Complexes of calixarenes

The titanium complexes of calixarene were obtained by Olmstead et al. [44] and Bott et al. [45], who examined their x-ray characteristics. Recent research in that field has been conducted by Rudkevich et al, [46]. They prepared calix[4]arene-triacids as receptors for lan-tanides. 

Roundhill, D. Max, Metal Complexes of Calixarenes Rovis, Tomislav, and Evans, David A., Structural and Mechanistic 43 533... 

Complexes of calixarenes with bipyridyl chromophores can be stabilized by the addition of anionic side arms, such as iminodiacetate units (85). Whilst the lanthanide complexes of ligands [L51]4- and [L52]4- are not soluble in water, their photophysical properties in... 

Alkenes and Alkynes. A series of metal carbonyl cations, such as [Au(CO)n]+,287,288 [c-Pd( i-CO)2]2+,289 [Rh(CO)4]+,290 and [(Pt(CO)3)2]2+,291 was found to induce the formation of carboxylic acids from alkenes and CO in the presence of H2SO4 under mild conditions. A novel water-soluble Pd catalyst292 and Pd complexes of calixarene-based phosphine ligands293 showed high activity in the regioselective carboxylation of vinyl arenes to yield 2-arylpropionic acids or... 

Figure 4.25 X-ray structure of the chloride complex of calixarene receptor 4.64.

There are some 3,000 publications reporting calixarenes, many of which can be obtained by searching databases under the term calix. In addition, several books have been written on calixarenes, and metal complexes are described in all of them.1-6 Reviews on metal complexes of calixarenes has been published,7-10 and a book published in 2001 also makes numerous references to them.11 Among the other calixarenes are the calix[4]arene thiol (7) and the thiacalix[4]arene (8). Related compounds are the oxacalix[3]arene (9) and the azacalix[3]arene (10), both of which have been used as complexants for metal ions. 

Only few investigations have been published on the gas-phase ion chemistry of host-guest complexes of calixarenes. With the advent of ESI mass spectrometry, especially when combined with ion-trap and FT-ICR mass spectrometry, this field has started to be developed. Binding selectivities of alkali metal ions to cahxarene-based crown ethers and open-chain ethers have been studied , the inclusion of neutral guests into the protonated resorcarene-based cavitand hosts by gas-phase ion-molecule reactions with amines have been studied and the formation of capsules from various calixarene tetraether derivatives and alkylammonium ions as ionic guests (notably enabling their detection by mass spectrometry) have been described recently . ... 

Metal complexes of calixarenes, D. M. Roundhill, in Progress in Inorganic Chemistry, Vol. 43, K. D. Karlin (ed.), John Wiley Sons Inc., New York, 1995. 

Roundhill. M.D. Metal Complexes of Calixarenes. In Progress in Inorganic Chemistiy Kenneth. D.M.. Ed. John Wiley Sons, Inc., 1995 533 pp. 

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). 

Kane. P. Kincaid, K. Fayne, D. Diamond. D. McKervey, M.A. Modelling metal complexes of calixarene esters and phosphine oxides using molecular mechanics. J. Mol. Model. 2000. 6. 272-281. 

The number of papers reporting the role of CH/ti interaction is rapidly increasing. Only recent key papers are cited here. Chloroform interacts favorably with an arene n-oloud of fullerene complexes of calixarenes " and cyclotriveratrylene. Evidence for the role of CH/ti interaction in self-assembly was presented.The significance in molecular capsules " " and lattice- and cavity-inclusion type clathrates is well documented. 

D.M. RoundhUl, Metal complexes of calixarenes. Prog. Inorg. Chem., 43, 533,1995. 

Zheng Y-S, Ying L-Q, Shen Z-Q. Polymerization of propylene oxide by a new neodymium complex of calixarene derivative. Polymer 2000 41(4) 1641-3. 

The complexation of calixarene derivatives and lanthanide cations has been studied by H NMR spectroscopy. Both 1 1 and 1 2 complexes between lanthanides and cyclohexanetriols have been demonstrated by H NMR spectroscopy. Pr +-serine complexation has been monitored by H NMR spectroscopy in aqueous solution. NMR titrations have been used to investigate... 

Metal Complexes of Calixarenes as Artificial Esterases or Phosphodiesterases... 

Owing to the unique host-guest properties of calixarene macrocycles, calixarene-functionalized silica particles were used as cation-selective receptor colloids [81], and separator of lanthanides and actinides [82]. Calixarenes were also used for the syntheses of Ru, Pt and Pd NPs [83-85]. Furthermore, photoluminescence and charge-transfer complexes of calixarenes and calix[4]arene-based glycoclusters were grafted onto the surface of Ti02 NPs [64, 86]. 

The research on guest-inclusion complexes of calixarene based molecular crystals paved the way for different type of gas-sorption studies in these materials under various conditions. Although these materials generally dcai t possess uniform pore nor have high surface area (unlike traditional porous materials such as zeolite, molecular sieves or MOFs), their unique void structures make them attractive candidates for selective gas-sorption and separation applications. It should be noted that no uniform method were used to analyze the gas-sorption capacity (or separation capability) of these... 

Fig. 4. Complex of calixarene 3 with Na". Only four bonds are formed with this cation.

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