Electronic structure and spectra of ruthenium diimine complexes by density functional theory and INDO/S. Comparison of the two methods

Gorelsky, S. I.; Lever, A. B. P.

doi:10.1016/s0022-328x(01)01079-8

Cited by 924 publications

(282 citation statements)

References 54 publications

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“…ZINDO has been successfully applied to simulate the spin states and the electronic spectra of transition metal complexes with an accuracy comparable to that of DFT (time-dependent DFT for spectra) (21)(22)(23). The Heisenberg spin Hamiltonian and the resulting spin states of polynuclear transition metal complexes computed with ZINDO agree well with the experimental data (24).…”

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confidence: 74%

Electron tunneling in respiratory complex I

Hayashi

Stuchebrukhov

2010

Proc. Natl. Acad. Sci. U.S.A.

119

120

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NADH:ubiquinone oxidoreductase (complex I) plays a central role in the respiratory electron transport chain by coupling the transfer of electrons from NADH to ubiquinone to the creation of the proton gradient across the membrane necessary for ATP synthesis. Here the atomistic details of electronic wiring of all Fe/S clusters in complex I are revealed by using the tunneling current theory and computer simulations; both density functional theory and semiempirical electronic structure methods were used to examine antiferromagnetically coupled spin states and corresponding tunneling wave functions. Distinct electron tunneling pathways between neighboring Fe/S clusters are identified; the pathways primarily consist of two cysteine ligands and one additional key residue. Internal water between protein subunits is identified as an essential mediator enhancing the overall electron transfer rate by almost three orders of magnitude to achieve a physiologically significant value. The identified key residues are further characterized by sensitivity of electron transfer rates to their mutations, examined in simulations, and their conservation among complex I homologues. The unusual electronic structure properties of Fe 4 S 4 clusters in complex I explain their remarkable efficiency of electron transfer.electron transfer in proteins | respiratory chain | iron-sulfur clusters N ADH:ubiquinone oxidoreductase (complex I) is a large L-shaped membrane-bound enzyme involved in cellular respiration that catalyzes the oxidation of NADH and the reduction of ubiquinone in mitochondria and respiring bacteria (1-3). This reaction involves the transfer of electrons over approximately 90 Å from NADH bound to the hydrophilic domain to ubiquinone in or near the hydrophobic membrane-bound domain of complex I (4). In turn, the reaction provides the driving force for translocation of four protons across the membrane, thus generating, in part, the proton gradient necessary for ATP synthesis (5). Complex I defects are the cause of several neurodegenerative diseases including Parkinson disease, Alzheimer's disease, and Huntington disease (6).The transfer of electrons from NADH to ubiquinone is facilitated by flavin mononucleotide (FMN), two binuclear (2Fe-2S) iron-sulfur clusters (N1a and N1b), and six tetranuclear (4Fe-4S) iron-sulfur clusters (N3, N4, N5, N6a, N6b, and N2) (Fig. 1A). NADH, a two-electron donor, initially passes both electrons, as hydride, to the FMN cofactor. From FMN one electron enters a transport chain leading to the ubiquinone-binding site; the second electron enters a side path to N1a that appears to serve as a control mechanism to prevent generation of superoxide ions (4).The crystal structure of hydrophilic domain of complex I from Thermus thermophilus was reported in 2006 (4), and recently the whole architecture of the enzyme has been revealed (7); however, until now, the atomistic details of electron transfer along the chain of Fe/S metal clusters have remained unknown. Recently, a hopping (stepwise) electron transfer (...

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confidence: 74%

Electron tunneling in respiratory complex I

Hayashi

Stuchebrukhov

2010

Proc. Natl. Acad. Sci. U.S.A.

119

120

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“…The calculations were performed using the Amsterdam Density Functional suite version 2010.01 (refs 57,58). The overlap populations and orbital compositions were analysed by AOMix 59,60 . Further details are available in the Supplementary Methods.…”

Section: Discussionmentioning

confidence: 99%

Reductive assembly of cyclobutadienyl and diphosphacyclobutadienyl rings at uranium

et al. 2013

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Despite the abundance of f-block-cyclopentadienyl, arene, cycloheptatrienyl and cyclooctatetraenide complexes, cyclobutadienyl derivatives are unknown in spite of their prevalence in the d-block. Here we report that reductive [2 þ 2]-cycloaddition reactions of diphenylacetylene and (2,2-dimethylpropylidyne)phosphine with uranium(V)-inverted sandwich 10p-toluene tetra-anion complexes results in the isolation of inverted sandwich cyclobutadienyl and diphosphacyclobutadienyl dianion uranium(IV) complexes. Computational analysis suggests that the bonding is predominantly electrostatic. Although the c 4 molecular orbital in the cyclobutadienyl and diphosphacyclobutadienyl ligands exhibits the correct symmetry for d-bonding to uranium, the dominant covalent contributions arise from p-bonding involving c 2 and c 3 orbital combinations. This contrasts with uranium complexes of larger arenes and cyclo-octatetraenide, where d-bonding dominates. This suggests that the angular requirements for uranium to bond to a small four-membered ring favours p-bonding, utilizing 5f-instead of 6d-orbitals, over d-bonding that is favoured with larger ligands, where 6d-orbitals can become involved in the bonding.

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“…In this way relativistic effects, especially scalar effects, are included implicitly rather than as four-component, one-electron functions in the Dirac equation. Percentage compositions of molecular orbitals, overlap populations, and bond orders between fragments were calculated by using the AOMix program of Gorelsky (76,77). …”

Section: Methodsmentioning

confidence: 99%