Synthesis and reactivity of [ReBr2(NCCH3)2(CO)2]−: A new precursor for bioorganometallic chemistry

We have synthesised (Et4N)[ReBr2(NCCH3)2(CO)2] 1 in two steps from [ReBr3(CO)3]2−. Complex 1 is water and air stable and the two Br− ligands are easily exchanged for coordinating solvent molecules such as water. The reactivity of 1 with several ligands such as imidazole (imz) and 2-picolinic acid (2-pic) are easily possible with substitution exclusively occurring in trans-position to the carbonyl groups. The resulting complexes [Re(imz)2(NCCH3)2(CO)2]+ and [Re(2-pic)(NCCH3)2(CO)2] have been isolated and structurally characterised. The two acetonitrile ligands are strongly bound and are not substituted under any conditions. Complex 1 represents therefore the new moiety “trans,cis-[Re(NCCH3)2(CO)2]+” which can be considered as a further building block in organometallic chemistry.