Collman Group
20+ years of excellence in metalloporphyrin chemistry
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Heterodinuclear transition metal complexes with multiple metal-metal bonds.
- Over the past 25 years the Collman group has
developed
methodologies
for syntheses of a wide variety of homodinuclear and heterodinuclear
multiply bonded transition metal cores supported by porphyrins. - The high-vacuum solid-state pyrolysis is the only method developed so far that is applicable to most 2nd and 3rd row transition metals. Indeed, our group has prepared more novel heterodinuclear multiply bonded transition metal cores than any other group in the world.
- Porphyrin has proven to be a uniquely suitable ligand to stabilize dinuclear cores containing multiple metal-metal bonds. Some of the properties of the porphyrin ligand include: (i) relative rigidity and planarity; (ii) inability to bridge two metals; (iii) very high stability of the complexes (metalloporphyrins); (iv) ease of derivatization at the periphery, which can affect the steric, electronic properties or both.
- These porphyrin’s properties allowed our lab to carry out unique physicochemical measurements, such as the barrier for rotation around the quadruple-bond, and the resonance Raman vibrational frequencies of the multiple metal-metal bonds.
- Our most recent success (see the picture) was synthesis and characterization of a complex containing the first example of a quadruple metal-metal bond between elements from different groups of the periodic table. Until our work, heterodinuclear quadruple bonds were limited to group 6 metals. Some even thought that other elements can not form such bonds.
- We recently reviewed the progress in the field of heterodinuclear transition metal complexes with multiple metal-metal bonds in Angewandte Chemie.