Synthetic Models for Low-Molecular-Weight Chromium-Binding Substance: Synthesis and Characterization of Oxo-Bridged Tetranuclear Chromium(III) Assemblies

Ellis, Truitt; Glass, M. A. W.; Harton, Anthony; Folting, K.; Huffman, John C.; Vincent, John B.

doi:10.1021/ic00102a028

Cited by 50 publications

(21 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results obtained by ES-MS and EPR (both at 9.5 and 282 GHz) provided unequivocal evidence of the predominance of a dimeric Cr(V) 2 GSH 2 species (36) in which the two metal ions are bridged by the γ-Glu carboxylate, as confirmed by the structure of several polynuclear chromium complexes (34). Structural details of this cluster are shown in Figure 7; it is apparent that the γ-Glu amino and the γ-Glu amide groups complete the coordination donor set to chromium (36).…”

Section: Resultsmentioning

confidence: 66%

See 1 more Smart Citation

Metabolic pathways of carcinogenic chromium.

Gaggelli

Berti

D’Amelio

et al. 2002

Environ Health Perspect

View full text Add to dashboard Cite

The products of hexavalent chromium [Cr(VI)] reduction by glutathione (GSH) alone or in the presence of equimolar quantities of aspartate (Asp) and/or glutamate (Glu) and a chromium-containing material extracted from bovine liver were studied by ultraviolet-visible spectrum (UV-vis) studies, electrospray mass spectrometry (ES-MS), electron paramagnetic resonance (EPR), and nuclear magnetic resonance (NMR). Reduction of chromate by GSH was followed by UV-vis and NMR, revealing the formation of a paramagnetic complex in which GSH acts as a ligand. ES-MS and EPR measurements provided unequivocal evidence of a dimeric Cr (

show abstract

Section: Resultsmentioning

confidence: 66%

“…LMWCr has been investigated extensively for its chemical and biological features (28,29,34): • The protein is isolated with the best yield from bovine liver, with few separation procedures (10-30 mg of protein from 1 kg of diced liver).…”

mentioning

confidence: 99%

Metabolic pathways of carcinogenic chromium.

Gaggelli

Berti

D’Amelio

et al. 2002

Environ Health Perspect

View full text Add to dashboard Cite

show abstract

“…The complex has a [Fe 4 O 2 ] +8 “butterfly” core (Fig. 2) that has been observed for a number of tetranuclear iron 82, 91–94, manganese 95–103, chromium 104, 105, and vanadium 106 complexes. This topology has two “body” metals bridged by two μ 3 ‐oxide ligands and two “wingtip” metals that each share a μ 3 ‐O ligand with the body metals.…”

Section: Test Casesmentioning

confidence: 69%

Semiempirical local spin: Theory and implementation of the ZILSH method for predicting Heisenberg exchange constants of polynuclear transition metal complexes

O'Brien

Davidson

2003

Int J of Quantum Chemistry

101

View full text Add to dashboard Cite

ABSTRACT:The local spin formalism (Clark, A. E.; Davidson, E. R. J Chem Phys 2001, 115, 7382-7392) for computing expectation values ͗S A ⅐ S B ͘ that appear in the Heisenberg spin model has been extended to semiempirical single determinant wave functions. An alternative derivation of expectation values in restricted and unrestricted cases is given that takes advantage of the zero differential overlap (ZDO) approximation. A formal connection between single determinant wave functions (which are not in general spin eigenfunctions) and the Heisenberg spin model was established by demonstrating that energies of single determinants that are eigenfunctions of the local spin operators with eigenvalues corresponding to high-spin radical centers are given by the same Heisenberg coupling constants { J AB } that describe the true spin states of the system. Unrestricted single determinant wave functions for transition metal complexes are good approximations of local spin eigenfunctions when the metal d orbitals are local in character and all unpaired electrons on each metal have the same spin (although spins on different metals might be reversed). Good approximations of the coupling constants can then be extracted from local spin expectation values ͗S A ⅐ S B ͘ energies of the single determinant wave functions. Once the coupling constants are obtained, diagonalization of the Heisenberg spin Hamiltonian provides predictions of the energies and compositions of the spin states. A computational method is presented for obtaining coupling constants and spin-state energies in this way for polynuclear ϩ , a priori predictions of the coupling constants yield a ground-state spin of zero, in agreement with variable-temperature magnetization data, and corroborate spin alignments proposed earlier on the basis of structural considerations. This demonstrates the potential of the ZILSH method to aid in understanding magnetic interactions in polynuclear transition metal complexes.

show abstract

“…Historically, the first of these were the ubiquitous oxo-centred triangles of general formula [Cr 3 O(O 2 CR) 6 (H 2 O) 3 ]X (X = anion, R = alkyl or aryl), [9][10][11][12][13][14] all of which display antiferromagnetic exchange interactions between the metal ions. [9][10][11][12][13][14][15] The stability of this structural unit saw it widely employed thereafter as a starting material for the synthesis of a range of novel complexes, such as [Cr 4 O 4 ] 8+ butterflies, 16 an unusual tetrahedral [Cr 4 S] 10+ cage which displays ferromagnetic interactions resulting in the stabilisation of an S = 6 ground state, 17 and an extensive family of Cr 6 , Cr 8 and Cr 10 wheels. [18][19][20][21][22][23][24] These rings are bridged by a combination of carboxylate ligands and F − or OH − ions, leading, in the main, to complexes with S = 0 ground states; the exception being the complex [Cr 10 (OMe) 20 (O 2 CMe) 10 ] which shows weak ferromagnetic exchange and an S = 15 ground state.…”

Section: Introductionmentioning

confidence: 99%

Magneto-structural correlations in a family of di-alkoxo bridged chromium dimers

et al. 2017

View full text Add to dashboard Cite

A series of di-alkoxo bridged Cr(iii) dimers have been synthesised using pyridine alcohol ligands. The structures fall into four general categories and are of formula: [Cr(OMe)(pic)]·½MeOH·½EtO (1), [Cr(hmp)(pic)X] (where X = Cl (2), Br (3)), [Cr(L)Cl(A)]·2S (where L = hmp, A = HO and S = EtO (4); L = hmp, A = pyridine and S = pyridine (5); L = hmp, A = 4-picoline and no S (6); L = hep, A = HO and S = MeCN (7)), and [Cr(hmp)(hmpH)Cl]·MeCN (8). Direct current (DC) magnetic susceptibility measurements show relatively weak antiferromagnetic exchange interactions between the Cr(iii) centres with J values <|15| cm in all of the complexes measured. DFT calculations performed on complexes 1-8 reproduce both the sign and strength of the exchange interactions found experimentally, and confirm that the magnitude and sign of the J value is strongly dependent upon the orientation of the dihedral angle formed between the bridging CrO plane and the O-R vector of the bridging group (θ), and the Cr-O-Cr-O dihedral angle (ψ).

show abstract

Synthetic Models for Low-Molecular-Weight Chromium-Binding Substance: Synthesis and Characterization of Oxo-Bridged Tetranuclear Chromium(III) Assemblies

Cited by 50 publications

References 0 publications

Metabolic pathways of carcinogenic chromium.

Metabolic pathways of carcinogenic chromium.

Semiempirical local spin: Theory and implementation of the ZILSH method for predicting Heisenberg exchange constants of polynuclear transition metal complexes

Magneto-structural correlations in a family of di-alkoxo bridged chromium dimers

Contact Info

Product

Resources

About