Tripropoxy-p-tert-butylcalix[4]arene and tripentoxy-p-tert-butylcalix[4]arene and their complexes with chromium, cobalt and niobium were synthesized. New compounds were characterized by infrared and nuclear megnatic resonance. All complexes were monometallic system. The ability of the complexes toward polymerization of -caprolactone was investigated by ring opening polymerization mode. One can co...