TY  - JOUR
A1  - Jansen, K.
A1  - Buschmann, Hans-Jürgen
A1  - Wego, A.
A1  - Dopp, D.
A1  - Mayer, C.
A1  - Holdt, Hans-Joachim
A1  - Schollmeyer, E.
T1  - Curcubit[5]uril, decamethylcururbit[5]uril and curcurbit[6]uril : synthesis, solubility and amin complex formation
N2  - A simple way to prepare cucurbit[5]uril is described. The macrocycles of the cucurbituril type are nearly insoluble in water. The solubilities of cucurbit[5]uril, decamethylcucurbit[5]uril and cucurbit[6]uril in hydrochloric acid, formic acid and acetic acid of different concentrations have been investigated. Due to the formation of complexes between cucurbit[n]urils and protons the solubility increases in aqueous acids. The macrocyclic ligands are able to form complexes with several organic compounds. Thus, the complex formation of the cucurbituril macrocycles with different amines has beenstudied by means of calorimetric titrations. The reaction enthalpy gives noevidence of the formation of inclusion or exclusion complexes. 1H-NMR measurements show that in the case of cucurbit[5]uril and cucurbit[6]uril the organic guest compound is included within the hydrophobic cavity. Decamethylcucurbit[5]uril forms only exclusion complexes with organicamines. This was confirmed by the crystal structure of the decamethylcucurbit[5]uril-1,6- diaminohexane complex. complex formation - cucurbit[5]uril - cucurbit[6]uril - decamethylcucurbit[5]uril - solubility - synthesis
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Spannenberg, A.
A1  - Buschmann, Hans-Jürgen
A1  - Holdt, Hans-Joachim
A1  - Schollmeyer, E.
T1  - Complex formation of noncyclic, monocyclic and bicyclic ligands with nickel(II) and cobalt(II) in acetonitrile
N2  - Equilibrium constants and thermodynamic parameters for the complexation of nickel(II) and cobalt(II) by noncyclic, monocyclic and bicyclic ligands in acetonitrile have been determined by calorimetric titrations. The donor atoms and the ring size of the ligands play an important role for the stabilities of the complexes formed. An increasing number of nitrogen atoms in the crown ether favours complex formation. The number of nitrogen donor atoms of the macro- cyclic ligands examined has a direct influence on the values of the reaction enthalpies. Keywords: Complex formation; crown ethers; azacrown ethers; thiacrown ethers; cryptands; acetonitrile
Y1  - 1999
SN  - 0095-8972
ER  -