Functional Heterometallic Layered Hybrid Magnets by Double Ion‐Exchange

Abstract

New 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.

Functional Hybrid Materials Based on Layered Simple Hydroxide Hosts and Dicarboxylate Schiff Base Metal Complex Guests

“…[68,69] The basal spacings of the Cu-SED-M compounds (M = Cu, Ni, Co, "MnCl") are in good agreement with the sizes of the SED-H 2 -M complexes and the thicknesses of the inorganic layers (about 2.5 Å [68] ). [32] The interlamellar distances observed after the insertion of the other complexes, SCD-K 2 -M M and SBD-H 2 -M (M = Co and "MnCl"), are also larger (by about 3 Å) than expected for "simple" insertion-grafting of the complexes. Moreover, the XRD pattern of this compound exhibits features at around 33 and 60°, similar to those observed in the cobalt hydroxide derivatives and considered as typical of the formation of a triple inorganic layer.…”

“…Sect.). [31,32] The final exchange reaction of the alkyl chains by the salencarboxylate complexes took place in 1:1 water/ethanol, which favored the solvation of the dodecyl sulfonate or dodecyl sulfate when removed from the interlamellar space. This increase allows for easier insertion-grafting of large molecules.…”

“…The complete list of absorption bands is given in Table SI1 in the Supporting Information. [31,32,77] Concomitantly, characteristic bands of the Schiff base complexes are observed, for which the data are summarized in Table SI1 in the Supporting Information. [70][71][72][73][74][75][76] After the exchange reaction, the spectra of all the hybrids indicate the almost complete disappearance of the very strong CH and CH 2 absorption bands at ν = 2925 and 2854 cm -1 and the vanishing of the -SO 3 or -SO 4 bands at ν = 1300-1000 cm -1 arising from the dodecyl sulfate or dodecyl sulfonate in the copper or cobalt hydroxide precursors, respectively.…”

“…Treatment of the starting hydroxides with a solution of the nickel Schiff bases [Ni{salen(SO 3 ) 2 }] 2and [Ni{(R,R)-or (S,S)-Cysalen-(SO 3 ) 2 }] 2led to the substitution of the alkyl anions by the nickel complexes retaining the structures of the parent hydroxide layers. [32] However, the exchange reactions were not as straightforward as for the nickel complexes. This approach is very promising for the construction of new multifunctional layered compounds.…”

Hybrid interfaces in layered hydroxides: magnetic and multifunctional superstructures by design

“…[142,143] Brought to you by | Stockholms Universitet Authenticated Download Date | 8/15/15 9:13 PM involving different diamine bridges. [140,144,145] The insertion of such complexes generates specific difficulties due to their possible hydrolysis during the exchange reaction. [144] This difficulty has been overcome by working from (Figure 21).…”