An official website of the United States government
Understanding how a ligand affects the steric and electronic properties of a metal is the cornerstone of the inorganic chemistry enterprise. What happens when the ligand is an extended surface? This question is central to the design and implementation of state-of-the-art functional materials containing transition metals. This perspective will describe how these two very different sets of extended surfaces can form well-defined coordination complexes with metals. In the Green formalism, functionalities on oxide surfaces react with inorganics to form species that contain X-type or LX-type interactions between the metal and the oxide. Carbon surfaces are neutral L-type ligands; this perspective focuses on carbons that donate six electrons to a metal. The nature of this interaction depends on the curvature, and thereby orbital overlap, between the metal and the extended π-system from the nanocarbon.
more »
« less
Metals in polymers: hybridization enables new functions
Adding metals into synthetic polymers is of broad interest to design multifunctional materials, particularly harnessing unique properties and functionalities not found in pure organic polymers. Other than simple emergence of the two, such hybridization often enables synergies to amplify the existing properties and/or create new properties not existing in either component. In this review, we highlight recent examples of metal/polymer hybrids based on either well-defined or ill-defined metal–ligand (M–L) coordination to design multifunctional materials. This review describes how in the hybridization of metal ions and polymers they complement each other synergistically in terms of their optical, mechanical and catalytic functionalities. Synthetic polymers once bound to metals enable stimuli-responsive properties of the metals and control over the luminescence of the metals in response to a change in the environment. As the second coordination sphere, synthetic polymers also enhance the reactivity of metal sites as a means to design bioinspired artificial enzymes. Additionally, the impact of the M–L coordination on the dynamic properties of polymers is summarized in the context of self-healable and tough materials built on the reversible network of interchangeable M–L coordination.
more »
« less
- Award ID(s):
- 1705566
- PAR ID:
- 10294084
- Date Published:
- Journal Name:
- Journal of Materials Chemistry C
- Volume:
- 8
- Issue:
- 45
- ISSN:
- 2050-7526
- Page Range / eLocation ID:
- 15956 to 15980
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Metal–organic frameworks (MOFs) are crystalline, 2‐ and 3‐dimensional coordination polymers formed by bonding interactions between metals and multitopic organic ligands. These are typically formed using hard Lewis basic organic ligands with high oxidation state metal ions. The use of low‐valent metals as structural elements in MOFs is far less common, despite the widespread use of such metals for catalysis, luminescence, and other applications. This Minireview focuses on recent advances in the field of low‐valent MOFs and offers a perspective on the future development of these materials.more » « less
-
Biological photonic structures can precisely control light propagation, scattering, and emission via hierarchical structures and diverse chemistry, enabling biophotonic applications for transparency, camouflaging, protection, mimicking and signaling. Corresponding natural polymers are promising building blocks for constructing synthetic multifunctional photonic structures owing to their renewability, biocompatibility, mechanical robustness, ambient processing conditions, and diverse surface chemistry. In this review, we provide a summary of the light phenomena in biophotonic structures found in nature, the selection of corresponding biopolymers for synthetic photonic structures, the fabrication strategies for flexible photonics, and corresponding emerging photonic-related applications. We introduce various photonic structures, including multi-layered, opal, and chiral structures, as well as photonic networks in contrast to traditionally considered light absorption and structural photonics. Next, we summarize the bottom-up and top-down fabrication approaches and physical properties of organized biopolymers and highlight the advantages of biopolymers as building blocks for realizing unique bioenabled photonic structures. Furthermore, we consider the integration of synthetic optically active nanocomponents into organized hierarchical biopolymer frameworks for added optical functionalities, such as enhanced iridescence and chiral photoluminescence. Finally, we present an outlook on current trends in biophotonic materials design and fabrication, including current issues, critical needs, as well as promising emerging photonic applications.more » « less
-
null (Ed.)One of the notable advantages of molecular materials is the ability to precisely tune structure, properties, and function via molecular substitutions. While many studies have demonstrated this principle with classic carboxylate-based coordination polymers, there are comparatively fewer examples where systematic changes to sulfur-based coordination polymers have been investigated. Here we present such a study on 1D coordination chains of redox-active Fe 4 S 4 clusters linked by methylated 1,4-benzene-dithiolates. A series of new Fe 4 S 4 -based coordination polymers were synthesized with either 2,5-dimethyl-1,4-benzenedithiol (DMBDT) or 2,3,5,6-tetramethyl-1,4-benzenedithiol (TMBDT). The structures of these compounds have been characterized based on synchrotron X-ray powder diffraction while their chemical and physical properties have been characterized by techniques including X-ray photoelectron spectroscopy, cyclic voltammetry and UV–visible spectroscopy. Methylation results in the general trend of increasing electron-richness in the series, but the tetramethyl version exhibits unexpected properties arising from steric constraints. All these results highlight how substitutions on organic linkers can modulate electronic factors to fine-tune the electronic structures of metal–organic materials.more » « less
-
Abstract Developing eco‐friendly electrochemical devices for electrosynthesis, fuel cells (FCs), and metal‐air batteries (MABs) requires precisely designing the electronic pathway in the oxygen reduction reaction (ORR) process. Understanding the principle of developing low‐cost, highly active, and stable catalysts helps to reduce the usage of noble metals in ORR. Atomically dispersed metal catalysts (ADMCs) emerge as promising alternatives to replace commercial noble metals due to their high utilization of active metal atoms, high intrinsic activity, and controllable coordination environments. In this review, the research tendency and reaction mechanisms in ORR are first summarized. The basic principles concerning the geometric size and chemical coordination of two‐electron ORR (2e−ORR) catalysts were then discussed, aiming to outline the evolution of material design from 2e−ORR to four‐electron ORR (4e−ORR). Subsequently, recent advances in ADMCs primarily investigated for the 4e−ORR are well‐documented. These advances encompass studies on M−N−C coordination, light heteroatom doping, dual‐metal atoms‐based coordination, and interaction between nanoparticle (NPs)/nanoclusters (NCs) and atomically dispersed metals (ADMs). Finally, the setups for 2/4e−ORR applications, key challenges, and opportunities in the future design of ADMCs for the ORR are highlighted.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d0tc03810e
