A critical quantum chemical and experimental study of the potentiality of direct labeling of the CN group with [99mTc(CO)3]+ or [186/188Re(CO)3]+ in CN containing biomolecules

Both theory and experiments prove that [CN-Tc(CO)3(H2O)(2−x)Lx]+ complexes are weak and that in vitamin B12 most probably the benzimidazole group is involved.