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Title: Chemistry of a cofacial dirhodium diporphyrin: Synthesis and reactivity of Rh[sub 2]DPB

Journal Article · · Inorganic Chemistry; (United States)
DOI:https://doi.org/10.1021/ic00061a040· OSTI ID:6260095

A novel cofacial dirhodium diporphyrin with a metal-metal single bond has been synthesized in two steps from the corresponding free base cofacial porphyrin H[sub 4]DPB. Rhodium insertion and subsequent photolysis yield the cofacial dirhodium diporphyrin Rh[sub 2]DPB. This cofacial dirhodium diporphyrin activates H[sub 2] with the assistance of ancillary ligands which attack the rhodium centers externally, weakening the metal-metal bond. The reaction of the dirhodium diporphyrin with H[sub 2] and CO yields the dirhodium diporphyrin dihydride Rh(H)Rh(H)DPB. The H[sub 2] cleavage reaction seems to occur within the cavity of the cofacial diporphyrin, on the basis of the unusually high T[sub 1] values of the resultant hydrides and the predicted regiospecific bonding pattern of additional, bulky ancillary ligands. This reactivity differs from that of a monomeric rhodium porphyrin system which gives a formyl complex. Phosphines have also been employed in reaction with the dirhodium diporphyrin and H[sub 2], resulting in a different type of hydride complex, seemingly one having three-center two-electron bonds. 25 refs., 8 figs., 1 tab.

OSTI ID:
6260095
Journal Information:
Inorganic Chemistry; (United States), Vol. 32:9; ISSN 0020-1669
Country of Publication:
United States
Language:
English