title: The first scorpionate ligand based on diazaphosphole.
abstract: The reaction of PhBCl2 with 1H-1,2,4-λ(3)-diazaphosphole in the presence of NEt3 gives a new scorpionate ligand, phenyl-tris(1,2,4-diazaphospholyl)borate (PhTdap). The coordination behaviour of this ligand toward transition and non-transition metals has been comprehensively studied. In the thallium(I) complex, Tl(PhTdap), κ(2)-N,N bonding supported with intramolecular η(3)-phenyl coordination has been observed in the solid state. Tl(PhTdap) also shows unusual intermolecular π-interactions between five-membered diazaphosphole rings and the thallium atom giving infinite molecular chains in the crystal. In the square planar complex [Pd(C,N-C6H4CH2NMe2)(PhTdap)], κ(2)-bonded scorpionate has been detected in both solution and in the solid state. For other studied compounds with the central metal ion Ti(IV), Mo(II), Mn(I), Fe(II), Ru(II), Co(II), Co(III), Ni(II) and Cd(II), the κ(3)-N,N,N coordination pattern was observed. Electronic properties of PhTdap and its ligand-field strength were elucidated from UV-Vis spectra of transition-metal species. The CH/P replacement on going from tris(pyrazolyl)borate to the ligand PhTdap causes a slight increase in electronic density rendered to the central metal atom. The following order of ligand-field strength has been established: HB(3,5-Me2pz)3 < PhB(pz)3 < HB(1,2,4-triazolyl) < HB(pz)3 < PhB(1,2,4-triazolyl) < PhTdap. The crystal structures of ten metal complexes bearing the new ligand are reported. The possibility of PhTdap coordination through the phosphorus atom is also briefly discussed.
authors.affiliation: Department of General and Inorganic Chemistry, Faculty of Chemical Technology, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Mlateček
authors.affiliation: Department of General and Inorganic Chemistry, Faculty of Chemical Technology, Czech Republic.
authors.forename: Libor
authors.initials: L
authors.lastname: Dostál
authors.affiliation: Department of General and Inorganic Chemistry, Faculty of Chemical Technology, Czech Republic.
authors.forename: Zdeňka
authors.initials: Z
authors.lastname: Růžičková
authors.affiliation: Institute of Chemistry and Technology of Macromolecular Materials, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic. milan.erben@upce.cz.
authors.forename: Jan
authors.initials: J
authors.lastname: Honzíček
authors.affiliation: Department of General and Inorganic Chemistry, Faculty of Chemical Technology, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Holubová
authors.affiliation: Department of General and Inorganic Chemistry, Faculty of Chemical Technology, Czech Republic.
authors.forename: Milan
authors.initials: M
authors.lastname: Erben