Coordination polymers reversible

Lewis-Acid Catalyzed. Recently, various Lewis acids have been examined as catalyst for the aldol reaction. In the presence of complexes of zinc with aminoesters or aminoalcohols, the dehydration can be avoided and the aldol addition becomes essentially quantitative (Eq. 8.97).245 A microporous coordination polymer obtained by treating anthracene- is (resorcinol) with La(0/Pr)3 possesses catalytic activity for ketone enolization and aldol reactions in pure water at neutral pH.246 The La network is stable against hydrolysis and maintains microporosity and reversible substrate binding that mimicked an enzyme. Zn complexes of proline, lysine, and arginine were found to be efficient catalysts for the aldol addition of p-nitrobenzaldehyde and acetone in an aqueous medium to give quantitative yields and the enantiomeric excesses were up to 56% with 5 mol% of the catalysts at room temperature.247... 

Paulusse JMJ, Sijbesma RP. Reversible mechanochemistry of a Pdll coordination polymer. Angew Chem Int Ed 2004 43 4460-4462. 

Vermonden T, van Steenbergen MJ, Besseling NAM, Marcehs ATM, Hennink WE, Sudholter EJR, Stuart MAC. Linear rheology of water-soluble reversible neodymium(III) coordination polymers. J Am Chem Soc 2004 126 15802-15808. 

Heo J, Jeon Y-M, Mirkin CA. Reversible inteiconversion of homochiral triangular macrocycles and heUcal coordination polymers. J Am Chem Soc 2007 129 7712-7713. 

Vetmonden T, van der Gucht J, de Waard P, Marcelis ATM, Besseling NAM, Sudhdlter EJR, Fleer GJ, Stuart MAC. Water-soluble reversible coordination polymers chains and rings. Macromolecules 2003 36 7035-7044. 

Coordination Poiymers as CO2 Absorbents. This is a long-term (2002-2006) basic research project conducted at the University of Oslo. In this project new and novel adsorbent materials (coordination polymers) will be studied that can selectively and reversibly adsorb/desorb carbon dioxide from ambient to 300°C. 

Novel Ag1 coordination polymers with a diarylethene derivative, cis-dbe, have been synthesized by Munakata et al. [31]. Polymers with a onedimensional infinite chain structure, 33, and another with a two-dimensional sheet structure, 34, were synthesized and their reversible photoreactions with 450 nm and 560 nm light in the solid state were revealed. 

Borylated ferrocenes have been exploited by Wagner as building blocks for the assembly of macrocycles and coordination polymers (Scheme 15). Treatment of the diborylated ferrocene l,L-fc(BMe2)2 with the bifunctional aromatic amines pyrazine and 4,4 -bipyridine, respectively, led to spontaneous and reversible formation of (89) and related ferrocenylborane polymers.The polymeric nature of... 

The interaction of beryllium acetylacetonate with bis(acetoacetyl) compounds leads to coordination polymers. With bis(acetoacetyl)phenyl ether in dimethylformamide the reaction was found to be reversible [214], viz. 

Coordination polymers consist of long-chain polytopic ligands which are interconnected by metal-ligand bonds. Bernhard et al. reported the synthesis of a copper(l) coordination polymer using n-decane-linked bis-phenanthrolines (42), whose morphology changes reversibly... 

In a third approach, supramolecular polymers are based on the reversibility of metal-coordination bonding. These polymers are the closest analogues to conventional macromolecules, because most of the polymers disclosed make use of strong bonding,16 in which the reversibility can be tuned by chemical means only. However, appropriate choice of the metal ion can give rise to bonding that resembles that of the other two approaches. The DP of the polymers in the case of the coordination polymers is similar to that of the condensation polymers, and achieving exact stoichiometry is of distinct importance here. 

Figure 31. Peptide-based ligand 56 which forms reversible coordination polymers with Ag(I).

Through coordination of O-bridged trinuclear Zn2+ clusters with chiral ligands, chiral porous coordination polymers may be obtained.[207] Because the two enantiomers of the ligand may be isolated separately, the obtained porous coordination polymers may also be present as the separate enantiomers. The guest water molecules in the polymer channels may be reversibly adsorbed and desorbed, and this lays the foundation for these... 

A large number of host-guest structures are known, but a reversible guest exchange or chemical transformation of the guest inside a coordination polymer framework has been described for only a few (257, 281-283). In most cases the integrity of the inclusion lattice cannot be effectively maintained in the absence of guest molecules... 

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