Structural features of 3d metal compounds with 1-hydroxyethylidenediphosphonic acid

Structural features of 3d metal complexes with anions of 1-hydroxyethyliden ediphosphonic acid (HEDP, H4L), in which the M : HEDP ratios are equal to I : 2, 1 : 1, 3 : 2, and 5 : 2, al e discussed. The Cu(II) : HEDP : 2 comple xes are characterized by five types of structures: monomer ic structures tr ans-[Cu(H4-nL)(2)(H2O)(2)](2-2n), cis-[Cu(H4-nL)(2)(H2O)(2)](2-2n), an [Cu( L)(2)](6-); the dimeric structure {[Cu(H2L)(H2O)](2)(mu (2)-H2L)(2)}(4-); a nd the polymeric chain structure {[Cu(mu (2)-H2L)(2)](2-)}(infinity). Six c oordination modes exhibited by HEDP in the Cu(II) compounds are described. (C) 2001 MAIK "Nauka/Interperiodica".