scholarly journals Synchronization in Non-Mirror-Symmetrical Chirogenesis: Non-Helical π–Conjugated Polymers with Helical Polysilane Copolymers in Co-Colloids

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 594
Author(s):  
Michiya Fujiki ◽  
Shun Okazaki ◽  
Nor Azura Abdul Rahim ◽  
Takumi Yamada ◽  
Kotohiro Nomura
Keyword(s):  
Conjugated Polymers ◽  
Mirror Symmetry ◽  
Main Chain ◽  
Fundamental Question ◽  
Type I ◽  
Type Ii ◽  
Circularly Polarized ◽  
Chain Stiffness ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence

A curious question is whether two types of chiroptical amplifications, called sergeants-and-soldiers (Ser-Sol) and majority-rule (Maj) effects, between non-charged helical copolymers and non-charged, non-helical homopolymers occur when copolymer encounter homopolymer in co-colloids. To address these topics, the present study chose (i) two helical polysilane copolymers (HCPSs) carrying (S)- or (R)-2-methylbutyl with isobutyl groups as chiral/achiral co-pendants (type I) and (S)- and (R)-2-methylbutyl groups as chiral/chiral co-pendants (type II) and (ii) two blue luminescent π-conjugated polymers, poly[(dioctylfluorene)-alt-(trans-vinylene)] (PFV8) and poly(dioctylfluorene) (PF8). Analyses of circular dichroism (CD) and circularly polarized luminescence (CPL) spectral datasets of the co-colloids indicated noticeable, chiroptical inversion in the Ser-Sol effect of PFV8/PF8 with type I HCPS. PF8 with type IIHCPS showed the anomalous Maj rule with chiroptical inversion though PFV8 with type IIHCPS was the normal Maj effect. The noticeable non-mirror-symmetric CD-and-CPL characteristics and marked differences in hydrodynamic sizes of these colloids were assumed to originate from non-mirror-symmetrical main-chain stiffness of HCPSs in dilute toluene solution. The present chirality/helicity transfer experiments alongside of previous/recent publications reported by other workers and us allowed to raise the fundamental question; is mirror symmetry on macroscopic levels in the ground and photoexcited states rigorously conserved?

scholarly journals Questions of Mirror Symmetry at the Photoexcited and Ground States of Non-Rigid Luminophores Raised by Circularly Polarized Luminescence and Circular Dichroism Spectroscopy: Part 1. Oligofluorenes, Oligophenylenes, Binaphthyls and Fused Aromatics

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2606 ◽  
Author(s):  
Michiya Fujiki ◽  
Julian Koe ◽  
Takashi Mori ◽  
Yoshihiro Kimura
Keyword(s):  
Circular Dichroism ◽  
Mirror Symmetry ◽  
Neutral Current ◽  
Visible Region ◽  
Cd Spectroscopy ◽  
Mirror Image ◽  
Circularly Polarized ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence ◽  
Circular Dichroïsm

We report experimental tests of whether non-rigid, π-conjugated luminophores in the photoexcited (S1) and ground (S0) states dissolved in achiral liquids are mirror symmetrical by means of circularly polarized luminescence (CPL) and circular dichroism (CD) spectroscopy. Herein, we chose ten oligofluorenes, eleven linear/cyclic oligo-p-arylenes, three binaphthyls and five fused aromatics, substituted with alkyl, alkoxy, phenyl and phenylethynyl groups and also with no substituents. Without exception, all these non-rigid luminophores showed negative-sign CPL signals in the UV-visible region, suggesting temporal generation of energetically non-equivalent non-mirror image structures as far-from equilibrium open-flow systems at the S1 state. For comparison, unsubstituted naphthalene, anthracene, tetracene and pyrene, which are achiral, rigid, planar luminophores, did not obviously show CPL/CD signals. However, camphor, which is a rigid chiral luminophore, showed mirror-image CPL/CD signals. The dissymmetry ratio of CPL (glum) for the oligofluorenes increased discontinuously, ranging from ≈ −(0.2 to 2.0) × 10−3, when the viscosity of the liquids increased. When the fluorene ring number increased, the glum value extrapolated at [η] = 0 reached −0.8 × 10−3 at 420 nm, leading to (–)-CPL signals predicted in the vacuum state. Our comprehensive CPL and CD study should provide a possible answer to the molecular parity violation hypothesis arising due to the weak neutral current mediated by the Z0-boson.

