Nitrogen‐Bridged Metallodiazaporphyrin Dimers: Synergistic Effects of Nitrogen Bridges and meso‐Nitrogen Atoms on Structure and Properties

Abstract

NH-bridged and pyrazine-fused metallodiazaporphyrin dimers have been prepared from nickel(II) and copper(II) complexes of 3-amino-5,15-diazaporphyrin by Pd-catalyzed C-N cross-coupling and oxidative dimerization reactions, respectively. The synergistic effects of the nitrogen bridges and meso-nitrogen atoms play major roles in enhancing the light-harvesting properties and delocalization of an electron spin over the entire π-skeletons of the metallodiazaporphyrin dimers.

Direct and Regioselective Amination of β‐Unsubstituted 5,15‐Diazaporphyrins with Amines: A Convenient Route to Near‐Infrared‐Responsive Diazaporphyrin Sensitizers

“…For example, electrodonating meso ‐diarylamino porphyrins are effective photosensitizers for dye‐sensitized solar cells . Recently, we reported P1 and P2 as the first examples of 5,15‐diazaporphyrins (DAPs) bearing an amino group at the periphery (Scheme ) . Notably, P1 (M=Ni, Cu) and P2 (M=Ni) have large charge‐transfer (CT) character, reflecting the high‐lying highest occupied molecular orbital (HOMO) of the peripheral amino group and the low‐lying lowest unoccupied molecular orbital (LUMO) of the DAP ring .…”

Direct and Regioselective Amination of β‐Unsubstituted 5,15‐Diazaporphyrins with Amines: A Convenient Route to Near‐Infrared‐Responsive Diazaporphyrin Sensitizers

“…These properties are important in materials science,f or example,f or photodynamic therapy and organic solar cells.The introduction of an amino group on aporphyrin ring is areliable strategy for achieving high lightharvesting ability in the long-wavelength region. [3] Notably, P1 (M = Ni, Cu) and P2 (M = Ni)have large charge-transfer (CT) character,reflecting the high-lying highest occupied molecular orbital (HOMO) of the peripheral amino group and the low-lying lowest unoccupied molecular orbital (LUMO) of the DAPr ing. [2] Recently,w er eported P1 and P2 as the first examples of 5,15-diazaporphyrins (DAPs) bearing an amino group at the periphery (Scheme 1).…”

“…[2] Recently,w er eported P1 and P2 as the first examples of 5,15-diazaporphyrins (DAPs) bearing an amino group at the periphery (Scheme 1). [3] We envisioned that the further amination of DAPw ould afford ap romising scaffold for constructing new NIR-light-responsive photosensitizers. [4] As ar esult, P1 and P2 exhibit considerably red shifted CT absorption bands,a t7 00 and 760 nm, respectively.…”

“…[8] The3 -amino-DAPs P1 and P2 were also prepared by the reduction of 2M-NO 2 and the N À Cc ross-coupling reaction of 2M-Br with P1,r espectively (Scheme 1). [3] However,t hese reactions require prefunctionalization (nitration and halogenation) of porphyrin/DAP rings or astoichiometric amount of an oxidant, such as ahypervalent iodine compound or an amyl radical, to generate the precursors.F urthermore, synthetic difficulties concerning amination at multiple peripheral positions precludes straightforward access to multiaminated porphyrin/DAP derivatives. [9] Therefore,t he development of am ore convenient method for introducing one or more amino groups onto aD AP ring is an important challenge in both organic synthesis and materials science.…”

Subporpholactone, Subporpholactam, Imidazolosubporphyrin, and Iridium Complexes of Imidazolosubporphyrin: Formation of Iridium Carbene Complexes

“…Since the pioneering work of Crossley et al, [1] pyrrolemodification has been demonstrated to be effective in diversification of porphyrins by producing various pyrrolemodified porphyrins,t he structural, optical, and electrochemical properties of which depend on introduced acyclicor cyclic units. [1,2] Among pyrrole-modification strategies, as equence of pyrrole-ring-cleavage and non-pyrrolic-ringreconstruction has been often used to explore novel pyrrolemodified porphyrins.I nc ontrast to the rich chemistry of pyrrole-modified porphyrins,s uch strategy has been only scarcely accomplished for other porphyrinoids.A sr are examples, [3][4][5] Barrett and Hoffman et al reported the synthesis of seco-porphyrazine by oxidative cleavage of the diaminopyrrole unit in porphyrazine, [3] and Matano et al reported the synthesis of diazaporpholactone by oxidation of 3-aminodiazaporphyrin with m-chloroperbenzoic acid, [4] which is the same procedure used for the synthesis of porpholactone reported by Crossley et al [1] Boron(III) subporphyrins (hereinafter referred to as subporphyrins), genuine ring-contracted congeners of porphyrins,h ave been extensively explored in the last decade because of the attractive attributes such as 14p aromaticity, bowl-shaped structure,b right fluorescence,a nd large substituent effect. [6] Recently,w er eported the synthesis of subsecochlorin dicarboxylic acid 1 and subchlorophin 2 from subporphyrin 0 through cleavage of one pyrrole ring (Scheme 1).…”