Magnetism, Spectroscopy and Structure of Tri-mu-hydroxobis{[N,N',N''-trimethyl-1,1,1-tris(aminomethyl)ethane]chromium(III)} Chloride Tetrahydrate.

Synthesis and Characterisation of Luminescent [CrIII2L(μ‐carboxylato)]3+ Complexes with High‐Spin S=3 Ground States (L=N6S2 donor ligand)

“…It should be mentioned that the mechanisms and parameters that govern the exchange interactions in chromium(III) dimers bridged by oxido, hydroxido, or alkoxido ligands are qualitatively quite well understood. [71] For doubly and triply bridged dimers of the type [Cr III ( μ ‐OR) 2 Cr III ] [25] and [Cr III ( μ ‐OR) 2 (μ‐O 2 CR)Cr III ] (R=H or alkyl), [37] respectively, the magnitude and sign of the magnetic interaction has been shown to correlate with several structural parameters, as for instance the Cr−O−Cr bridging angle, the Cr−O bond length, and the dihedral angle spanned between the bridging Cr 2 O 2 plane and the OR vector. Magnetic susceptibility measurements and accompanying DFT calculations shows that the bridging Cr−O−Cr angle has the largest effect on the coupling type.…”

“… [20] The intensity enhancement of transitions involving ligand‐field states (LF) has also been a well‐known effect of binuclear interactions in chromium(III) dimers. The vast majority of exchange‐coupled chromium(III) complexes employ bridging oxido,[ 21 , 22 , 23 ] hydroxido,[ 24 , 25 ] alkoxido, [26] halido, [27] and carboxylato [28] ligands. Recently, a number of semiquinoid radical bridging ligands have been used to obtain large magnetic exchange interactions between Cr III centers.…”

Theoretical Models of Exchange Interactions in Dimeric Transition-Metal Complexes

“…3-52-54 and tris-µ-hydroxo Cr(III) complexes with Wieghardt-type ligands. [55][56][57][58][59][60] The derivations of the Landé interval rule can be expressed by adding higher order terms to the phenomenological Hamiltonian…”

Chromium(III) Complexation to Natural Organic Matter: Mechanisms and Modeling

“…12 For the modeling only samples that had been equilibrated for 90 d were considered, as 204 almost all of these were at equilibrium (see Results section). Modeling was done in two steps: Table S3), the two considered …”

“…[2][3][4][5][6][7][8] as well as triple hydroxo bridges (d(Cr⋅⋅⋅⋅Cr)=2.67 Å). [9][10][11][12][13][14] There are also examples where dimeric complexes with a single and additionally two carboxylate groups bridging the chromium(III) ions, [15][16][17][18] or double hydro bridge with an additional carboxylate group bridging the chromium(III) ions. [19][20] This causes a slight shortening to 3.50 and 2.90 Å, respectively.…”