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Title: Temperature-dependent polymorphism and magnetic properties of three-dimensional copper pyromellitate coordination polymers containing 4,4′-dipyridylamine

Journal Article · · Journal of Solid State Chemistry

A pair of three-dimensional divalent copper pyromellitate (1,2,4,5-benzene-tetracarboxylate, pyro) coordination polymers containing 4,4′-dipyridylamine (dpa) was hydrothermally prepared and structurally characterized by single-crystal X-ray diffraction. The higher-temperature phase ([H{sub 2}dpa][Cu{sub 3}(pyro){sub 2}(H{sub 2}O){sub 3}]·2.5H{sub 2}O){sub n} (1) displays an acentric 3-D 4,4,6-connected anionic network with (4{sup 4}5.6)(5{sup 4}8{sup 2})(4{sup 4}5{sup 4}6{sup 3}7{sup 4}) topology, featuring (Cu{sub 2}(OCO){sub 4}) paddlewheel dimers and isolated copper ions. Charge-balancing H{sub 2}dpa cations are embedded in incipient voids. Prepared at lower temperature, ([Cu{sub 3}(pyro){sub 2}(dpa){sub 2}(dpaH){sub 2}]·3H{sub 2}O){sub n} (2) manifests a 3-D 4,4,4-connected neutral network with uncommon (4{sup 2}6{sup 4}){sub 4}(6{sup 4}8{sup 2}) frl topology based on (Cu{sub 3}(OCO){sub 2}) linear trimers. Antiferromagnetic coupling (J=–82(5) cm{sup –1}) was observed within the (Cu{sub 2}(OCO){sub 4}) dimeric units in 1, while weak ferromagnetic coupling (J=1.0(4) cm{sup –1}) was evident for the (Cu{sub 3}(OCO){sub 2}) linear trimers in 2. Thermal degradation behavior of these new materials is also presented. - Graphical abstract: Two copper pyromellitate coordination polymers containing 4,4′-dipyridylamine were prepared. The higher-temperature phase ([H{sub 2}dpa][Cu{sub 3}(pyro){sub 2}(H{sub 2}O){sub 3}]∙2.5H{sub 2}O){sub n} displays an acentric 3-D trinodal anionic network with (4{sup 4}5.6)(5{sup 4}8{sup 2})(4{sup 4}5{sup 4}6{sup 3}7{sup 4}) topology, featuring antiferromagnetically coupled (Cu{sub 2}(OCO){sub 4}) paddlewheel dimers and isolated copper ions. - Highlights: • Copper pyromellitate (pyro) coordination polymers with 4,4′-dipyridylamine (dpa). • Higher-temperature phase 1 has 3-D anionic trinodal network with H{sub 2}dpa cations. • Lower-temperature phase 2 has rare 3-D frl network. • Dimers and chains in 1 show antiferromagnetism, trimers in 2 show ferromagnetism.

OSTI ID:
22475598
Journal Information:
Journal of Solid State Chemistry, Vol. 225; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
Country of Publication:
United States
Language:
English