We report synthesis and characterization of near-infrared (NIR)-absorbing/emitting Thiele's hydrocarbon derivatives, in which four aryl groups are bridged to a quinodimethane skeleton. The quinoid structure of the bridged-tetra-aryl-p-quinodimethanes (BTAQs) was confirmed by spectroscopic, X-ray crystallographic, and computational methods. Although quinodimethane derivatives with a small HOMO−LUMO energy gap often exhibit biradical character, BTAQs showed no biradical character. Instead, they exhibited two-step near-infrared electrochromism. The donor/acceptor properties of the aryl groups were found to play a key role in the unique properties of BTAQs.

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A novel hepta-coordinated mononuclear manganese(II) complex, [Mn(L)2(H2O)](ClO4)2·2.5H2O [L=1,2-bis(2′-pyridylmethyleneamino)propane], was obtained by assembly reaction of a di-Schiff base ligand L with manganese(II) perchlorate. The crystal structure shows that one of the L ligand acts as a quadridentate ligand, while the other one serves as a bidentate. The Mn(II) complex was found to have activity of dismutation of superoxide (O2·-) in the riboflavin-methionine-nitro blue tetrazolium assay.