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Triple-negative breast cancer (TNBC) is one of the most aggressive and challenging subtypes with limited treatment options and poor prognosis. To overcome these obstacles, Ag-doped SnSe (ASS) nanosheets were used as photonic hyperthermia agents for treating TNBC. ASS featured a high photothermal-conversion efficiency and photon hyperthermia effect. Additionally, biosafety assessments, including hemolysis assays and histopathological analysis, confirmed that ASS was biosafety. These findings suggest that ASS, in synergy with the second near-infrared biowindow (NIR-II) light irradiation, offers a noninvasive, effective, and safe therapeutic strategy for TNBC. This innovative approach exemplifies the evolving landscape of TNBC treatment, where technology and biology converge to offer more precise and personalized therapies. [ABSTRACT FROM AUTHOR]

Wecombine ultrafast electronic and vibrational spectroscopy andcomputational modeling to investigate the photoinduced excited-stateintramolecular hydrogen-transfer dynamics in 1,8-dihydroxy-9,10-anthraquinone(DHAQ) in tetrachloroethene, acetonitrile, dimethyl sulfoxide, andmethanol. We analyze the electronic excited states of DHAQ with variouspossible hydrogen-bonding schemes and provide a general descriptionof the electronic excited-state dynamics based on a systematic analysisof femtosecond UV/vis and UV/IR pump–probe spectroscopic data.Upon photoabsorption at 400 nm, the S2electronic excitedstate is initially populated, followed by a rapid equilibration within150 fs through population transfer to the S1state whereDHAQ exhibits ESIHT dynamics. In this equilibration process, the excited-statepopulation is distributed between the 9,10-quinone (S2)and 1,10-quinone (S1) states while undergoing vibrationalenergy redistribution, vibrational cooling, and solvation dynamicson the 0.1–50 ps time scale. Transient UV/vis pump–probedata in methanol also suggest additional relaxation dynamics on thesubnanosecond time scale, which we tentatively ascribe to hydrogenbond dynamics of DHAQ with the protic solvent, affecting the equilibriumpopulation dynamics within the S2and S1electronicexcited states. Ultimately, the two excited singlet states decay witha solvent-dependent time constant ranging from 139 to 210 ps. Theconcomitant electronic ground-state recovery is, however, only partialbecause a large fraction of the population relaxes to the first tripletstate. From the similarity of the time scales involved, we conjecturethat the solvent plays a crucial role in breaking the intramolecularhydrogen bond of DHAQ during the S2/S1relaxationto either the ground or triplet state. [ABSTRACT FROM AUTHOR]

We study the solvent-induced frequency shifts of the OH-stretching mode of 1-naphthol and 2-naphthol in nonpolar/weakly polar solvents, subject to electronic excitation, with ultrafast UV/mid-infrared pump–probe spectroscopy and theoretical modeling based on Pullin’s perturbative treatment of vibrational solvatochromic effects. The model is parametrized at the density functional theory (DFT) level, including the B3LYP/TZVP and TD-B3LYP/TZVP descriptions, for the naphthol chromophores in the S0- and 1Lb-states and accounts for both the static and the optical dielectric response of the solvent on time scales comparable to that of the OH-stretching vibrational motions. The favorable comparison between experimental and theoretical values of the solvent-induced vibrational frequency shifts suggests that the ultrafast dielectric response of the solvent contributes predominantly to the solvatochromic shifts in solvents of moderate polarity where specific solute–solvent interactions are absent. [ABSTRACT FROM AUTHOR]

We investigate the OH stretch vibrational frequency shifts of a prototype photoacid, 2-naphthol (2N), when dissolved in solvents of low polarity. We combine femtosecond mid-infrared spectroscopy and a theoretical model based on the Pullin-van der Zwan-Hynes perturbative approach to explore vibrational solvatochromic effects in the ground S0 and the first electronically excited ¹Lb states. The model is parametrized using density functional theory (DFT), at the B3LYP/TZVP and TD-B3LYP/TZVP levels for the 2N chromophore in the S0 and ¹Lb states, respectively. From the agreement between experiment and theory we conclude that vibrational solvatochromic effects are dominated by the instantaneous dielectric response of the solvent, while time-dependent nuclear rearrangements are of secondary importance. [ABSTRACT FROM AUTHOR]

