Article
Chemistry, Physical
William R. Jeffries, Jordan L. Wallace, Kenneth L. Knappenberger
Summary: The electronic relaxation dynamics of neutral Au-38(SC6H13)(24) monolayer-protected clusters following excitation of a charge transfer resonance were studied using femtosecond transient absorption and two-dimensional electronic spectroscopy. Results showed multiple relaxation mechanisms occurring within 100 femtoseconds and picoseconds, with detailed fine-structure peaks resolving state-to-state dynamics. This study highlights the importance of using 2DES with precise MPCs for understanding electronic dynamics in metal nanoclusters and metal-chalcogenide interfaces.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Zhicheng Su, Matias Bejide, Piero Ferrari, Kevin Anthony Kaw, Michele Moris, Koen Clays, Stefan Knoppe, Peter Lievens, Ewald Janssens
Summary: In the past decade, the structural and electronic properties of monolayer-protected metal clusters have been extensively researched for their potential optical applications. This study investigates the wavelength-dependent nonlinear optical absorption and refraction of two specific clusters and discovers various nonlinear optical phenomena occurring at different excitation wavelengths.
Article
Chemistry, Multidisciplinary
Patrick J. Herbert, Kenneth L. Knappenberger
Summary: The study reports on the observation of spin-polarized emission for the Au-25(SC8H9)(18) monolayer-protected cluster. By analyzing variable-temperature variable-field magnetic circular photoluminescence (VTV (H) over right arrow, MCPL) measurements, the degree of spin polarization for different relaxation mechanisms is determined and discussed in terms of relative intensities of different emission mechanisms. Additionally, it is found that the emission characteristics of the Au-25(SC8H9)(18) monolayer-protected cluster vary with temperature.
Article
Chemistry, Physical
Rajarshi Sinha-Roy, Xochitl Lopez-Lozano, Robert L. Whetten, Hans-Christian Weissker
Summary: This study investigates the interaction mechanisms between ligands and metallic cores in metal cluster compounds, focusing on the influence of monolayer-protected clusters on electronic, optical properties, and transport properties.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Hong Yi, Kimberly M. Osten, Tetyana Levchenko, Alex J. Veinot, Yoshitaka Aramaki, Takashi Ooi, Masakazu Nambo, Cathleen M. Crudden
Summary: A series of chiral Au-13 nanoclusters were successfully synthesized and characterized, exhibiting high luminescence and stability. This opens up opportunities for further investigation into the impact of chirality on the properties of these clusters.
Article
Chemistry, Physical
Vikas Tiwari, Tarak Karmakar
Summary: Monolayer-protected atomically precise nanoclusters (MPCs) are important molecules with unique structural features and diverse applications. In this study, we used molecular dynamics and enhanced sampling simulations to understand the atomistic and dynamical details of the aggregation process of Au-25(pMBA)(18) MPCs in aqueous and methanol solutions. The results showed that MPCs interact via hydrogen bonds and π-stacks between aromatic ligands to form stable dimers, oligomers, and crystals. The study also revealed the role of ligand charged state and solvent in molecular aggregation. Our work provides unprecedented molecular-level dynamical details of the aggregation process and conformational dynamics of MPCs ligands in solution and crystalline phases.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Justin B. Patty, Shana Havenridge, Dylan Tietje-Mckinney, Maxime A. Siegler, Kundan K. Singh, Roumina Hajy Hosseini, Mohamed Ghabin, Christine M. Aikens, Anindita Das
Summary: The article reports the first example of a chiral mixed thiolate/stibine-protected gold cluster, with the chirality originating from a unique arrangement on an achiral Au-13 core. The structure and properties of this new Au-18 cluster are found to be different from other reported achiral Au-18 clusters and the only other stibine-protected [Au-13(SbPh3)(8)Cl-4](+) cluster, highlighting the importance of detailed analysis on its geometric and electronic structures for understanding its optical properties, reactivity, and stability.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Papri Chakraborty, Sami Malola, Marco Neumaier, Patrick Weis, Hannu Hakkinen, Manfred M. Kappes
Summary: The fragmentation dynamics of ligated coinage metal clusters provides insights into their structural and bonding properties. However, the challenges in methodology have limited the investigation of fragment structures. In this study, we used trapped ion mobility mass spectrometry to determine the geometric structures of the primary fragments of [Ag29L12](3-) and compared them to density functional theory calculations. We also observed a new dissociation channel in the further dissociation of [Ag19L6](-), indicating a competition between retaining electronic stability and increasing steric strain of ligands and staples. These findings have potential implications for studying the catalytic behavior of Ag clusters on supports through soft-landing deposition.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Editorial Material
Multidisciplinary Sciences
Sami Malola, Hannu Hakkinen
Summary: This passage discusses how precise knowledge of the chemical composition and atomic structure of nanosized systems can be used for detailed computational work to understand structure-property relations in metal clusters. It also mentions the challenges of developing effective simulation methods to account for cluster-environment interactions, potentially using components of electronic structure theory combined with machine learning algorithms.
