Thomas L. Groy

Bio: Thomas L. Groy is an academic researcher from Arizona State University. The author has contributed to research in topics: Crystal structure & Diimine. The author has an hindex of 29, co-authored 120 publications receiving 7295 citations. Previous affiliations of Thomas L. Groy include University of Michigan.

Synthetic Strategies, Structure Patterns, and Emerging Properties in the Chemistry of Modular Porous Solids†

Abstract: The designed construction of extended porous frameworks from soluble molecular building blocks represents one of the most challenging issues facing synthetic chemistry today. Recently, intense research activities directed toward the development of this field have included the assembly of inorganic metal clusters,1 coordination complexes,2 and organic molecules3 of great diversity into extended motifs that are held together either by strong metal-ligand bonding or by weaker bonding forces such as hydrogen-bonding and π-π interactions. Materials that have been produced in this way are referred to as modular since they are assembled from discrete molecules which can be modified to have well-defined function.4 The fact that the integrity of the building blocks is preserved during the synthesis and ultimately translated into the resulting assembled network offers numerous opportunities for designing frameworks with desirable topologies and architectures, thus paving the way for establishing connections between molecular and solid properties. At least three challenges have emerged in this area that must be reckoned with in order for the ideas of rational and designed synthesis of porous materials to become a reality with routine utility. First, it is difficult to control the orientation and stereochemistry of the building blocks in the solid state in order to achieve a given target molecular topology and architecture. Second, in most cases, the products of such assembly reactions are obtained as poorly crystalline or amorphous solids, thus prohibiting their full characterization by single-crystal X-ray diffraction techniques. Third, access to the pores within open structuressan aspect that is so critical to their utility as porous materialssis often prevented by either selfinterpenetration as observed for very open frameworks or strong host-guest interactions that lead to the destruction of the host framework when removal or exchange of guests is attempted. To define and investigate the parameters contributing to the assembly of materials from molecular building blocks, we have established a program aimed at constructing modular porous networks by linking inorganic metal sulfide clusters and organic molecules with transition metal ions. Our work has focused primarily on studying the issues outlined above, and this Account presents our progress toward finding viable and general solutions to these challenges. This is illustrated by some representative examples chosen from the chemistry developed in our research effort for the three building blocks shown in a-c. Their functionality, shape, size, and

Establishing Microporosity in Open Metal−Organic Frameworks: Gas Sorption Isotherms for Zn(BDC) (BDC = 1,4-Benzenedicarboxylate)

Abstract: Construction of microporous metal-organic frameworks by copolymerization of organic molecules with metal ions has received widespread attention in recent years, with significant strides made toward the development of their synthetic and structural design chemistry.1 Cognizant of the fact that access to the pores and understanding the inclusion chemistry of these materials are essential to their ultimate utility, we prepared rigid frameworks that maintain their structural integrity and porosity during anion-exchange and guest sorption from solution and in the absence of guests.2-4 Although gas sorption isotherm measurements are often used to confirm and study microporosity in crystalline zeolites and related molecular sieves,5 such studies have not been established in the chemistry of open metal-organic frameworks6 thus leaving unanswered vital questions regarding the existence of permanent porosity in this class of materials. Herein, we present the synthesis, structural characterization, and gas sorption isotherm measurements for the Zn(BDC) microporous framework of crystalline Zn(BDC)‚(DMF)(H2O) (BDC ) 1,4benzenedicarboxylate and DMF ) N,N′-dimethylformamide). Slow vapor diffusion at room temperature of triethylamine (0.05 mL) and toluene (5 mL) into a DMF solution (2 mL) containing a mixture of Zn(NO3)2‚6H2O (0.073 g, 0.246 mmol) and the acid form of BDC (0.040 g, 0.241 mmol) diluted with toluene (8 mL) yields colorless prism-shaped crystals that were formulated as Zn(BDC)‚(DMF)(H2O). X-ray single-crystal analysis8 on a sample obtained from the reaction product revealed an extended open-framework structure composed of the building unit shown in Figure 1. A total of four carboxylate units of different, but symmetrically equivalent, BDC building blocks are bonded to two zinc atoms in a di-monodentate fashion. Each zinc is also linked to a terminal water ligand to form an overall arrangement that is reminiscent of the carboxylate bridged M-M bonded molecular complexes. Although the Zn-Zn distance (Zn1-Zn1A ) 2.940 (3) A) is indicative of some M-M interaction, it does not represent an actual bond.9 The structure extends into the (011) crystallographic plane by having identical Zn-Zn units linked to remaining carboxylate functionalities of BDC to yield 2-D microporous layers. These layers are held together along the a axis by hydrogen-bonding interactions between water ligands of one layer and carboxylate oxygens of an adjacent layer as illustrated in a. Stacking of the layers in the

Construction of Porous Solids from Hydrogen-Bonded Metal Complexes of 1,3,5-Benzenetricarboxylic Acid

Abstract: The reaction of M(II) acetate hydrate (M = Co, Ni, and Zn) with 1,3,5-benzenetricarboxylic (BTC) acid yields a material formulated as M3(BTC)2·12H2O. These compounds are isostructural as revealed by their XRPD patterns and a single crystal structure analysis performed on the cobalt containing solid [monoclinic, space group C2, a = 17.482 (6) A, b = 12.963 (5) A, c = 6.559 (2) A, β = 112.04°, V = 1377.8 (8) A, Z = 4]. This solid is composed of zigzag chains of tetra-aqua cobalt(II) benzenetricarboxylate that are hydrogen-bonded to yield a tightly held 3-D network. Upon liberating 11 water ligands per formula unit a porous solid results, M3(BTC)2·H2O, which was found to reversibly and repeatedly bind water without destruction of the framework. The proposed 1-D channels of the monohydrate have a pore diameter of 4 × 5 A, which is typical of those observed in zeolites and molecular sieves. The successful inclusion of ammonia into the porous solid was demonstrated. Larger molecules and others without a reactiv...

