Conjugated microporous polymers (CMPs) have attracted much interest due to their intrinsic porosity, outstanding stability, and high variability. However, the processing of these materials for membrane application has been limited due to their insoluble nature when synthesized as bulk material. Here we report the synthesis of freestanding CMP-nanomembranes via layer-by-layer growth of a "click" based conjugated microporous polymer on a sacrificial substrate. After dissolution of the substrate the CMPnanomembrane can be transferred to porous substrates and continuously cover holes of up to 50 μm diameter. The CMPnanomembranes appear defect-free as inferred from high selectivity values obtained from gas permeation experiments and from electrochemical investigation in the presence of ferrocene. The presented synthesis method represents a versatile strategy to incorporate CMP materials in functional devices for membrane separation, catalysis, or organic electronics. C onjugated microporous polymers (CMP) are a class of microporous solids which have recently attracted wide interest due to their large surface areas, low densities, and the possibility to incorporate different kinds of functional groups in a modular fashion. 1 In contrast to related metal organic frameworks (MOF) 2−5 or covalent organic frameworks (COF) 6,7 which are formed through reversible reactions, CMPs are formed through high yielding irreversible reactions of rigid building blocks. The resulting CMP materials are amorphous and at the same time often show narrow pore size distribution. 8 The exceptional thermal and chemical stability goes well beyond that of MOFs and COFs and makes this class of porous materials particularly appealing for practical applications such as gas storage, catalysis, and molecular separation. 9,10 Among the numerous synthetic routes used in the past, click reaction chemistry has played a special role as a result of its ease of operation. The high purity and readily accessible products of click chemistry are particularly attractive to produce CMP materials. 11 Among the large variety of CMP applications, two-dimensional nanomembranes with a thickness below 10 nm exhibiting tunable pore sizes that can act as molecular sieves have a particularly large potential, since they are predicted to be ideal separation membranes with many advantages over bulk membranes. 12,13 However, the inert nature of most CMP materials causes severe, intrinsic challenges in their processing to yield large scale membranes. Indeed, only branched "soluble conjugated microporous polymers" (SCMPs) 14 and linear conjugated polymers of intrinsic microporosity (C-PIMs) 15 can be processed from solution. Usually CMPs are, in contrast to most polymers, not soluble in organic solvents, 1 and as a result, common processing techniques to fabricate polymer films from a solution such as spin coating cannot be applied.Considering the recent success in using layer-by-layer or quasi-epitaxial approaches for the fabrication of thin MOFlayers (SURMOFs) 16,17 we fabric...

Five conical calix[4]arenes that have a PPh(2) group as the sole functional group anchored at their upper rim were assessed in palladium-catalysed cross-coupling reactions of phenylboronic acid with aryl halides (dioxane, 100 degrees C, NaH). With arylbromides, remarkably high activities were obtained with the catalytic systems remaining stable for several days. The performance of the ligands is comparable to a Buchwald-type triarylphosphane, namely, (2'-methyl[1,1'-biphenyl]-2-yl)diphenylphosphane, which in contrast to the calixarenyl phosphanes tested may display chelating behaviour in solution. With the fastest ligand, 5-diphenylphosphanyl-25,26,27,28-tetra(p-methoxy)benzyloxy-calix[4]arene (8), the reaction turnover frequency for the arylation of 4-bromotoluene was 321,000 versus 214,000 mol(ArBr).mol(Pd)(-1).h(-1) for the reference ligand. The calixarene ligands were also efficient in Suzuki cross-coupling reactions with aryl chlorides. Thus, by using 1 mol% of [Pd(OAc)(2)] associated with one of the phosphanes, full conversion of the deactivated arenes 4-chloroanisole and 4-chlorotoluene was observed after 16 h. The high performance of the calixarenyl-phosphanes in Suzuki-Miyaura coupling of aryl bromides possibly relies on their ability to stabilise a monoligand [Pd(0)L(ArBr)] species through supramolecular binding of the Pd-bound arene inside the calixarene cavity.

Abstract:The combination of calixarene-derived surfactants and neutral rhodium complexes containing a hemispherical "1,3-calix-diphosphite" ligand led to efficient catalysts for the hydroformylation of octene and other olefins in water. While the surfactants allowed the formation of micelles that dissolve both the catalyst and the alkene, thereby resulting in high olefin:rhodium ratios, the diphosphite provided a tight envelope about the catalytic centre able to drive the reaction towards the linear aldehydes. Best results in the hydroformylation of 1-octene were obtained when using [tetra(p-sulfonato)]-(tetra-nbutoxy)-calix[4]arene as surfactant. With this additive remarkable linear to branched aldehyde ratios of up to 62 were obtained, the corresponding activities being higher than those observed when operating in an organic solvent [turnover frequencies (TOFs) up to 630 mol(converted 1-octene)· mol(Rh)].

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Abstract:The dynamic complex cis-P,P'-(h 5 -cyclopentadienyl)-{5, 17-bis(diphenylphosphino)-25,26,27, 28-tetrabenzyloxycalix[4]arene}nickel(II) tetrafluoro-A C H T U N G T R E N N U N G borate (2) in which the PNiP plane undergoes a rapid fanning motion was assessed in the cross-coupling reacting between phenylmagnesium bromide (PhMgBr) and aryl halides (ArX). TOFs, of up to 21250 mol(converted ArBr)·mol(2), were obtained with electron-rich as well as congested bromoarenes using catalyst loadings as low as 1 10À3 mol%, provided that the reactions were carried out at 100 8C in dioxane with a PhMgBr/ArX ratio of 2:1. The high activities observed contrast with those observed for triphenylphosphine-based catalysts and furthermore, outperforms the fastest diphosphinebased catalysts reported, a behaviour which is likely to rely on a bite angle effect.

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Combining diaryl-calixarenyl phosphines with [Ni(cod)(2)] resulted in highly active Kumada-Tamao-Corriu cross-coupling catalysts. With one of the ligands, TOFs up to 439,000 mol(ArBr) mol(Ni)(-1) h(-1) were observed in the reaction of 1-bromonaphthalene with PhMgBr. The systems were also found to be active at room temperature with aryl chlorides.