Discrete Binuclear Cobalt(III) Bis-dioximates with Wheel-and-Axle Topology as Building Blocks To Afford Porous Supramolecular Metal–Organic Frameworks

详细信息    查看全文

• 作者：Eduard Coropceanu ; Andrei Rija ; Vasile Lozan ; Ion Bulhac ; Gheorghe Duca ; Victor Ch. Kravtsov ; Paulina Bourosh
• 刊名：Crystal Growth & Design
• 出版年：2016
• 出版时间：February 3, 2016
• 年：2016
• 卷：16
• 期：2
• 页码：814-820
• 全文大小：542K
• ISSN：1528-7505

文摘

Three binuclear and one mononuclear cobalt(III) dioximates with the compositions [Cob>2b>(dmgH)b>4b>(bpy)Clb>2b>]·1.5dmf (<b>1b>), [Cob>2b>(nioxH)b>4b>(bpy)Clb>2b>]·0.5Hb>2b>O (<b>2b>), [Cob>2b>(dmgH)b>4b>(bpe)Clb>2b>]·0.5Hb>2b>O (<b>3b>), and [Co(dmgH)b>2b>(bpy)Cl]·Hb>2b>O (<b>4b>) (where dmgHb>2b> = dimethylglyoxime, nioxHb>2b> = 1,2-cyclohexanedionedioxime, bpy = 4,4′-bipyridine, bpe = 1,2-bis(4-pyridyl)ethane, and dmf = N,N-dimethylformamide) were prepared by replacement of water molecule in Co(III) mononuclear dioximates by bpy and bpe ligands. All compounds were characterized by single-crystal X-ray diffraction and spectroscopic techniques. In all complexes Co(III) atoms have an identical octahedral Nb>5b>Cl environment formulated by four nitrogen atoms of two mono-deprotonated oxime ligands in a square planar mode, and the nitrogen atom of the bpy/bpe molecules and chloride atom in the axial positions. In <b>1b>–<b>3b> bpy/bpe exobidentate spacer ligands serve as bridging “rods” and unite two planar cobalt(III) bis-dioximates in binuclear complex with wheel-and-axle topology. The packing of bulky binuclear complexes results in formation of porous structure with hourglass-like channels of diameter ca. 0.6–1.3 nm in the crystal of compound <b>1b> and smaller cavities in <b>2b>. The sorption properties for <b>1b> were also measured. The π···π stacking interaction between monodentate bpy ligands of mononuclear complexes <b>4b> emulate supramolecular binuclear assembly with wheel-and-axle topology.