Inelastic electron-transfer kinetics in molecules with electron donor and acceptor units connected by a bridge is expected to be sensitive to bridge-localized vibronic interactions. Here, we show how inelastic electron transfer may be turned on and off in a double-slit style experiment that uses the molecule as an interferometer. We describe donor−acceptor interactions in terms of interfering vibronic coupling pathways that can be actively selected (“labeled”) when pathway-specific vibrations are excited by infrared radiation. Thus, inelastic tunneling may be actively controlled, and we suggest strategies for building molecular scale quantum interferometers and switches based on this phenomenon. [ABSTRACT FROM AUTHOR]

The exploration of non-noble metal catalysts for alkane dehydrogenation and their catalytic mechanisms is the priority in catalysis research. Here, we report a high-density coordinatively unsaturated Zn cation (Zn cus ) catalyst for the direct dehydrogenation (DDH) of ethylbenzene (EB) to styrene (ST). The catalyst demonstrated good catalytic performance (∼40% initial EB conversion rate and >98% ST selectivity) and excellent regeneration ability in the reaction, which is attributed to the high-density (HD) distribution and high-stability structure of Zn cus active sites on the surface of zinc silicate (HD-Zn cus @ZS). Density functional theory (DFT) calculations further illustrated the reaction pathway and intermediates, supporting that the Zn cus sites can efficiently activate the C-H bond of ethyl on ethylbenzene. Developing the high-density Zn cus catalyst and exploring the catalytic mechanism laid a good foundation for designing practical non-noble metal catalysts.

The atomically dispersed metal catalyst or single-atom catalyst (SAC) with the utmost metal utilization efficiency shows excellent selectivity toward ethylene compared to the metal nanoparticles catalyst in the acetylene semi-hydrogenation reaction. However, these catalysts normally work at relatively high temperatures. Achieving low-temperature reactivity while preserving high selectivity remains a challenge. To improve the intrinsic reactivity of SACs, rationally tailoring the coordination environments of the first metal atom by coordinating it with a second neighboring metal atom affords an opportunity. Here, we report the fabrication of a dual-atom catalyst (DAC) that features a bonded Pd 1 -Cu 1 atomic pair anchoring on nanodiamond graphene (ND@G). Compared to the single-atom Pd or Cu catalyst, it exhibits increased reactivity at a lower temperature, with 100% acetylene conversion and 92% ethylene selectivity at 110 °C. This work provides a strategy for designing DACs for low-temperature hydrogenation by manipulating the coordination environment of catalytic sites at the atomic level.

Heterogeneous catalytic processes produce the majority of the fuels and chemicals in the chemical industry and have kept improving the welfare of human beings for centuries. Although most of the heterogeneous catalytic reactions occur at the gas-solid interface, numerous cases have demonstrated that the condensed water near the active site and/or the aqueous phase merging the catalysts play positive roles in enhancing the performance of heterogeneous catalysts and creating novel catalytic conversion routes. We enumerate the traditional heterogeneous catalytic reactions that enable significant rate/selectivity promotion in the aqueous phase or adsorbed micro water environment and discuss the role of water in specific systems. Some of the novel heterogeneous reactions achieved with only the assistance of the aqueous phase have been summarized. The development of reactions with the participation of the aqueous phase/water and the investigation of the role of water in the heterogeneous catalytic reactions will open new horizons for catalysts with better activity, improved selectivity, and novel processes., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

