“…One logical approach to increase the predictability in copper-organophosphonate systems is to engineer the coordination environment of metal centers by using chelating organoimine ligands to limit the number of phosphonate coordination over the copper coordination sphere. The chelating ligands including 2,2′:6′,2″-Terpyridine (terpy), 4′,4⁗-(1,4-Phenylene)bis(2,2′:6′,2″-terpyridine) (pbterpy), or 2,2′-bipyridine (2,2′-bpy) regularly produce square pyramidal {Cu(2,2′-bpy)} 2+ , {Cu(terpy)} 2+ , and {Cu 2 (pbterpy)} 2+ centers where Cu(II) has two and three open sites for phosphonate coordination, respectively. − This method has previously been shown to be influential in controlled formation of macrocyclic Cu(II)-organophosphonate building blocks . Another report using a similar method has used a bridging 4,4′-bipyridine ligand to form isoreticular porous frameworks with the H 2 O 3 PCH 2 -NR-CH 2 PO 3 H 2 type of organophosphonates .…”