Ligand influence on the electronic spectra of monocationic copper–bipyridine complexes

Xu, Shuang; Gozem, Samer; Krylov, Anna I.; Christopher, Casey R.; Weber, J. Mathias

doi:10.1039/c5cp05063d

Cited by 39 publications

(44 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The highly complex nature of the macromolecular systems involved has, however, always served to complicate such attempts. In recent years, experimental approaches have been joined by theoretical/computational methods, and this has permitted studies at levels of detail that were previously unattainable …”

Section: Figurementioning

confidence: 99%

On the Exciton Coupling between Two Chlorophyll Pigments in the Absence of a Protein Environment: Intrinsic Effects Revealed by Theory and Experiment

et al. 2016

View full text Add to dashboard Cite

Exciton coupling between two or more chlorophyll (Chl) pigments is ak ey mechanism associated with the color tuning of photosynthetic proteins but it is difficult to disentangle this effect from shifts that are due to the protein microenvironment. Herein, we report the formation of the simplest coupled system, the Chl adimer,tagged with aquaternary ammonium ion by electrospray ionization. Based on action spectroscopic studies in vacuo,t he dimer complexes were found to absorb 50-70 meV to the red of the monomers under the same conditions.First-principles calculations predict shifts that somewhat depend on the relative orientation of the two Chl units,namely 50 and 30 meV for structures where the Chl rings are stacked and unstacked, respectively.O ur work demonstrates that Chl association alone can produce al arge portion of the color shift observed in photosynthetic macromolecular assemblies.The absorption wavelengths of chlorophyll (Chl) molecules are modulated by the microenvironment surrounding each pigment molecule.I nt his way,n ature has evolved am ethod by which the coverage of the optical spectrum and the subsequent transfer of the absorbed energy is optimized, [1,2] leading to photon energy conversion efficiencies of 95 %i n photosynthetic systems.[3] Theh arvesting of light energy in photosynthesis is therefore far more efficient than anything thus far developed by our most cutting-edge scientific and technological efforts.Furthermore,small modifications to the basic Chl structure,for example,the replacement of amethyl group in Chl awith aformyl group in Chl b, also lead to some fine-tuning of the absorption spectra. [4] Ford ecades ag reat deal of research activity has been directed at understanding precisely how natural systems modulate the absorption energies of Chl species.T he highly complex nature of the macromolecular systems involved has, however, always served to complicate such attempts.Inrecent years,experimental approaches have been joined by theoretical/computational methods,and this has permitted studies at levels of detail that were previously unattainable. [5][6][7][8][9][10][11][12] Experimental methods have also continued to develop, and recently it has become possible to study absorption processes in Chl molecules free of solvent and other microenvironmental effects.Inpioneering experiments,Shafizadeh et al.[13] utilized two-color pump-probe spectroscopy to measure the lowest energy absorption band of neutral Chl a evaporated from spinach leaves.T hey found the origin band of the Q y transition to be at 647 nm. Recent action spectroscopy experiments on Chl at agged with quaternary ammonium cations,i nc ombination with theory,p rovided an absorption band maximum of similar value (642 nm). [14,15] In this case,the absorption was obtained from the dissociation of the complex, and ac alibrated value was determined for the neutral molecule based on the deviation between theory and experiment. Using this same technique,Q-band maxima were obtained for Chl b, [14] and the Soret ban...

show abstract

Section: Figurementioning

confidence: 99%

On the Exciton Coupling between Two Chlorophyll Pigments in the Absence of a Protein Environment: Intrinsic Effects Revealed by Theory and Experiment

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The use of this technique is widespread. For examples on molecular ions, see Dunbar & Fu (1973), Drzaig & Brauman (1984), Wetzel & Brauman (1987), Dunbar (1988), Willey et al, (1991); for clusters, see Borggreen et al (1993), Collings et al (1994, , Vogel, Herlert, & Schweikhard (2003), Gilb et al (2004), Kaydashev et al (2016); and for biomolecular ions, see Nielsen et al (2001), Andersen et al (2005), Antoine & Dugourd (2013), Yao & Jockusch (2013), Bellina et al (2014), Harvey et al (2015), Wellman & Jockusch (2015), Xu et al (2015), Milne et al (2016), O'Connor et al (2017, Woodhouse et al (2017).…”

Section: Action Spectroscopymentioning

confidence: 99%

Decay Dynamics in Molecular Beams

Hansen

2020

Mass Spectrometry Reviews

View full text Add to dashboard Cite

The phenomenon of power law decays in molecular beams is reviewed. The transition from a canonical to a microcanonical description of the decay is analyzed, and the appearance of the power law decay derived. Deviations from a power law often contain information on parallel competing processes. This is illustrated with examples where thermal radiation or dark unimolecular channels are the competing processes. Also corrections to the power law due to finite heat capacities and from nonideal energy distributions are derived. Finally, the consequences for the interpretation of action spectroscopy data are reviewed.

show abstract

“…Typically, such a setup consists of an ion source, a first mass filter (which could be a quadrupole or a time-of-flight mass analyzer), the ion trap, followed again by a second mass filter and finally the ion detector. Several such cryogenic trap machines have been described in the literature in detail 35,42,[46][47][48][49][50][51][52][53] , as well as the central part, typically a multipolar cryogenic ion trap [54][55][56] . The experiments are conducted in a pulsed mode.…”

Section: Introductionmentioning

confidence: 99%