Elusive Double-Eight-Ring Zeolitic Secondary Building Unit.

The double-eight-ring (D8R), an elusive secondary building unit of zeolites, has been stabilized for the first time, both in solution and solid-state. The present study further establishes that any of the three double-ring building blocks of zeolites, viz. D4R, D6R and D8R ([ArPO3Zn(L)]n (n = 4, 6 or 8)), can be preferentially isolated (over the other two) through a careful choice of metal source, aryl phosphate and ancillary ligand, apart from maintaining a meticulous control on the reaction conditions.