These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: A New Donor Atom System [(SNN)(S)] for the Synthesis of Neutral Oxotechnetium(V) Mixed-Ligand Complexes.
    Author: Papadopoulos MS, Pelecanou M, Pirmettis IC, Spyriounis DM, Raptopoulou CP, Terzis A, Stassinopoulou CI, Chiotellis E.
    Journal: Inorg Chem; 1996 Jul 17; 35(15):4478-4483. PubMed ID: 11666668.
    Abstract:
    A new approach to the "3 + 1" mixed ligand oxotechnetium complexes of the general formula TcOL1L2, with ligands (L1H(2)) containing the SNN donor set and various monodentate thiols as coligands (L2H) is reported. The ligands L1H(2) (1-3, general formula R(1)CH(2)CH(2)NHCH(2)C(R(2))(2)SH where R(1) = N(CH(3))(2) and R(2) = H in 1, R(1) = pyrrolidin-1-yl and R(2) = H in 2, and R(1) = piperidin-1-yl and R(2) = CH(3) in 3) act as tridentate SNN chelates to the TcO(3+) core, leaving open one coordination site cis to the oxo group. In the presence of a monodentate thiol (L2H) and using (99)Tc(V)-gluconate as precursor, the vacancy is filled by the thiol which acts as the coligand. With this approach four neutral oxotechnetium complexes (4-7, general formula TcO[R(1)CH(2)CH(2)NCH(2)C(R(2))(2)S][SR] where RSH = p-methoxybenzenethiol, or p-methylbenzenethiol or benzyl mercaptan) were prepared in high yield by reacting L1H(2) and L2H with Tc(V)-gluconate in a ratio 1:1:1. The complexes were characterized by elemental analysis and spectroscopic methods. Complete assignments of (1)H and (13)C NMR resonances were made for all complexes. X-ray crystallographic studies of 5 (R(1) = pyrrolidin-1-yl, R(2) = H, RSH = p-methylbenzenethiol) and 7 (R(1) = piperidin-1-yl, R(2) = CH(3), RSH = benzyl mercaptan) showed that the complexes crystallize in the monoclinic space group P2(1)/n (a = 10.223(1) Å, b = 9.283(1) Å, c = 18.337(2) Å, beta = 97.262(2) degrees, V = 1726.3(4) Å(3), Z = 4; a = 11.876(2) Å, b = 10.470(2) Å, c = 17.098(3) Å, beta = 105.990(4) degrees, V = 2043.8(6) Å(3), Z = 4, for 5 and 7, respectively). Complexes5 and 7 have distorted square pyramidal coordination geometry with the oxo ligand in the axial position. The steric requirements of the oxo group cause the Tc atom to be displaced 0.68 Å out of the mean equatorial plane of the NNSS donor atoms in both complexes.
    [Abstract] [Full Text] [Related] [New Search]