Light-induced giant dipoles in simple model compounds for photosynthesis

Warman, John M.; Haas, Matthijs P. de; Paddon‐Row, Michael N.; Cotsaris, E.; Hush, Noel S.; Oevering, Henk; Verhoeven, J. W.

doi:10.1038/320615a0

Cited by 130 publications

(40 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because of the semiconductor-like electronic spectra, the polycarbyne backbones appear to be σ-conjugated. Such σ-conjugation of C-C bonds is also seen in small molecules which incorporate strained fused rings (29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40). The strain which our calculations indicate is present in the fused rings of the polycarbyne backbones should lower the C-C bond strength and thus the energy of the bonds' σ-σ* transitions from the vacuum UV (where the σ-σ* transition of unstrained C-C bonds occurs (28)) to the observed UV and visible frequencies.…”

Section: Resultsmentioning

confidence: 99%

Structural Analysis of Carbyne Network Polymers

Best

Bianconi

Merz

1995

ACS Symposium Series

View full text Add to dashboard Cite

Molecular dynamics simulations of oligomers of the recently reported polycarbyne network backbone polymers indicate that calculated bondlengths between adjacent carbon backbone atoms are very long compared to the bond distance of a C-C single bond. Some degree of bond cleavage is theorized to occur between adjacent carbon atoms of the polymers' network backbones, resulting in the formation of biradicals. This theory is supported experimentally by the polymers' electronic absorption spectra, their degrees of polymerization, and their ESR spectra, which show a decreasing signal as the steric bulk between adjacent carbons is decreased.The synthesis of the first member of a new class of carbon-based polymers, poly(phenylcarbyne) [PhC] n (1), has recently been reported (7,2). This polymer's stoichiometry is identical to that of poly(diphenylacetylene) (3,4) yet its structure is significantly different. Unlike the polyacetylenes, which are linear polymers whose backbones consist of alternating single and double bonds, poly(phenylcarbyne) has a random network backbone which consists of sp 3 -hybridized carbon atoms bonded via carbon-carbon single bonds to three other backbone atoms and one phenyl substituent. This backbone structure is unique in carbon-based polymers and has been found to confer novel properties and reactivity on 1, as, for example, pyrolytic conversion to diamond or diamondlike carbon at atmospheric pressures (7). Because of this pyrolytic conversion, numerous applications for this polymer can be envisioned.Although the network backbone microstructure of poly(phenylcarbyne) and its Group 14 congeners (7,2,5-9) has been confirmed by 13 C and ^9Si NMR, the macrostructures of this class of polymers have not been established. The seemingly completely random assembly of the polymer backbones defeats any spectroscopic or diffraction characterization technique, since no two polymer molecules in a given sample may display identical macrostructures and therefore no one macrostructure gives rise to enough characteristic signal to be unequivocally detected. Information about the macrostructure of the polymers is important, however, as polymer macrostructure appears to influence the materials' properties (see below). We have therefore used molecular modeling techniques to provide insights into possible macrostructures for the polycarbyne class of network backbone polymers, and to 0097-6156/95/0589-0304$12.00A)

show abstract

Section: Resultsmentioning

confidence: 99%

Structural Analysis of Carbyne Network Polymers

Best

Bianconi

Merz

1995

ACS Symposium Series

View full text Add to dashboard Cite

show abstract

“…Historically, electron-transfer processes at electrodes and in solution, as well as use of colour and reactivity in well designed molecules such as the CreutzTaube ion [1] and related systems [2] have been of central importance in the elucidation of mechanism and reactivity. More recently organic molecules that act as biological mimics [3,4] and current carrying systems [5,6], including transistors [7], have come to the fore. After 60 years of development, this area remains one that is rapidly expanding, with new methods, molecules, theories, and applications appearing continuously.…”

Section: Preface To Partmentioning

confidence: 99%

“The molecules and methods of chemical, biochemical, and nanoscale electron transfer”

et al. 2006

View full text Add to dashboard Cite

“…Hush was collaborating with Michael Paddon-Row at the University of New South Wales, synthesizing, measuring (by Jan Verhoeven in The Netherlands) primary charge separation rates, and interpreting the data. [161] An unexpected result, questioning the conceptual understanding of the process, was that electronic symmetry-forbidden reactions were occurring only slightly slower than Franck-Condon allowed ones. My contribution was to apply the spectroscopic methods of Craig, Ross and Fischer to understand the kinetics process, showing that the observed fast rates were completely consistent with known spectroscopic properties.…”

mentioning

confidence: 99%

“…A centrepiece of Hush's work was the assignment of the nature of unknown electronic transitions observed in mixed-valence species, leading to the field of intervalence spectroscopy. [32] This process was identified by Hush as producing primary charge separation, converting solar into electrical energy [161] and providing a basis for the subsequent understanding of the operation of natural photosynthesis and most processes involved in modern molecular-based artificial solar-energy harvesting systems.…”

mentioning

confidence: 99%

Putting David Craig’s Legacy to Work in Nanotechnology and Biotechnology

Reimers¹

2016

Aust. J. Chem.

View full text Add to dashboard Cite

left us with a lasting legacy concerning basic understanding of chemical spectroscopy and bonding. This is expressed in terms of some of the recent achievements of my own research career, with a focus on integration of Craig's theories with those of Noel Hush to solve fundamental problems in photosynthesis, molecular electronics (particularly in regard to the molecules synthesized by Maxwell Crossley), and self-assembled monolayer structure and function. Reviewed in particular is the relation of Craig's legacy to: the 50-year struggle to assign the visible absorption spectrum of arguably the world's most significant chromophore, chlorophyll; general theories for chemical bonding and structure extending Hush's adiabatic theory of electron-transfer processes; inelastic electron-tunnelling spectroscopy (IETS); chemical quantum entanglement and the Penrose-Hameroff model for quantum consciousness; synthetic design strategies for NMR quantum computing; Gibbs free-energy measurements and calculations for formation and polymorphism of organic self-assembled monolayers on graphite surfaces from organic solution; and understanding the basic chemical processes involved in the formation of gold surfaces and nanoparticles protected by sulfur-bound ligands, ligands whose form is that of Au 0 -thiyl rather than its commonly believed Au I -thiolate tautomer.

show abstract

Light-induced giant dipoles in simple model compounds for photosynthesis

Cited by 130 publications

References 21 publications

Structural Analysis of Carbyne Network Polymers

Structural Analysis of Carbyne Network Polymers

“The molecules and methods of chemical, biochemical, and nanoscale electron transfer”

Putting David Craig’s Legacy to Work in Nanotechnology and Biotechnology

Contact Info

Product

Resources

About