View : 9 Download: 0

Crystal structures and solution properties of discrete complexes composed of saddle-distorted molybdenum(V)-dodecaphenylporphyrins and Keggin-type heteropolyoxometalates linked by direct coordination

Title
Crystal structures and solution properties of discrete complexes composed of saddle-distorted molybdenum(V)-dodecaphenylporphyrins and Keggin-type heteropolyoxometalates linked by direct coordination
Authors
Yokoyama A.Kojima T.Ohkubo K.Fukuzumi S.
Ewha Authors
Shunichi Fukuzumi
SCOPUS Author ID
Shunichi Fukuzumiscopus
Issue Date
2010
Journal Title
Inorganic Chemistry
ISSN
0020-1669JCR Link
Citation
vol. 49, no. 23, pp. 11190 - 11198
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
Reactions of a saddle-distorted Mo(V)-porphyrin complex, [Mo(DPP)(O)(H 2O)]ClO4 (1·ClO4; DPP2- = dodecaphenylporphyrin dianion), with tetra-n-butylammonium (TBA) salts of Keggin-type heteropolyoxomatalates (POMs), α-[XW12O 40]n- (X = P, n = 3, 2; X = Si, n = 4, 3; X = B, n = 5; 4), in ethyl acetate/acetonitrile gave 2:1 complexes formulated as [{Mo(DPP)(O)}2(HPW12O40)] (5), [{Mo(DPP)(O)}2(H2SiW12O40)] (6), and [(n-butyl)4N]2[{Mo(DPP)(O)}2(HBW 12O40)] (7) under mild reaction conditions. The crystal structures of the complexes were determined by X-ray crystallography. In these three complexes, named Porphyrin Hamburgers, the POM binds to two Mo(V) centers of porphyrin units directly via coordination of two terminal oxo groups. In spite of the similarity of those POM's structures, those Porphyrin Hamburgers exhibit different coordination bond angles between POM and the Mo(V) center in the porphyrin: 5 and 7 show two different coordination bond angles in one molecule in contrast to 6, which exhibits only one coordination bond angle. The Porphyrin Hamburgers involve protonation of the POM moieties to adjust the charge balance, as confirmed by spectroscopic titration with bases. In the crystals, the Porphyrin Hamburgers form two-dimensional (2D) sheets in the ac plane based on π-π interactions among peripheral phenyl substituents. Stacking of the 2D sheets toward the b axis constructs a 3D layered structure involving channels running into the crystallographic [1 0 0] and [0 0 1] directions in the crystal to include solvent molecules of crystallization for 5-7, and also counter cations for 7. Three complexes were revealed to be stable enough to maintain their structures even in solutions to show molecular ion peaks in the MALDI-TOF-MS measurements. They also exhibited different electron paramagnetic resonance (EPR) signals because of the Mo(V) (S = 1/2, I = 0) centers, reflecting the difference in the crystal structures. In addition, these complexes showed reversible multistep redox processes as observed in their cyclic voltammograms in benzonitrile to demonstrate high stability throughout the redox reactions in solution. © 2010 American Chemical Society.
DOI
10.1021/ic1019586
Appears in Collections:
자연과학대학 > 화학·나노과학전공 > Journal papers
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE