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The synthesis and characterization of base-stabilized and base-free pincer-type bis(phosphine)/silylene [P2Si]Ru complexes are reported. The base-free complex readily reduces CO2 and CS2via silylene-assisted hydride transfer, affording structurally distinct products with silicon-to-ruthenium formate and dithioformate bridges. [ABSTRACT FROM AUTHOR]

Sandwich coordination complexes, [LnIII(H3L)2]X3∙solvents, of Tb(III), Eu(III), Dy(III), Ho(III) and Er(III) were prepared with two new zwitterionic ester-substituted tripodal amine ligands, tris((2-hydroxy-5-n-butyl benzoate)aminoethyl)-amine (H3L1) and tris((2-hydroxy-5-methyl benzoate)aminoethyl)-amine (H3L2). These ligands were synthesised by condensation of the appropriately substituted salicylaldehyde with tris(2-aminoethyl)amine (tren) followed byin situreduction of the tris-imine to tris-amine. Subsequent 2:1 reaction with lanthanide(III) ions yields [LnIII(H3L)2]X3∙solvents(L = L1,L2; X = Cl−, NO3−;solvents = MeOH or H2O). All complexes were characterised by microanalysis, infrared spectroscopy, high resolution mass spectrometry and solid-state photoluminescence measurements. The crystal structures of [TbIII(H3L1)2]Cl3·6MeOH, [Dy(H3L1)2]Cl3·6MeOH, [EuIII(H3L1)2]Cl3·6MeOH and [TbIII(H3L1)2](NO3)3reveal high-crystallographic −3 symmetry at the O6-coordinated octahedral lanthanide(III) ions and that the tripodal ligands are bound in zwitterionic form: the protons from the phenolic oxygens have migrated to the amino nitrogens. Photoluminescence measurements indicate various degrees of energy transfer of the ligand chromophore to the lanthanide ions, as both ligand and lanthanide emission features are observed. Despite the high-crystallographic symmetry and the likely small transverse magnetic anisotropy of the complexes, no evidence of slow relaxation of the magnetisation, characteristic of a single-molecule magnet, was observed for [TbIII(H3L1)2]Cl3·MeOH·3H2O, [DyIII(H3L1)2]Cl3·6H2O, [HoIII(H3L1)2](NO3)3·2H2O, [ErIII(H3L1)2]·H2O and [TbIII(H3L1)2](NO3)3down to 2.0 K. [ABSTRACT FROM AUTHOR]

A convenient synthetic scheme was developed to access a series of square-planar Pt(ii) complexes of the form (TBA)[Pt(CN)3(CNR)] (TBA = tetra-n-butyl ammonium cation, R = CH3, c-C6H11, p-(C2H5)-C6H4). These heteroleptic complexes were characterized by combustion analyses, single-crystal X-ray structure determinations, HRFAB-MS, 1H NMR, ATR-IR, solution UV-Vis, and solid-state emission spectroscopies. Surprisingly, each of these complexes exhibit low energy room temperature solid-state luminescence in the absence of intermolecular Pt–Pt interactions. Additionally, the polymorphic behavior of (TBA)[Pt(CN)3(CN-c-C6H11)] was elucidated through a combination of single-crystal X-ray structure determinations, X-ray powder diffraction, and mass uptake experiments. Vapoluminescence and polymorphic transformations of (TBA)[Pt(CN)3(CN-c-C6H11)] were concomitant with water vapor absorption. A new double-salt complex [Pt(terpy)Cl] [Pt(CN)3(CNCH3)] (terpy = 2,2′,6′,2′′-terpyridine) was also synthesized and characterized by combustion analysis, ATR-IR, HRFAB-MS, and solid-state UV-Vis and emission spectroscopies. The vapoluminescent properties of this salt in response to water were examined by mass uptake experiments, ATR-IR, and solid-state emission spectroscopy. A principal component analysis (PCA) of the solid-state emission changes induced by water vapor confirmed the presence of an intermediate emissive species. [ABSTRACT FROM AUTHOR]

