http://www.mdpi.com/journal/ijms/special_issues/mof-ijms/ Dear Colleagues, In recent years several metallorganic frameworks (MOFs) have been deeply investigated for their properties and potential application in catalysis, gas storage, ion exchange, separation, and polymerization. The main properties of MOFs are ordered structures, the presence of channels or cavities with defined shapes and dimensions, a large surface area, and in some cases, a peculiar lattice flexibility. Due to these properties, MOFs are very attractive materials for their potential applications, as compared to "classic" porous materials, such as zeolites and active carbons. MOFs can be considered as three-dimensionally structured coordination metal complexes, in which the metal ions are connected to the ligands through covalent coordination bonds. The key to their success is the appropriate design of molecular building blocks (linkers, connectors, counter-ions, etc.), to obtain the desired structure and physico-chemical properties. For example, N-, O-, and S-donor ligands are suitable candidate building blocks for the obtainment of unique structural motifs, that can show not only a great aesthetic and conceptual appeal, but also attractive functional properties. The MOFs described in the recent literature can be divided into the following classes: i) porous materials containing solvents, or other neutral or ionic guest species,whose porous structure irreversibly collapses upon their removal (1st generation MOFs), ii) materials with a stable, rigid, and robust framework, that remain unchanged after the removal of the guests (2nd generation MOFs), and iii) flexible structures able to adapt themselves to a modification, or removal, of guest species or to external stimuli, by a reversible change of the shape and dimensions of pores, or, more generally, of the geometrical parameters of their crystal lattice (3rd generation MOFs). Silvia Bordiga, Ph.D. Guest Editor Related Special Issue Metal Organic Frameworks in Materials {snippet name="submission_info"} http://www.mdpi.com/1422-0067/12/3/1964/ Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis and spectral studies (IR, 1H and 13C-NMR). The single crystal X-ray structure of the mercury complex revealed that the complex contains a Hg centre with a distorted tetrahedral coordination sphere in which the dinuclear Hg complex resides on a crystallographic inversion centre and each Hg atom is coordinated to four S atoms from the dithiocarbamate moiety. One dithiocarbamate ligand acts as chelating ligand while the other acts as chelating bridging ligand between two Hg atoms, resulting in a dinuclear eight-member ring. The course of the thermal degradation of the complexes has been investigated using thermogravimetric and differential thermal analyses techniques. Thermogravimetric analysis of the complexes show a single weight loss to give MS (M = Zn, Cd, Hg) indicating that they might be useful as single source precursors for the synthesis of MS nanoparticles and thin films. http://www.mdpi.com/1422-0067/12/3/1964/ Thu, 17 Mar 2011 00:00:00 CET International Journal of Molecular Sciences 2011-03-17 12 3 Article 1964 1978 1422-0067 Synthesis, Characterization and Thermal Studies of Zn(II), Cd(II) and Hg(II) Complexes of N-Methyl-N-Phenyldithiocarbamate: The Single Crystal Structure of [(C6H5)(CH3)NCS2]4Hg2 2011-03-17 doi: 10.3390/ijms12031964 Damian C. Onwudiwe Peter A. Ajibade http://www.mdpi.com/1422-0067/11/10/3803/ Coordination polymers (CPs) or metal-organic frameworks (MOFs) have attracted considerable attention because of the tunable diversity of structures and functions. A 4,4'-bipyridine molecule, which is a simple, linear, exobidentate, and rigid ligand molecule, can construct two-dimensional (2D) square grid type CPs. Only the 2D-CPs with appropriate metal cations and counter anions exhibit flexibility and adsorb gas with a gate mechanism and these 2D-CPs are called elastic layer-structured metal-organic frameworks (ELMs). Such a unique property can make it possible to overcome the dilemma of strong adsorption and easy desorption, which is one of the ideal properties for practical adsorbents. http://www.mdpi.com/1422-0067/11/10/3803/ Thu, 30 Sep 2010 00:00:00 CEST International Journal of Molecular Sciences 2010-09-30 11 10 Review 3803 3845 1422-0067 Flexible Two-Dimensional Square-Grid Coordination Polymers: Structures and Functions 2010-09-30 doi: 10.3390/ijms11103803 Hiroshi Kajiro Atsushi Kondo Katsumi Kaneko Hirofumi Kanoh http://www.mdpi.com/1422-0067/11/8/2821/ Crystal structures and dynamic rearrangements of one-dimensional coordination polymers with 4,4'-dipyridylsulfide (dps) have been studied. Reaction of Ni(NO3)2·6H2O with dps in EtOH yielded [Ni(dps)2(NO3)2]·EtOH (1), which had channels filled with guest EtOH molecules among the four Ni(dps)2 chains. This coordination polymer reversibly transformed the channel structure responding to temperature variations. Immersion of 1 in m-xylene released guest EtOH molecules to yield a guest-free coordination polymer [Ni(dps)2(NO3)2] (2a), which was also obtained by treatment of Ni(NO3)2·6H2O with dps in MeOH. On the other hand, removal of the guest molecules from 1 upon heating at 130 °C under reduced pressure produced a guest-free coordination polymer [Ni(dps)2(NO3)2] (2b). Although the 2a and 2b guest-free coordination polymers have the same formula, they showed differences in the assembled structures of the one-dimensional chains. Exposure of 2b to EtOH vapor reproduced 1, while 2a did not convert to 1 in a similar reaction. Reaction of Ni(NO3)2·6H2O with dps in acetone provided [Ni(dps)(NO3)2(H2O)]·Me2CO (4) with no channel structure. When MeOH or acetone was used as a reaction solvent, the [Ni(dps)2(NO3)2]·(guest molecule) type coordination polymer ,which was observed in 1, was not formed. Nevertheless, the reaction of Ni(NO3)2·6H2O with dps in MeOH/acetone mixed solution produced [Ni(dps)2(NO3)2]·0.5(MeOH·acetone) (5), which has an isostructural Ni-dps framework to 1. http://www.mdpi.com/1422-0067/11/8/2821/ Mon, 02 Aug 2010 00:00:00 CEST International Journal of Molecular Sciences 2010-08-02 11 8 Article 2821 2838 1422-0067 Syntheses and Characterization of New Nickel Coordination Polymers with 4,4’-Dipyridylsulfide. Dynamic Rearrangements of One-Dimensional Chains Responding to External Stimuli: Temperature Variation and Guest Releases/Re-Inclusions 2010-08-02 doi: 10.3390/ijms11082821 Mitsuru Kondo Hideaki Takahashi Hirotaka Watanabe Yusuke Shimizu Katsunori Yamanishi Makoto Miyazawa Naoko Nishina Yutaka Ishida Hiroyuki Kawaguchi Fumio Uchida