title: High-spin iron(II) complexes with mono-phosphorylated 2,6-diaminopyridine ligands.
abstract: Several new monophosphorylated 2,6-diaminopyridine ligands bearing PiPr2and PtBu2units (PNNH2-iPr, PNNH2-tBu, PNNHMe-iPr, and PNNHEt-iPr) are prepared by treatment of the respective 2,6-diaminopyridines with the chlorophosphines PiPr2Cl and PtBu2Cl in the presence of a base. Treatment of anhydrous FeCl2with 1 equiv of these afforded the tetracoordinated coordinatively unsaturated 14e-complexes [Fe(κ2P,N-PNNH2-iPr)Cl2] and [Fe(κ2P,N-PNNH2-tBu)Cl2], while with PNNHMe-iPr and PNNHEt-iPr a phosphine transfer reaction of a second PN ligand took place to yield the known PNP pincer complexes [Fe(κ3P,N,P-PNPMe-iPr)Cl2] and [Fe(κ3P,N,P-PNPEt-iPr)Cl2]. The four-coordinate complexes [Fe(κ2P,N-PNNH2-iPr)Cl2] and [Fe(κ2P,N-PNNH2-tBu)Cl2] did not react with CO and the formation of iron PNC pincer complexes was not observed. The reason for the reluctance to add CO was investigated in detail by DFT calculations.
authors.affiliation: Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-OC, 1060 Vienna, Austria.
authors.forename: Christan
authors.initials: C
authors.lastname: Schröder-Holzhacker
authors.affiliation: Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria.
authors.forename: Berthold
authors.initials: B
authors.lastname: Stöger
authors.affiliation: Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria.
authors.forename: Ernst
authors.initials: E
authors.lastname: Pittenauer
authors.affiliation: Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria.
authors.forename: Günther
authors.initials: G
authors.lastname: Allmaier
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais No. 1, 1049-001 Lisbon, Portugal.
authors.forename: Luis F
authors.initials: LF
authors.lastname: Veiros
authors.affiliation: Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-OC, 1060 Vienna, Austria.
authors.forename: Karl
authors.initials: K
authors.lastname: Kirchner
keywords: Aminophosphine ligands; Carbon monoxide; DFT calculations; Iron