Functional Heterometallic Layered Hybrid Magnets by Double Ion‐Exchange

Abstract

AbstractNew hybrid compounds have been synthesized by functionalization of cobalt and copper layered hydroxides by salen complexes. Two kinds of compounds have been obtained from [M(SalenSO3Na2)] (M = Cu2+, Ni2+, Co2+ and Zn2+) and the preintercalated copper and cobalt hydroxides Cu2(OH)3(DS) and Co2(OH)3(DS0) [SalenSO3Na2 = N,N′‐bis(5‐sulfonatosalicylidene)‐1,2‐diaminoethane disodium salt, DS– = dodecylsulfate, DS0– = dodecylsulfonate]. The reaction of [M(SalenSO3Na2)] with layered copper hydroxide led to the anion‐exchanged compounds Cu2(OH)3.00(CuSalenSO3)0.50·0.20H2O [Cu(SalenSO3)⊂Cu (1)] and Cu2(OH)3.24(NiSalenSO3)0.38·2.6H2O [Ni(SalenSO3)⊂Cu (2)] where M = Cu2+ or Ni2+. Similarly, the reaction with layered cobalt hydroxide leads to the exchanged compounds Co2(OH)3.18(NiSalenSO3)0.41·4.0H2O [Ni(SalenSO3)⊂Co (6)] and Co2(OH)3.44(CoSalenSO3)0.28·3.7H2O [Co(SalenSO3)⊂Co (8)] where M = Ni2+ or Co2+. The reaction of [M(SalenSO3)Na2] with layered copper hydroxide where M = Co2+ or Zn2+ and that of layered cobalt hydroxide where M = Cu2+ or Zn2+ resulted in the modification of the host structure because of concomitant partial cation exchange between the salen complex and the inorganic layers. Mixed‐ion‐exchanged compounds were obtained, Cu1.16Co0.84(OH)3.28(CoSalenSO3)0.36·6.4H2O [Co(SalenSO3)⊂Cu/Co (4)], Cu0.7Zn1.30(OH)3.20(ZnSalenSO3)0.40·2.11H2O [Zn(SalenSO3)⊂Cu/Zn (3)], Co1.72Cu0.28(OH)3.28(CuSalenSO3)0.36·3.20H2O [Cu(SalenSO3)⊂Co/Cu (5)] and Co0.80Zn1.20(OH)3.20(ZnSalenSO)0.40·2.25H2O [Zn(SalenSO3)⊂Co/Zn (7)]. The magnetic behaviour of the compounds is drastically modified depending on the structure of the inorganic layers induced by the functionalization and partial cation exchange. The hybrid copper layered hydroxides show antiferromagnetic (for 3) or weak ferromagnetic (for 1, 2 and 4) behaviour. The cobalt analogues 5, 6 and 8 are ferrimagnets with ordering temperatures at ca. 6 K, whereas the Co/Zn heterometallic layered simple hydroxide 7 presents dominant antiferromagnetic interactions.