Synthesis of some macrocycles/bicycles from bis(o-formylphenyl) selenide: X-ray crystal structure of bis(o-formylphenyl) selenide and the first 28-membered selenium containing macrocyclic ligand

Abstract

Bis(o-formylphenyl) selenide (7) was synthesized using the ortholithiation methodology. The reaction of o-lithiobenzaldehyde acetal (5) with Se(dtc)(2) (dtc = diethyldithiacarbamate) afforded bis(o-formylphenyl) selenide acetal (6) in good yield. The key starting material 7 was isolated as pale yellow solid upon refluxing 6 with concentrated HCl. The structure of 7 was solved in the monoclinic space group P2/c with cell constants a = 8.0170(6) Angstrom, b = 8.4514(6) Angstrom and c = 17.5289(12) Angstrom, Z = 4. The condensation of 7 with diethylenetriamine yielded the novel macrocyclic ligand [C36H38N6Se2] 8 via metal-free dimerization. Crystals of 8 are monoclinic, space group C2/c with a = 18.732(3) Angstrom, b = 8.6515(10) Angstrom, c = 22.590(3) Angstrom and Z = 4. Hydrogenation of macrocycle 8 provided the corresponding saturated tetraazamacrocycle [C36H46N6Se2] (9). protonation of which with HBr afforded [C36H52N6Se2Br6.H2O] (10). The two novel cryptands [C54H46N8Se3] (12) and [C54H54N8Te3] (13) were prepared from the reaction of tris(2 aminoethyl)amine (tren) and the chalcogenides (7) and bis(o-formylphenyl) telluride (11) respectively using cesium ion as the template. (C) 2001 .