Two independent, 1-D metal–organic nanotubes based on rings or helical chain units

Abstract

Three coordination polymers {[Mn(bte)(NO2-1,3-bdc)(H2O)]·H2O}n (1), {[Mn(btp)(NO2-1,3-bdc)(H2O)]·2H2O}n (2), and {[Mn(btb)(NO2-1,3-bdc)(H2O)]·H2O}n (3) (bte, 1,2-bis(1,2,4-triazol-1-yl)ethane; btp, 1,3-bis(1,2,4-triazol-1-yl)propane; btb, 1,4-bis(1,2,4-triazol-1-yl)butane, NO2-1,3- H2bdc, 5-nitroisophthalic acid) were synthesized by combination of bte, btp, and btb, conformationally flexible ligands with different spacer lengths, and the rigid [NO2-1,3-bdc]2−. In 1, two [NO2-1,3-bdc]2− anions link adjacent [Mn2(bte)2] rings to give an independent, 1-D metal–organic nanotube (MONT). The structure of 2 is an undulating 2-D (4,4) network. In 3, the combination of a [Mn(btb)]n single helical chain and two [Mn(NO2-1,3-bdc)]n linear chains assemble an intriguing independent, 1-D MONT. An interesting structural feature of 1 and 3 is that the nitro groups of each 1-D MONT interpenetrate into two adjacent 1-D MONTs to form a 1-D → 2-D interdigitated array. 3-D architectures in 1 and 3 are assembled via hydrogen bond interactions. The luminescent properties and thermal stabilities of 1, 2, and 3 were investigated.