Adaptable coordination modes of conjugated 1,3-diene: uniqueness of s-trans coordination

We briefly describe the unique coordination mode of s-trans-1,3-diene complexes in this review. Since the first discovery of mononuclear s-trans-1,3-diene complexes of zirconocene and hafnocene, this unique coordination mode has been found for a wide variety of transition metals over the Periodic Table. Herein we summarize general aspects of the mononuclear s-trans diene complexes including the recent results, and also describe dinuclear and multinuclear complexes that coordinate in an s-trans fashion to polyenes.