title: The Synthesis and X-ray Structural Characterization of mer and fac isomers of the Technetium(I) Nitrosyl Complex [TcCl(2)(NO)(PNPpr)].
abstract: The nitrosyl complex H[TcNOCl(4)] reacts with the tridentate ligand bis[(2-diphenylphosphino)propyl]amine (PNPpr) to yield a mixture of the mer or fac isomers of [TcCl(2)(NO)(PNPpr)]. In acetonitrile, where the ligand is freely soluble, reaction occurs at room temperature to yield mostly the mer isomer with the linear nitrosyl ligand cis to the amine ligand; and the phosphine ligands arranged in a mutually trans orientation. The reaction in methanol requires reflux to dissolve the lipophilic ligand and generates the fac isomer of [TcCl2(NO)(PNPpr)] as the major product, with the tridentate ligand in a facial arrangement, leaving the chlorides and nitrosyl ligand in the remaining facial sites. The steric bulk of the tridentate ligand's diphenylphophino- moieties results in a significant distortion from octahedral geometry, with the P-Tc-P bond angle expanded to 99.48(4)°. The infrared spectra display absorptions from these nitrosyl ligands in the 1700 and 1800 cm(-1) regions for the fac and mer isomers respectively. The ESI(+) mass spectra each display the parent ion at 647 m/z.
authors.affiliation: The Department of Radiology, Harvard Medical School, Boston, Massachusetts 02215.
authors.forename: T L
authors.initials: TL
authors.lastname: Nicholson
authors.forename: A
authors.initials: A
authors.lastname: Mahmood
authors.forename: F
authors.initials: F
authors.lastname: Refosco
authors.forename: F
authors.initials: F
authors.lastname: Tisato
authors.forename: P
authors.initials: P
authors.lastname: Müller
authors.forename: A G
authors.initials: AG
authors.lastname: Jones