Coordination Polymers of the Macrocyclic Nickel(II) and Copper(II) Complexes with Isomeric Benzenedicarboxylates: The Case of Spatial Complementarity between the Bis-Macrocyclic Complexes and o-Phthalate

Starting from isomeric benzenedicarboxylate dianions, phthalate (1,2-bdc2–), isophthalate (1,3-bdc2–), and terephthalate (1,4-bdc2–), and the nickel(II) and copper(II) macrocyclic cations of 3R-1,3,5,8,12-pentaazacyclotetradecane (R = allyl (L1), benzyl (L2), 4-methylbenzyl (L3)), 3,10-R2-1,3,5,8,10,12-hexaazacyclotetradecane (R = methyl (L4) and allyl (L5)), and 1,3,6,10,12,15-hexa-azatricyclo(13.3.1.16,10)icosane (L6) as building blocks, eight one-dimensional (1D) coordination polymers were synthesized and characterized by single crystal X-ray diffraction (SC-XRD), namely, ([Ni(L1)(1,2-bdc)]n (1), {[Ni(L6)(1,2-bdc)]·DMF}n (2), {[Ni(L2)(1,3-bdc)]·H2O}n (3), {[Ni(L3)(1,3-bdc)]·H2O}n (4), {[Ni(L1)(1,3-bdc)]·2H2O}n (5), {[Ni(L4)(1,3-bdc)]·2H2O}n (6), {[Ni(L4)(1,4-bdc)]·2H2O}n (7), and {[Cu(L5)(1,4-bdc)]·4H2O}n (8). This investigation revealed that in all complexes the carboxylates demonstrate syn/syn mode of coordination acting as μ2-bis-monodentate bridges joining the macrocyclic units. Based on geometrical parameters of coordinated anions, an assumption was made about the possibility of intracationic binding of the carboxylates by the parent bis-macrocyclic cations [M2Len]4+ (Len = 1,2-bis(1,3,4,8,12-pentaazacyclotetradecan-3-yl)ethane). This was further confirmed by the formation of the ionic complex [Cu2(H2O)4(Len)](1,4-bdc)2 (9) in the case of terephthalate dianion and 1D coordination polymers {[M2(Len)](1,2-bdc)2}n (M = Cu2+ (10) and Ni2+ (11) with the phthalate bridge.