Circularly Polarized Luminescence from Supramolecular Chiral Complexes of Achiral Conjugated Polymers and a Neutral Polysaccharide

2009 ◽  
Vol 38 (3) ◽  
pp. 254-255 ◽  
Author(s):  
Shuichi Haraguchi ◽  
Munenori Numata ◽  
Chun Li ◽  
Yoko Nakano ◽  
Michiya Fujiki ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Chiral Complexes ◽  
Circularly Polarized ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence

scholarly journals Questions of Mirror Symmetry at the Photoexcited and Ground States of Non-Rigid Luminophores Raised by Circularly Polarized Luminescence and Circular Dichroism Spectroscopy. Part 2: Perylenes, BODIPYs, Molecular Scintillators, Coumarins, Rhodamine B, and DCM

Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 363
Author(s):  
Michiya Fujiki ◽  
Julian R. Koe ◽  
Seiko Amazumi
Keyword(s):  
Circular Dichroism ◽  
Rhodamine B ◽  
Mirror Symmetry ◽  
Visible Region ◽  
Cd Spectroscopy ◽  
Mirror Image ◽  
Circularly Polarized ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence ◽  
Circular Dichroïsm

We investigated whether semi-rigid and non-rigid π-conjugated fluorophores in the photoexcited (S1) and ground (S0) states exhibited mirror symmetry by circularly polarized luminescence (CPL) and circular dichroism (CD) spectroscopy using a range of compounds dissolved in achiral liquids. The fluorophores tested were six perylenes, six scintillators, 11 coumarins, two pyrromethene difluoroborates (BODIPYs), rhodamine B (RhB), and 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM). All the fluorophores showed negative-sign CPL signals in the ultraviolet (UV)–visible region, suggesting energetically non-equivalent and non-mirror image structures in the S1 state. The dissymmetry ratio of the CPL (glum) increased discontinuously from approximately −0.2 × 10−3 to −2.0 × 10−3, as the viscosity of the liquids increased. Among these liquids, C2-symmetrical stilbene 420 showed glum ≈ −0.5 × 10−3 at 408 nm in H2O and D2O, while, in a viscous alkanediol, the signal was amplified to glum ≈ −2.0 × 10−3. Moreover, BODIPYs, RhB, and DCM in the S0 states revealed weak (−)-sign CD signals with dissymmetry ratios (gabs) ≈ −1.4 × 10−5 at λmax/λext. The origin of the (−)-sign CPL and the (−)-sign CD signals may arise from an electroweak charge at the polyatomic level. Our CPL and CD spectral analysis could be a possible answer to the molecular parity violation hypothesis based on a weak neutral current of Z0 boson origin that could connect to the origin of biomolecular handedness.

Circularly Polarized Luminescence from Supramolecular Chiral Complexes of Achiral Conjugated Polymers and a Neutral Polysaccharide

2010 ◽  
Vol 39 (1) ◽  
pp. 76-76 ◽  
Author(s):  
Shuichi Haraguchi ◽  
Munenori Numata ◽  
Chun Li ◽  
Yoko Nakano ◽  
Michiya Fujiki ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Chiral Complexes ◽  
Circularly Polarized ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence

Circularly polarized luminescence spectroscopy

1977 ◽  
Vol 77 (6) ◽  
pp. 773-792 ◽  
Author(s):  
Frederick S. Richardson ◽  
James P. Riehl
Keyword(s):  
Luminescence Spectroscopy ◽  
Circularly Polarized ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence
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