Palladium(II) cage compounds based on diphenylglycoluril

Abstract

A four-armed tetra-l-imidazolyl ligand (Lig) equipped with the concavc framework of diphenylglycoluril (tetrahydro-3a,6a-diphenylimidazo[4,5-<7] imidazole-2,5(l//,3//)-dione) has been designed to construct a host that contains a potentially catalytically active metal center in or close to a cavity. Reaction of Lig (arm = CH2(OCH2CH2)2Im) with Pd(CH3CN)2Cl2 results in the formation of a complex with the general formula [Pd(Lig)]Cl2. This complex has a cage structure that is unstable and collapses. The collapsed structure has either a left or a right twisted conformation. These conformations intcrconvert rapidly, the activation free energy of the process being 30 ± 2 kJ-mol"1. Ligands without oxygen atoms or only one oxygen atom per arm react with Pd(CH3CN)2Cl2 to afford cage complexes with the molecular formula [Pd(Lig)Cl]Cl. The cages of these complexes do not collapse. The imidazolyl groups and the chloride ions are involved in a scrambling process in such a way that at any moment the Pd2+ ion is surrounded by three imidazolyl groups and one chloride ion. Data are presented suggesting that intramolecular H bonding is a driving force for cage collapse.

Synthesis and Alkali Metal Picrate Extraction Capabilities of Novel Bis(benzocrown Ether)s Based on Diphenylglycoluril

“…[12][13][14][15][16] Наиболее часто для этих целей используют диэфир 1, который легко получается при конденсации дифенилгликольурила с формальдегидом с образова-нием тетракис(гидроксиметил)дифенилгликольурила и его последующей дегидратации. [19] За исключением взаимодействия с гидрохиноном, уреидоалкилирова-ние других производных бензола с участием эфира 1 осложнено длительным временем реакции и умеренны-ми выходами продуктов. Диметиловый эфир пирокате-хина и бензо-15-краун-5, очевидно и другие бензокраун-эфиры, в эту реакцию вообще не вступают.…”

“…Чистоту всех синтезированных веществ контро-лировали методом ТСХ (Sorbfil УФ-254). Бензо-18-краун-6 (Б18К6), [17] дифенилгликольурил, [18] диэфир 1, [19] и тетрахло-рид 4 [20] получали, как описано. Дибензо-18-краун-6 (ДБ18К6) коммерчески доступен.…”

Molecular clips and cages derived from glycoluril

“…The concave framework of diphenylglycoluril has been used to construct metallo-cages [27,28]. To this end the molecule has been provided with four alkyl or oxyethylene chains terminating in ligating groups such as (benz)imidazolyl or pyridyl groups.…”

Structure of a glycouril derivative: tetrahydro-1,6:3,4-di(methanoxymethano)-3a,6a-dimethylimidazo[4,5-d]imidazole-2,5(1H,3H)-dione

“…Crystals were obtained by heating an aqueous solution of 3a,6a-dimethylglycouril (Himes, Hubbard, Mighell & Fatiadi, 1978) and formaldehyde, adjusting to pH 1 with concentrated hydrochloric acid and recrystallizing from dimethyl sulfoxide (Niele & Nolte, 1988). Colorless, transparent, plate-shaped crystal of dimensions 0.8 x 0.3 × 0.01 mm was used for data collection on an Enraf-Nonius CAD-4 diffractometer with Zr-filtered Mo Ka radiation.…”