V precursor

O-donor complexes that are currently used as Tc(V) precursors in the chemical and radiopharmaceutical synthesis are listed in Table 1. 

Table 10.2 Curve-fitting results of Fourier transformed EXAFS spectra (16 K) at V K-edge for a V precursor (L-leucine), its fresh supported V complex (3.4% V) and that treated with 2-naphthol the coordination number of V=0 was fixed as unity.

V precursor on Si02 and the assembly of V complexes on the surface by DFT calculahons. 

An unusual synthesis of a rhenium(VI) nitrido complex has been observed with the ligand reaction of the rhenium(V) precursor [ReNCl2(PPh3)2] with 2,4,6-tri-isopropylbenzenethiolate, tipt, which gave the green rhenium(VI) complex [ReN(tipt)4], when the reaction mixture was exposed to air, whereas the pale orange rhenium(V) compound [ReN(tipt)4] was obtained in an inert atmosphere. ... 

Yields of penicillin G and V precursors from fermentation have been increased ca. 10 fold over a 25 year period making available much cheaper precursors (see Figures 13.14 and 13.15). 

Hoff, J. E., Wertheim, J. H. and Proctor, B. E. 1959. Radiation preservation of milk and milk products. V. Precursors to the radiation-induced oxidation flavor of milk fat. J. Dairy Sci. 42, 468-475. 

The v(c=N) was very similar to that of the V precursor (1), indicating no significant change in the original coordination of its moiety upon support. In contrast, the four v(ph) peaks differ from those of the precursor (1) in both their positions and relative... 

Figure2.2 V K-edge (a) XANES and (b) EXAFS Fouriertransforms for a L-leucine V precursor (1) and its Si02-supported V complex (V 3.4 wt%) (2). Black and gray lines represent observed and fitted spectra, respectively.

Technetium(V) complexes with /u,v(ohydroxyphenyl)phenylphosphine and (o-hydroxyphenyl)diphenylphosphine ligands were prepared by metathesis reactions with the appropriate Tc(V) precursor and/or by reduction/ligand-exchange reactions with ammonium pertechnetate [530]. It was expected that the combination of one soft phosphine P-donor and two hard phenolate O-donors in the chelate should stabilize Tc centers in intermediate oxidation states. 

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