Cleavage of the Indium(III) Octaethyloxophlorin Dimer, {In-III(OEPO)}(2), with Lewis Bases. Importance of Outer-Sphere Hydrogen Bonding in Adduct Structures

摘要

Splitting of the oxygen-bridged dimer {In-III(OEPO)}(2) [where (OEPO)(3-) is the trianion of octaethyloxophlorin] by potential axial ligands has been examined and compared to results obtained previously for the cleavage of {Fe-III(OEPO)}(2). Treatment of {In-III(OEPO)}(2) with an excess of imidazole (im) produced the crystalline complex {(im)(2)In-III(OEPO center dot center dot center dot im)}(2)center dot(im)(2)In-III(OEPO)center dot 2Cl(2)C(6)H(4). This solid contains two different {In-III(OEPO)}(2) units that are bridged through hydrogen bonding by an uncoordinated imidazole. Treatment of {In-III(OEPO)}(2) with an excess of pyridine (py) produced (py)(2)In-III(OEPO), which is isostructural with (py)(2)Fe-III(OEPO). Although {Fe-III(OEPO)}(2) reacted with xylyl isocyanide (xylyINC) to form the novel free-radical complex (2,6-xylyINC)(2)Fe-II(OEPO center dot) [where (OEPO center dot)(2-) is the radical dianion of octaethyloxophlorin], {In-III(OEPO)}(2) was unreactive toward xylyl isocyanide.