메뉴 건너뛰기




Volumn 104, Issue 44, 2000, Pages 9990-10000

Carbon-13 solid-state NMR studies on synthetic model compounds of [4Fe-4S] clusters in the 2+ state

Author keywords

[No Author keywords available]

Indexed keywords

ANTIFERROMAGNETIC MATERIALS; CARBON; CRYSTAL STRUCTURE; FLUORINE COMPOUNDS; MAGNETIC RELAXATION; MAGNETIC SUSCEPTIBILITY; PARAMAGNETISM; PROTEINS; RADIOISOTOPES; SULFUR COMPOUNDS; THERMAL EFFECTS;

EID: 0034323364     PISSN: 10895639     EISSN: None     Source Type: Journal    
DOI: 10.1021/jp002005o     Document Type: Article
Times cited : (27)

References (70)
  • 46
    • 85037292097 scopus 로고    scopus 로고
    • note
    • In II and III, we have tried to determine with X-rays toward the low temperatures whether these rotations of the t-Bu groups and the movements of the methyl carbons of the counterions become blocked. In effect, at 90 K, the two compounds present a new phase and a different structure of lower symmetry than that observed at 300 K. This structure is fairly complicated (probably triclinic but with α, β, and γ angles very close to 90°), and it probably contains a large number of inequivalent molecules. We have been unable to solve it without ambiguity. The change from this low-symmetry phase to the phase described at room temperature occurs at ∼120-130 K for II and ∼150-160 K for III. Therefore, these X-ray observations confirm that the movements-in the solid state and especially the rotations of the t-Bu groups of the thiolate ligands are operative in the whole range of temperatures where we perform these solid-state NMR experiments.
  • 53
    • 85037290862 scopus 로고    scopus 로고
    • note
    • 1+/3+ systems.
  • 59
    • 0003420490 scopus 로고    scopus 로고
    • Belinsky, M. I. JBIC 1996, 1, 186-188.
    • (1996) JBIC , vol.1 , pp. 186-188
    • Belinsky, M.I.1
  • 62
    • 85037316172 scopus 로고    scopus 로고
    • note
    • 13C lines will be published in a separate note.
  • 63
    • 0029181728 scopus 로고
    • 13C chemical shift measured for the β-caibon of reduced cysteine is between 27 and 28 ppm, depending on the nearestneighbor amino acid (Wishart et al. J. Biomol. NMR, 1995, 5, 67-81), whereas we measured it to be 32 ppm in the solid state. In the case of the t-Bu thiolate sodium salt, we measured 49 and 36 ppm for the quaternary and methyl carbon nuclei, respectively.
    • (1995) J. Biomol. NMR , vol.5 , pp. 67-81
    • Wishart1
  • 66
    • 85037306471 scopus 로고    scopus 로고
    • note
    • 2 carbon p orbital pointing toward the thiolate sulfur bears some spin density leading to a non-negligible anisotropy contribution, we took this term explicitly into account, evaluating its relative weight from density functional calculations, in a manner described elsewhere. This is in contrast to the proton case, whose s Orbitals do not allow for some local source of dipolar anisotropy. Results to be published.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.