Synthesis, characterization and structure of tribromo(2-phenyl-1,8- naphthyridine)gold(III)

Abstract

Neutral tribromo(2-phenyl-1,8-naphthyridine)gold(III), AuBr 3(N-N), has been prepared by reaction of KAuBr4 with the ligand in CHCl3/C2H5OH and was characterized by 1H NMR spectroscopy and X-ray diffraction. The molecular and crystal structure of AuBr3(N-N) · 0.5 THF (triclinic, P1-, a = 11.314(2), b = 12.350(3), c = 14.628(3) Å , α = 107.96(3), β = 98.86(3), γ = 107.29(3)°, Z = 4, 173 K) shows coordination of the N8 nitrogen atom situated in the unsubstituted pyridine ring to the planar four-coordinate AuIII center. Whereas the AuBr 3N best planes and the coordinated naphthyridine rings are not far from orthogonal (ω ∼ 105°), the phenyl substituents were found in the crystal with a ca. 22° dihedral angle relative to the naphthyridine plane. Intermolecular Au⋯Br distances close to the sum of the van der Waals radii indicate very weak interactions to form a quasi-dimeric arrangement in the crystal. © 2011 Verlag der Zeitschrift für Naturforschung, Tübingen.