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.

We have established a convenient method for the base-promoted direct amination of β-unsubstituted 5,15-diazaporphyrins (DAPs) with secondary and primary amines to produce 3,7,13,17-tetraamino- and 3-amino-DAPs, respectively, regioselectively. The amino groups attached at the periphery cause significant red shifts of the absorption bands as a result of their perturbation of the HOMO and/or LUMO in the DAP π-system. The palladium complex of a 3,7,13,17-tetrakis(diphenylamino)-DAP generated singlet oxygen in high yield under irradiation with near-infrared light.

The β-functionalization of 5,15-diazaporphyrins (DAPs) with phosphoryl, phenoxy, sulfanyl, and sulfonyl groups was achieved by either cross-coupling or aromatic nucleophilic substitution reactions of β-bromo- and β,β′-dibromo-DAPs. The heteroatom-containing functional groups at the β-positions strongly affected the redox properties of the DAP π-systems.

We have established ac onvenient method for the base-promoted direct amination of b-unsubstituted 5,15-diazaporphyrins (DAPs) with secondary and primary amines to produce 3,7,13,17-tetraamino-and 3-amino-DAPs,r espectively,r egioselectively.T he amino groups attached at the periphery cause significant red shifts of the absorption bands as aresult of their perturbation of the HOMO and/or LUMO in the DAP p-system. The palladium complex of a3 ,7,13,17tetrakis(diphenylamino)-DAP generated singlet oxygen in high yield under irradiation with near-infrared light.Recently,considerableattentionhasbeenpaidtoporphyrin-Scheme 1. Synthesis of amino-DAPs. a) Nitration (to 2M-NO 2 )o r bromination (to 2M-Br); b) reduction (from 2M-NO 2 to P1)orN ÀC cross-coupling (from 2M-Br to P2); 3-NiDAP = 10,20-dimesityl-5,15diaza(nickel)porphyrin-3-yl. c) Base-promoted direct substitutionw ith amines (this study).Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

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