Reduction of dioxygen by a dimanganese unit bonded inside a cavity provided by a pyrrole-based dinucleating ligand.

Details

Serval ID
serval:BIB_14393
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Reduction of dioxygen by a dimanganese unit bonded inside a cavity provided by a pyrrole-based dinucleating ligand.
Journal
Chemistry (weinheim An Der Bergstrasse, Germany)
Author(s)
Franceschi F., Guillemot G., Solari E., Floriani C., Re N., Birkedal H., Pattison P.
ISSN
0947-6539 (Print)
ISSN-L
0947-6539
Publication state
Published
Issued date
2001
Volume
7
Number
7
Pages
1468-1478
Language
english
Notes
Publication types: Journal Article
Publication Status: ppublish
Abstract
A novel class of dinucleating ligands has been introduced into manganese chemistry to study the reactivity of this metal towards dioxygen under strictly controlled conditions. Such N4 ligands combine some of the major peculiarities of tetradentate Schiff bases and the porphyrin skeleton. They are derived from the condensation between 2-pyrrolaldehyde and ethylenediamine or o-phenylenediamine, leading to pyrenH2 (LH2, 1), pyrophenH2 (L'H2, 2) and Me2pyrophenH2, (L"H2, 3), respectively. Their metallation with [Mn3-(Mes)6] (Mes = 2,4,6-trimethylphenyl) led to [Mn2L2] (4), [MnL'(thf)2] (5) and [MnL"(thf)2] (6). Complex 4 displays a double-stranded helical structure, while 5 and 6 are mononuclear complexes containing hexacoordinated metals. Regardless of their structure, complexes 5 and 6 behave in a similar manner to 4 in their reaction with dioxygen, namely, as a dimetallic unit inside a cavity defined by two dinucleating ligands. These reactions led to dinuclear MnIII/MnIV oxo-hydroxo derivatives, [Mn2L2(mu-O)(mu-OH)] (7), [Mn2L'2(mu-O)(mu-OH)] (8) and [Mn2L"2(mu-O)(mu-OH)] (9), in which the two Mn ions are strongly antiferromagnetically coupled [J = -53 (7), J = -64 (8), J = -60 cm(-1) (9)]. The crystal structure of 7 could only be solved with synchrotron radiation as the crystals diffracted very poorly and suffered from twisting and disorder. The formation of 7-9 has been proposed to occur through the formation of an intermediate dinuclear hydroperoxo species.
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Create date
19/11/2007 9:34
Last modification date
20/08/2019 12:42
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