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Abstract A bimetallic hydroxychalcogenide, BaZn2Se2(OH)2, was synthesized through hydrothermal pouch methods. The single crystal X‐ray diffraction and electron diffraction indicates that the phase crystallizes in the orthorhombic space groupPnmaand is composed of anionic layers [ZnSe3/3(OH)1/1]−that are separated and charged balanced by Ba2+cations. The [ZnSe3/3(OH)1/1]–layer comprises two unique Zn sites, which form interpenetrating zigzag chains with an in‐plane dipole moment and adopts a brownmillerite‐type structural motif. The adjacent layers contain tetrahedrally coordinated Zn chains of opposite handedness related by an inversion center, which cancel the microscopic dipoles to minimize the macroscopic electric polarization. The adoption of a brownmillerite structural motif in BaZn2Se2(OH)2can be rationalized by the distinct charge difference between Se2−and OH−anions, which creates a sufficient dipole moment in the ZnSe3(OH) tetrahedra to allow the occurrence of twisted chains. FTIR spectroscopy confirms the existence of OH−anions and DFT calculations indicate that BaZn2Se2(OH)2is a semiconductor with a direct band gap. This work expands the chemistry of the brownmillerite family from traditional homoanionic oxides to multianion hydroxychalcogenides, offering a new opportunity to explore tunable structural complexity for better design of functional materials.
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Maximizing Step‐Normalized Increases in Molecular Complexity: Formal [4+2+2+2] Photoinduced Cyclization Cascade to Access Polyheterocycles Possessing Privileged Substructures
Abstract A new complexity building photoinduced cascade which amounts to an unprecedented formal [4+2+2+2] cycloaddition topology is developed to access complex nitrogen polyheterocycles. This photocascade is initiated by the excited state intramolecular proton transfer (ESIPT) in aromatic amino ketones with tethered dual unsaturated pendants, i.e. pyrrole and alkenic moieties, resulting in the formation of four σ‐bonds and setting six new stereogenic centers in a single experimentally simple photochemical step with up to 220 mcbit complexity increases.
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- Award ID(s):
- 1955892
- PAR ID:
- 10363199
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 61
- Issue:
- 4
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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