Single crystals of DPPH grown from diethyl ether and carbon disulfide solutions - crystal structures, IR, EPR and magnetization studies.
Single crystals of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) obtained from diethyl ether (ether) and carbon disulfide (CS₂) were characterized by the X-ray diffraction, IR, EPR and SQUID magnetization techniques. The X-ray structural analysis and IR spectra showed that the DPPH form crystallized from ether (DPPH1) is solvent free, whereas that one obtained from CS₂ (DPPH2) is a solvate of the composition 4DPPH·CS₂. Principal values of the g-tensor were estimated by the X-band EPR spectroscopy at room and low (10 K) temperatures. Magnetization studies revealed the presence of antiferromagnetically coupled dimers in both types of crystals. However, the way of dimerization as well as the strength of exchange couplings are different in the two DPPH samples, which is in accord with their crystal structures. The obtained results improved parameters accuracy and enabled better understanding of properties of DPPH as a standard sample in the EPR spectrometry.
Zilić
Dijana
D
Ruder Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia. dzilic@irb.hr
Pajić
Damir
D
Jurić
Marijana
M
Molčanov
Krešimir
K
Rakvin
Boris
B
Planinić
Pavica
P
Zadro
Krešo
K
D000465:Algorithms; D001713:Biphenyl Compounds / Q000737:chemistry*; D002246:Carbon Disulfide / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D004574:Electromagnetic Fields; D004578:Electron Spin Resonance Spectroscopy; D004986:Ether / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D010851:Picrates / Q000737:chemistry*; D012996:Solutions; D013055:Spectrophotometry, Infrared
D001713:Biphenyl Compounds; D010851:Picrates; D012996:Solutions; D004986:Ether; C004931:1,1-diphenyl-2-picrylhydrazyl; D002246:Carbon Disulfide