Assembling bi-, tri- and pentanuclear complexes into extended structures using a desolvation reaction: Synthesis, structure, and magnetic properties of manganese(III)-Schiff-base-hexacyanoferrate polymeric compounds and their derived extended structu

摘要

Mn(BS)(H2O)]ClO4 and [NEt4](3)[Fe(CN)(6)] react in methanol or ethanol to give a binuclear [NEt4](2)[{Mn(BS)(S)}(Fe(CN)(6)}], 1, three trinuclear [NEt4][{Mn(BS)(S)}(2){Fe(CN)(6)}], 2-4, and a pentanuclear [Mn(BS)(S)](4)[Fe(CN)(6)]ClO4, 5, heterometal complex, depending on the nature of the quadridentate Schiff-base ligands and regardless of the stoichiometric ratio of the precursor components (BS = saldmen = N,N'-(1,1-dimethylethylene)bis(salicylideneiminato) dianion, S = H2O for 1; BS rac-salmen = rac-N,N'-(1-methylethylene)bis (salicylideneiminato) dianion, S = MeOH for 2; BS = rac-salcy = rac-N,N'-(1,2-cyclohexanediylethylene)bis(salicylideneiminato) dianion, S = MeOH for 3; (R,R)-salcy = (R,R)-N,N'-(1,2-cyclohexanediylethylene)bis (salicylideneiminato) dianion, S = H2O for 4; BS = saltmen = N,N'-(1,1,2,2-tetramethylethylene)bis(salicylideneiminato) dianion, S = H2O for 5). Complexes 1 and 2 have been characterized by X-ray analyses, Complex 1 consists of a discrete CN-bridged Mn(III)-Fe(III) binuclear unit [(H2O)Mn(saldmen)Fe(CN)(6)](2-) hydrogen-bonded into a one-dimensional chain structure. Complex 2 consists of a discrete centrosymmetric trinuclear unit [(MeOH)Mn(salmen)Fe(CN)(6)Mn(salmen)(MeOH)](-) hydrogen-bonded, thus forming a two-dimensional network with a repeating cyclic octamer [-NC-Fe-CN-Mn-MeOH-](4) unit. Complexes 1-5 led to desolvated forms 1'-5'. Some of these forms (1'-3') show spontaneous magnetization according to an extended structure where the original magnetically isolated oligomeric forms now communicate with each other, In the case of 4' and 5', the desolvation probably occurs with a severe reorganization of the parent hydrogen-bonded extended structure, and hence, cooperative magnetic effects were not observed. [References: 54