Phenoxyl Radicals Hydrogen-Bonded to Imidazolium: Analogues of Tyrosyl D. of Photosystem II: High-Field EPR and DFT Studies

Hydrogen-bonded ferroelectric liquid crystals (HBFLC) are designed and synthesized from nonmesogenic chiral proton donor compound of (R)-([Formula: see text])-Methylsuccinic acid (MSA) and mesogenic proton acceptor compound of 4-undecyloxybenzoic acid (11OBA) in a different mole ratio. Intermolecular hydrogen bonds (H-bond) between the nonmesogenic and mesogenic compounds have been confirmed through experimental Fourier transform infrared spectroscopy (FTIR) and density functional theory (DFT) computational studies. The steric hindrance and inductive effects of the present complex and its influence on the structure are discussed. A rich phase polymorphism in the liquid crystalline complex has been studied using polarizing optical microscope (POM) and differential scanning calorimetry (DSC). The chiral phases observed in the present complex are due to the presence of lone pair (n) to anti-bonding ([Formula: see text]) transition symmetry which is validated by DFT studies. A noteworthy observation of induced smectic A[Formula: see text](Sm A[Formula: see text]) by quenching of traditional phase (nematic) has been identified and the reason for the same has been discussed by DFT studies. The unusual phase order of Sm A[Formula: see text], smectic C[Formula: see text](Sm C[Formula: see text]) and smectic G[Formula: see text][Formula: see text](Sm G[Formula: see text]) mesogenic phases are observed. The other liquid crystalline parameters are evaluated by experimental and theoretical calculations and the same has been compared. Increased tilt angle in liquid crystal (LC) molecules has been theoretically analyzed by natural bond orbital (NBO) studies. Stability of the HBFLC phases and its origination mechanism have been discussed with the help of highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO–LUMO) energies.

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Multifrequency High-Field EPR Study of the Interaction between the Tyrosyl Z Radical and the Manganese Cluster in Plant Photosystem II

The Journal of Physical Chemistry B ◽

10.1021/jp992420k ◽

1999 ◽

Vol 103 (49) ◽

pp. 10945-10954 ◽

Cited By ~ 20

Author(s):

Pierre Dorlet ◽

Alain Boussac ◽

A. William Rutherford ◽

Sun Un

Keyword(s):

Photosystem Ii ◽

High Field ◽

Manganese Cluster

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Orientation Study on the Stable Tyrosyl Radical in Photosystem II by High Field EPR

Photosynthesis: Mechanisms and Effects ◽

10.1007/978-94-011-3953-3_329 ◽

1998 ◽

pp. 1395-1398

Author(s):

P. Dorlet ◽

J. Hanley ◽

A. W. Rutherford ◽

S. Un

Keyword(s):

Photosystem Ii ◽

High Field ◽

Tyrosyl Radical ◽

Orientation Study

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Rigidly hydrogen-bonded water molecules facilitate proton transfer in photosystem II

Physical Chemistry Chemical Physics ◽

10.1039/d0cp00295j ◽

2020 ◽

Vol 22 (28) ◽

pp. 15831-15841

Author(s):

Naoki Sakashita ◽

Hiroshi Ishikita ◽

Keisuke Saito

Keyword(s):

Photosystem Ii ◽

Proton Transfer ◽

Water Molecules ◽

Hydrogen Bonded

In the channel of photosystem II, rigidly hydrogen-bonded water molecules facilitate the Grotthuss-like proton transfer, whereas flexible water molecules prevent proton transfer in the channel of aquaporin.

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