title: Selective P4Activation by a Highly Reduced Cobaltate: Synthesis of Dicobalt Tetraphosphido Complexes.
abstract: Although the chemistry of transition metal polyphosphide anions has attracted significant attention, there are few reports of studies in which such species have been synthesized directly from white phosphorus. [K(OEt2)2{Co(BIAN)(cod)}] (1, BIAN=1,2-bis(2,6-diisopropylphenylimino)acenaphthene, cod=1,5-cyclooctadiene), which is readily prepared by ligand exchange from [K(thf)x{Co(cod)2}], reacts with P4to afford [{K(thf)}2{(BIAN)Co}2(μ-η4:η4-P4)] (2 a) in 61 % yield (isolated product). [{K(OEt2)}2{(BIAN)Co}2(μ-η4:η4-P4)] (2 b) and [K([18]crown-6)(MeCN)]2[{(BIAN)Co}2(μ-η4:η4-P4)] (2 c) were obtained by recrystallizing 2 a from diethyl ether and acetonitrile (and using [18]crown-6 in case of 2 c). Oxidation of 2 a with [Cp2Fe]BArF4(one equivalent) and subsequent recrystallization of the product from different solvents gave [K(OEt2){(BIAN)Co}2(μ-η4:η4-P4)] (3 a) and [K(dme)4][{(BIAN)Co}2(μ-η4:η4-P4)] (3 b; dme=1,2-dimethoxyethane). Neutral [{(BIAN)Co}2(μ-η4:η4-P4)] (4) was obtained in moderate yield by oxidizing 2 a with two equivalents of [Cp2Fe]BArF4. The new complexes were characterized by NMR, EPR (in the case of 3 a), and UV/Vis spectroscopy, and elemental analysis. The molecular structures revealed by X-ray crystallography display planar cyclic or open-chain P44-units sandwiched between {(BIAN)Co} fragments.
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Pelties
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Maier
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Herrmann
authors.affiliation: Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 9747 AG, Groningen, Netherlands.
authors.forename: Bas
authors.initials: B
authors.lastname: de Bruin
authors.affiliation: Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 9747 AG, Groningen, Netherlands.
authors.forename: Christophe
authors.initials: C
authors.lastname: Rebreyend
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Gärtner
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany.
authors.forename: Ilya G
authors.identifier: http://orcid.org/0000-0001-6713-9080
authors.initials: IG
authors.lastname: Shenderovich
authors.affiliation: Institute of Inorganic Chemistry, University of Regensburg, 93040, Regensburg, Germany.
authors.forename: Robert
authors.identifier: http://orcid.org/0000-0003-4066-6483
authors.initials: R
authors.lastname: Wolf
keywords: anions; cobalt; phosphorus; polyphosphides; redox-active ligands