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Three functionalised PnAO ligands, 3,3,9,9-tetramethyl-6-R-4, 8-diazaundecane-2,10-dionedioxime (R=benzyl, p-nitrobenzyl and p-aminobenzyl) were synthesized. ^99mTc complexes of these ligands were prepared at both tracer levels and carrier added levels with ^99mTcO⁻4 and with ⁹⁹TcO⁻4. Complexation yields were estimated by thin layer chromatography, HPLC and solvent extraction studies. The complexes were formed in high yields; the resultant complexes were neutral, highly lipophilic (log P∽2.3–2.5) and elute as single peak on a reverse phase HPLC column. Complexes with all the three ligands showed excellent stability over 24 h period of storage at room temperature. Biodistribution studies of the ^99mTc complexes of the benzyl and nitrobenzyl ligands in Wistar rats showed brain uptake of 1.2±0.25% and 0.88±0.10% at 1 min post injection, respectively. The blood clearance was rapid in both the cases while the main excretory route was the hepatobiliary system. The aminobenzyl derivative is a bifunctional ligand which could be used for labeling antibodies and peptides with radiometals. Copyright © 1999 John Wiley & Sons, Ltd.

Palladium(II) complexes of an imine-thiophene ligand N,N' bis(1-methylenethiophene)-1,3-diaminopropane and an amine-phenol ligand N,N'-bis(2-hydroxybenzyl)1,3-diamino-2,2-dimethylpropane were synthesized by reacting K2PdCl4 with alcoholic solutions of the ligands. X-ray structures of the complexes were determined using data from a CAD-4 Nonius diffractometer (MoKa radiation). The structures were solved by conventional methods resulting inR factors of 0.044 and 0.061 using 1841 and 2241 independent reflections, respectively. Crystal data: Complex I, orthorhombic, space groupPbca,a=11.323(2),b=14.819(2),c=23.873(3)Å,V=4006(1)Å3,Z=8. Complex II: Space groupP21/c,a=9.169(2),b=31.920(4),c=8.902(6),ß=90.38(2)°,V=2605(1)Å3.Z=4. Both complexes showed coordination of the ligands through the nitrogens only while the sulphur and the oxygen atoms were uncoordinated. Square planar coordination is completed bycis chloro ligands.

[MoOCl5]2- aquates rapidly in solutions ofca. 5 M or less in HCl or MeSO3H to give an intermediate which changes to the well known ion, Mo2O4aq2+ at a lower rate. Solutions of molybdenum(V) in 12M MeSO3H, when diluted, also change at a similar rate to Mo2O42+. The rate of reaction, d[Mo2O42+]/ dt=k[MoV] has a value of k=30.(1)s-1 at 0°C in 5.00 MMeSO3H. At constant ionic strength, k is nearly independent of acidity (5.2–0.5 M) and is only slightly affected by exchanging MeSO3- with Cl- orp-toluenesulfonate ion. At low ionic strength k increases dramatically. In 4.78 MMeSO3H, the activation parameters are: ?H?=72.68(29) kJ/mole, ?S?=16.63(8) jmole · K and k=5.01(5)×102s-1 at 0°C.18O measurements on the oxygen transfer between MoOaq3+ and Mo2O4aq.2+ were partially inconclusive. A mechanistic interpretation is given to the kinetic results. The x-ray crystal structure of KMoOCl4(OH2)·H2O is reported.