It remains a general challenge to computationally design optimal catalytic structures based on earth-abundant metals for hydrogenation. Here, we demonstrate an effective computational approach based on inverse molecular design to deterministically design optimal catalytic sites on the Cu(100) surface through the doping of Fe and/or Zn, and a stable Zn-doped Cu(100) surface was found with minimal binding energy to H atoms. By the calculations at the level of density functional theory, the optimized catalyst sites are verified to be valid on the Cu(100) surface in an infinite periodic system. We analyze the electronic structure cause of the optimal binding sites using the analysis of the density of states. In addition, we use a Cu 29 Zn 3 atomic cluster, where such an optimum catalytic site is valid on the Cu(100) surface, to understand the role of doped Zn atoms on lowering the H atom binding energy. We found that in the atomic cluster, the atomic orbitals of surface Zn-atoms show less participation in the binding of H atoms, compared to the atomic orbitals of surface Cu atoms. Our study provides valuable chemistry insights on designing catalytic structures using earth-abundant metals, and it may lead to the development of novel Cu-based earth-abundant alloys in bulk, nanoparticles, atomic clusters, or single-atom catalysts for important catalytic applications such as lignin degradation or CO 2 conversion.

Two-dimensional (2D) heterostructures of black phosphorus (BP)/bismuth vanadate (BVO) have attracted much attention due to their potential uses in photocatalytic water splitting. However, the interfacial photoinduced electron- and hole-transfer dynamics are not explored computationally. Herein, we have used density functional theory (DFT) calculations and DFT-based fewest-switches surface-hopping dynamics simulations to investigate the light-driven electron and hole dynamics taking place at the interface of BP and the BVO(010) surface. Our results show that the BP monolayer is adsorbed on BVO(010) via van der Waals interaction. Upon irradiation, the electron transfer takes place from BP to BVO(010) within 500 fs but with two distinct processes. In the first phase, the electron transfer proceeds adiabatically and is mainly driven by atomic motions. In the second phase, the electron transfer decays very slowly. The hole-transfer dynamics from BVO(010) to BP exhibits a similar ultrafast decay in the first stage followed by a slow decay; however, there is a comparable amount of hole trapped in a BP state due to a large energy gap from its higher state. These insights may be useful for the design of novel photocatalytic water-splitting materials.

To assess the potential use of O-H stretching modes of aromatic alcohols as ultrafast local probes of transient structures and photoacidity, we analyze the response of the O-H stretching mode in the 2-naphthol-acetonitrile (2N-CH3CN) 1:1 complex after UV photoexcitation. We combine femtosecond UV-infrared pump-probe spectroscopy and a theoretical treatment of vibrational solvatochromic effects based on the Pullin perturbative approach, parametrized at the density functional theory (DFT) level. We analyze the effect of hydrogen bonding on the vibrational properties of the photoacid-base complex in the S0 state, as compared to O-H stretching vibrations in a wide range of substituted phenols and naphthols covering the 3000-3650 cm(-1) frequency range. Ground state vibrational properties of these phenols and naphthols with various substituent functional groups are analyzed in solvents of different polarity and compared to the vibrational frequency shift of 2N induced by UV photoexcitation to the (1)Lb electronic excited state. We find that the O-H stretching frequency shifts follow a linear relationship with the solvent polarity function F0 = (2ε0 - 2)/(2ε0 + 1), where ε0 is the static dielectric constant of the solvent. These changes are directly correlated with photoacidity trends determined by reported pKa values and with structural changes in the O···N and O-H hydrogen-bond distances induced by solvation or photoexcitation of the hydrogen-bonded complexes.

Characterization of protein secondary structures at interfaces is still challenging due to the limitations of surface-selective optical techniques. Here, we address the challenge of characterizing parallel β-sheets by combining chiral sum frequency generation (SFG) spectroscopy and computational modeling. We focus on human islet amyloid polypeptide aggregates and a de novo designed short polypeptide at lipid/water and air/glass interfaces. We find that parallel β-sheets adopt distinct orientations at various interfaces and exhibit characteristic chiroptical responses in the amide I and N-H stretch regions. Theoretical analysis indicates that the characteristic chiroptical responses provide valuable information on the symmetry, orientation, and vibrational couplings of parallel β-sheet at interfaces.

