Synthesis of a Tetrahomodioxacalix[4]arene Tetraamide and the Crystal Structure of Its Lead Ion Complex

Abstract

The 1,4-alternate tetrahomodioxacalix[4]arene tetraamide 4 with four p-phenyl groups on its upper rim was synthesized. In two-phase metal picrate extraction, 4 exhibited Pb2+ selectivity with formation of a 1:1 complex in chloroform. In the solid-state structure of the 4*Pb(Pic)2 complex, Pb2+ is bound by the carbonyl oxygens of two adjacent amide groups and an aryl-alkyl ether oxygen atom of one of these amide-containing substituents. The crystal structure and 1H NMR spectrum of the 4*Pb2+ complex reveals pi-metal ion complexation of one aromatic ring in the ligand with Pb2+.

Homooxacalixarenes: II. Receptor properties

“…The complexing activity with respect to cations of alkali, alkaline-earth, and transition metals of dioxacalix [4]arene 97 tetraamide with phenyl substituents in the para-positions of the aromatic rings was investigated [85]. The comparison was carried out with the corresponding tetraethylacetate of dioxacalix [4]arene 107.…”

Metal ion induced FRET On–Off in naphthyl-pyrenyl pendent tetrahomodioxacalix[4]arene

“…14 For a corresponding monoalkyl amide, the conformation changed to 1,3-alternate due to intramolecular hydrogen bonding, resulting in weak binding of metal ions. 14 We also previously reported that a series of C-1,2-alternate tetrahomodioxacalix[4]arene pyreneamides were synthesized. Pb 2+ coordination gave a quenched monomer and excimer fluorescence emission, while upon Ca 2+ ion binding the receptor provides an enhanced excimer and declined monomer emission with ratiometric response.…”

“…1,2-alternate conformer in which the adjacent syn aryl moieties are joined by a CH 2 group is designated as the C-1,2-alternate, while the 1,2-alternate conformer in which the adjacent syn aryl moieties are joined by a CH 2 -O-CH 2 moiety is designated as the COC-1,2-alternate. 14 For the detailed study of FRET occurring in 7, we examined its fluorescence and UV/vis spectral behaviors upon addition of various metal ions such as Li + , Na + , K + , Rb + , Cs + , Ag + , Cu 2+ , Co 2+ , Ba 2+ , Pb 2+ , Ca 2+ , Hg 2+ , Mg 2+ , Sr 2+ , Zn 2+ , and Al 3+ . As seen in Figure 2, 7 shows a weak naphthalene emission at 331 nm and strong pyrene monomer and excimer emission bands at 382 and 470 nm, respectively, with an excitation at 280 nm.…”

Preparation of Lower Rim Functionalized Tetrahomodiaza p-Phenylcalix[4]arenes

“…7 The conformation of tetrahomodiazcalix [4]arenes can be described along the same categories as those of tetrahomodioxacalix [4]arenes, i.e., cone, partial cone, COC-1,2-alternate, C-1,2-alternate and 1,3-alternate. 9 Ethyl acetate groups at lower rim of calix [4]arene can be converted to the various other useful functional groups such as acid, 10 hydroxy 11 or amide, 12 therefore we tried to introduce alkyl ester function into the lower rim of tetrahomodiazacalix [4] In the 13 C NMR spectrum, two peaks are observed at 60.91, 59.68 ppm for the ArCH2N(R)CH2Ar bridged methylene carbons and one peak at 29.89 ppm for the ArCH2Ar bridge carbons. The methylene carbons of ArCH2N from benzyl amine appear as two peaks at 53.62 and 50.49 ppm.…”