(cis-syn-cis-Dicyclohexano-18-crown-6)potassium chlorochromate

Abstract

The title compound, (cis‐syn‐cis‐icosa­hydro­dibenzo­[b,k][1,4,7,10,13,16]­hexaoxa­cyclo­octadecin)­potassium chloro­chromate, [K(C20H36O6)][CrClO3], is the complex of a potassium cation with one crown ether mol­ecule and a chloro­chromate anion. The cation is situated in the macrocyclic cavity and bonded to the ether O atoms with K—O distances in the range 2.749 (4)–2.991 (3) Å. It also forms two bonds with O atoms of the anion [2.789 (5) and 3.315 (7) Å].

Synthesis, characterization, X-ray structural analysis and study of oxidative properties of a chlorochromate(VI) complex with benzyltriphenylphosphonium cation

“…The Cr(VI) atom is in a tetrahedral environment, with Cr-O distances in the 1.58-1.64 Å range and the Cr-Cl distance of 2.1836(13) Å in the anion not affected by disorder (the Cr-Cl distance is found to be shorter in the other anion, 2.04-2.07 Å , probably as an effect of disorder). The above values of distances in the first anion agree with those recently reported for this species: Cr-O distances in the 1.582-1.596 Å range and Cr-Cl of 2.196 Å [16]. If the geometry of the anion not affected by disorder is considered, the angles formed to the metal by pairs of oxygen atoms are found to be slightly larger, in the mean, than are the angles formed by the chlorine atom and each of the oxygens in turn ( Table 1).…”

“…The same trend is found for the anion of ref. [16]. This is likely to be caused by stronger repulsions between the oxygens, as well as between the electron density involved in the three Cr-O bonds, than between such oxygens and the chlorine atom (and/or between the electron density in the corresponding bonds to the metal), since the Cr-Cl bond is definitely longer than the Cr-O ones.…”

([1.5]Dibenzo-18-crown-6)potassium chlorochromate

“…1) lies near atom O8, and consequently atom O8 0 lies near atom Cl1. In contrast with previously reported structures of CE complexes with potassium chlorochromate Kotlyar, Zubatyuk, Zhygalko et al, 2004;Kotlyar, Zubatyuk et al, 2005), the Cl atom of the anion also participates in the formation of complex (IV).…”

(4-Bromobenzo-18-crown-6)potassium chlorochromate

“…Complexes of aliphatic, mono-and dicycloaliphatic CEs (CE = crown ether) are easily crystallized from acid aqueous solutions and we have determined several crystal structures of these compounds (Kotlyar et al, 2004a,b;Kotlyar, Zubatyuk, Zhigalko et al, 2004;Kotlyar et al, 2005a). Pure crystalline complexes of benzo-and dibenzo-CE with halogenochromates were obtained for the first time by mixing ethyl acetate solutions of the inorganic salt and ligand at room or increased temperature (Kotlyar et al, 2000).…”

“…No restraints were applied to the K-O distances involving the anion, and hence the disorder of O7A/O7B has led to differences between the bond lengths K1-O7A and K1-O7A (Table 1). The bond lengths for typical K-O distances in related compounds are 2.55-3.32 Å (Kotlyar et al, 2004(Kotlyar et al, , 2004b(Kotlyar et al, , 2005a).…”