Studying hydrogen/deuterium (H/D) exchange in proteins can provide valuable insight on protein structure and dynamics. Several techniques are available for probing H/D exchange in the bulk solution, including NMR, mass spectroscopy, and Fourier transform infrared spectroscopy. However, probing H/D exchange at interfaces is challenging because it requires surface-selective methods. Here, we introduce the combination of in situ chiral sum frequency generation (cSFG) spectroscopy and ab initio simulations of cSFG spectra as a powerful methodology to probe the dynamics of H/D exchange at interfaces. This method is applied to characterize H/D exchange in the antiparallel β-sheet peptide LK7β. We report here for the first time that the rate of D-to-H exchange is about 1 order of magnitude faster than H-to-D exchange in the antiparallel structure at the air/water interface, which is consistent with the existing knowledge that O-H/D dissociation in water is the rate-limiting step, and breaking the O-D bond is slower than breaking the O-H bond. The reported analysis also provides fundamental understanding of several vibrational modes and their couplings in peptide backbones that have been difficult to characterize by conventional methods, including Fermi resonances of various combinations of peptide vibrational modes such as amide I and amide II, C-N stretch, and N-H/N-D bending. These results demonstrate cSFG as a sensitive technique for probing the kinetics of H/D exchange in proteins at interfaces, with high signal-to-noise N-H/N-D stretch bands that are free of background from the water O-H/O-D stretch.

An inverse design methodology suitable to assist the synthesis and optimization of molecular sensitizers for dye-sensitized solar cells is introduced. The method searches for molecular adsorbates with suitable photoabsorption properties through continuous optimization of "alchemical" structures in the vicinity of a reference molecular framework. The approach is illustrated as applied to the design and optimization of linker chromophores for TiO(2) sensitization, using the recently developed phenyl-acetylacetonate (i.e., phenyl-acac) anchor [McNamara et al. J. Am. Chem. Soc.2008, 130, 14329-14338] as a reference framework. A novel anchor (3-acac-pyran-2-one) is found to be a local optimum, with improved sensitization properties when compared to phenyl-acac. Its molecular structure is related to known coumarin dyes that could be used as lead chromophore anchors for practical applications in dye-sensitized solar cells. Synthesis and spectroscopic characterization confirms that the linker provides robust attachment to TiO(2), even in aqueous conditions, yielding improved sensitization to solar light and ultrafast interfacial electron injection. The findings are particularly relevant to the design of sensitizers for dye-sensitized solar cells because of the wide variety of structures that are possible but they should be equally useful for other applications such as ligand design for homogeneous catalysis., (© 2011 American Chemical Society)

We have characterized the covalent binding of the CO(2) reduction electrocatalyst ReC0A (Re(CO)(3)Cl(dcbpy) (dcbpy =4,4'-dicarboxy-2,2'-bipyridine)) to the TiO(2) rutile (001) surface. The analysis based on sum frequency generation (SFG) spectroscopy and density functional theory (DFT) calculations indicates that ReC0A binds to TiO(2) through the carboxylate groups in bidentate or tridentate linkage motifs. The adsorbed complex has the dcbpy moiety nearly perpendicular to the TiO(2) surface and the Re exposed to the solution in a configuration suitable for catalysis., (© 2011 American Chemical Society)

Ultrafast UV-vibrational spectroscopy was used to investigate how vibrational excitation of the bridge changes photoinduced electron transfer between donor (dimethylaniline) and acceptor (anthracene) moieties bridged by a guanosine-cytidine base pair (GC). The charge-separated (CS) state yield is found to be lowered by high-frequency bridge mode excitation. The effect is linked to a dynamic modulation of the donor-acceptor coupling interaction by weakening of H-bonding and/or by disruption of the bridging base-pair planarity.

Studies of the nonlinear electronic response of donor/acceptor substituted nanotubes suggest a behavior that is both surprising and qualitatively distinct from that in conventional conjugated organic species. We find that the carbon nanotubes serve as both electronic bridges and acceptors, leading to a donor-nanotube paradigm for the effective design of large first hyperpolarizabilities. We also find that tuning the donor orientation, relative to the nanotube, can significantly enhance the first hyperpolarizability.