Density Functional Study of Manganese Complexes: Protonation Effects on Geometry and Magnetism
Protonation processes are ubiquitous in various biochemical reactions such as the water-oxidizing reaction in photosystem II and detoxications of active oxygen species in Mn catalase and Mn superoxide dismutase. In order to investigate them, experiments to probe protons often need supplementary computational results to support the experimental spectra, for which reliable DFT methods are required for description of protonation processes. In this study, we investigated manganese complexes, [Mn(IV)2O2Hn(salpn)2] n+ (n = 0,1,2), of which geometries and magnetism show systematic changes due to protonations to bridged oxygen anions. We examined the performance of B3LYP, B3LYP-D, BP86, BP86-D, and LC-ωPBE on these changes. With all methods, the observed changes during protonation processes can be reproduced, and the quantitatively best procedure is found to be LC-ωPBE/LACVP* for geometry optimization calculations and LC-ωPBE/chem for calculations of magnetic interactions. This conclusion is expected to be a numerical foundation for theoretical investigation of reaction centers in manganese-containing proteins.
KeywordsElectron Spin Resonance Magnetic Interaction Spin Orbital Dispersion Correction Manganese Complex
We acknowledge financial support by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) (Grant-in-Aid for Scientific Research C No. 23550016 and B No. 23350064), and by Research and Development of the Next-Generation Integrated Simulation of Living Matter, as a part of the Development and Use of the Next-Generation Supercomputer Project. A part of the calculations were carried out on computer systems in the Institute for Molecular Science Computer Center.
- 1.Fersht A (1999) Structure and mechanism in protein science. W. H. Freeman and Co, New YorkGoogle Scholar
- 2.Lippard SJ, Berg JM (1994) Principles of bioinorganic chemistry. University Science, Mill ValleyGoogle Scholar
- 3.Solomon EI, Scott RA, King RB (eds) (2009) Computational inorganic and bioinorganic chemistry. Wiley, New YorkGoogle Scholar
- 27.Yamanaka S, Kanda K, Saito T, Kitagawa Y, Kawakami T, Ehara M, Okumura M, Nakamura H, Yamaguchi K (2011) Chem Phys Lett 519–520:134–140Google Scholar
- 28.Yamanaka S, Kanda K, Saito T, Ehara M, Okumura M, Nakamura H, Yamaguchi K (to be published).Google Scholar
- 41.Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Scalmani G, Barone V, Mennucci B, Petersson GA, Nakatsuji H, Caricato M, Li X, Hratchian HP, Izmaylov AF, Bloino J, Zheng G, Sonnenberg JL, Hada M, Ehara M, Toyota K, Fukuda R, Hasegawa J, Ishida M, Nakajima T, Honda Y, Kitao O, Nakai H, Vreven T, Montgomery JA Jr, Peralta JE, Ogliaro F, Bearpark M, Heyd JJ, Brothers E, Kudin KN, Staroverov VN, Kobayashi R, Normand J, Raghavachari K, Rendell A, Burant JC, Iyengar SS, Tomasi J, Cossi M, Rega N, Millam NJ, Klene M, Knox JE, Cross JB, Bakken V, Adamo C, Jaramillo J, Gomperts R, Stratmann RE, Yazyev O, Austin AJ, Cammi R, Pomelli C, Ochterski JW, Martin RL, Morokuma K, Zakrzewski VG, Voth GA, Salvador P, Dannenberg JJ, Dapprich S, Daniels AD, Farkas Ö, Foresman JB, Ortiz JV, Cioslowski J, Fox DJ (2010) Gaussian 09. Revision B.01. Gaussian, Inc., WallingfordGoogle Scholar
- 43.Yoshida K (1966) Theory of magnetism. Springer, BerlinGoogle Scholar