Anionic Activation of CO via (M-CO) Complex on Magic-Numbered Anionic Coinage Metal Clusters M (M = Cu, Ag, Au).

Given the immense challenge of excessive accumulation of carbon dioxide (CO) in the earth's atmosphere, an extensive search is under way to convert atmospheric CO to compounds of more utility. With CO being thermodynamically extremely stable, activation of CO is the first and most important step toward its chemical conversion. Building upon our earlier model for the anionic activation of CO with azabenzene and inspired by the work of others on metal atom-CO complexes, we investigated the possibility of anionic activation of CO on small anionic metal clusters, which would have implications for catalytic conversion of CO on metal surfaces with atomic-scale structural irregularities.

Selective thiolation and photoswitching mechanism of Cy5 studied by time-dependent density functional theory.

Cy5 is one of the most widely used organic dyes with a photoswitching property. It can be reversibly photoconverted to the dark state through thiolation with primary thiols. Although photoswitching of Cy5 has been widely used in super-resolution nanoscopy, its thiolation mechanism remains unclear.

An atomistic mechanism for the degradation of perovskite solar cells by trapped charge.

It is unmistakably paradoxical that the most vulnerable aspect of the photoactive organic-inorganic hybrid perovskite is its instability against light. Why and how perovskites break down under light irradiation and what happens at the atomistic level of these materials during the degradation process still remain unanswered. In this paper, we found the culprit and verified the mechanism for the irreversible degradation of hybrid perovskite materials from our experimental investigation and ab initio molecular dynamics (AIMD) simulation.

Shedding new light on an old molecule: quinophthalone displays uncommon N-to-O excited state intramolecular proton transfer (ESIPT) between photobases.

Excited state dynamics of common yellow dye quinophthalone (QPH) was probed by femtosecond transient absorption spectroscopy. Multi-exponential decay of the excited state and significant change of rate constants upon deuterium substitution indicate that uncommon nitrogen-to-oxygen excited state intramolecular proton transfer (ESIPT) occurs. By performing density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations, we found that adiabatic surface crossing between the S and S states takes place in the photoreaction.

Ab initio study on anomalous structures of anionic [(N-heterocycle)-CO] complexes.

Several unusual anionic complexes between carbon dioxide (CO) and N-heterocycles (NHCs) possessing a significantly positive adiabatic electron affinity over 0.7 eV were studied by density functional theory calculations (UB3LYP/6-311++g(d,p)). Unlike all previously reported [NHC-CO] anions with a coplanar structure that ensures full delocalization of the negative charge through extended π-conjugation, this new class of anionic [NHC-CO] complexes has a strongly non-coplanar geometry and no π-bond character between CO and NHC.

Photoelectron spectroscopic and computational study of (M-CO2)(-) anions, M = Cu, Ag, Au.

In a combined photoelectron spectroscopic and computational study of (M-CO2)(-), M = Au, Ag, Cu, anionic complexes, we show that (Au-CO2)(-) forms both the chemisorbed and physisorbed isomers, AuCO2(-) and Au(-)(CO2), respectively; that (Ag-CO2)(-) forms only the physisorbed isomer, Ag(-)(CO2); and that (Cu-CO2)(-) forms only the chemisorbed isomer, CuCO2(-). The two chemisorbed complexes, AuCO2(-) and CuCO2(-), are covalently bound, formate-like anions, in which their CO2 moieties are significantly reduced. These two species are examples of electron-induced CO2 activation.