Terminology of metal–organic frameworks and coordination polymers (IUPAC Recommendations 2013)

A set of terms, definitions, and recommendations is provided for use in the classification of coordination polymers, networks, and metal–organic frameworks (MOFs). A hierarchical terminology is recommended in which the most general term is coordination polymer. Coordination networks are a subset of coordination polymers and MOFs a further subset of coordination networks. One of the criteria an MOF needs to fulfill is that it contains potential voids, but no physical measurements of porosity or other properties are demanded per se. The use of topology and topology descriptors to enhance the description of crystal structures of MOFs and 3D-coordination polymers is furthermore strongly recommended

Coordination polymers, metal–organic frameworks and the need for terminology guidelines

Coordination polymers (CPs) and metal–organic frameworks (MOFs) are among the most prolific research areas of inorganic chemistry and crystal engineering in the last 15 years, and yet it still seems that consensus is lacking about what they really are, or are not

Highly efficient carbon dioxide capture with a porous organic polymer impregnated with polyethylenimine

Various amounts of a branched polyethylenimine are impregnated into a porous aromatic framework. PEI (40 wt%) subset of PAF-5 shows exceptionally high capacity and selectivity of CO2 adsorption at 313 K. The material also displays fast adsorption/desorption kinetics and low energy penalty for regeneration in addition to water stability.N

Coordination polymer open frameworks constructed of macrocyclic complexes

Coordination polymer open frameworks having voids and channels of various aperture sizes and shapes can be assembled by using metal azamacrocyclic complexes and organic carboxylates as molecular building blocks. In the assembly, the azamacrocyclic complexes in square-planar geometries act as linear linkers for the carboxylate ligands that have linear, triangular, and tetrahedral shapes to provide primary 1D, 2D, and 3D networks. The primary networks pack three-dimensionally in the solid state to generate open structures with pores and channels. Some of the coordination polymer open frameworks show porosity and hydrogen storage capabilities (up to 1.0 wt% at 77 K and 1 atm). The hydrogen storage data are better than those for zeolites but not as good as those of the metal-organic frameworks prepared from free metal ions. The coordination polymer open frameworks generate various degrees of hydrophobic or hydrophilic environments on the surface of the voids, which are advantageous for the selective binding of organic guest molecules. In addition, some coordination polymers containing flexible molecular components show sponge like shrinkage on removal of the guest molecules that involves dynamic motions of molecular components. In particular, the coordination polymer frameworks incorporating Ni(II) macrocyclic species are redox-active in the solid state and react with the solutions of oxidizing agents such as I2 and Ag+ to produce oxidized frameworks incorporating Ni(III) species and the reduced substrate such as I3 - anions and the small-sized silver nanoparticles. A variety of azamacrocyclic complexes that contain various functional groups attached to the macrocycles can be prepared by the simple template condensation reactions. By employing them as the metal building blocks, various types of networks are expected to be prepared, which would show high specificity for particular guests, novel crystal dynamics, and the formation of nanoparticles from various metal ions.open221

Guest-dependent host structures and host-induced guest assemblies

Coordination polymer networks, [Cu-2(C26H52N10)(BDC)(2)]center dot 4H(2)O (1) and [Cu-2(C26H52N10)(BDC)(2)]center dot 2DHB center dot 4H(2)O (2) with 2Dbrick-wall structures, [Cu-2(C26H52N10)(BDC)(2)]center dot 4HB center dot 4H(2)O (3) with a 1D ladder structure, and [Cu-2(C26H52N10)(BDC)(H2O)(2)]center dot 2(THB)-(BDC)center dot 8H(2)O (4) with a 1D chain structure, have been assembled in water from a Cu-II bismacrocyclic complex [Cu-2(C26H52N10)(Cl)(4)]center dot 6H(2)O (A) and sodium 1,4-benzenedicarboxylate (Na2BDC) in the presence of no organic guest for 1, 1,4-dihydroxybenzene (DHB) for 2, hydroxybenzene (HB) for 3, and 1,3,5-trihydroxybenzene (THB) for 4. In the assembly of the networks, the guest molecule acts as a template and stabilizes the host structure by the hydrogen bonding or pi-pi stacking interactions. In addition, the guest molecules interact with each other as well as with the host to form 1D columns that occupy the channels in 1, 2, and 3, and the 2D noncovalent organic layers that are alternately packed with the host layers in 4.N

Porous metal-organic framework with coordinatively unsaturated Mn-II sites: Sorption properties for various gases

A 3D porous metal-organic framework generating 1D channels, [Mn(NDC)(DEF)](n) (1), has been prepared from the solvothermal reaction of Mn-II and 2,6-naphthalenedicarboxylic acid (H2NDC) in diethylformamide (DEF). When DEF molecules coordinating MnII, which occupy the channels, are removed from 1 by heating the crystal of 1 at 250 degrees C under vacuum for 18 h, structural change occurs as evidenced by X-ray powder diffraction patterns. Desolvated solid [Mn(NDC)](n) (2), which contains coordinatively unsaturated MnII sites, reveals remarkable sorption capabilities for N-2, H-2, CO2, and CH4 gases and exhibits type I sorption behavior indicative of permanent microporosity.close94

Fabrication of metal nanoparticles in metal-organic frameworks

In this review, we highlight various preparative strategies and characterization methods for metal nanoparticles fabricated in porous metal-organic frameworks (MOFs) or porous coordination polymers (PCPs), and their applications in hydrogen storage and heterogeneous catalysis.close814