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Synthesis and Characterization of Nickel(II) Phosphonate Complexes Utilizing Pyridonates and Carboxylates as Co-ligands

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posted on 21.01.2014, 00:00 by Stuart K. Langley, Madeleine Helliwell, Simon J. Teat, Richard E. P. Winpenny
The synthesis and structures of five new nickel complexes containing phosphonate ligands are reported. The compounds utilize pivalic acid (HPiv) and 6-chloro-2-pyridonate (Hchp) as co-ligands with the resulting complexes being of formulas [Ni10(chp)4­(Hchp)4.5­(O3PtBu)3­(Piv)5(HPiv)2­(OH)6(H2O)4.5]­(HNEt3)·0.5MeCN·2.5H2O 1, [Ni12(chp)12(Hchp)2(PhPO3)2­(Piv)5(HPiv)2­(OH)2(H2O)6]­(F)·4.5MeCN·2H2O 2, [Ni10(chp)6(O3PCH2Ph)2­(Piv)8(F)2­(MeCN)4] 3, [Ni10(chp)6­(O3PMe)2­(Piv)8(F)2 (MeCN)4]·5MeCN·2H2O 4, and [Ni10(chp)6(O3PCH2Nap)2­(Piv)8(F)2­(MeCN)2(H2O)2] 5. The metallic core of compounds 1 and 2 display tetra- and hexa-capped trigonal prismatic arrangements, while the metallic and phosphorus core of 3, 4, and 5 display three face-sharing octahedra. Variable temperature direct current (dc) magnetic susceptibility measurements reveal dominant antiferromagnetic exchange interactions within each cluster, with diamagnetic spin ground states found.