Reactivity of [NBu4]2[{(C6X5)2M(μ-OH)}2] (X=F or Cl; M=Pd or Pt) towards heterocyclic thiones: crystal structure of [NBu4]2[{(C6F5)2Pd(μ-ν2-LL′)}2] (LL′=methylimidazole-2-thiolate)
摘要:
The di-mu-hydroxo complexes [NBu4](2)[{(C6X5)(2)M(mu-OH)(2)}(2)] (M=Pd or Pt; X=F or Cl) react with heterocyclic thiones H(LL') (1:2 molar ratio) to give the heterocyclic-2-thiolate complexes [NBu4][(C6X5)(2)M(eta(2)-LL')] (LL' = pyridine-2-thiolate (pyS), pyrimidine 2-thiolate (pyrimS), 2,6-dimethyl-5-oxo-1,2,4-triazine-3-thiolate (MetazS), 6-methyl-5-oxo-1,2,4-triazine-3-thiolate (MetazS)) or [NBu4](2)[{(C6F5)(2)M(mu-eta(2)-MeimidS)}(2)] (MeimidS = methylimidazole-2-thiolate). The variable-temperature H-1 NMR spectra of the complexes [NBu4] [(C6X5)(2)M(eta(2)-LL')] over the range -50 to +60 degrees C are all static, but those of the methylimidazole-2-thiolate complexes [NBu4](2)[{(C6F5)(2)M(mu-eta(2)-MeimidS)}(2)] (M=Pd and Pt) suggest the existence of dynamic chemical processes involving both dimeric and monomeric species. Crystallization of [NBu4](2)[{(C6F5)(2)Pd(mu-eta(2)-MeimidS)}(2)] from wet dichloromethane-hexane-ether afford the mixed complex [NBu4](2)[{(C6F5)(2)Pd}(2)(mu-OH)(mu-eta(2)-MeimidS)]. The analogous mixed-platinum complex [NBu4](2)[{(C6F5)(2)Pt}(2)(mu-OH)(mu-eta(2)-MeimidS)] was prepared by reaction of [NBu4](2)[{(C6X5)(2)Pt(mu-OH)(2)}(2)] with the corresponding heterocyclic thione H(LL') in 1:1 molar ratio. The crystal structure of [NBu4](2)[{(C6F5)(2)Pd(mu-eta(2)-MeimidS)}(2)], determined by X-ray diffraction, confirmed the dimeric structure with a head-to-tail arrangement. C64H82F20N6Pd2S2, orthorhombic Pca2(1), a = 19.552(8), b = 25.160(3), c = 14.727(3) Angstrom, Z = 4. (C) 1998 Elsevier Science S.A. All rights reserved.