The [Cu2(O2CMe)4(btd)2] complex as a bridging unit: preparation, characterisation, X-ray structure and magnetism of the 2D coordination polymer {[Cu6(O2CMe)8(OMe)4(btd)2]}n (btd=2,1,3-benzothiadiazole)
摘要:
A systematic investigation of the [Cu-2(O2CMe)(4) (H2O)(2)]/btd reaction system is described, where btd = 2,1,3-benzothiadiazole. Reaction of [Cu-2(O2CMe)(4)(H2O)(2)] with 5-8 equiv. of btd in both MeCN and MeOH yields [Cu-2(O2CMe)(4)(btd)(2)] (1) in 40-50% yields. Treatment of [Cu-2(O2CMe)(4)(H2O)(2)] With 1.4 or 0.7 equiv. of btd in MeOH leads to the precipitation of the polymeric compound {[Cu-6(O2CMe)(8)(OMe)(4)(btd)(2)]} (2) in 82% yield. Reaction of 1 with two equivalents of [Cu-2(O2CMe)(4)(H2O)(2)] in MeOH under reflux provides an additional route to 2. The structure of 1 consists of centrosymmetric dinuclear [Cu-2(O2CMe)(4)(btd)(2)] molecules of the paddle-wheel cage type. The two Cu-II ions are bridged by four eta (1):eta (1):mu (2) acetates, while a monodentate btd is at the apex of the square pyramid of each metal centre. The 2D structure of 2 consists of chains of tetranuclear, planar Cu-4(OMe)(4)(O2CMe)(4) repeating units running along the a axis, which are connected along the cell body diagonal via Cu-2(O2CMe)(4)(btd)(2) paddle-wheel dinuclear units. The btd molecules behave as bidentate bridging ligands. Within the tetranuclear units, each Cu-II ion is connected via two acetate bridges with one neighbouring Cu-II ion and via two methoxo bridges with the other neighbouring Cu-II ion; intertetranuclear linking is provided by two monoatomic acetate bridges. The results of solid state magnetic susceptibility studies are described for complex 2 in the temperature range 3-300 K. The results reveal antiferromagnetic exchange interactions between the Cu-II ions. The complicated structure of 2 does not permit an exact treatment for the determination of the various exchange interactions. However, an approximate 3-J magnetic model was constructed, resulting in an excellent fit. An orbital interpretation of the J-trend derived is also attempted. (C) 2001 Elsevier Science B.V. All rights reserved.
The [Cu2(O2CMe)4(btd)2] complex as a bridging unit: preparation, characterisation, X-ray structure and magnetism of the 2D coordination polymer {[Cu6(O2CMe)8(OMe)4(btd)2]}n (btd=2,1,3-benzothiadiazole)
摘要:
A systematic investigation of the [Cu-2(O2CMe)(4) (H2O)(2)]/btd reaction system is described, where btd = 2,1,3-benzothiadiazole. Reaction of [Cu-2(O2CMe)(4)(H2O)(2)] with 5-8 equiv. of btd in both MeCN and MeOH yields [Cu-2(O2CMe)(4)(btd)(2)] (1) in 40-50% yields. Treatment of [Cu-2(O2CMe)(4)(H2O)(2)] With 1.4 or 0.7 equiv. of btd in MeOH leads to the precipitation of the polymeric compound {[Cu-6(O2CMe)(8)(OMe)(4)(btd)(2)]} (2) in 82% yield. Reaction of 1 with two equivalents of [Cu-2(O2CMe)(4)(H2O)(2)] in MeOH under reflux provides an additional route to 2. The structure of 1 consists of centrosymmetric dinuclear [Cu-2(O2CMe)(4)(btd)(2)] molecules of the paddle-wheel cage type. The two Cu-II ions are bridged by four eta (1):eta (1):mu (2) acetates, while a monodentate btd is at the apex of the square pyramid of each metal centre. The 2D structure of 2 consists of chains of tetranuclear, planar Cu-4(OMe)(4)(O2CMe)(4) repeating units running along the a axis, which are connected along the cell body diagonal via Cu-2(O2CMe)(4)(btd)(2) paddle-wheel dinuclear units. The btd molecules behave as bidentate bridging ligands. Within the tetranuclear units, each Cu-II ion is connected via two acetate bridges with one neighbouring Cu-II ion and via two methoxo bridges with the other neighbouring Cu-II ion; intertetranuclear linking is provided by two monoatomic acetate bridges. The results of solid state magnetic susceptibility studies are described for complex 2 in the temperature range 3-300 K. The results reveal antiferromagnetic exchange interactions between the Cu-II ions. The complicated structure of 2 does not permit an exact treatment for the determination of the various exchange interactions. However, an approximate 3-J magnetic model was constructed, resulting in an excellent fit. An orbital interpretation of the J-trend derived is also attempted. (C) 2001 Elsevier Science B.V. All rights reserved.