NATURE COMMUNICATIONS
(2021)
Review
Chemistry, Multidisciplinary
Leyi Chen, Lei Wang, Quanli Shen, Yonggang Liu, Zhenghua Tang
Summary: Atomically precise metal nanoclusters have attracted significant research interest due to their quantum confinement effect and molecule-like properties. Ligand engineering, especially using alkynyl molecules, can lead to versatile interfacial bonding motifs and drastically different properties compared to thiolate ligands. This review discusses the unique advantages of alkynyl-protected metal nanoclusters, synthetic strategies, their applications in electrochemical CO2 reduction, and proposes challenges and future perspectives. The review aims to stimulate further research efforts in developing effective synthesis strategies and advancing the understanding of alkynyl-protected metal nanoclusters in catalysis.
MATERIALS CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Felix Stete, Matias Bargheer, Wouter Koopman
Summary: The strong interaction between plasmons and excitons can generate new hybrid polariton states with potential applications. However, the transient behavior of these systems is not fully understood. In this study, we provide conclusive evidence that the interesting nonlinear features observed in the picosecond time scale are due to heat generation inside the particles. We introduce a concise model that can accurately recreate the transient spectra by assuming an initial temperature rise of the electron gas inside the particles.
Article
Chemistry, Multidisciplinary
Jia Dong, Ze-Hua Gao, Qian-Fan Zhang, Lai-Sheng Wang
Summary: The research reports the synthesis and characterization of a gold nanohydride protected by diphosphine ligands. The nanohydride consists of an Au-22 core with two Au-11 units bridged by four H atoms and delocalized Au-H-Au bonds. It exhibits various transformations related to hydrogen and serves as a versatile model catalyst for understanding hydrogen reactions on gold nanoparticle surfaces.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Inorganic & Nuclear
Arijit Jana, Parvathy M. Unnikrishnan, Ajay K. Poonia, Jayoti Roy, Madhuri Jash, Ganesan Paramasivam, Jan Machacek, Kumaran Nair Valsala Devi Adarsh, Tomas Base, Thalappil Pradeep
Summary: We report the synthesis, structural characterization, and photophysical properties of a propeller-shaped Ag21 nanomolecule with six rotary arms, which exhibits high thermal stability and light-activated structural distortion. The structure and photophysical properties of the nanomolecule are confirmed by various characterization methods.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Yeakub Zaker, Brian A. Ashenfelter, Badri Bhattarai, Nathan A. Diemler, Timothy R. Brewer, Terry P. Bigioni
Summary: Silver monolayer-protected clusters (MPCs) are a new class of small metal nanoparticles with discrete sizes and unique properties that can be controlled. The formation mechanism of silver-glutathione MPCs is established through a sequential growth model, which explains how MPCs systematically grow and transform from one known species to another. The interplay between relative MPC stabilities and reaction kinetics directs reactions, providing tools for the synthesis of specific MPCs in high yield.
Article
Chemistry, Physical
Angus I. Sullivan, Joseph F. DeJesus, Sami Malola, Shinjiro Takano, Tatsuya Tsukuda, Hannu Haekkinen, Cathleen M. Crudden
Summary: Atomically precise gold nanoclusters protected with N-heterocyclic carbenes (NHCs) using potassium intercalated graphite (KC8) as a reducing agent were successfully synthesized and characterized. The resulting Au11 nanocluster, [Au11(NHC)8Br2]Br, showed improved stability and optical properties. This work expands the synthetic toolbox for gold nanoclusters and contributes to the understanding of their structures.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
James E. Bruno, K. B. Sravan Kumar, Nicolas S. Dwarica, Alexander Huther, Zhifeng Chen, Clemente S. Guzman, Emily R. Hand, William C. Moore, Robert M. Rioux, Lars C. Grabow, Bert D. Chandler
Article
Chemistry, Physical
Masoud Shabaninezhad, Guda Ramakrishna
JOURNAL OF CHEMICAL PHYSICS
(2019)
Article
Chemistry, Physical
Masoud Shabaninezhad, Abubkr Abuhagr, Naga Arjun Sakthivel, Chanaka Kumara, Amala Dass, Kyuju Kwak, Kyunglim Pyo, Dongil Lee, Guda Ramakrishna
JOURNAL OF PHYSICAL CHEMISTRY C
(2019)
Article
Chemistry, Physical
Naga Arjun Sakthivel, Mauro Stener, Luca Sementa, Marco Medves, Guda Ramakrishna, Alessandro Fortunelli, Allen G. Oliver, Amala Dass
JOURNAL OF PHYSICAL CHEMISTRY C
(2019)
Article
Chemistry, Multidisciplinary
K. B. Sravan Kumar, Todd N. Whittaker, Christine Peterson, Lars C. Grabow, Bert D. Chandler
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2020)
Article
Chemistry, Physical
James E. Bruno, Nicolas S. Dwarica, Todd N. Whittaker, Emily R. Hand, Clemente S. Guzman, Anish Dasgupta, Zhifeng Chen, Robert M. Rioux, Bert D. Chandler
