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 a s 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 crys tallizes 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 wi th 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 fo r 1, antiferromagnetic coupling for 3, and alternating ferro-antiferromagne tic interactions for 2. EPR data measured on powdered samples and single cr ystals 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 dista nces.