Structures and Magnetic Properties of Novel 1-D Coordination Polymers Containing Both Dicyanamide and Pyridine-Type Ligands

Three novel 1-D coordination polymers consisting of {Mn[N(CN)2]2} structural units and L=2 pyridines (i.e., 2), 2,2ʹbipyridine (i.e., 3), and 4,4ʹ-bipyridine (i.e., 4) have been synthesized and characterized by single crystal X-ray crystallography and magnetic susceptibility studies. Compound 2 crystallizes in the monoclinic space group P21/n with a= Z7.5401 (7) ?, b=13.2643 (4) ?, c=8.6973 (9) ?, =114.954 (2)°, V= 788.65 (11) ?3, and Z=2 with R(Rw)=0.0451 (0.1067). In 2, linear 1-D chains containing trans--[N(CN)2]- ligands and two pyridine ligands are formed while cis--[N (CN)2]- coordination gives rise to zigzag chains with chelated 2,2ʹ-bipyridine ligands in 3 which crystallizes in the monoclinic space group C2/c with a=6.6769 (3) ?, b=17.2008 (2) ?, c=13.0142 (4) ?, b=90.110 (4)°, V=1494.65 (8) ?3, and Z=4 with R(Rw)=0.0514 (0.1218). Interestingly, incorporation of 4,4ʹ-bipyridine into the structure of 4 produces a unique cylindrical 1-D chain consisting of four trans--[N(CN)2]-ʹs, one coordinated water, and an unusual monodentate 4,4ʹbipyridine ligand. X-ray crystallography established the orthorhombic space group Iba2 with a=22.378 (6) ?, b=22.517 (5) ?, c=13.519 (5) ?, V=6812 (3) ?3, and Z=8 with R(Rw)=0.0384 (0.0861). The magnetic susceptibilities of eac h compound were studied in the 2–300 K temperature range and the data fitted to the 1-D Fisher chain model for S=5/2 with g-values of 2.00 and intrachain exchange constants, J/kB=-0.10, -0.17, and -0.24 K for 2, 3, and 4, respectively.