Crystal structure of bis[trans-dichloridobis(propane-1,3-diamine-κ² N,N′)chromium(III)] dichromate from synchrotron data

Abstract

In the title organic–inorganic salt, [CrCl2(tn)2]2[Cr2O7] (tn is propane-1,3-di­amine), the CrIII ions are coordinated by four N atoms from two tn ligands and two chloride ions in a trans geometry, displaying a distorted octa­hedral arrangement. The crystal packing is stabilized by N—H⋯Cl and N—H⋯O hydrogen bonds.

Crystal structure of bis[cis-(1,4,8,11-tetraazacyclotetradecane-κ4N)bis(thiocyanato-κN)chromium(III)] dichromate monohydrate from synchrotron X-ray diffraction data

“…The bridging Cr2B-O1B bond has a length of 1.746 (9) Å . These values are comparable to those reported for the anions in the structures of [Cr(urea) 6 ]-(Cr 2 O 7 )BrÁH 2 O (Moon et al, 2015b) or [CrCl 2 (tn) 2 ] 2 (Cr 2 O 7 ) (tn = propane-1,3-diamine; Moon & Choi, 2016). A further distortion of the anion is due to its involvement in hydrogenbonding interactions with water molecule and complex cation (see Supramolecular features).…”

“…anion in (I) has a staggered conformation while a nearly eclipsed conformation is observed in ionic compounds K 2 Cr 2 O 7 , Rb 2 Cr 2 O 7 and (C 3 H 5 N 2 )(NH 4 )[Cr 2 O 7 ] (Brandon & Brown, 1968;Lö fgren, 1971;Zhu, 2012). The conformation of the dichromate anion is influenced by the charge and size of the counter-cation (Moon et al, 2015b;Moon & Choi, 2016). The O-Cr2B-O bond angles range from 102.3 (3) to 119.5 (2) ; the terminal Cr2B-O bond lengths vary from 1.596 (2) to 1.612 (2) Å , with a mean terminal Cr2B-O bond length of 1.604 (12) Å .…”