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          Institute: MPI für bioanorganische Chemie     Collection: MPI für bioanorganische Chemie     Display Documents

ID: 708922.0, MPI für bioanorganische Chemie / MPI für bioanorganische Chemie
Tuning a Single Ligand System to Stabilize Multiple Spin States of Manganese: A First Example of a Hydrazone-Based Manganese(III) Spin-Crossover Complex
Authors:Shongwe, Musa S.; Al-Barhi, Kaltham S.; Mikuriya, Masahiro; Adams, Harry; Morris, Michael J.; Bill, Eckhard; Molloy, Kieran C.
Date of Publication (YYYY-MM-DD):2014
Title of Journal:Chemistry-A European Journal
Journal Abbrev.:Chem. Eur. J.
Issue / Number:31
Start Page:9693
End Page:9701
Review Status:Internal review
Audience:Experts Only
Abstract / Description:A series of bis-chelate pseudo-octahedral mono-nuclear coordination complexes of manganese with the chromophore [MnN4O2](n+) (n=0, 1) have been generated in all three principal oxidation states of this transition-metal center under ambient conditions by utilizing a readily tunable, versatile phenolic pyridylhydrazone ligand system (i.e., H-2(3,5-R-1, R-2)-L; L= ligand). Strategic combinations of the nature and position of a variety of substituent groups afforded selective, spontaneous stabilization of multiple spin states of the manganese center, which, upon close crystallographic scrutiny, appears to be in part due to the occurrence or absence of hydrogen-bonding interactions that involve the phenolate/phenolic oxygen atom. The divalent complexes are isolable in two forms, namely, molecular [Mn-II{H(3,5-R-1, R-2)-L}(2)] and ionic [Mn-II{H-2(3,5-R-1, R-2)-L}{H(3,5-R-1, R-2)-L}]ClO4, with the latter complex converting easily into the former complex on deprotonation. Accessibility of the higher-valent states is achievable only when the phenolate oxygen atom is sterically hindered from participation in hydrogen bonding. The [Mn-III{H(3,5-tBu(2))-L}(2)]ClO4 complex is the first example of a hydrazone-based Mn-III complex to exhibit spin crossover. Formation of the tetravalent complexes [Mn-IV{(3,5-R-1, R-2)-L}(2)] (R-1 = tBu, R-2 = H; R-1 = R-2 = tBu) necessitates base-assisted abstraction of the hydrazinic proton.
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für bioanorganische Chemie
External Affiliations:[Shongwe,S; Al-Barhi,K.S.; ] Sultan Qaboos Univ., Coll.Sci., Dept.Chem., Muscat, Oman.
[Mikuriya,M.;] Kwansei Gakuin Univ., Sch.Sci.& Technol., Dept.Chem., Sanda 6691337, Japan.
[Adams,H.; Morris,M.J.;] Univ.Sheffield, Dept.Chem., Sheffield S3 7HF, S Yorkshire, England.
[Molloy,K.C.;] Univ Bath, Dept Chem, Bath BA2 7AY, Avon, England.
Identifiers:ISI:000340176600031 [ID No:1]
ISSN:0947-6539 [ID No:2]
DOI:10.1002/chem.201402634 [ID No:3]
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