Solvothermal Synthesis and Crystal Structure of the Non-Centrosymmetric Thioantimonate [Ni(tren)2]2[Ni(tren)(en)]2(Sb4S8)2·0.25H2O

Inducing Ferrimagnetic Exchange in 1D-FeSe2 Chains Using Heteroleptic Amine Complexes: [Fe(en)(tren)][FeSe2]2

[Fe(en)(tren)][FeSe2]2 (en = ethylenediamine, C2H8N2, tren = tris(2-aminoethyl)amine, C6H18N4) has been synthesized by a mixed-ligand solvothermal method. Its crystal structure contains heteroleptic [Fe(en)(tren)]2+ complexes with distorted octahedral coordination, incorporated between 1D-FeSe2 chains composed of edge-sharing FeSe4 tetrahedra. The twisted octahedral coordination environment of the Fe-amine complex leads to partial dimerization of Fe-Fe distances in the FeSe2 chains so that the FeSe4 polyhedra deviate strongly from the regular tetrahedral geometry. 57Fe Mössbauer spectroscopy reveals oxidation states of +3 for the Fechain atoms and +2 for the Fecomplex atoms. The close proximity of Fe atoms in the chains promotes ferromagnetic nearest neighbor interactions, as indicated by a positive Weiss constant, θ = +53.8(6) K, derived from the Curie-Weiss fitting. Magnetometry and heat capacity reveal two consecutive magnetic transitions below 10 K. DFT calculations suggest that the ordering observed at 4 K is due to antiferromagnetic intrachain interactions in the 1D-FeSe2 chains. The combination of two different ligands creates an asymmetric coordination environment that induces changes in the structure of the Fe-Se fragments. This synthetic strategy opens new ways to explore the effects of ligand field strength on the structure of both Fe-amine complexes and surrounding Fe-Se chains.

Room-Temperature Synthesis of Thiostannates from {[Ni(tren)]2[Sn2S6]}n

The compound {[Ni(tren)]2[Sn2S6]}n (1) (tren = tris(2-aminoethyl)amine, C6H18N4) was successfully applied as source for the room-temperature synthesis of the new thiostannates [Ni(tren)(ma)(H2O)]2[Sn2S6]·4H2O (2) (ma = methylamine, CH5N) and [Ni(tren)(1,2-dap)]2[Sn2S6]·2H2O (3) (1,2-dap = 1,2-diaminopropane, C3H10N2). The Ni-S bonds in the Ni2S2N8 bioctahedron in the structure of 1 are analyzed with density functional theory calculations demonstrating significantly differing Ni-S bond strengths. Because of this asymmetry they are easily broken in the presence of an excess of ma or 1,2-dap immediately followed by Ni-N bond formation to N donor atoms of the amine ligands thus generating [Ni(tren)(amine)](2+) complexes. The chemical reactions are fast, and compounds 2 and 3 are formed within 1 h. The synthesis concept presented here opens hitherto unknown possibilities for preparation of new thiostannates.

Two manganese–amine complexes incorporating thioantimonates and exhibiting diversiform roles of amine ligands

Two manganese–amine complexes incorporating thioantimonates with diversiform structure-directing actions of the amine ligands have been synthesized and characterized.

[N,N-Bis(2-amino-eth-yl)ethane-1,2-diamine](ethane-1,2-diamine)-nickel(II) thio-sulfate trihydrate

The title compound, [Ni(C₂H₈N₂)(C₆H₁₈N₄)]S₂O₃·3H₂O, was accidentally synthesized under solvothermal conditions applying [Ni(en)₃]Cl₂ (en is ethane-1,2-diamine) as the Ni source. The asymmetric unit consists of one discrete [Ni(tren)(en)]²⁺ complex [tren is N,N-bis­(2-amino­eth­yl)ethane-1,2-diamine] in which the Ni²⁺ cation is sixfold coord­inated within a slightly distorted octa­hedron, one thio­sulfate anion and three water mol­ecules. In the crystal, the complex cations, anions and water mol­ecules are linked by an intricate hydrogen-bonding network. One C atom of the tren ligand, as well as one O atom of a water mol­ecule, are disordered over two sites and were refined using a split model (occupancy ratios = 0.85:15 and 0.60:0.40, respectively).