Two new two-dimensional organically templated phosphite compounds: (C 6H 16N 2) 0.5[ M(HPO 3)F], M=Fe(II) and Co(II): Solvothermal synthesis, crystal structures, thermal, spectroscopic, and magnetic properties

Abstract

The organically templated (C 6H 16N 2) 0.5[ M(HPO 3)F] [ M(II)=Fe ( 1) and Co ( 2)] compounds have been synthesized by using mild hydrothermal conditions under autogeneous pressure. The crystal structures have been determined from X-ray single-crystal diffraction data. The compounds are isostructural and crystallize in the C2/ c monoclinic space group. The unit-cell parameters are a = 5.607 ( 1 ) , b = 21.276 ( 4 ) , c = 11.652 ( 1 ) Å , β = 93.74 ( 1 ) ° for the iron phase and a = 5.5822 ( 7 ) , b = 21.325 ( 3 ) , c = 11.4910 ( 1 ) Å , β = 93.464 ( 9 ) ° for the cobalt compound with Z = 4 . The crystal structure of these compounds consists of [ M(HPO 3)F] − anionic sheets. The layers are constructed from chains which contain [ M 2O 6F 3] dimeric units linked by fluoride ions. The trans-1,4-diaminocyclohexane cations are placed in the interlayer space. The IR and Raman spectra show the bands corresponding to the phosphite oxoanion and organic dication. The Dq and Racah ( B and C) parameters have been calculated from the diffuse reflectance spectra in the visible region. Dq parameter is 790 cm −1 for compound ( 1). For phase ( 2) the Dq value is 725 cm −1 and B and C are 930 and 4100 cm −1, respectively. The thermal evolution of the molar magnetic susceptibilities of these compounds show maxima at 20.0 and 6.0 K for the iron(II) and cobalt(II) phases, respectively. These results indicate the existence of antiferromagnetic interactions in both compounds.