Synthesis, structures, and magnetic properties of transition metal-based supramolecules

Abstract

Three novel carboxylate complexes were synthesized and characterized: $[Cu_2(pdc)_2(H_2O)_5]_n(H_2O)_{2n}$ (1), $[Mn(H_2O)_6]_n[Cu(pdc)_2(H_2O)_2]_n(H_2O)_{8n}$ (2), and $[Cu(ida)(H_2O)_2]_n$ (3) [pdc = 3,4-pyridinedicarboxylate, ida = iminodiacetate] were synthesized and characterized. Complex 1 has helical channels composed of $[Cu_5(pdc)_5]$ units that span along the \ita axis with trapezoidal cross section in \it{bc} plane, and the channels are linked to each other with edge-sharing mode to construct three-dimensional structure. Complex 2 is composed of negatively charged layers made of $[Cu(pdc)_2]^{2-}$ units with $[Mn(H_2O)_6]^{2+}$ complex cations intercalated. Complex 3 forms a zigzag chain by the bridging mode coordination of ida. The magnetic study reveals the existence of weak antiferromagnetic interactions in all three complexes. Two cyano-bridged transition metal complexes were synthesized and characterized: $[Ni(baepn)(CN)]_n(ClO_4)_n$ (1) and $[Ni(baepn)]_{2n}[Fe(CN)_6]_n(H_2O)_{8n}$ (2) $[baepn = N, N‘ -bis(2-amioethyl)-1,3-propanediamine]$. Complex 1 forms linear chains running through the b axis with baepn ligands and perchlorate anions alternately arranged up and down in the c direction. Complex 2 is composed of the neutral layers based on the square grid composed of $[Ni_4Fe_4]$ unit, spanning along the bc plane, with layer separation ca. 3.4Å, as small as that of graphite. Interpretation of the magnetic data reveals that there exist strong antiferromagnetic interactions in 1 with Haldane gap, and weak antiferromagnetic interactions in 2. Five novel mixed valence cyano-bridged copper complexes were synthesized: $[Cu^I(CN)_3][Cu^{II}(baepn)]$ (1), $[Cu^I(CN)_3]_n[Cu^{II}(apn)]_n$ (2), $[Cu^I(CN)_4]_n[Cu^{II}(cyclam)]_{1.5n}(H_2O)_{2.5n}$ (3), $[Cu^I_2(CN)_4]_n[Cu^{II}(cyclam)]_n$ (4), and $[Cu^I(CN)_3]_n[Cu^{II}(cyclam)]_n(CH_3OH)_n$ (5) [baepn = N, N‘-(2-aminoethyl)-1,3-propanediamine, apn = N-(3-aminopropyl)-1,3-propanediamine, and cycl...