Abstract
The visible-light driven cyclometalation of arene substrates containing an N-donor
heteroaromatic moiety as directing group by monocyclometalated Pt(II)
complexes is reported. Precursors of the type [PtMe(C^N)(N^CH)], where
N^CH is 2-phenylpyridine (ppyH) or related compunds with diverse
electronic properties and C^N is the corresponding cyclometalated
ligand, afford homoleptic cis-[Pt(C^N)2] complexes upon irradiation with blue LEDs at room temperature with evolution of methane. Heteroleptic derivatives cis-[Pt(ppy)(C′^N′)]
are obtained analogously from [PtMe(ppy)(N′^C′H)], where N′^C′H
represents an extended set of heteroaromatic compounds. Experimental and
computational studies demonstrate an unprecedented C–H oxidative
addition, which is initiated by a triplet excited state of
metal-to-ligand charge-transfer (MLCT) character and leads to a
detectable Pt(IV) methyl hydride intermediate.
heteroaromatic moiety as directing group by monocyclometalated Pt(II)
complexes is reported. Precursors of the type [PtMe(C^N)(N^CH)], where
N^CH is 2-phenylpyridine (ppyH) or related compunds with diverse
electronic properties and C^N is the corresponding cyclometalated
ligand, afford homoleptic cis-[Pt(C^N)2] complexes upon irradiation with blue LEDs at room temperature with evolution of methane. Heteroleptic derivatives cis-[Pt(ppy)(C′^N′)]
are obtained analogously from [PtMe(ppy)(N′^C′H)], where N′^C′H
represents an extended set of heteroaromatic compounds. Experimental and
computational studies demonstrate an unprecedented C–H oxidative
addition, which is initiated by a triplet excited state of
metal-to-ligand charge-transfer (MLCT) character and leads to a
detectable Pt(IV) methyl hydride intermediate.
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