Group 9 Chalcogenometalates

Abstract

The compounds [K(18-crown-6)](3)[Ir(Se(4))(3)] (1), [K(2.2.2-cryptand)](3)[Ir(Se(4))(3)].C(6)H(5)CH(3) (2), and [K(18-crown-6)(DMF)(2)][Ir(NCCH(3))(2)(Se(4))(2)] (3) (DMF = dimethylformamide) have been prepared from the reaction of [Ir(NCCH(3))(2)(COE)(2)][BF(4)] (COE = cyclooctene) with polyselenide anions in acetonitrile/DMF. Analogous reactions utilizing [Rh(NCCH(3))(2)(COE)(2)][BF(4)] as a Rh source produce homologues of the Ir complexes; these have been characterized by (77)Se NMR spectroscopy. [NH(4)](3)[Ir(S(6))(3)].H(2)O.0.5CH(3)CH(2)OH (4) has been synthesized from the reaction of IrCl(3).nH(2)O with aqueous (NH(4))(2)S(m)(). In the structure of [K(18-crown-6)](3)[Ir(Se(4))(3)] (1) the Ir(III) center is chelated by three Se(4)(2)(-) ligands to form a distorted octahedral anion. The structure contains a disordered racemate of the Deltalambdalambdalambda and Lambdadeltadeltadelta conformers. The K(+) cations are pulled out of the planes of the crowns and interact with Se atoms of the [Ir(Se(4))(3)](3)(-) anion. [K(2.2.2-cryptand)](3)[Ir(Se(4))(3)].C(6)H(5)CH(3) (2) possesses no short K.Se interactions; here the [Ir(Se(4))(3)](3)(-) anion crystallizes as the Deltalambdalambdadelta/Lambdadeltadeltalambda racemate. In the crystal structure of [K(18-crown-6)(DMF)(2)][Ir(NCCH(3))(2)(Se(4))(2)] (3), the K(+) cation is coordinated by an 18-crown-6 ligand and two DMF molecules and the anion comprises an octahedral Ir(III) center bound by two chelating Se(4)(2)(-) chains and two trans acetonitrile groups. The [Ir(Se(4))(3)](3)(-) and [Rh(Se(4))(3)](3)(-) anions undergo conformational transformations as a function of temperature, as observed by (77)Se NMR spectroscopy. The thermodynamics of these transformations are: [Ir(Se(4))(3)](3)(-), DeltaH = 2.5(5) kcal mol(-)(1), DeltaS = 11.5(2.2) eu; [Rh(Se(4))(3)](3)(-), DeltaH = 5.2(7) kcal mol(-)(1), DeltaS = 24.7(3.0) eu.

Expanding the Remarkable Structural Diversity of Uranyl Tellurites: Hydrothermal Preparation and Structures of K[UO2Te2O5(OH)], Tl3{(UO2)2[Te2O5(OH)](Te2O6)}·2H2O, β-Tl2[UO2(TeO3)2], and Sr3[UO2(TeO3)2](TeO3)2

“…In addition, the K + cations form rather short ionic contacts of 2.716(4) Å with oxygen atoms from uranyl groups in adjacent layers. The eight coordinate environment for the K + cations observed here is quite similar to that of [K(18-crown-6)(DMF) 2 ] + . In this latter cation, the K + ···O contact distances are as follows: 2.707(14) (×2) Å to the oxygen atoms of the dimethylformamide molecules, and 2.830(13) (×2), 2.775(14) (×2), and 2.707(14) (×2) Å to the oxygen atoms in the 18-crown-6 molecule.…”

Bond Valence Sums in Coordination Chemistry Using New R0 Values. Potassium−Oxygen Complexes

“…To our knowledge the suggestion that the electron distribution is important in the stability of crown ether complexes has not been suggested previously. We might note that in the case of ZILXUN, the compound was retrieved as a KO 3 and the initial BVS was only 0.45. In the original report the K was coordinated to the 18-crown-6 with only three of the six K−O bonds included in the CSD entry, but the addition of three interactions increased the BVS to 0.89.…”

Trimethylsilylchalcogenolates of Co(II) and Mn(II): From Mononuclear Coordination Complexes to Clusters Containing −ESiMe3 Moieties (E = S, Se)

“…These bond lengths are themselves longer than those reported in the tetrahedral bis(tetraselenide) manganese complex [Mn(Se 4 ) 2 ] 2− (2.537(5)−2.553(5) Å) . [Pt(Se 4 ) 3 ] 2− , [Ir(Se 4 ) 3 ] 3− , and [Sn(Se 4 ) 3 ] 2− , represent other examples of structurally characterized octahedral selenometalates containing three tetraselenide ligands. The origin for the reproducible formation of 6 in the reaction is unclear but requires partial oxidation of Se 2− species present in the reaction.…”