122822-70-2Relevant articles and documents
Synthesis and characterization of mixed-ligand technetium(II) complexes containing halides, phosphines, and either 2,2′-bipyridine, 1,10-phenanthroline, or 2,2′:6′,2″-terpyridine. X-ray crystal structures of cis(Cl),trans(P)-[TcCl2(P(CH3)2C 6H5)2(phen)] and ...
Wilcox, Bruce E.,Ho, Douglas M.,Deutsch, Edward
, p. 3917 - 3923 (2008/10/08)
Full title: Synthesis and characterization of mixed-ligand technetium(II) complexes containing halides, phosphines, and either 2,2′-bipyridine, 1,10-phenanthroline, or 2,2′:6′,2″-terpyridine. X-ray crystal structures of cis(Cl),trans(P)-[TcCl2(P(CH3)2C 6H5)2(phen)] and trans(P)-[TcBr(P(CH3)2C6H5) 2(terpy)]SO3CF3. Technetium(II) complexes of the general formula cis(X),trans(P)-[TcX2(PR2R′)2L], where X = Cl or Br, PR2R′ = dimethylphenylphosphine or ethyldiphenylphosphine, and L = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen), have been synthesized and characterized. They are prepared by replacement of one halide and one phosphine ligand of mer-TcX3(PR2R′)3 by the bidentate L ligand in refluxing ethanol, followed by reduction to the Tc(II) oxidation state and precipitation from solution by the addition of aqueous hydroxide. Additionally, related technetium(II) complexes of the general formula trans(P)-[TcX(PR2R′)2(terpy)]+, where terpy = 2,2′:6′,2″-terpyridine, have been synthesized and characterized. They are prepared by terpy substitution onto and displacement of one phosphine and two halide ligands from mer-TcX3(PR2R′)3 in refluxing ethanol with concomitant reduction of Tc(III) to Tc(II). Evidence suggests a two-step synthetic process wherein the terpy ligand first displaces one halide and one phosphine moiety to form a Tc(III) complex in which terpy functions as a bidentate ligand, followed by subsequent displacement of the second halide ligand with coordination of the third heterocyclic nitrogen of the terpy ligand and reduction to the Tc(II) state. All of the complexes have been characterized by elemental analyses of prototypes, by UV-visible spectrophotometry, and by fast atom bombardment mass spectrometry in the positive ion mode. These fingerprint mass spectra exhibit peaks assigned to the molecular ion as well as peaks resulting from the loss of one or more monodentate ligands from the molecular ion. A single-crystal X-ray structure determination for cis(Cl),trans(P)-[TcCl2(P(CH3)2C 6H5)2(phen)], formula weight 626.41, shows that the technetium(II) center resides in a distorted octahedral environment. This complex crystallizes in the tetragonal space group P41212 with a = b = 10.666 (2) ?, c = 24.610 (4) ?, and V = 2799.4 (9) ?3, with Z = 4 for 1635 observed reflections with F > 3σ(F). The single-crystal X-ray structure determination for trans(P)-[TcBr(P(CH3)2C6H5) 2(terpy)]SO3CF3, formula weight 837.54, shows that this complex, which also contains technetium(II) in a distorted-octahedral coordination environment, crystallizes in the orthorhombic space group P212121 with a = 18.975 (3) ?, b = 19.336 (4) ?, c = 9.615 (1) ?, and V= 3527.7 (8) ?3, with Z = 4 for 3462 observed reflections with F > 3σ(F).
