What the study found
The study found that Pictet-Spengler cyclization produced fused azepine-bridged and 1 H -azocine-bridged nickel(II) porphyrin dimers. Some of these products were also converted into free-base and zinc(II) forms with absorption and fluorescence shifted toward the near-infrared region.
Why the authors say this matters
The authors say the converted free-base and zinc(II) complexes display fairly red-shifted absorption bands and fluorescence in the near-infrared (NIR) region. The study suggests this behavior is relevant to the optical properties of these porphyrin dimers.
What the researchers tested
The researchers tested Pictet-Spengler cyclization of meso-amino and meso, meso'-diamino beta-beta'-linked nickel(II) porphyrin dimers with paraformaldehyde. They also tested oxidation of the cyclized products with FeCl3 and DDQ, and prepared the corresponding free bases and zinc(II) complexes.
What worked and what didn't
Cyclization of 1Ni and 2Ni gave fused azepine-bridged dimers 3Ni and 4Ni, respectively. Oxidation of 3Ni gave meso-tert-butylphenyl-fused dimer 5Ni in 43% yield, while oxidation of 4Ni gave singly meso-tert-butylphenyl-fused dimer 6Ni in 94% yield. A similar cyclization of 7Ni produced fused 1 H -azocine-bridged dimer 8Ni.
What to keep in mind
The abstract does not describe detailed limitations or broader scope beyond the specific porphyrin dimers studied. It also does not provide experimental conditions or comparative data for the near-infrared optical measurements.
Key points
- Pictet-Spengler cyclization produced fused azepine-bridged nickel(II) porphyrin dimers.
- A similar cyclization of another precursor produced a fused 1 H -azocine-bridged nickel(II) porphyrin dimer.
- Oxidation of one cyclized product gave a meso-tert-butylphenyl-fused dimer in 43% yield.
- Oxidation of a second cyclized product gave a singly meso-tert-butylphenyl-fused dimer in 94% yield.
- Free-base and zinc(II) versions of two dimers showed red-shifted absorption and near-infrared fluorescence.
Disclosure
- Research title:
- Ni II porphyrin dimers gain fused bridged ring structures
- Authors:
- Yuanyuan Li, Xiaojie Liu, H. Alexander Chen, Mingbo Zhou, Ling Xu, Yutao Rao, Bangshao Yin, Tomohiro Higashino, Atsuhiro Osuka, Jianxin Song
- Institutions:
- Hunan Normal University, Hunan Normal University, Hunan Normal University, Hunan Normal University, Hunan Normal University, Hunan Normal University, Hunan Normal University, Hunan Normal University, Hunan Normal University, Kyoto University, Kyoto University of Education
- Publication date:
- 2026-02-25
- DOI:
- 10.1002/anie.7602426
- OpenAlex record:
- View
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