A Molecular Railroad with Large Pores: Synthesis and Structure of Ni(4,4‘-bpy)2.5(H2O)2(ClO4)2·1.5(4,4‘-bpy)·2H2O†

Abstract: The hydrothermal reaction of Ni(II) and the rodlike 4,4‘-bipyridine ligand yields an extended 1-D noninterpenetrated open framework resembling a railroad with large pores of 11 × 11 A aperture. (4,4‘-Bipyridine is illustrated as lines, and Ni atoms are at the intersections.)

Coordinatively Unsaturated Metal Centers in the Extended Porous Framework of Zn3(BDC)3·6CH3OH (BDC = 1,4-Benzenedicarboxylate)

Abstract: homogeneous transformations. However, the presence of such accessible metal centers in extended 3-D infinite crystalline solids has been elusive at best, with no established synthetic routes leading to their formation. 3 In this report, we present an example of how coordinatively unsaturated metal centers can be achieved in the chemistry of metal-organic porous frameworks. There has been intense activities devoted to the development of this chemistry4 due to the expected impact on many technologies including separations of gases and liquids, 5,6 sensors 7 and lowtemperature catalysis. 8 Here, we describe the synthetic, structural and inclusion principles of this chemistry as they have been demonstrated for the copolymerization of 1,4-benzenedicarboxylate (BDC), with zinc(II), to give a 3-D porous framework, Zn3(BDC)3‚6CH3OH, where coordinatively unsaturated zinc centers allow for highly selective binding of incoming guests sa process that occurs reversibly and without destruction of the Zn BDC framework. An N,N′-dimethylformamide solution (8.0 mL) of Zn(NO 3)2‚6H2O (0.56 g, 1.89 mmol) and 1,4-benzenedicarboxylic acid (H 2BDC) (0.32 g, 1.93 mmol) was diluted with absolute methanol (72.0 mL). To deprotonate the acid and initiate the copolymerization process, ann-propanol solution of triethylamine was allowed to diffuse into an aliquot (10 mL) of the mixture at room temperature. Block-shaped crystals of Zn 3(BDC)3‚6CH3OH appeared after 12 days, which were collected, washed with methanol and acetone, and air-dried to give 0.195 g (35% yield based on zinc nitrate). 9

The Chemistry and Applications of Metal-Organic Frameworks

Abstract: Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.

Reticular synthesis and the design of new materials

Abstract: The long-standing challenge of designing and constructing new crystalline solid-state materials from molecular building blocks is just beginning to be addressed with success. A conceptual approach that requires the use of secondary building units to direct the assembly of ordered frameworks epitomizes this process: we call this approach reticular synthesis. This chemistry has yielded materials designed to have predetermined structures, compositions and properties. In particular, highly porous frameworks held together by strong metal-oxygen-carbon bonds and with exceptionally large surface area and capacity for gas storage have been prepared and their pore metrics systematically varied and functionalized.

Selective gas adsorption and separation in metal–organic frameworks

Abstract: Adsorptive separation is very important in industry. Generally, the process uses porous solid materials such as zeolites, activated carbons, or silica gels as adsorbents. With an ever increasing need for a more efficient, energy-saving, and environmentally benign procedure for gas separation, adsorbents with tailored structures and tunable surface properties must be found. Metal–organic frameworks (MOFs), constructed by metal-containing nodes connected by organic bridges, are such a new type of porous materials. They are promising candidates as adsorbents for gas separations due to their large surface areas, adjustable pore sizes and controllable properties, as well as acceptable thermal stability. This critical review starts with a brief introduction to gas separation and purification based on selective adsorption, followed by a review of gas selective adsorption in rigid and flexible MOFs. Based on possible mechanisms, selective adsorptions observed in MOFs are classified, and primary relationships between adsorption properties and framework features are analyzed. As a specific example of tailor-made MOFs, mesh-adjustable molecular sieves are emphasized and the underlying working mechanism elucidated. In addition to the experimental aspect, theoretical investigations from adsorption equilibrium to diffusion dynamics via molecular simulations are also briefly reviewed. Furthermore, gas separations in MOFs, including the molecular sieving effect, kinetic separation, the quantum sieving effect for H2/D2 separation, and MOF-based membranes are also summarized (227 references).

Design and synthesis of an exceptionally stable and highly porous metal-organic framework

Abstract: Open metal–organic frameworks are widely regarded as promising materials for applications1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 in catalysis, separation, gas storage and molecular recognition. Compared to conventionally used microporous inorganic materials such as zeolites, these organic structures have the potential for more flexible rational design, through control of the architecture and functionalization of the pores. So far, the inability of these open frameworks to support permanent porosity and to avoid collapsing in the absence of guest molecules, such as solvents, has hindered further progress in the field14,15. Here we report the synthesis of a metal–organic framework which remains crystalline, as evidenced by X-ray single-crystal analyses, and stable when fully desolvated and when heated up to 300?°C. This synthesis is achieved by borrowing ideas from metal carboxylate cluster chemistry, where an organic dicarboxylate linker is used in a reaction that gives supertetrahedron clusters when capped with monocarboxylates. The rigid and divergent character of the added linker allows the articulation of the clusters into a three-dimensional framework resulting in a structure with higher apparent surface area and pore volume than most porous crystalline zeolites. This simple and potentially universal design strategy is currently being pursued in the synthesis of new phases and composites, and for gas-storage applications.