Photocatalysis of oligo(p-phenylenes): photoreductive production of hydrogen and ethanol in aqueous triethylamine

Matsuoka, Shinya; Fujii, Hiroyuki; Yamada, Tadao; Pac, Chyongjin; Ishida, Akihiro; Takamuku, Setsuo; Kusaba, Mitsuhiro; Nakashima, Nobuaki; Yanagida, Shozo

doi:10.1021/j100168a018

Cited by 91 publications

(88 citation statements)

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“…This fact is also reflected in smaller excitation energies in the absorption spectra obtained for films and crystals in comparison with solvent measurements. 34,35 The calculated average C-C bond lengths between two phenyl rings in the oligophenylenes are 1.485 (twisted) and 1.489 Å (planar), which are similar to the experimental average C-C bond lengths (1.499 Å (4), 29 1.482 Å (5), 33 1.481 Å (6) 33 and 1.479 Å (7) 33 ) of crystal structure. These distances are much shorter than the typical C-C single bond length (1.54 Å) due to the -electron delocalization of the oligo-p-phenylenes.…”

Section: Bcsupporting

confidence: 80%

Calculated and Experimental UV and IR Spectra of Oligo-para-phenylenes

Park¹,

Lee²,

Yoon³

et al. 2014

Bulletin of the Korean Chemical Society

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The quantum mechanical properties of a series of oligo-para-phenylenes (2-11) were characterized using DFT B3LYP/6-311G(d,p) calculations. The global minimum among the various torsional conformers of an oligo-pphenylene is calculated to be a twist conformation. A less stable planar conformation, in which all the dihedral angles in oligo-p-phenylene are restricted to be planar, has also been calculated. The total electronic energies, normal vibrational modes, Gibbs free energies, and HOMOs and LUMOs of the two different conformations (twisted and planar) of the oligo-p-phenylenes were analyzed. The energy differences between the HOMOs and LUMOs of the substrates are in accord with the maximum absorption peaks of the experimental UV spectra of 2-6. The calculated normal vibrational modes of 2-6 were comparable with their experimental IR spectra.

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Section: Bcsupporting

confidence: 80%

Calculated and Experimental UV and IR Spectra of Oligo-para-phenylenes

Park¹,

Lee²,

Yoon³

et al. 2014

Bulletin of the Korean Chemical Society

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“…An advantage of soluble, linear polymers over branched phenyl-triazine oligomers [40] or oligo(phenylene)s [42] is that they can form coherent films with reasonable mechanical strength. Initially, we prepared a film of P8-s by drop casting from chloroform solution onto a glass slide.…”

Section: Doi: 101002/aenm201700479mentioning

confidence: 99%

A Solution‐Processable Polymer Photocatalyst for Hydrogen Evolution from Water

Woods

Sprick

Smith

et al. 2017

Advanced Energy Materials

142

125

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exhibit photocatalytic hydrogen evolution in 2009, [12] and many advances have been made since then. [13,14] After the potential of g-C 3 N 4 was first observed, while focusing on the hydrogen evolution half-reaction, interest has begun to shift to achieving overall water splitting using these materials. [15,16] However, the exact structure of most g-C 3 N 4 materials is unknown and the synthesis usually involves high temperature processing, which offers limited scope for fine-tuning structure and properties. Also, while g-C 3 N 4 can be produced from inexpensive starting materials, the synthetic yield of the material is typically low. [15,17] Of special relevance here, graphitic carbon nitrides are insoluble solids: as for many inorganic catalysts, this can present challenges in terms of processing.Rather few organic photocatalysts have been studied for hydrogen evolution other than g-C 3 N 4 . Recently, nitrogencontaining poly(azomethine) networks and covalent triazinebased frameworks (CTFs) were shown to have photocatalytic activity with the addition of platinum cocatalysts. [18,19] We have shown that a series of conjugated microporous polymers (CMPs) could facilitate hydrogen evolution from water in the presence of a sacrificial electron donor, without any additional heavy metal cocatalyst. [20,21] Other CMPs have since been studied for photocatalysis [22,23] and recent studies have demonstrated that linear conjugated polymers can have high photocatalytic activities. [24,25] However, as with g-C 3 N 4 , none of these organic materials are soluble in common organic solvents. This insolu bility makes it more challenging to process these materials into functional composites. Moreover, photocatalysts are typically kept in suspension by stirring to prevent sedimentation, which results in loss of photocatalytic activity. [26] The loss of activity of insoluble catalysts can be prevented with the use of support substrates, [27] however, using solution processability allows the use of simpler supports and easier development of photoelectrodes.Soluble oligo(phenylene)s have been previously reported as photocatalysts, however, they displayed low activity, were only active under UV light, required a Ru cocatalyst and were only poorly soluble in organic solvents limiting processability. [28] More recently soluble metal-chelating polymers have been prepared although the photocatalytic activity of these polymers also appear to be very low with apparent quantum yields (AQY) below 3 × 10 −4 %. [29] The solubility of some alkylated conjugated polymers has also facilitated the preparation of polymer nanoparticles (PDots). [30,31] The preparation of these PDots enabled significant enhancements in rate over the pristine polymer although scalability and long-term stability of this approach has yet to be shown. Direct photocatalytic water splitting is an attractive strategy for clean energy production, but multicomponent nanostructured systems that mimic natural photosynthesis can be difficult to fabricate because of the insolubil...

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“…2 shows the dependence of the maximum of the p-p * absorption band on the size of OPP. The dots show the experimental data [10], while the solid line represents the theoretical curve based on Eq. (3) (k = 1) with x 0 = 6.164 eV and J = 1.265 eV.…”

Section: Excitation Energy For a Model With One-building Block Per Rementioning

confidence: 99%

“…Typically, the pp * absorption band undergoes a progressive red shift with increasing length of the conjugated oligomer measured by the number of monomer repeat units. Several series of conjugated oligomers consisting of repeat units based on thiophenes, phenylenes or mixed building blocks (in the following also denoted as monomers) have been synthesized and their photophysical properties analyzed [4][5][6][7][8][9][10][11][12][13]. A general non-linear dependence of the absorption energy on the number of repeat units is observed for all these systems.…”

Section: Introductionmentioning

confidence: 99%