Portal de Periódicos da CAPES

Synthesis and Characterization of [Yb(NH 3 ) 8 ][Cu(S 4 ) 2 ]·NH 3 , [Yb(NH 3 ) 8 ][Ag(S 4 ) 2 ]·2NH 3 , and [La(NH 3 ) 9 ][Cu(S 4 ) 2 ] in Supercritical Ammonia: Metal Sulfide Salts of the First Homoleptic Lanthanide Ammine Complexes

1996; American Chemical Society; Volume: 35; Issue: 26 Linguagem: Inglês

10.1021/ic9601403

1520-510X

Dianna M. Young, George L. Schimek, Joseph W. Kolis,

Iron-based superconductors research

Three new lanthanide metal polysulfides have been synthesized in supercritical ammonia: [Yb(NH3)8][Cu(S4)2]· NH3 (I), [Yb(NH3)8][Ag(S4)2]·2NH3 (II), [La(NH3)9][Cu(S4)2] (III). Compounds were prepared in sealed quartz tubes which were filled to one-third volume with liquid ammonia and heated at 170 °C for 3 days. Compounds I and II were obtained from the reaction of a premade ytterbium polysulfide with M and S in the ratio of 1:1:4, while [La(NH3)9][Cu(S4)2], III, was obtained by reacting La, Cu, and S in the ratio of 1:1:8. In all these compounds, the lanthanide cation is coordinated only by ammonia, while the M+ is chelated by S42- to form metal tetrasulfide rings. [Yb(NH3)8][Cu(S4)2]·NH3 and [Yb(NH3)8][Ag(S4)2]·2NH3 contain [M(S4)2]3- anionic units with M+ in a distorted tetrahedral coordination environment chelated by two S42- groups. Compound III, [La(NH3)9][Cu(S4)2], also contains anionic [Cu(S4)2]3- units; however, Cu+ is in a trigonal planar coordination geometry due to the presence of one monodentate S42-. All the compounds are unstable with respect to loss of ammonia, and decomposition yielded known ternary and binary phases. Crystallographic data for the compounds are the following: I, space group = I4̄ , Z = 2, a = 10.024(4) Å, c = 9.752(4) Å; II, space group = P212121, Z = 4 , a = 11.177(4) Å, b = 20.472(6) Å, c = 9.754(3) Å; III, space group = P21/n, Z = 4, a = 9.891(2) Å, b = 12.600(3) Å, c = 17.812(3) Å, β = 103.57(2)°.