Solid-state (55)Mn NMR spectroscopy of bis(μ-oxo)dimanganese(IV) [Mn(2)O(2)(salpn)(2)], a model for the oxygen evolving complex in photosystem II.
We have examined the antiferromagneticly coupled bis(μ-oxo)dimanganese(IV) complex [Mn(2)O(2)(salpn)(2)] (1) with (55)Mn solid-state NMR at cryogenic temperatures and first-principle theory. The extracted values of the (55)Mn quadrupole coupling constant, C(Q), and its asymmetry parameter, η(Q), for 1 are 24.7 MHz and 0.43, respectively. Further, there was a large anisotropic contribution to the shielding of each Mn(4+), i.e. a Δσ of 3375 ppm. Utilizing broken symmetry density functional theory, the predicted values of the electric field gradient (EFG) or equivalently the C(Q) and η(Q) at ZORA, PBE QZ4P all electron level of theory are 23.4 MHz and 0.68, respectively, in good agreement with experimental observations.
Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battlelle Boulevard, Richland, Washington 99352, United States, USA.
Paul D
PD
Ellis
Jesse A
JA
Sears
Ping
P
Yang
Michel
M
Dupuis
Thaddeus T
TT
Boron
Vincent L
VL
Pecoraro
Troy A
TA
Stich
R David
RD
Britt
Andrew S
AS
Lipton
D040761:Biomimetic Materials / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D017895:Manganese Compounds / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D013696:Temperature
D017895:Manganese Compounds; D009942:Organometallic Compounds; D010087:Oxides; D045332:Photosystem II Protein Complex; C027424:manganese oxide; D010100:Oxygen