Flash Communication: Synthesis of Nickel-Lanthanide Sulfido-bridged Coordination Clusters Using an Acid–Base Interaction

Abstract

The reactions between [Cp*2Ln(allyl)] and [(dppe)Ni(SH)2] (dppe = Ph2PCH2CH2PPh2) or [(POCOPiPr)Ni(SH)] (POCOPiPr = C6H3(OP(iPr)2)2) proceed as a classic acid–base interaction in which the nickel hydrosulfide complexes serve as typical Brønsted acids. In case of the dibasic acid [(dppe)Ni(SH)2] the reactions lead to tetrametal coordination clusters [{(dppe)Ni}2(μ3-S)4{LnCp*}2] (Ln = Dy (1), Ho (2)) and accompanied by elimination of propene and Cp*H, while in case of monobasic acid [(POCOPiPr)Ni(SH)] only (allyl)− serves as a proton acceptor and the reactions result in formation of bimetal species [(POCOPiPr)Ni(μ-S){LnCp*2}] (Ln = Dy (3), Ho (4), Y (5)). Single-crystal X-ray diffraction (XRD) revealed correspondingly tetrametal and dimetal sulfido-bridged Ni/S/Ln frameworks, with the binuclear complexes exhibiting exceptionally short Ln–S bond distances. Magnetic measurements of the Ni/Dy and Ni/Ho complexes showed that the Ni(II) centers are diamagnetic and that the magnetic behavior is governed by corresponding lanthanide ion(s). For 3 field-induced slow magnetic relaxation was observed, with an effective relaxation barrier of 22 K.