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) Å, b=8.4514(6) Å and c=17.5289(12) Å, Z=4. The condensation of 7 with diethylenetriamine yielded the novel macrocyclic ligand [C 36H 38N 6Se 2] 8 via metal-free dimerization. Crystals of 8 are monoclinic, space group C2/ c with a=18.732(3) Å, b=8.6515(10) Å, c=22.590(3) Å and Z=4. Hydrogenation of macrocycle 8 provided the corresponding saturated tetraazamacrocycle [C 36H 46N 6Se 2] ( 9), protonation of which with HBr afforded [C 36H 52N 6Se 2Br 6·H 2O] ( 10). The two novel cryptands [C 54H 54N 8Se 3] ( 12) and [C 54H 54N 8Te 3] ( 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.