Porous organic polymers (POPs), a class of highly cross-linked, amorphous polymers possessing micropores, have recently emerged as a versatile platform for the deployment of catalysts. These materials can be divided into three major classes: POPs that incorporate rigid well-defined homogeneous catalysts as building blocks, POPs that can be modified post-synthesis, and POPs that encapsulate metal particles. This perspective article summarizes the recent developments in POP-based catalysis and outlines the potential of POPs as platforms of heterogeneous catalysts along with some of the challenges.

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Porous organic polymers in catalysis: Opportunities and challenges

Conducting Stacked Metallophthalocyanines and Related Compounds

LiFePO{sub 4}, Li{sub 0.98}Mg{sub 0.01}FePO{sub 4}, and Li{sub 0.96}Ti{sub 0.01}FePO{sub 4} were synthesized via a sol-gel method, using a variety of processing conditions. For comparison, LiFePO{sub 4} was also synthesized from iron acetate by a solid state method. The electrochemical performance of these materials in lithium cells was evaluated and correlated to mean primary particle size and residual carbon structure in the LiFePO{sub 4} samples, as determined by Raman microprobe spectroscopy. For materials with mean agglomerate sizes below 20 {micro}m, an association between structure and crystallinity of the residual carbon and improved utilization was observed. Addition of small amounts of organic compounds or polymers during processing results in carbon coatings with higher graphitization ratios and better electronic properties on the LiFePO{sub 4} samples and improves cell performance in some cases, even though total carbon contents remain very low (<2%). In contrast, no performance enhancement was seen for samples doped with Mg or Ti. These results suggest that it should be possible to design high power LiFePO{sub 4} electrodes without unduly compromising energy density by optimizing the carbon coating on the particles.

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Electrochemical performance of Sol-Gel synthesized LiFePO{sub 4} in lithium batteries

Phthalocyanine-based nanoporous network polymers

The optical and electronic properties of the phthalocyanine (Pc)
macrocycle make it suitable for a wide range of applications. The enormous
diversity of Pc-containing polymers, developed over thirty years of research,
offers the prospect of readily processed materials in which covalent linkages
can be used to control the ordering and arrangement of the Pc units. This
article reviews both the synthesis and study of Pc-containing polymers.
The types of polymer are classified by the way in which the macrocycle is
incorporated within the macromolecular structure as either network, main-chain
or side-chain polymers. In addition, recent work on the incorporation
of the Pc macrocycle as polymer end-groups or as the core unit in a number
of dendrimers is also described.

Phthalocyanine-containing polymers

Phthalocyanine moieties containing polymers 3 a – e were prepared by the reaction of several oxy- and arylenedioxy-bridged diphthalonitriles 2 a – e in the absence or the presence of metal salts or metals. The structure of the polymers was thoroughly discussed on the basis of their IR and UV/VIS spectra. According to the nitrile end groups determined by IR spectroscopy, the structurally uniform polymers consist of phthalocyanine moieties. Saponification of the nitrile end groups of 3 a – e leads to polymeric phthalocyanines with carboxylic acid end groups with a lower degree of annulation than that of the polymers before saponification. The low-molecular-weight phthalocyanines 5a, b were prepared as model compounds for the polymers.

Polymeric phthalocyanines and their precursors, 14. Synthesis and analytical characterization of polymers from oxy‐ and arylenedioxy‐bridged diphthalonitriles

The thermal stabilities of structurally uniform polymeric phthalocyanines 2 and their lowmolecular-weight model compounds 5 were examined Thermal analyses under inert and oxidative conditions showed that the nature of the metal as well as that of the substituents and end groups has a decisive influence on the thermal stability Polymers 2 turned out to be less stable as compared to their low-molecular-weight analogues 5 Generally, the stability under inert conditions was found to be higher than under oxidative conditions For polymer 2b (Mt = Cu) it could be shown that 400°C must not be exceeded during its synthesis, whereas the polymer withstands isothermic temperatures of up to 500°C without decomposition

Polymeric phthalocyanines and their precursors, 10. Thermal stability of polymeric phthalocyanines and their low molecular analogues

Alkylenedioxy bridged polymeric phthalocyanines 3a – d were synthesized by the reaction of the tetracarbonitriles 2a–d with copper(II) chloride or copper in bulk. As compared with other tetracarbonitriles the reactions applying 2a – d, which contain a flexible alkylene chain, run at relatively low reaction temperatures leading to good yields of polymers with a high degree of anelation of phthalocyanine rings (Pc > 100). In contrast to their low swelling factors and their low surface areas, polymeric phthalocyanines, with different bridging units between the chelate rings in the solid state exhibit good absorption capacities for organic solvents, mainly from the liquid state.

Polymeric phthalocyanines and their precursors, 15. Syntheses of alkylenedioxy bridged polymeric phthalocyanines and their absorption capacities for organic solvents in comparison to other phthalocyanines

Bernd Schulte

Papers

Polymeric phthalocyanines and their precursors, 14. Synthesis and analytical characterization of polymers from oxy‐ and arylenedioxy‐bridged diphthalonitriles

Polymeric phthalocyanines and their precursors, 10. Thermal stability of polymeric phthalocyanines and their low molecular analogues

Polymeric phthalocyanines and their precursors, 15. Syntheses of alkylenedioxy bridged polymeric phthalocyanines and their absorption capacities for organic solvents in comparison to other phthalocyanines