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Updated: Dec 26, 2025

Synthesis of Single-Crystalline Core-Shell Metal-Organic Frameworks
Published on: February 10, 2023
Hydrothermal Synthesis and Structure of a Dinuclear Molybdenum(III) Hydroxy Squarate with a Mo-Mo Bond
Greg D Barber1, Christy George2, Kathryn Hogg1
1Department of Chemistry, The Pennsylvania State University, Altoona, Pennsylvania 16601, United States.
Abstract:
The reaction of molybdenum(II) and chromium(II) acetates with squaric acid in degassed and deionized water under hydrothermal conditions at 150 °C is described. The products have been formulated as M2(μ-OH)2(μ-C4O4)2(H2O)4·2H2O, where M = Cr (1) and Mo (2), based on combustion elemental analysis, infrared spectroscopy, magic angle spinning (MAS) solid-state carbon-13 nuclear magnetic resonance (NMR), and single-crystal X-ray diffraction. The edge-shared bioctahedral structures involve doubly bridging hydroxide ligands and μ-squarate ligands. The chromium compound lacks a direct metal-metal-bonding interaction, while in contrast the molybdenum compound contains a Mo-Mo bond [2.491(2) Å]. The nature of the Mo-Mo-bonding interaction is compared with that of other similar d3-d3 dimers.
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