Luminescent Functional Metal–Organic Frameworks

Metal–organic frameworks (MOFs) are a unique class of crystalline solids comprised of metal cations (or metal clusters) and organic ligands that have shown promise for a wide variety of applications Over the past 15 years, research and development of these materials have become one of the most intensely and extensively pursued areas A very interesting and well-investigated topic is their optical emission properties and related applications Several reviews have provided a comprehensive overview covering many aspects of the subject up to 2011 This review intends to provide an update of work published since then and focuses on the photoluminescence (PL) properties of MOFs and their possible utility in chemical and biological sensing and detection The spectrum of this review includes the origin of luminescence in MOFs, the advantages of luminescent MOF (LMOF) based sensors, general strategies in designing sensory materials, and examples of various applications in sensing and detection

Luminescent metal–organic frameworks for chemical sensing and explosive detection

Hydrogen Storage in Metal–Organic Frameworks

Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

/pdf/metal-organic-frameworks-and-self-assembled-supramolecular-2xs948xxr9.pdf

Metal–Organic Frameworks and Self-Assembled Supramolecular Coordination Complexes: Comparing and Contrasting the Design, Synthesis, and Functionality of Metal–Organic Materials

ConspectusNanosized supramolecular metallocages have a unique self-assembly process that allows chemists to both understand and control it. In addition, well-defined cavities of such supramolecular aggregates have various attractive applications including storage, separation, catalysis, recognition, drug delivery, and many others. Coordination-driven self-assembly of nanosized supramolecular metallocages is a powerful methodology to construct supramolecular metallocages with considerable size and desirable shapes. In this Account, we summarize our recent research on controllable coordination-driven assembly of supramolecular metallocages and infinite cage-based frameworks.To this end, we have chosen flexible ligands that can adopt various conformations and metal ions with suitable coordination sites for the rational design and assembly of metal–organic supramolecular ensembles. This has resulted in various types of metallocages including M3L2, M6L8, M6L4, and M12L8 with different sizes and shapes. Because...

Controllable coordination-driven self-assembly: from discrete metallocages to infinite cage-based frameworks.

Two classical metal clusters, CuI4I4 and CuI6S6, are introduced as functional connecting nodes to construct a novel multi-metal-cluster MOF [(CuI4I4)3(CuI6)2(3-ptt)12]n·24nDEF·12nH2O (1) that incorporate their inherent luminescent properties, induced by their respective metal–metal interactions. These two distinct clusters are combined together for the first time to perform as functional luminophores that display unusual dual emission with both thermochromic luminescence and near-infrared (NIR) character.

A multi-metal-cluster MOF with Cu4I4 and Cu6S6 as functional groups exhibiting dual emission with both thermochromic and near-IR character

A blue luminescent tetradecavanadate compound, [Et4N]5[V14O36Cl], has been synthesized. It possesses an unprecedented half-open basket framework. Through the {ABAB}-type stacking, the {V14O36} clusters form infinite one-dimensional channels with considerable accessible volume in the crystalline state.

A Basket Tetradecavanadate Cluster with Blue Luminescence

A new complex, [In2(μ-OH)2(btc)2]n·2nHpy (1) (btc = 1,3,5-benzenetricarboxylate; py = pyridine), is hydrothermally synthesized from the reaction of InCl3, H3btc, and pyridine. Complex 1 crystallizes in the monoclinic P21 space group [a = 7.3181(12) A, b = 17.0195(23) A, c = 10.5789(17) A, β = 102.651(6)°, and Z = 2]. Indium(III) centers in 1 are bridged by btc ligands in various coordination modes to form the nonclose rings which are further interlinked along crystallographic a-axis and (011) plane to result in a nonpenetrated 3-D anionic framework growing as homochiral tunnels. Compound 1 is fully characterized by fluorescence spectroscopy, second harmonic generation measurement, infrared, and thermogravimetric analysis.

New 3-d chiral framework of indium with 1,3,5-benzenetricarboxylate.

The self-assembly of cationic tetranuclear-metal building blocks generated in situ based on p-tert-butylthiacalix[4]arene and linear anionic ligands (1,4-benzenedicarboxylic acid) gave rise to an anionic truncated octahedral coordination cage through a [6 + 12] condensation. This research provides a new building block with unique geometry to construct coordination cages with multifunctional properties.

Lian Chen

Papers

Controllable coordination-driven self-assembly: from discrete metallocages to infinite cage-based frameworks.

A multi-metal-cluster MOF with Cu4I4 and Cu6S6 as functional groups exhibiting dual emission with both thermochromic and near-IR character

A Basket Tetradecavanadate Cluster with Blue Luminescence

New 3-d chiral framework of indium with 1,3,5-benzenetricarboxylate.

Truncated octahedral coordination cage incorporating six tetranuclear-metal building blocks and twelve linear edges