Topological ferrimagnetic behavior of one new chain with the new AF/F/F'/F'/F alternating sequence

An azido-bridged chain with formula [Mn(Menic)(N-3)(2)](n), where Menic is methylnicotinate, was prepared and studied from the magnetic point-of-view. This compound crystallizes in the monoclinic system, space group P21/a, with a = 15.556(2), b = 16.831(2), c = 17.595(2) Angstrom, beta = 110.80(1)degrees and Z = 10. The structure consist of a one-dimensional system in which each manganese atom is bridged by two azido ligands in a trans arrangement. Along the chain there are four double end-on azido bridges followed by one double end-to-end azido bridge. This unusual kind of alternation leads to a new one-dimensional magnetic behavior, which has been studied by means of susceptibility and single crystal ESR measurements. The magnetic response has been reproduced by Monte Carlo simulations and exact laws following the classical approach. The characteristic signature of the magnetic behavior has allowed us to determine the three different magnetic coupling constants present in this system. These results have been analyzed in the framework of a theoretical and experimental magneto-structural correlation.