Bis(pyrazol-l-yl)acetates as tripodal 'scorpionate' ligands in transition metal carbonyl chemistry: syntheses, structures and reactivity of manganese and rhenium carbonyl complexes of the type [LM(CO)_3] (L = bpza, bdmpza)

摘要

The coordination of the ligands bis(3,5-dimethylpyrazol-l-yl)acetate (bdmpza) and bis(pyrazol-l-yl)acetate (bpza) to Group VII metal carbonyls has been investigated. The compounds [LM(CO)_3], where M = Mn, Re and L = bpza, bdmpza (2a-3b0, have been synthesised. The new complexes [(bdmpza)Mn(CO)_3] (2b), [(bpza)Re(CO)_3] (3a) and [(bdmpza)Re(CO)_3] (3b), and bis(pyrazol-l-yl)acetic acid (1a) have been characterised by single-crystal X-ray analyses. Based on IR-spectroscopic and structural data the electronic properties of these ligands are compared with those of Tp, Tp~(Me_2), Cp and Cp~*. The reaction of [(bdmpza)Re(CO)_3] (3b) with NOBF_4 afforded [(bdmpza)Re(CO)_2(NO)]BF_4 (4).