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Sn clusters have been grown on highly oriented pyrolytic graphite (HOPG) surfaces and investigated by scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations. At low Sn coverages ranging from 0.02-0.25 ML, Sn grows as small clusters that nucleate uniformly on the terraces. This behavior is in contrast with the growth of transition metals such as Pd, Pt, and Re on HOPG, given that these metals form large clusters with preferential nucleation for Pd and Pt at the favored low-coordination step edges. XPS experiments show no evidence of Sn-HOPG interactions, and the activation energy barrier for diffusion calculated for Sn on HOPG (0.06 eV) is lower or comparable to those of Pd, Pt and Re (0.04, 0.22, and 0.61 eV, respectively), indicating that the growth of the Sn clusters is not kinetically limited by diffusion on the surface. DFT calculations of the binding energy/atom as a function of cluster size demonstrate that the energies of the Sn clusters on HOPG are similar to that of Sn atoms in the bulk for Sn clusters larger than 10 atoms, whereas the Pt, Pd, and Re clusters on HOPG have energies that are 1-2 eV higher than in the bulk. Thus, there is no thermodynamic driving force for Sn atoms to form clusters larger than 10 atoms on HOPG, unlike for Pd, Pt, and Re atoms, which minimize their energy by aggregating into larger, more bulk-like clusters. In addition, annealing the Sn/HOPG clusters to 800 K and 950 K does not increase the cluster size but instead removes the larger clusters, while Sn deposition at 810 K induces the appearance of protrusions that are believed to be from subsurface Sn. DFT studies indicate that it is energetically favorable for a Sn atom to exist in the subsurface layer only when the Sn atom is located at a subsurface vacancy. 

Metal node engineering in combination with modularity, topological diversity, and porosity of metal–organic frameworks (MOFs) could advance energy and optoelectronic sectors. In this study, we focus on MOFs with multinuclear heterometallic nodes for establishing metal−property trends, i.e. , connecting atomic scale changes with macroscopic material properties by utilization of inductively coupled plasma mass spectrometry, conductivity measurements, X-ray photoelectron and diffuse reflectance spectroscopies, and density functional theory calculations. The results of Bader charge analysis and studies employing the Voronoi–Dirichlet partition of crystal structures are also presented. As an example of frameworks with different nodal arrangements, we have chosen MOFs with mononuclear, binuclear, and pentanuclear nodes, primarily consisting of first-row transition metals, that are incorporated in HHTP-, BTC-, and NIP-systems, respectively (HHTP 3− = triphenylene-2,3,6,7,10,11-hexaone; BTC 3− = 1,3,5-benzenetricarboxylate; and NIP 2− = 5-nitroisophthalate). Through probing framework electronic profiles, we demonstrate structure–property relationships, and also highlight the necessity for both comprehensive analysis of trends in metal properties, and novel avenues for preparation of heterometallic multinuclear isoreticular structures, which are critical components for on-demand tailoring of properties in heterometallic systems. 

Abstract The efficient delivery of reactive and toxic gaseous reagents to organic reactions was studied using metal‐organic frameworks (MOFs). The simultaneous cargo vehicle and catalytic capabilities of several MOFs were probed for the first time using the examples of aromatization, aminocarbonylation, and carbonylative Suzuki–Miyaura coupling reactions. These reactions highlight that MOFs can serve a dual role as a gas cargo vehicle and a catalyst, leading to product formation with yields similar to reactions employing pure gases. Furthermore, the MOFs can be recycled without sacrificing product yield, while simultaneously maintaining crystallinity. The reported findings were supported crystallographically and spectroscopically (e.g., diffuse reflectance infrared Fourier transform spectroscopy), foreshadowing a pathway for the development of multifunctional MOF‐based reagent‐catalyst cargo vessels for reactive gas reagents as an attractive alternative to the use of toxic pure gases or gas generators. 

Abstract The effect of donor (D)–acceptor (A) alignment on the materials electronic structure was probed for the first time using novel purely organic porous crystalline materials with covalently bound two‐ and three‐dimensional acceptors. The first studies towards estimation of charge transfer rates as a function of acceptor stacking are in line with the experimentally observed drastic, eight‐fold conductivity enhancement. The first evaluation of redox behavior of buckyball‐ or tetracyanoquinodimethane‐integrated crystalline was conducted. In parallel with tailoring the D‐A alignment responsible for “static” changes in materials properties, an external stimulus was applied for “dynamic” control of the electronic profiles. Overall, the presented D–A strategic design, with stimuli‐controlled electronic behavior, redox activity, and modularity could be used as a blueprint for the development of electroactive and conductive multidimensional and multifunctional crystalline porous materials. 

Abstract The effect of donor (D)–acceptor (A) alignment on the materials electronic structure was probed for the first time using novel purely organic porous crystalline materials with covalently bound two‐ and three‐dimensional acceptors. The first studies towards estimation of charge transfer rates as a function of acceptor stacking are in line with the experimentally observed drastic, eight‐fold conductivity enhancement. The first evaluation of redox behavior of buckyball‐ or tetracyanoquinodimethane‐integrated crystalline was conducted. In parallel with tailoring the D‐A alignment responsible for “static” changes in materials properties, an external stimulus was applied for “dynamic” control of the electronic profiles. Overall, the presented D–A strategic design, with stimuli‐controlled electronic behavior, redox activity, and modularity could be used as a blueprint for the development of electroactive and conductive multidimensional and multifunctional crystalline porous materials.