102491-41-8Relevant academic research and scientific papers
High-field EPR study and crystal and molecular structure of trans-RSSR-[CrCl2(cyclam)]nX (X=ZnCl4 2-, Cl- and Cl-·4H 2O·0.5HCl)
Solano-Peralta, Alejandro,Sosa-Torres, Martha E.,Flores-Alamo, Marcos,El-Mkami, Hassane,Smith, Graham M.,Toscano, Ruben A.,Nakamura, Takato
, p. 2444 - 2449 (2004)
For the first time, HF-EPR (94.5 GHz) spectroscopy has been used to determine crystal field parameters in chromium(III) coordination compounds. The large zero-field splitting parameters of the dark-green photochromic trans-RSSR-[CrCl2(cyclam)]2ZnCl4,1, the red-purple trans-RSSR-[CrCl2(cyclamy)Cl, 2 and the red-purple trans-RSSR-[CrCl2-(cyclan)]Cl·4H2O·0.5HCl, 3, where cyclam = 1,4,8,11-tetraazacyclotetradecane, have been obtained. A full analysis of EPR spectra at 94.5 GHz of diluted complexes 1,2 and 3 at 300 K revealed that they are extremely sensitive to D and E values. The rhombic distortion was precisely determined for each compound. For l, g = 2.01, D = -0.305 cm-1, E = 0.041 cm-1 and λ = |E/D| = 0.1396; for 2, g = 2.01; D = -0.348 cm-1, E = 0.042 cm-1 and λ = |E/D| = 0.1206 and for 3, g = 1.99, D = -0.320 cm-1, E = 0.041 cm-t and λ = |E/D| = 0.1281. The EPR study at 94.5 GHz at 10 K allowed us to confirm the sign of the D value for all compounds. These data indicate that at room temperature the crystal field is mainly rhombic and as the temperature decreases, the rhombicity of the D tensor increases slightly. These found differences between 1, 2 and 3 allowed us to establish the importance of the intermolecular interactions in the solid state due to different hydrogen bonding networks in their crystalline arrangement.
