Calixarenes solid-state complexes

Complex Formation Involving Calixarenes 7.1 Solid State Complexes with Neutral Molecules... 

X-Ray crystallographic structures of solid state complexes of several of the parent calixarenes with metal ions have been obtained, early examples including the titanium complexes of 4 and 6 , a complex containing two Eu ... 

The first solid state complex to be studied involving a calixarene was that between 4 and toluene, the X-ray crystal structure of which was published in I979166 pp 149-158) xhis complex has since been studied via inelastic... 

The structures of complexes of calixarenes are most effectively revealed by x-ray crystallography. The first solid-state complex published was that of p-tert-butyl-ca ix[4]arene with toluene (Fig. 1). 

The alkene-W complexes used in this study are complexes 33, 166, and 168 (Schemes 5 and 31). The deprotonation of the W-alkene functionality has been carried out on 166, which has three methyl substituents at the C=C bond, in order to prevent any rearrangement of the 1-metallacyclopropene to the corresponding alkylidyne.22b The reaction of 166 with LiBu led to the 1-metallacyclopropene 169 (Scheme 32), which was isolated in quite good yield. The alkylidene 169, a very stable compound, was characterized both in solution and in the solid state.28 The h NMR spectrum shows a four-fold symmetry calixarene skeleton, while the 13C NMR spectrum contains a resonance at 271.0 ppm for the alkylidene carbon. 

The mono- and dinuclear ethylzinc complexes 137 and 138, respectively, were obtained when a 1,3-dimethylether /j-BT-calixMarene was treated with one and two equivalents of diethylzinc (Scheme 87).198 Excess [ZnEt2(tmeda)], in turn, reacted with this calixarene to furnish a pentanuclear dicalixarene. The syntheses and structures of related diorganozinc calixarenes, featuring both identical and non-identical organozinc moieties, were reported recently.199 The solid-state structure of the bis(ethylzinc)-l,3-dibenzylether-/)-But-calix[4]arene 139, which bears a close resemblance to 138, is shown in Figure 64. 

The structure of the tetranitro derivative was confirmed by X-ray diffraction in the solid state, this compound does not possess any symmetry element. The conformation of the calixarene structure is less symmetrical than for calix[4]arene(bis crown-6). The nitro groups appear to strongly modify the usual conformation of this calixarene, and a decrease in the preorganization toward cesium complexation can be expected. 

Contrary to derivative 3, calixarene 5 was found to create a 1 2 complex with chloride anion in the solid state. Both amidic functions introduced into the upper rim of calixarene operated independently of each other and held one chloride anion with a Cl... HN distance of approx. 2.37 A and two CH... Cl con-... 

Fullerenes C60 and C70 form supramolecular adducts with a variety of molecules, such as crown ethers, ferrocene, calixarene, and hydroquinone. In the solid state, the intermolecular interactions may involve ionic interaction, hydrogen bonding, and van der Waals forces. Figure 14.2.9 shows a part of the structure of [K(18C6)]3-C6o-(C6H5CH3)3, in which Cgg is surrounded by a pair of [K+(18C6)] complexed cations. 

Abstract New applications of ID and 2D solid state (SS) NMR spectroscopy in structural studies of inclusion complexes (ICs) formed by organic host lattices (cyclodextrins, calixarenes, cyclophosphazenes, and fullerenes) are described. Each section of the review gives short characteristics of host molecules and recent applications of SS NMR. Less common systems, which are interesting as models for SS NMR studies, (bis[6-0,6-0 -(l,2 3,4-diiso-propylidene-a-D-galactopyranosyl) thiophosphoryl] disulfide (DGTD) and 1,2-dichloro-ethane/tris(5-acetyl-3-thienyl) methane (TATM)), are also discussed. 

The complex was characterized by thermogravimetric analysis (TGA) and solid state NMR. Low temperature X-ray crystal structure analysis of the compound indicated the inclusion of CS2 in the calixarene cavity to be highly symmetrically oriented directly on the C4 axis of the host. The CP/MAS experiment showed significant complexation-induced chemical shift (CIS=... 

One of the important applications of butylcalix[4]arenes arises from their ability to trap alkali metal ions. In particular, Cs+-calixarene complexes have received much attention because of the need to remove the Cs radionucleotide from nuclear wastes. Benevelli et al. have used one-pulse solid state NMR experiments to directly observe Li, Na and Cs ions in the host cavity [52]. More advanced experiments, which allow the investigation of metal lattice interactions were also reported. Rotational-echo double resonance (REDOR) NMR is a useful tool for obtaining structural details of butylcalix[4]arene [53]. Gullion and coworkers used REDOR to determine the position of the... 

Structural studies of two complexes with dimethylformamide (DMF) and dimethylacetamide (DMA) were reported. In the former, three types of solvent molecules are embedded in the crystal lattice first, disordered isolated molecules located just above the cavities formed by the resorcinol units second, clusters of four DMF molecules located between the calixarene layers and third, single DMF molecules located inside the layers close to the alkyl chains. The challenge for solid state NMR is to recognize and locate guest molecules in the lattice. CP/MAS, dipolar dephasing and variable contact-time exper-... 

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