, and the relevant electric and magnetic tra...

Chiral molecules play indispensable roles in advanced materials and technologies. Nevertheless, no conventional, yet reliable logical strategies are available for designing chiral molecules of desired chiroptical properties. Here, we propose a general protocol for rationally aligning multiple chiral units to boost the chiroptical responses, using hexahelicene as a prototype. In this proof-of-concept study, we align two hexahelicenes in various orientations and examine by theoretical calculations to predict the best chiroptical performance for X-shaped and S-shaped double hexahelicenes. We synthesize and optically resolve both double hexahelicenes and show that they exhibit more than a twofold increase in intensity of circular dichroism and circularly polarized luminescence, experimentally validating the protocol. The enhanced chiroptical responses are theoretically assignable to the electric and magnetic transition dipole moments of component hexahelicenes aligned in the correct symmetry. A guiding principle for designing advanced molecular and supramolecular chiral materials is further discussed. Combining chiral monomers can enhance chiroptical properties, but there are few principles to guide design. Here a combined experimental and computational study suggests rational principles for the design of double hexahelicenes with improved chiroptical responses in circular dichroism and circularly polarized luminescence.

To understand how polymers physisorb onto solid surfaces, we investigated the physisorption behavior of non-charged, semiflexible poly(9,9-dioctylfluorene) (PF8) with three different number-average degrees of polymerization (DPn) as photoluminescent and chromophoric probes onto cuboidal γ-alumina in toluene at 5, 25, and 50 °C. PF8 revealed noticeable DPn and temperature dependencies in its physisorption behaviors. Molecular mechanics (MM)/molecular dynamics (MD) simulations [consistent valence force field (CVFF)] and Moller–Plesset second-order perturbation theory (MP2) with 6-31 G(d,p) calculations suggested that the PF8 in toluene has multiple interactions from CH/π to C–H/O interactions on the (110) surface of γ-alumina. The competition between multiple intermolecular CH/π and C–H/O interactions was crucial for the spontaneous physisorption of PF8 to occur in the presence of a solvent quantity of toluene. Calculations by time-dependent density functional theory (TD-DFT) with Becke three parameter Lee-Yang-Par (B3LYP) method and 6–31 G(d,p) basis set of a model fluorene 9-mer indicated that the π–π* absorption wavelength largely depends on the regularity of the dihedral angles between fluorene rings, while the intensity and spectral width of the π–π* absorption band are largely influenced by the regularity of the dihedral angles. Solution-phase physisorption systems are a result of the inherent nature of several competitive weak intermolecular interactions coexisting among the polymers, surface, and solvents. Noticeable molecular weight and temperature dependency for physisorption behavior of semiflexible, non-charged poly(9,9-n-dioctylfluorene) (PF8) onto cuboidal γ-alumina in toluene were found. MM/MD simulations (CVFF) and quantum mechanical (MP2/6-31G(d,p)) calculations suggested that PF8 swaps interacting toluene for (110) surface of γ-alumina by changing the interaction from CH/π interactions to C-H/O interactions of γ-alumina in toluene. The competition between multiple intermolecular CH/π and C-H/O interactions was crucial whether the spontaneous physisorption of PF8 occurs in place of solvent quantity of toluene. The solution-phase physisorption systems should be the consequence of several weak attractive intermolecular interactions coexisting between polymers, surface, and solvents

Although chiral 1,1′-binaphthalene-2,2′-diyl-O,O-bis(N,N-dimethylthiocarbamate) (1) revealed no circularly polarized luminescence (CPL) signals, Newman–Kwart rearrangement of O-thiocarbamate groups at 1 yielded clear CPL signals from 1,1′-binaphthalene-2,2′-diyl-S,S-bis(N,N-dimethylthiocarbamate) (2), which acts as a CPL-gen molecule.

Effects of chiral alkyl side chains in poly(9,9-dialkyl-fluorene-2,7-vinylene)s [PFVs, (S)-3-methylpentyl (3mpe), (S)-4-methylhexyl (4mhex), (S)-5-methylheptyl (5mhep), (S)-6-methyloctyl (6moct), and (S)-3,7-dimethyloctyl (dmo)] toward aggregation-induced circular dichroism (AICD) and circularly polarized luminescence (AICPL) and CD/CPL spectra in solution and in thin film have been explored. The (all-trans) PFV samples with similar conjugation repeat units containing well-defined (vinyl) end groups were prepared by acyclic diene metathesis polymerization using Ru catalyst. The PFV aggregates, prepared in situ in a mixed solution of CHCl3/MeOH, showed clear CD signals ascribed to AICD, whereas these samples showed CD-silent in the CHCl3 solution. The absolute magnitude (gCD value) was affected by the chiral side chains (without obey the even–odd rule) and increased in the order 3mpe, 5mhep < 4mhex < dmo < 6mcot. Both the 6-moct and dmo aggregates showed clear CPL signals ascribed to AICPL, whereas signals...

The present paper reports on three new achiral terbiumIII inorganics that emit strong green-color magnetic circularly polarized luminescence (MCPL) (|gMCPL| ≤ 5.4 × 10–3 T-1 at 490–550 nm) when embedded in a KBr pellet in the presence of a 1.7 T external magnetic field. The signs of the green MCPL spectra are controllable by altering the S-up and N-up directions of the external magnetic field. Divalent manganeseII and trivalent terbiumIII emit similar green luminescence; however, their wavelengths and MCPL characteristics are very different. Hence, we anticipate that these green-color MCPL substances can be used as new security pigments.