the complexation reactions between tl+ and pb2+ ions and crown ethers 12-crown-4(12c4), 15-crown-5 (15c5), benzo-15-crown-5 (b15c5), 18-crown-6 (18c6), dicyclohexyl-18-crown-6 (dc18c6) and aza-18-crown-6 (a18c6) were studied in 90% acetonitrile and 90% ethanol solutions at 25 °c, using an a.c. polarographic technique. the stoichiometry and stability of the complexes were determined by monitorin...

the macrocyclic ligands 2,3,5,6-bis{3’-bromo-5’-tert-butyl benzo-5-phenyl benzo} 12c3 (l1), 2,3,5,6-bis{3’-bromo-5’-tert butyl-benzo-5’-phenyl-benzo}15c4 (l2), 2,3,5,6-bis{3’-bromo-5’-tert butyl-benzo-5’-phenyl-benzo}18c5 (l3) have been synthesized and their alkaline metal compounds with naclo4∙h2o and kclo4  have been prepared. chemical formulas of all compounds have been characterized by usin...

The aza-Morita-Baylis-Hillman (azaMBH) reaction has been studied for electronically and sterically deactivated Michael acceptors. It is found that electronically deactivated systems can be converted with electron-rich phosphanes and pyridines as catalysts equally well. For sterically deactivated systems clearly better catalytic turnover can be achieved with pyridine catalysts. This is in accord...

In the title complex, (NH3OH)2[PtCl6]·2C12H24O6, the Pt(IV) atom is coordinated by six chloride anions in a slightly distorted octa-hedral geometry. The Pt-Cl bond lengths are comparable to those reported for other hexa-chlorido-platinate(IV) species. The hy-droxy-ammonium groups act as linkers between the [PtCl6](2-) anion and the crown ether mol-ecules. The anion is linked to two hy-droxy-amm...

In the title compound, C(8)H(7)ClN(4)S(2), the dihedral angle between the thia-zolidine ring (r.m.s. deviation = 0.028 Å) and the thia-zole ring (r.m.s. deviation = 0.004 Å) is 74.74 (6)°. The formonitrile group is almost coplanar with the attached ring [C-N-C-N torsion angle = 167 (2)°.

The imidazopyridine ring system in the title compound, C(9)H(8)BrN(3)S, is almost planar [r.m.s. deviation of the C and N atoms = 0.007 (1) Å]. The S and methyl-ene C atoms connected to the five-membered ring lie within this plane. The remaining two methyl-ene groups of the thia-zine ring are disordered over two sets of sites in a 0.817 (5):0.183 (5) ratio.

In the title compound, C(31)H(39)Br(2)N(3)O(6)S(2), a 17-membered aza-macrocyclic ligand containing two ether O and three aza N atoms, the three pendant aromatic rings form an 'E' shape. The dihedral angles between the central benzene ring and the side ones are 17.8 (3) and 7.4 (3)°, and the dihedral angle between the tosyl rings is 10.6 (3)°. The methyl group is disordered over two orientation...