Synthesis and characterization of a pentadentate Schiff base N[sub 3]O[sub 2] ligand and its neutral technetium(V) complex. X-ray structure of (N,N[prime]-3-azapentane-1,5-diylbis(3-(1-iminoethyl)-6-methyl-2H-pyran-2,4(3H)-dionato)(3-)-O,O[prime],N,N[prime],N[double prime])oxotechnetium(V)

• Published in: Inorganic chemistry Vol. 30:26
• Main Authors: Shuang Liu, Rettig, S.J., Orvig, C.
• Format: Journal Article
• Language: English
• Published: United States 25.12.1991
• Subjects: CARBON 13; CARBON ISOTOPES; CHALCOGENIDES; CHEMICAL PREPARATION; COHERENT SCATTERING; COMPLEXES; CRYSTAL LATTICES; CRYSTAL STRUCTURE; DIFFRACTION; EVEN-ODD NUCLEI; IMINES; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ISOTOPES; LATTICE PARAMETERS; LIGHT NUCLEI; MAGNETIC RESONANCE; NITROGEN COMPOUNDS; NITROGEN OXIDES; NUCLEAR MAGNETIC RESONANCE; NUCLEI; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; ORTHORHOMBIC LATTICES; OXIDES; OXYGEN COMPOUNDS; RESONANCE; SCATTERING; SCHIFF BASES; STABLE ISOTOPES; SYNTHESIS; TECHNETIUM COMPLEXES; TRANSITION ELEMENT COMPLEXES 400201 > Chemical & Physicochemical Properties; X-RAY DIFFRACTION
• ISSN: 0020-1669; 1520-510X

Preparations of a potentially pentadentate ligand, N,N[prime]-3-azapentane-1,5-diylbis(3-(1-iminoethyl)-6-methyl-2H-pyran-2,4-(3H)-dione) (H[sub 3]apa), and its neutral technetium(V) complex, [TcO(apa)], are described. The [sup 13]C and [sup 1]H NMR, infrared, optical, and mass spectra of the pentadentate ligand and its technetium(V) complex are reported. The X-ray structure of [TcO(apa)] has been determined. Crystals are orthorhombic, space group Pbca, with a = 12.833 (2) [angstrom], b = 33.320 (5) [angstrom], c = 9.942(4) [angstrom], V = 4251 (2) [angstrom], and Z = 8. The structure was solved by Patterson and Fourier methods and was refined by full-matrix least-squares procedures to R = 0.028 and R[sub W] = 0.032 for 4054 reflections with I [ge] 3[sigma](I). The technetium(V) complex has a highly distorted octahedral coordination geometry comprising a [TcO][sup 3+] core and the triply deprotonated pentadentate ligand wrapping around the metal center. One of the two oxygen donor atoms of the pentadentate ligand is located trans to the Tc[double bond]O bond while the remaining four donor atoms, N[sub 3]O, occupy the equatorial sites. The distance between the deprotonated N(1) atom to the Tc center is significantly shorter than a normal Tc-N single bond length of 2.10 angstroms, but longer than that for a Tc-N triple bond. [sup 1]H NMR spectral data reveal a rigid solution structure for the complex, which undergoes no conformational and configurational exchange at temperatures up to 50C.