Synthesis and characterization of symmetric and unsymmetric oxo-bridged trinuclear chromium benzoate complexes: Crystal and molecular structure of [Cr3O(O2CPh)6(py)3]ClO4

Aminopyridine complexes of Cr(III) basic carboxylates as potential polymer precursors: Synthesis, characterization, and crystal structure of [Cr3O(propionate)6(X-aminopyridine)3]+ (X = 3 or 4)

“…The structural parameters in the [Cr 3 O(O 2 CR) 6 ] + cores of 1 and 2 ( Table 2) are similar to those other members of the chromium basic carboxylate family [4,13,, while the Cr-N distances are similar to other members of the family with terminal pyridine ligands [4,13,34]. The number of different trinuclear cations characterized by X-ray crystallography is actually not nearly as large as the number of papers may suggest as the Despite the number of crystal structures reported for Cr basic carboxylate assemblies, the presence of an imposed threefold symmetry axis as found for [Cr 3 O(O 2 CEt) 6 (3-NH 2 -py) 3 ]Cl (2)ÁH 2 O is rare [4].…”

“…The terminal water ligands of basic carboxylate assemblies can often readily be replaced with nitrogen-containing heterocyclic ligands such as pyridines or imidazoles [12,13]. The central [Cr 3 O(O 2 CR) 6 ] + triangle of basic carboxylate type assemblies provides an excellent platform on which to add monodentate ligands.…”

Structural and magnetic studies on mono- and polynuclear chromium ascorbate complexes

“…Recently, FAB and EI mass spectrometry have found essential applications in structure elucidation of various mono-and polynuclear chromium complexes [23,28,[53][54][55]. Although the present data cannot unambigously delineate the proposed bridged structures of the binuclear and trinuclear complexes; in the absence of any 3D crystal structure, the magnetic measurements and the following FAB/EI mass spectral data supply substantial corroboration.…”

Mass Spectrometric and Spectroscopic Studies of the Nutritional Supplement Chromium(III) Nicotinate

“…As the solid chromium nicotinate does not dissolve in NBA, obtaining a spectrum should be most unlikely. In the current investigation, no FAB signals arising from the compound could be detected in either positive mode using NBA or NBA with 2% ethanol, although this laboratory has substantial experience collecting FAB spectra of chromium carboxylate complexes [30][31][32]. Explaining the presence of the feature at m/z of 52 is most difficult; contemplating a potential mechanism for the formation of naked Cr 1+ ions in the experiment is difficult.…”

“…Given Cr(III)'s strong preference for six coordinations, this suggests that water may have been lost from a precursor or that the unit is a fragment of a multinuclear species. The loss of water is common in the ESI and FAB MS of chromium(III) aqua complexes [30,33]; also, the replacement of some of the water molecules in the species by methanol solvent molecules is consistent with loss of water and subsequent replacement by the methanol ligands. Thus, most of these species probably arise from loss of water in the MS experiment.…”