Encoding and decoding hydrogen-bond patterns of organic compounds

Metal–organic frameworks (MOFs) are a class of hybrid materials with unique optical and electronic properties arising from rational self-assembly of the organic linkers and metal ions/clusters, yielding myriads of possible structural motifs. The combination of order and chemical tunability, coupled with good environmental stability of MOFs, are prompting many research groups to explore the possibility of incorporating these materials as active components in devices such as solar cells, photodetectors, radiation detectors, and chemical sensors. Although this field is only in its incipiency, many new fundamental insights relevant to integrating MOFs with such devices have already been gained. In this review, we focus our attention on the basic requirements and structural elements needed to fabricate MOF-based devices and summarize the current state of MOF research in the area of electronic, opto-electronic and sensor devices. We summarize various approaches to designing active MOFs, creation of hybrid material systems combining MOFs with other materials, and assembly and integration of MOFs with device hardware. Critical directions of future research are identified, with emphasis on achieving the desired MOF functionality in a device and establishing the structure–property relationships to identify and rationalize the factors that impact device performance.

MOF-based electronic and opto-electronic devices.

2.2. Cathodic Electropolymerization 4732 2.2.1. Electropolymerization of PPXs and PPVs 4732 3. Charging-Discharging of Conducting Polymers 4733 3.1. Redox Properties of Oligomers and Polymers 4733 3.2. Specific Phenomena of n-Doping 4739 3.3. Conductivity in Charged Systems 4740 4. Controlling the Electropolymerization Process 4742 4.1. Influence of the Polymerization Technique 4742 4.2. Influence of Experimental Conditions 4743 4.3. Electropolymerization in Novel Electrolytic Media 4745

Electrochemistry of Conducting Polymers—Persistent Models and New Concepts†

Molecule-based materials with active physical properties, in particular electrical, magnetic, and optical, are a focus of contemporary materials chemistry research. Certainly, one reason for this interest has been the realization that these materials can exhibit cooperative properties typically associated with the inorganic network solids, as for example metallic conduction or even superconductivity,1 ferromagnetism,2 and nonlinear optical properties.3 With respect to the electrical properties, many important achievements were obtained in the 1970s with the discovery of the first molecule-based metal in 1972,4 namely the π-electron donor-acceptor complex [TTF][TCNQ] (TTF ) tetrathiafulvalene, TCNQ ) tetracyano-p-quinodimethane),5 and the report of the first molecule-based superconductors in 1979 based on the Bechgaard salts [TMTSF]2X (X ) PF6, AsF6; TMTSF ) tetramethyltetraselenafulvalene).6 The recognition of molecule-based ferromagnetic compounds is more recent and has emerged only in the past decade with the discovery of the electron-transfer salt [Fe(C5Me5)2][TCNE] (TCNE ) tetracyanoethylene) in 1985.7 Since these pioneering studies, the two areassmolecule-based metals and magnetsshave witnessed rapid development, and many new molecules have been designed which, if assembled in the appropriate manner in the solid, will enable researchers to improve the physical properties by increasing superconducting and ferromagnetic critical temperatures. A current development in the general area of molecule-based materials is to design, from a wise choice of the constituent molecules, new materials that combine properties not normally associated with a single material. Some intriguing applications of this concept would be to couple conductivity or optical phenomena with magnetic properties. In fact, this challenging goal was proposed8 in the mid-1980s but has only recently begun to be explored. Efforts in this direction nucleated with the design of hybrid materials formed by two molecular networks, such as anion/cation salts or host/guest solids, where each network furnishes distinct physical properties. In these new types of materials, each network contributes distinct physical properties to the solid. Examples include hybrid molecule-based materials, combining inorganic metal complexes that act as structural or magnetic components with an organic π-electron donor or acceptor molecule that furnishes the pathway for electronic conductivity.9 Polyoxometalates have been found to be extremely versatile inorganic building blocks for the construction of the aforementioned functionally active solids.10 The present article highlights recent results and provides a perspective of the use of polyoxometalates in the construction of molecule-based materials. We present herein the different classes of polyoxometalate-based hybrid materials that are of considerable interest due to their electrical or/and magnetic properties. These are (i) organic/inorganic hybrid salts in which the electron donors are organic molecules of the TTF type, (ii) organometallic/inorganic salts in which the electron donor is the decamethylferrocene complex, and (iii) organic/inorganic films in 273 Chem. Rev. 1998, 98, 273−296

http://www1.udel.edu/chem/polenova/PDF/Polyoxometalates/POM_materials_ChemRev1998.pdf

Jerry B. Torrance

Papers

The difference between metallic and insulating salts of tetracyanoquinodimethone (TCNQ): how to design an organic metal