Engineering the metal-terpy grid with complexes containing 4′-hydroxy terpyridine

We report and analyse the crystallisation and crystal structures of [Ni(terpyOH)(2)](BF4)(2) (1), [Fe(terpyOH)(2)](BF4)(2)(H2O)-H-. (2a) isomorphous with [Ru(terpyOH)(2)](BF4)(2)(H2O)-H-. (2b), [Cu(terpyOH)(2)](BF4)(2)(H2O)-H-. (3a) isomorphous with [Ru(terpyOH)(terpy)](BF4)2(.)H(2)O (3b) and with [Co(terpyOH)(2)](ClO4)(2)(H2O)-H-. already published (terpyOH = 4'-hydroxy-2,2':6',2 ''-terpyridine, or 2,6-bis(2-pyridyl)-4(1H)-pyridone). All of these crystals contain the standard two-dimensional terpy embrace (2D-TE) grid of metal complexes, with secondary variations in stacking patterns and inter- and intra-layer hydrogen bonding connectivities. There is no hydrogen bonding between the 4'-OH groups of opposing layers (which would require large and potentially unstable separation of layers). Instead the 4'-OH groups are located in the deep grooves of the surface of the opposing layer, where the anions and water ( when present) are located. Crystal structure types 2 and 3 contain alternating hydrated and anhydrous interlayer domains. All evidence points to stability and reproducibility for this general class of 2D-TE grid network.