Preparation and characterization of tetrachlorocobaltates(II) of alpha,omega-alkylenediammonium. Magnetic and thermal properties. Crystal structure of
Tetrachlorocobaltates(II) of diprotonated alpha,omega-diaminoalkanes with the formula [NH(3)(CH(2))(n)NH(3)]CoCl(4), where n = 5 (cadaverine; 1,5-pentanediammonium tetrachlorocobaltate), 8 (1,8-octanediammonium tetrachlorocobaltate) and 10 (1,10-decanediammonium tetrachlorocobaltate), were prepared. The compounds were studied by mass spectrometry, FT-IR and visible spectroscopy, magnetic susceptibility techniques and thermal analysis. The compounds contain the tetrahedral tetrachlorocobaltate(II) ion and the corresponding diprotonated diamine (cadaverine, 1,8-octamethylenediamine and 1,10-decamethylenediamine). The compound corresponding to cadaverine crystallizes in the monoclinic space group P2(1)/c, with lattice parameters a = 7.1633 (7), b = 15.940 (3), c = 11.137 (2) Å, beta = 98.44 (1) degrees and Z = 4. Its crystal structure contains slightly distorted tetrahedral CoCl(4)(2-) ions: the largest difference in Co-Cl bond lengths is 0.029 Å and the largest difference in Cl-Co-Cl angles is 7.76 degrees. The compound also contains diprotonated cadaverine ions. An extensive hydrogen-bonding network connects these ions. The slightly positive deviations of the magnetic susceptibility from the Curie-Weiss law are in agreement with the (4)A(2) ground state for the tetrachlorocobaltate anion. The compounds with eight and ten C atoms show phase transitions in the solid state and a greater complexity is observed in their differential scanning calorimetry curves. Unfortunately, no suitable single crystals of these could be obtained.
Departamento de Química Inorgánica, Plaza de la Merced s/n, E-37008 Salamanca, Spain.
JJ
Criado
A
Jiménez-Sánchez
FH
Cano
R
Sáez-Puche
E
Rodríguez-Fernández