کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1235110 | 968842 | 2007 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Synthesis and spectroscopic studies on chromium(III) complex containing mixed-valence chrysenesemiquinone-chrysenecatecholate ligands and 2,2′-bipyridine coligand Synthesis and spectroscopic studies on chromium(III) complex containing mixed-valence chrysenesemiquinone-chrysenecatecholate ligands and 2,2′-bipyridine coligand](/preview/png/1235110.png)
The synthesis and spectroscopic properties of Cr(bpy)(chrySQ)(chryCat), a complex containing chromium(III) metal ion and chrysenequinone ligand in its partially reduced (chrySQ) and fully reduced (chryCat) forms, are described. The complex has been prepared by two different routes from Cr(CO)6 and Cr(chrySQ)3. Variable temperature magnetic susceptibility measurements indicated a strong antiferromagnetic coupling between Cr(III) (S = 3/2) and chrysenesemiquinone radical (S = 1/2), giving a magnetic coupling constant J = −342 cm−1. Ligand-based redox couples were observed in the electrochemical studies that consist of quasi-reversible chrySQ/chryCat and bpy/bpy− reductions and chryCat/chrySQ oxidation at negative potentials and irreversible chrySQ/chryBQ oxidation at positive potential. However, the metal was inert in the studied potential range. The electronic spectra of the complex revealed interesting properties. In addition to interaligand π–π* and n–π* transitions, other bands corresponding to Cr(t2g) → chrySQ(π*) and Cr(t2g) → bpy(π*) metal-to-ligand charge-transfer MLCT transitions were observed. The infrared spectral analysis was informative in assigning the vibrations due to SQ and Cat ligands. Also, it was a useful tool in confirming the coordination of bpy ligand to chromium metal ion.
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 67, Issue 5, August 2007, Pages 1339–1345