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Covalent functionalisation with alkyl tails is a common method for supporting molecular catalysts and photosensitisers onto lipid bilayers, but the influence of the alkyl chain length on the photocatalytic performances of the resulting liposomes is not well understood. In this work, we first prepared a series of rhenium‐based CO2‐reduction catalysts [Re(4,4'‐(CnH2n+1)2‐bpy)(CO)3Cl] (ReCn; 4,4'‐(CnH2n+1)2‐bpy=4,4'‐dialkyl‐2,2'‐bipyridine) and ruthenium‐based photosensitisers [Ru(bpy)2(4,4'‐(CnH2n+1)2‐bpy)](PF6)2 (RuCn) with different alkyl chain lengths (n=0, 9, 12, 15, 17, and 19). We then prepared a series of PEGylated DPPC liposomes containing RuCn and ReCn, hereafter noted Cn, to perform photocatalytic CO2 reduction in the presence of sodium ascorbate. The photocatalytic performance of the Cn liposomes was found to depend on the alkyl tail length, as the turnover number for CO (TON) was inversely correlated to the alkyl chain length, with a more than fivefold higher CO production (TON=14.5) for the C9 liposomes, compared to C19 (TON=2.8). Based on immobilisation efficiency quantification, diffusion kinetics, and time‐resolved spectroscopy, we identified the main reason for this trend: two types of membrane‐bound RuCn species can be found in the membrane, either deeply buried in the bilayer and diffusing slowly, or less buried with much faster diffusion kinetics. Our data suggest that the higher photocatalytic performance of the C9 system is due to the higher fraction of the more mobile and less buried molecular species, which leads to enhanced electron transfer kinetics between RuC9 and ReC9. [ABSTRACT FROM AUTHOR]

Highly electron deficient benzo[ghi]perylenetriimide (BPTI) chromophores were persistently anchored to a metal oxide electrode surface and reversible formation of their radical anions was shown in air-saturated aqueous buffer solution. Our results show a very low reaction-rate constant of BPTI.− with O2 ( k=1.92±0.05×10−2 s−1). BPTI is a robust chromophore that can be used as the electron acceptor in molecule-based artificial photosynthetic devices for direct water splitting in aqueous phase. [ABSTRACT FROM AUTHOR]

A detailed analysis of the computed structure, energies, vibrational absorption (VA) and circular dichroism (VCD) spectra of 30 low-energy conformers of dehydroquinidine reveals the existence of families of pseudo-conformers, the structures of which differ mostly in the orientation of a single OH bond. The pseudo-conformers in a family are separated by very small energy barriers (i.e., 1.0 kcal mol−1 or smaller) and have very different VCD spectra. First, we demonstrate the unreliable character of the Boltzmann factors predicted with DFT. Then, we show that the large differences observed between the VCD spectra of the pseudo-conformers in a family are caused by large-amplitude motions involving the OH bond, which trigger the appearance/disappearance of strong VCD exciton-coupling bands in the fingerprint region. This interplay between exciton coupling and large-amplitude-motion phenomena demonstrates that when dealing with flexible molecules with polar bonds, vibrational averaging of VCD spectra should not be neglected. In this regard, the dehydroquinidine molecule considered here is expected to be a typical example and not the exception to the rule. [ABSTRACT FROM AUTHOR]

Photochromism In their Full Paper on page 16492 ff, A. M. Brouwer, P. Saalfrank, S. Hecht, D. Bléger, and co ‐ workers present the design and synthesis of ortho ‐ fluoroazobenzene visible light switches together with a detailed analysis of their outstanding properties, with a particular emphasis on the remarkable thermal stability of the Z isomers. [ABSTRACT FROM AUTHOR]