Rhenium(V) oxo complexes relevant to technetium renal imaging agents derived from mercaptoacetylglycylglycylaminobenzoic acid isomers. Structural and molecular mechanics studies
- Emory Univ. Atlanta, GA (United States)
- Univ. of Siena (Italy)
The synthesis and characterization of three rhenium(V) oxo complexes derived from isomers of mercaptoacetylglycylglycylaminobenzoic acid (MAG[sub 2]-ABAH[sub 5]) are reported. The isomers were synthesized from o-, m- and p-aminobenzoic acid and differed in the position of the terminal carboxyl group. The anions of 8-10, [ReO(MAG[sub 2]-*ABAH)][sup [minus]] (* = para (8), meta (9), ortho (10)), contained the tetraanionic form of the ligands with the carboxyl group protonated. Compounds 8,9, and 10 were synthesized by exchange reactions of ReOCl[sub 3](Me[sub 2]SO)(Ph[sub 3]P) under moderate conditions and were isolated as [Ph[sub 4]P][sup +], [Bu[sub 4]N][sup +], and [Ph[sub 4]P][sup +] salts, respectively. The structures of 8 and 10 were determined by X-ray diffraction methods; except for the location of the carboxyl group, the structures are similar. The coordination geometry is pseudo square pyramidal, with nitrogen and sulfur donor atoms forming a square base and the oxo ligand at the apex. The orientation of the carboxyl group in 10 is anti to the Re[double bond]O group. Since the carboxyl groups are protonated in 8 and 10 and in other relevant structures from this class of radiopharmaceuticals including [Ph[sub 4]As][TcO(MAG[sub 3]H)] (MAG[sub 3]H = tetraanionic form of mercaptoacetyltriglycine), the authors developed molecular mechanics parameters that allowed them to calculate the structures of 8, 10, and [TcO(MAG[sub 3]H)][sup [minus]]. They then extended the calculations to all three isomeric complexes in their deprotonated forms and to [TcO(MAG[sub 3])][sup 2[minus]] in order to approximate their solution phase structures. They conclude that the [TcO(MAG[sub 3])][sup 2[minus]] species is conformationally flexible, and they have made an initial assessment of structures vs renal clearance.
- OSTI ID:
- 6913679
- Journal Information:
- Inorganic Chemistry; (United States), Vol. 31:13; ISSN 0020-1669
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
RADIOPHARMACEUTICALS
CHEMICAL PREPARATION
MOLECULAR STRUCTURE
RHENIUM COMPLEXES
BOND ANGLE
BOND LENGTHS
ISOMERS
LIGANDS
MONOCARBOXYLIC ACIDS
MONOCLINIC LATTICES
NMR SPECTRA
QUALITATIVE CHEMICAL ANALYSIS
RENAL CLEARANCE
TECHNETIUM 99
THEORETICAL DATA
TRICLINIC LATTICES
X-RAY DIFFRACTION
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CHEMICAL ANALYSIS
CLEARANCE
COHERENT SCATTERING
COMPLEXES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DATA
DIFFRACTION
DIMENSIONS
DRUGS
EXCRETION
HOURS LIVING RADIOISOTOPES
INFORMATION
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
LENGTH
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
RADIOISOTOPES
SCATTERING
SPECTRA
SYNTHESIS
TECHNETIUM ISOTOPES
TRANSITION ELEMENT COMPLEXES
YEARS LIVING RADIOI
550601* - Medicine- Unsealed Radionuclides in Diagnostics