Conversion of hydrogen-bonded manganese(II) and zinc(II) squarate (C₄O₄^2–) molecules, chains and sheets to three-dimensional cage networks

A High‐Throughput Composite Catalyst based on Nickel Carbon Cubes for the Hydrogenation of 5‐Hydroxymethylfurfural to 2,5‐Dimethylfuran

“…The squarate units are incorporated in ab ridging bis-(m-1,3) coordination motif,l eading to Zn-squarate chains linked by strong intermolecular hydrogen bonds, which form a3 DZ nsquarate framework. [39,40] The differences in the relative intensities of the XRD patterns of SAZn comparedw ith the corresponding database is owing to differences in the preferential growth of the crystal.…”

“…Here, the complex is constituted of Zn atoms coordinated by four squarate units and two water molecules in trans ‐positions to each other in a slightly distorted octahedron. The squarate units are incorporated in a bridging bis‐(μ‐1,3) coordination motif, leading to Zn‐squarate chains linked by strong intermolecular hydrogen bonds, which form a 3D Zn‐squarate framework . The differences in the relative intensities of the XRD patterns of SAZn compared with the corresponding database is owing to differences in the preferential growth of the crystal.…”

Structural relationship of various squarates

“…In addition to the aforementioned metal squarates, we have found two new types of structures: M(HC404)2(H20)4 [M= Fe II, Mn II* (Yaghi, Li & Groy, 1995)] and Fe(C4Oa)(H20)2. The former can be considered as a two-dimensional network built by (HC404) 2 and _M(H20)4 units.…”

“…One exception is the Cu complex in type (1) (Frankenbach et al, 1992), where the bond length of *While preparing this work, the Mn complex was published independently by Yaghi, Li & Groy (1995 Cu--O~q is much longer than both bond lengths of Cu--Ow, which may be due to the strong Jahn-Teller distortion of Cu I~ ions. (1) and (3) should be the C4042dianion and is likely to be in D4h symmetry with C--C and C--O distances of 1.46 and 1.26A, respectively.…”

Synthesis and Characterization of [M2(OH)2(C4O4)2(H2O)4]·2H2O (M = Al or Ga)

“…The characteristic bands of the squarate ligand are clearly visible in both spectra. The band of the C=O vibration in squaric acid (1822 cm –1 ) is shifted to 1620 cm –1 for 1 and 1613 cm –1 for 2 due to hydrogen bonding, and can be assigned to the stretching vibrations of non‐coordinating C–O groups. The broad band centered at 1495 cm –1 for 1 and 1487 cm –1 for 2 , respectively, is due to C–C and C–O vibrations , …”