1H-NMR EVIDENCE FOR η4-DIENE COORDINATION STRUCTURE OF ZrCp2(C4H6) AND HAFNACYCLO-3-PENTENE STRUCTURE OF HfCp2(C4H6) IN SOLUTION
The temperature-variant 1H-NMR study of a 1,3-diene complex, ZrCp2(CH2CHCHCH2), in toluene-d8 showed the η4 -diene coordination structure below −40 °C, while the corresponding Hf complex assumed the metallacyclo-3-pentene structure in the wide temperature range of −90∼80 °C.