Article
Chemistry, Physical
Akbar Mahdavi-Shakib, Janine Sempel, Lauren Babb, Aisha Oza, Maya Hoffman, Todd N. Whittaker, Bert D. Chandler, Rachel Narehood Austin
Article
Chemistry, Multidisciplinary
Naga Arjun Sakthivel, Masoud Shabaninezhad, Luca Sementa, Bokwon Yoon, Mauro Stener, Robert L. Whetten, Guda Ramakrishna, Alessandro Fortunelli, Uzi Landman, Amala Dass
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2020)
Article
Chemistry, Multidisciplinary
Akbar Mahdavi-Shakib, K. B. Sravan Kumar, Todd N. Whittaker, Tianze Xie, Lars C. Grabow, Robert M. Rioux, Bert D. Chandler
Summary: H-2 adsorption on Au catalysts is weak and reversible, posing challenges for quantitative studies. By investigating H-2 adsorption on Au/TiO2 catalysts, electron transfer to the support was observed, leading to shifts in FTIR background signals, which were used to quantify H-2 adsorption. Additionally, a new H-O-H bending vibration associated with proton adsorption on distinct metal-support interface sites was identified, providing new insights into the nature and dynamics of H-2 adsorption at the Au/TiO2 interface.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Energy & Fuels
Kyunglim Pyo, Sang Myeong Han, Hongmei Xu, Sukanya Saha, Guda Ramakrishna, Dongil Lee
Summary: The study investigated the size-dependent energy harvesting from nonthermalized, upper excited states of glutathione-protected gold clusters, showing that the upper excited-state energy can be efficiently harvested by an energy acceptor attached to the clusters. This opens up a new avenue for energy harvesting from nonthermalized upper excited states of gold clusters that would otherwise be lost as heat.
Article
Chemistry, Physical
Shahrea Mahbub, Sukanya Saha, Guda Ramakrishna, Joseph C. Furgal
Summary: Advancements in organic materials for devices like OLEDs, OFETs, and photovoltaics have shown great innovation potential. This research focuses on synthesizing SQ-based oligomers cross-linked by dibromo-aromatic linkers to explore their photophysical properties, using techniques such as UV/vis, fluorescence, FTIR, and TGA for characterization and understanding excited state dynamics. The study also investigates potential energy transfer and charge transfer within the materials, revealing short-range communication between moieties and significant thermal stability and solution processability of the SQ backbone in achieving energy transfer.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Chemistry, Physical
Akbar Mahdavi-Shakib, Lauren C. Rich, Todd N. Whittaker, Bert D. Chandler
Summary: Infrared spectroscopy reveals that H-2 adsorption on Au/TiO2 catalysts occurs heterolytically at the metal-support interface, generating stable protonated MSI hydroxyls. Au modifies the local structural and electronic properties of the support, leading to an increase in the basicity of electron-rich MSI hydroxyls. This synergism between Au and TiO2 results in electron-deficient Au particles and more electron-rich MSI hydroxyls, contributing to stronger Lewis acids and Bronsted bases, respectively.
Article
Chemistry, Multidisciplinary
Melanie M. Mitchell, Vageesha W. Liyana Gunawardana, Guda Ramakrishna, Gellert Mezei
Summary: This study presents the synthesis, characterization, and photophysical properties of pyrene-functionalized fluorescent nanojars. The fluorescence of pyrene is significantly quenched when attached to nanojars, indicating a strong contribution from the paramagnetic Cu2+ ions. Different types of quenching mechanisms were observed depending on how the pyrene is attached to the nanojars.
Article
Nanoscience & Nanotechnology
Tae Yong Yun, Bert D. Chandler
Summary: Surface hydroxyl groups on metal oxides have significant effects in catalyst synthesis and catalytic reactions, yet their broader material properties are not regularly reported. This study provides direct methods to quantify fundamental properties of surface hydroxyls on different titania- and alumina-based supports. The results show variations in surface hydroxyl density and intrinsic acidity/basicity among different titania sources, as well as the temperature effects on surface acid-base properties and isoelectric point changes.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Akbar Mahdavi-Shakib, Todd N. N. Whittaker, Tae Yong Yun, K. B. Sravan Kumar, Lauren C. C. Rich, Shengguang Wang, Robert M. M. Rioux, Lars C. C. Grabow, Bert D. D. Chandler
Summary: Hydrogen spillover is the migration of H atom equivalents from metal nanoparticles to a support. This study measures weak, reversible H-2 adsorption on Au/TiO2 catalysts and determines the surface concentration of spilled-over hydrogen. The adsorption behavior of H* on the titania surface is found to increase with temperature, which is attributed to high proton mobility, configurational surface entropy, and increasing hydroxyl acid-base equilibrium constants.