Synthesis and structure of novel sugar-substituted bipyridine complexes of rhenium and 99m-technetium.
Novel ligands have been obtained from the reaction of 4,4'-dibromomethyl-2,2'-bipyridine with 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosylthiol, 2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosylthiol or 2,3,4,6-tetra-O-acetyl-alpha-D-thioacetylmannopyranoside in which the sugar residues are thioglycosidically linked to the bipyridine in the 4,4'-position. Cleavage of the acetyl groups affords hydrophilic symmetric ligands with free hydroxyl groups. Reaction of the new glycoconjugated ligands (L) with [Re(CO)(5)Cl] yields fluorescent complexes of general formula [Re(L)(CO)(3)Cl], which were characterised by mass spectrometry, elemental analysis and (1)H and (13)C NMR, IR, UV/Vis and fluorescence spectroscopy. These complexes exhibit excellent solubility and stability in organic solvents or water, depending on the residues of the sugar. One complex, namely tricarbonyl-4,4'-bis[(2,3,4,6-tetra-O-acetyl-beta-D-glycopyranosyl)thiomethyl]-2,2'-bipyridinerheniumtricarbonylo chloride, has been characterised by X-ray crystallography. A non-symmetric structure of the complexes could be assigned. Radiolabelling of the unprotected ligands with [(99m)Tc(H(2)O)(3)(CO)(3)](+) affords the corresponding water-soluble technetium complexes (in quantitative yields), which were characterised by their HPLC radiation traces. The formed complexes are stable for several hours in the presence of histidine but show partial ligand-exchange after one day.
Gottschaldt
Michael
M
Institute for Organic and Macromolecular Chemistry, Friedrich Schiller University of Jena, Humboldtstrasse 10, 07743 Jena, Germany. Michael.Gottschaldt@uni-jena.de
Koth
Daniel
D
Müller
Dirk
D
Klette
Ingo
I
Rau
Sven
S
Görls
Helmar
H
Schäfer
Bernhard
B
Baum
Richard P
RP
Yano
Shigenobu
S
D000042:Absorption; D002241:Carbohydrates / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry; D012211:Rhenium / Q000737:chemistry*; D017556:Technetium Compounds / Q000138:chemical synthesis* / Q000737:chemistry
D002241:Carbohydrates; D011725:Pyridines; D017556:Technetium Compounds; D012211:Rhenium; C023666:pyridine