메뉴 건너뛰기




Volumn 129, Issue 43, 2007, Pages 12989-13000

Polarized X-ray absorption spectroscopy of single-crystal Mn(V) complexes relevant to the oxygen-evolving complex of photosystem II

Author keywords

[No Author keywords available]

Indexed keywords

ABSORPTION SPECTROSCOPY; DENSITY FUNCTIONAL THEORY; ELECTRONIC STRUCTURE; OXIDATION; SINGLE CRYSTALS; X RAY ABSORPTION NEAR EDGE STRUCTURE SPECTROSCOPY; X RAY DIFFRACTION;

EID: 35848940726     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja071286b     Document Type: Article
Times cited : (47)

References (71)
  • 50
    • 31044450583 scopus 로고    scopus 로고
    • Stanford Synchrotron Radiation Laboratory, Stanford Linear Accelerator Center, Stanford University: Stanford, CA 94309
    • George, G. N. EXAFSPAK and EDG_FIT; Stanford Synchrotron Radiation Laboratory, Stanford Linear Accelerator Center, Stanford University: Stanford, CA 94309, 2000.
    • (2000) EXAFSPAK and EDG_FIT
    • George, G.N.1
  • 53
    • 35848931571 scopus 로고    scopus 로고
    • Neese, F. ORCA-an ab initio, DFT, and Semiempirical Electronic Structure Package, version 2.6; University of Bonn: Bonn, Germany, 2003
    • Neese, F. ORCA-an ab initio, DFT, and Semiempirical Electronic Structure Package, version 2.6; University of Bonn: Bonn, Germany, 2003.
  • 54
    • 35848945169 scopus 로고    scopus 로고
    • Geometry-optimized calculations were also performed; however, it was found that the axial Mn-CN bond trans to the nitrido was ∼0.1 Å longer than in the experimental structure. This is consistent with previously reported calculations (refs 55 and 56).
    • Geometry-optimized calculations were also performed; however, it was found that the axial Mn-CN bond trans to the nitrido was ∼0.1 Å longer than in the experimental structure. This is consistent with previously reported calculations (refs 55 and 56).
  • 56
    • 0001593171 scopus 로고    scopus 로고
    • Bendix, J.; Meyer, K.; Weyhermuller, T.; Bill, E.; Metzler-Nolte, N.; Wieghardt, K. inorg. Chem. 1998, 37, 1767-1775.
    • Bendix, J.; Meyer, K.; Weyhermuller, T.; Bill, E.; Metzler-Nolte, N.; Wieghardt, K. inorg. Chem. 1998, 37, 1767-1775.
  • 62
    • 35848946047 scopus 로고    scopus 로고
    • Additional effect arises from the imperfect polarization ∼95, of the beam
    • Additional effect arises from the imperfect polarization (∼95%) of the beam.
  • 63
    • 35848961343 scopus 로고    scopus 로고
    • The experimental energy resolution is <0.2 eV.
    • The experimental energy resolution is <0.2 eV.
  • 64
    • 35848937241 scopus 로고    scopus 로고
    • Due to shortcomings of the DFT potentials in the core regions, a constant shift of 168.2 eV has been applied to all calculated spectra.
    • Due to shortcomings of the DFT potentials in the core regions, a constant shift of 168.2 eV has been applied to all calculated spectra.
  • 65
    • 35848941597 scopus 로고    scopus 로고
    • It should be noted that the 0.6% total intensity in the d xz and dyz orbitals does not yield significant transition intensity as the calculated oscillator strength for these transitions is an order of magnitude smaller
    • yz orbitals does not yield significant transition intensity as the calculated oscillator strength for these transitions is an order of magnitude smaller.
  • 66
    • 35848969649 scopus 로고    scopus 로고
    • An experimental estimate for the ratio of dipole to quadrupole transitions is based on polarized studies of D2d- and D4h-[CuCl4]2, The pre-edge intensity of centrosymmetric D4h-[CuCl 4]2- represents a pure quadrupole-based transition, while the increased intensity in D2d-[CuCl4] 2- represents an additional contribution due to an electric-dipole-allowed transition ref 42
    • 2- represents an additional contribution due to an electric-dipole-allowed transition (ref 42).
  • 67
    • 35848955084 scopus 로고    scopus 로고
    • It should be noted that a Mn(V)=O species has been proposed by Limburg et al. as an intermediate for their water-oxidizing binuclear Mn complex (refs 68 and 69, Nam and co-workers have also suggested that their Mn(V)-oxo porphyrin complexes have double bond character (ref 31, The present study shows that the calculated bond orders (based on Löwdin analysis) for five-coordinate Mn(V)-oxo species are close to the idealized value of 3.0, while for six-coordinate complexes, the bond order is reduced to ∼2.5. This indicates that the Mn(V)-oxo bond is weakened due to the presence of a trans-axial ligand (consistent with previous vibrational data refs 21 and 31, however, it is still a stronger bonding interaction than a double bond
    • It should be noted that a Mn(V)=O species has been proposed by Limburg et al. as an intermediate for their water-oxidizing binuclear Mn complex (refs 68 and 69). Nam and co-workers have also suggested that their Mn(V)-oxo porphyrin complexes have double bond character (ref 31). The present study shows that the calculated bond orders (based on Löwdin analysis) for five-coordinate Mn(V)-oxo species are close to the idealized value of 3.0, while for six-coordinate complexes, the bond order is reduced to ∼2.5. This indicates that the Mn(V)-oxo bond is weakened due to the presence of a trans-axial ligand (consistent with previous vibrational data (refs 21 and 31); however, it is still a stronger bonding interaction than a double bond.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.