title: Magnetocaloric Properties of Heterometallic 3d-Gd Complexes Based on the [Gd(oda)3 ](3-) Metalloligand.
abstract: A series of heterometallic 3d-Gd(3+) complexes based on a lanthanide metalloligand, [M(H2 O)6 ][Gd(oda)3 ]⋅3 H2 O [M=Cr(3+) (1-Cr)] (H2 oda=2,2'-oxydiacetic acid), [M(H2 O)6 ][MGd(oda)3 ]2 ⋅3 H2 O [M=Mn(2+) (2-Mn), Fe(2+) (2-Fe) and Co(2+) (2-Co)], and [M3 Gd2 (oda)6 (H2 O)6 ]⋅12 H2 O [M=Ni(2+) (3-Ni), Cu(2+) (3-Cu), and Zn(2+) (3-Zn)], are reported. Magnetic and heat-capacity studies revealed a significant impact on the magnetocaloric effect depending on the anisotropy of the 3d transition metal ions, as confirmed by comparison of the observed maximum values of -ΔSm between complexes 2-Co and 1-Cr. In these two complexes, the 3d metal ions have the same spin (S=3/2 for Co(2+) and Cr(3+) ions), and the theoretical calculation suggested a larger -ΔSm value for 2-Co (47.8 J K(-1)  kg(-1) ) than 1-Cr (37.5 J K(-1)  kg(-1) ); however, the significant anisotropy of Co(2+) ions in 2-Co, which can result in smaller effective spins, gives a smaller value of -ΔSm for 2-Co (32.2 J K(-1)  kg(-1) ) than for 1-Cr (35.4 J K(-1)  kg(-1) ) at ΔH=9 T.
authors.affiliation: Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry & Chemical Engineering, Sun Yat-Sen University, Guangzhou, 510275 (P. R. China), Fax: (+86) 20-8411-2245.
authors.forename: Jiang-Zhen
authors.initials: JZ
authors.lastname: Qiu
authors.affiliation: Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry & Chemical Engineering, Sun Yat-Sen University, Guangzhou, 510275 (P. R. China), Fax: (+86) 20-8411-2245.
authors.forename: Long-Fei
authors.initials: LF
authors.lastname: Wang
authors.affiliation: Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry & Chemical Engineering, Sun Yat-Sen University, Guangzhou, 510275 (P. R. China), Fax: (+86) 20-8411-2245.
authors.forename: Yan-Cong
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry & Chemical Engineering, Sun Yat-Sen University, Guangzhou, 510275 (P. R. China), Fax: (+86) 20-8411-2245.
authors.forename: Ze-Min
authors.initials: ZM
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry & Chemical Engineering, Sun Yat-Sen University, Guangzhou, 510275 (P. R. China), Fax: (+86) 20-8411-2245.
authors.forename: Quan-Wen
authors.initials: QW
authors.lastname: Li
authors.affiliation: Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry & Chemical Engineering, Sun Yat-Sen University, Guangzhou, 510275 (P. R. China), Fax: (+86) 20-8411-2245. tongml@mail.sysu.edu.cn.
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Tong
keywords: carboxylate ligands; heterometallic complexes; lanthanides; magnetic properties; transition metals