Synthesis of Zigzag-Chain and Cyclic-Octanuclear Calcium Complexes and Hexanuclear Bulky Aryl-Phosphate Sodium Complexes with Ortho-Amide Groups: Structural Transformation Involving a Network of Inter- and Intramolecular Hydrogen Bonds

Three new polynuclear Ca(II)- and Na(I) phosphate complexes with two strategically oriented
bulky amide groups, 2,6-(PhCONH)2C6H3OPO3H2, were synthesized, including one with a zigzag-chain,
[CaII{O3POC6H3-2,6-(NHCOPh)2}(H2O)4(EtOH)]n, a cyclic-octanuclear form, [CaII8{O3POC6H3-2,6-(NHCOPh)2}8(OCHNMe2)8(H2O)12], and a hexanuclear complex, (NHEt3)[Na3{O3POC6H3-2,6-(NHCOPh)2}2(H2O)(MeOH)7]. X-ray crystallography revealed that all have an unsymmetric ligand position due to the bulky
amide groups. A dynamic transformation of the Ca(II) zigzag-chain structure to the cyclic-octanuclear
complex was induced by changing coordination of DMF molecules, which caused a reorganization of the
intermolecular/intramolecular hydrogen bond network.