Preparation and characterization of the dichromates of the organic bases: 2,4′-bipyridine, 2,2′-dipyridylamine and 4,4′-bipyridine

Bis(2,6-dimethylpyridinium) dichromate

“…The shorter distances correspond to double bonds and the longer distances to single bonds. They are in good agreement with those found in bipyridinium dichromate (Martín-Zarza et al, 1995), bis(-octyltrimethylammonium) dichromate (Fossé et al, 1998) and tetramethylammonium dichromate (Fossé et al, 2001). The coordination geometry of each Cr atom is distorted tetrahedral.…”

Ethylenediaminium Dichromate

“…The structure consists of discrete dinegative dichromate anions hydrogen bonded to C2HloN22+.Cr2072-dipositive ethylenediaminium cations. The Cr----O bond distances are close to the expected values for the dichromate anion (1.60A) (Martfn-Zarza, Gili, RodrfguezRomero, Ruiz-P6rez & Solans, 1994;Pressprich, Willet, Sheets, Paudler & Gard, 1990) …”

Monodentate coordinated chromate(VI) ion in [Cu(phen)2OCrO3](phen)0.5·4H2O completing the square pyramidal geometry of the copper(II) in the solid state

“…The studied spectrum exhibits the band of medium intensity located at 427 cm -1 , which can be tentatively assigned to the Cu-O vibration. Additionally, the spectrum shows the strong bands located at 262 and 309 cm -1 , which may be ascribed to the m(Cu-N) vibrations [32][33][34][35][36]. (3) Cu-N(4) 2.008 ( (Table 1).…”