Effect of additional hydroxy group on self-aggregation of synthetic zinc bacteriochlorophyll-c analogs

Kishi, Masashi; Nakamura, Yugo; Tamiaki, Hitoshi

doi:10.1016/j.jphotochem.2020.112592

“…In these studies, the effect of peripheral substituents on the C3 1 -, C7-, C8-, C13 2 -, C17-and C20-positions were widely investigated (Fig. 1A) (19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34), and they could influence the supramolecular structures and optical properties of selfassemblies. In many cases, the 3 1 -hydroxy and 13-ketocarbonyl groups, and the coordinated metals (Mg, Zn, Cd) are essential for forming the J-aggregates along the molecular yaxis through hydrogen (3 1 -OH and 13-C=O) and coordination bonding (3 1 -O and M).…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Self‐Aggregation of Chlorophyll‐a Derivatives Possessing a Hydroxymethyl Group in the C20‐Substituent with Ethynylene and/or Phenylene Linkers

Nakano

¹

,

Hashimoto

²

,

Tamiaki

³

2022

Photochem & Photobiology

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Chlorophyll(Chl)-a derivatives containing some rigid linkers in the C20 substituents, which were inserted between a hydroxymethyl group and the chlorin p-skeleton, were synthesized and their self-aggregation abilities were investigated. Measurements of electronic absorption, circular dichroism and infrared absorption spectra revealed that the zinc complex of a Chl-a derivative bearing a (p-ethynyl)benzyl alcoholic moiety at the C20-position gave its J-aggregates in an aqueous micellar solution through the hydrogen and coordination bonding. These results exhibited the potential of Chl-a derivatives bearing a hydroxyl group in the C20 substituents as the model compounds for chlorosomal light-harvesting antennas.

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Sterisch erlaubte Supramolekulare Polymerisationen des H‐Typs

Manha Veedu,

Niemeyer,

Bäumer

et al. 2023

Angewandte Chemie

0

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The functionalization of pi‐conjugated scaffolds with sterically demanding substituents is a widely used tactic to suppress cofacial (H‐type) stacking interactions, which may even inhibit self‐assembly. Contrary to expectations, we demonstrate herein that increasing steric effects can result in an enhanced thermodynamic stability of H‐type supramolecular polymers. In our approach, we have investigated two boron dipyrromethene (BODIPY) dyes with bulky phenyl (2) and mesityl (3) meso‐substituents and compared their self‐assembly in nonpolar media with that of a parent meso‐methyl BODIPY 1 lacking bulky groups. While the enhanced steric demand induces pathway complexity, the superior thermodynamic stability of the H‐type pathways can be rationalized in terms of additional enthalpic gain arising from intermolecular C‐H···F‐B interactions of the orthogonally arranged aromatic substituents, which overrule their inherent steric demand. Our findings underline the importance of balancing competing non‐covalent interactions in self‐assembly.

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Sterically Allowed H‐type Supramolecular Polymerizations

Manha Veedu,

Niemeyer,

Bäumer

et al. 2023

Angew Chem Int Ed

10

0

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The functionalization of pi‐conjugated scaffolds with sterically demanding substituents is a widely used tactic to suppress cofacial (H‐type) stacking interactions, which may even inhibit self‐assembly. Contrary to expectations, we demonstrate herein that increasing steric effects can result in an enhanced thermodynamic stability of H‐type supramolecular polymers. In our approach, we have investigated two boron dipyrromethene (BODIPY) dyes with bulky phenyl (2) and mesityl (3) meso‐substituents and compared their self‐assembly in nonpolar media with that of a parent meso‐methyl BODIPY 1 lacking bulky groups. While the enhanced steric demand induces pathway complexity, the superior thermodynamic stability of the H‐type pathways can be rationalized in terms of additional enthalpic gain arising from intermolecular C‐H···F‐B interactions of the orthogonally arranged aromatic substituents, which overrule their inherent steric demand. Our findings underline the importance of balancing competing non‐covalent interactions in self‐assembly.

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Effect of additional hydroxy group on self-aggregation of synthetic zinc bacteriochlorophyll-c analogs

Cited by 5 publications

References 64 publications

Synthesis and Self‐Aggregation of Chlorophyll‐a Derivatives Possessing a Hydroxymethyl Group in the C20‐Substituent with Ethynylene and/or Phenylene Linkers

Synthesis and Self‐Aggregation of Chlorophyll‐a Derivatives Possessing a Hydroxymethyl Group in the C20‐Substituent with Ethynylene and/or Phenylene Linkers

Sterisch erlaubte Supramolekulare Polymerisationen des H‐Typs

Sterically Allowed H‐type Supramolecular Polymerizations

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