Inclusion compounds of the macrocyclic cavitand cucurbit[8]uril (CB[8]) with the nickel(II) complex, {trans [Ni(en) 2 (H 2 O) 2 ]@CB[8]}Cl 2 •23.5H 2 O, the copper(II) com plex, {2[Cu(dien)(bipy)(H 2 O)]@CB[8]}(ClO 4 ) 4 •11H 2 O, and the organic molecules, 2(pyCN)@CB[8]}•16H 2 O and {2(bpe)@CB[8]}•17H 2 O, where bipy is 4,4´ bipyridyl, pyCN is 4 cyanopyridine, and bpe is trans 1,2 bis(4 pyridyl)ethylene, were synthesized. The inclusion compounds with organic molecules were synthesized starting from inclusion compounds of cucurbit[8]uril with cyclam and ethylenediamine complexes of copper(II) and nickel(II) by the guest exchange method, which is based on the replacement of one guest with another in the cavity of the cavitand The resulting compounds were characterized by X ray diffraction, ESR, 1 H NMR, IR, and electronic absorption spectroscopy, and electrospray mass spectrometry. Photochemically induced [2+2] cycloaddition of two 1,2 bis(4 pyridyl)ethylene molecules included in cucurbit[8]uril was studied.Inclusion compounds of organic macrocyclic cavitands with metal complexes is a new rapidly developing field of supramolecular chemistry. Inclusion of transition metal complexes in organic cavitands gives rise to a unique mi croenvironment of the metal ion similar to that observed in metalloenzymes. Hence, these compounds hold prom ise as model systems in studies of small molecule activa tion and metal ion transport in biological systems. Inclu sion compounds of metal complexes can find use in the design of a new generation of prolonged action pharma ceuticals based on biologically active metal compounds encapsulated within the cavity of a host, which prevents the guest complex from rapid decomposition and per forms transport of the active component in organisms. 1-6Studies of inclusion compounds of cucurbit[n]urils with metal complexes have been started in the last few years, 1-3,7,8 although encapsulation of neutral organic molecules and organic cations in these cavitands has been investigated in depth. 9-13 Cucurbit[n]urils (CB[n]) be long to a family of macrocyclic molecules of composition C 6n H 6n N 4n O 2n (n = 5-10) consisting of n glycoluril frag ments linked to each other by 2n methylene bridges. 14,15 Cucurbit[n]urils have a rigid (unlike such molecular con tainers as calixarenes and cyclodextrins) hydrophobic in ner cavity, which is of importance for selective inclusion of guests of particular size. Guests can enter the cavity through two hydrophilic portals formed by n carbonyl groups.Several inclusion compounds of cucurbit[n]urils with metal complexes have been structurally character ized. These are copper(II) and zinc(II) complexes with cyclam (1,4,8,11 tetraazacyclotetradecane) and cyclene (1,4,7,10 tetraazacyclododecane) encapsulated in the cav ity of cucurbit[8]uril (CB[8]), 1 the inclusion compound of CB[7] with the [cis SnCl 4 (H 2 O) 2 ] complex, 8 and in clusion compounds of CB[8] with the [Ni(cyclam)] 2+ and [trans Cu(en) 2 (H 2 O) 2 ] 2+ complexes, whose syn thesis has been described in o...
