Synthesis, structural characterization, magnetic behavior, and single crystal EPR spectra of three new one-dimensional manganese azido systems with FM, alternating FM-AF, and AF coupling

Reaction of sodium azide with manganese(II) and pyridine derivatives such as 2-bzpy, 3-bzpy, and 3,5lut (2-benzoylpyridine, 3-benzoylpyridine, and 3,5-dimethylpyridine, respectively) led to the one-dimensional systems cis-[Mn(2-bzpy)(N-3)(2)](n) (1), trans-[Mn(3-Bzpy)(2)(N-3)(2)](n) (2), and cis-[Mn(3,5lut)(2)(N-3)(2)](n) (3). Compound 1 crystallizes in the P2(1)/n group: a = 14.413(4) Angstrom, b = 16.157(4) Angstrom, c = 18.478(5) Angstrom, and Z = 12. Compound 2 crystallizes in the C2/c group: a = 14.179(5) Angstrom, b = 9.698(4) Angstrom, c = 34.351(12) Angstrom, and Z = 8. Compound 3 crystallizes in the P21/n group: a 13.552(6) Angstrom, b = 7.730(3) Angstrom, c = 16.554(6) Angstrom, and Z = 4. Structural determination shows a chain with double mu(I,1) azido bridges for 1, an alternating system with double mu(I,1) and mu(I,3) azido bridges for 2, and finally a chain with double mu(I,3) azido bridges for 3. Susceptibility data shaw ferromagnetic coupling for 1, antiferromagnetic coupling for 3, and alternating ferro-antiferromagnetic interactions for 2. EPR data measured on powdered samples and single crystals show the ideal Heisenberg narrowing angular dependence for the three kinds of coupled systems and an increasing dipolar broadening mechanism in the order 3 < 2 < 1 according to the decreasing Mn ... Mn intrachain distances.