RESUMEN

The reaction of RH (1) with Hg(OAc)(2), in EtOH, gave the acetate RHgOAc (2) [R = 2,6-[O(CH(2)CH(2))(2)NCH(2)](2)C(6)H(3)]. The corresponding RHgCl (3) was obtained from 2 and LiCl. The reaction of 3 with TeCl(4) (1:1 molar ratio), in anhydrous 1,4-dioxane, resulted in the transfer of the organic ligand from mercury to tellurium and the isolation of the unexpected ionic compounds [RTe](2)[Hg(2)Cl(6)] (4) and [RH(3)][HgCl(4)] (5). The molecular structures of 1-4 and 5·H(2)O were established by single-crystal X-ray diffraction. The acetate 2 and the chloride 3 are monomeric in solid state. In both mercury and tellurium organometallic compounds the organic group acts as an (N,C,N) "pincer" ligand. This coordination pattern provided stability for the rare [RTe](+) cation. Weak cation-anion interactions [Te···Cl 3.869(3) Å] are present between [RTe](+) and the dinuclear anion [Hg(2)Cl(6)](2-) in the crystal of 4. Theoretical calculations with DFT methods were performed for models of 3 and 4. The results show that in the cation of 4 the coordination of the nitrogen atoms play an important role for the stabilization of the structure found in the crystal whereas in 3 the coordination of the nitrogen atoms to the metal centre stabilizes to a less extent the structure found in solid state.

RESUMEN

The reaction of [AuCl(tht)] (tht = tetrahydrothiophene) with SbMes(n)Ph(3-n) (n = 3 (1), 2 (2), 1 (3)) produces the 1:1 adducts [AuCl(SbMes(n)Ph(3-n))] (n = 3 (4), 2 (5), 1 (6)), with a Sb-Au-Cl environment, regardless of the molar ratio used (1:1 to 1:4). Addition of the same stibines to [Au(tht)(2)]ClO(4) (molar ratio 1:1 to 1:4) results in isolation of the 1:2 adducts [Au(SbMes(n)Ph(3-n))(2)]ClO(4) (n = 3 (7), 2 (10)), containing linear Sb-Au-Sb fragments, or the 1:3 adduct [Au(SbMesPh(2))(3)]ClO(4) (11), with a quasi trigonal planar AuSb(3) core. The same 1:2 cations are produced when [Au(tht)(2)]CF(3)SO(3) is reacted with 1 or following a rearrangement process when 4 is treated with AgSbF(6), that is, [Au(SbMes(3))(2)]X (X = CF(3)SO(3) (8), SbF(6) (9)). The compounds were characterized by spectroscopic methods, and the molecular structures of 2-4, 7, 8.2CDCl(3), 9, and 11 were established by single-crystal X-ray diffraction. Theoretical calculations were carried out on model systems of type ER(3) and [Au(ER(3))(n)](+) (E = P or Sb; R = Ph or Mes; n = 2, 3, or 4) to gain insight into the bonding nature of SbR(3) ligands in homoleptic gold-stibine adducts, in comparison with phosphine-gold(I) compounds. Steric effects govern the coordination of stibines with mesityl substituents. A preference for higher coordination numbers is observed for SbPh(3) when compared with PPh(3) and experimentally observed C-Sb-C and Sb-C structural distortions of stibines upon coordination are reproduced theoretically.

Asunto(s)

Antimonio/química , Oro/química , Compuestos Organometálicos/química , Cristalografía por Rayos X , Ligandos , Modelos Moleculares

RESUMEN

Hypervalent organoantimony(III) compounds of the type [2-(Me2NCH2)C6H4]PhSbCl (1), [2-(Me2NCH2)C6H4]MesSbBr (7) and [2-(Me2NCH2)C6H4]nAr(3-n)Sb [n = 1, Ar = Ph (4), Mes (9); n = 2, Ar = Ph (5), Mes (10)] were prepared via salt elimination reactions between [2-(Me2NCH2)C6H4]Li and MesMgBr and PhnSbCl(3-n), [2-(Me2NCH2)C6H4]SbBr2 or [2-(Me2NCH2)C6H4]nSbCl(3-n) (n = 1, 2), in appropriate molar ratios. Halogen exchange reactions with aqueous KBr or KI gave [2-(Me2NCH2)C6H4]ArSbX [Ar = Ph, X = Br (2), I (3); Ar = Mes, X = I (8)]. Metathesis reaction between 1 and MesMgBr affords [2-(Me2NCH2)C6H4]PhMesSb (6). Compounds 1-10 were investigated by means of NMR (1H, 13C) in solution and by mass spectrometry. The investigation of the molecular structures of 2-8 by single-crystal X-ray diffraction revealed that the nitrogen atoms of the pendant CH2NMe2 arms are strongly coordinated to the antimony atoms. All compounds exhibit chirality and crystallize as racemic mixtures.

RESUMEN

The title complex, [SbBr(0.33)Cl(0.67)(C(9)H(13)N)(C(9)H(12)N)]Br(0.75)Cl(0.25), exhibits substitutional disorder of both halogen atoms in the asymmetric unit, however, with different occupancies. Thus, the halogen atom bonded to Sb has 0.67 (4) occupancy for Cl and 0.33 (4) for Br, while the anionic halogen atom shows 0.75 (4) occupancy for Br and 0.25 (4) for Cl. An N-H⋯Cl/Br hydrogen bond is established between the cation and the halide anion. The coordination geometry of the Sb center in the cation is distorted pseudo-trigonal-bipyramidal as a result of the strong intra-molecular N→Sb coordination trans to the Sb-Cl/Br bond. The pendant arm on the second ligand is twisted away from the metal center. The compound crystallizes as a racemate, i.e. a mixture of (R(N2),C(Sb1)) and (S(N2),A(Sb1)) isomers with respect to planar chirality induced by the coordinating N atom and chelate-induced Sb chirality. These isomers are associated through C(phen-yl)-H⋯Cl/Br hydrogen bonds, forming a three-dimensional architecture.

RESUMEN

Dinuclear three-coordinate Au(I) complex [Au2{(Ph2Sb)2O}3](ClO4)2 1 displays an interesting phosphorescent behavior in which a large Stokes' shift is observed. Ab initio calculations show that the main distortion for the first triplet excited state, which is responsible for the luminescence behavior of complex 1, is a Jahn-Teller distortion for only one of the Au(I) centers together with a gold-gold distance shortening. This behavior could be extrapolated to other phosphorescent dinuclear three-coordinate Au(I) complexes.

Asunto(s)

Antimonio/química , Oro/química , Compuestos Organometálicos/química , Cristalización , Cristalografía por Rayos X , Mediciones Luminiscentes , Modelos Moleculares , Compuestos Organometálicos/efectos de la radiación