We report the synthesis and characterization of a series of cyclometallated complexes of Pd(II) incorporating the fluxional trithiacrown ligand 1,4,7-trithiacyclononane ([9]aneS 3 ). Reaction of palladium(II) acetate with 2,3′-thienylpyridine (2,3′thpy), 2,2′-thienylpyridine (2,3′thpy), 2-benzothienylpyridine (btp), and 2-phenylbenzothiazole (pbt) resulted in the formation of di-μ-acetate bridged dimers of the form [Pd(CˆN)(μ-O 2 CCH 3 )] 2 (CˆN = deprotonated cyclometallated ligand). The NMR spectra of these dimers indicate the presence of both anti and syn isomers in each cyclometallated ligand analog. X-ray crystal structures of anti -[Pd(CˆN)(μ-O 2 CCH 3 )] 2 (CˆN = 2,3′thpy and btp) show intermolecular π-stacking. Reaction of [Pd(CˆN)(μ-O 2 CCH 3 )] 2 with [9]aneS 3 followed by metathesis with NH 4 PF 6 yields [Pd(CˆN)([9]aneS 3 )](PF 6 ). 1 H and 13 C NMR studies demonstrate that the coordinated [9]aneS 3 ligand is fluxional on the NMR timescale at ambient temperature. X-ray crystallographic studies reveal the elongated square pyramidal structure of these [Pd(CˆN)([9]aneS 3 )](PF 6 ) complexes which possess two typical equatorial Pd–S bonds and an additional Pd⋯S interaction shorter than van der Waals radii sum. Intermolecular π-stacking features of these [Pd(CˆN)([9]aneS 3 )](PF 6 ) structures are discussed in light of previously described common motifs found in related structures. NMR and crystallographic evidence are presented that indicate the 2,3′thpy ligand coordinates to Pd(II) in both κC 2 and κC 3 modes, forming linkage isomers. Electrochemical studies of the [Pd(CˆN)([9]aneS 3 )](PF 6 ) complexes reveal two reversible one-electron oxidations, an exceptional behavior. These oxidations are assigned as metal-based Pd II/III and Pd III/IV processes. The complex cis -[Pd(2,3′thpy) 2 ], synthesized using a room temperature double C–H bond activation procedure, was characterized by 1 H NMR and X-ray crystallography. [ABSTRACT FROM AUTHOR]

Abstract: We report the synthesis and characterization for several gold(III) complexes involving a series of cyclometallating ligands. These cyclometallating ligands (CˆN) are: 2-phenylpyridine (ppy), 2-(p-tolyl)pyridine (tpy), 2-(2′-benzothienyl)pyridine (btp) and 7,8-benzoquinoline (bzq). With the assistance of TGA data, we have developed solventless reactions to prepare the neutral cyclometallated Au(III) dichloro complexes. Reaction of these with the crown trithioether [9]aneS3 (1,4,7-trithiacyclononane), followed by metathesis with NH4PF6, yields the heteroleptic complexes [Au([9]aneS3)(CˆN)](PF6)2. The X-ray structures of the gold(III) [9]aneS3 complexes display axial Au–S interactions formed by the endodentate conformation of the thiacrown, resulting in elongated square pyramidal geometries. The Au–S axial distance correlates with the electron-donating properties of the CˆN ligand with the better donating btp showing the longest distance (2.855(1) Å) while the ppy shows the shortest (2.818(1) Å). The coordinated [9]aneS3 ligand shows fluxional behavior by its NMR spectroscopy, resulting in a single 13C NMR resonance despite the asymmetric coordination environment of the cyclometallating ligand. Electrochemical studies of the [9]aneS3 complexes reveal irreversible one-electron reductions which are assigned as a Au(III)/Au(II) couple. The ease of reduction correlates with the axial Au–S distances with the btp being the easiest to reduce and the ppy the most difficult. In addition, we report the crystal structures for three intermediate complexes: [Au(H-tpy)Cl3], [Au(H-btp)Cl3], and [Au(btp)Cl2]. The [Au(H-btp)Cl3] complex shows an interesting Au–S axial interaction at 3.139(2) Å which alters the physicochemical properties of the complex. [Copyright &y& Elsevier]

Rhodium(I)silylamide complexes supported by the 1,2-bis(di-tert-butylphosphino)ethane (dtbpe) ligand have been preparedand their structures and reactivity studied. Although the complexesdegrade over time to release the corresponding silylamines, they reactcleanly with silver(I) salts to transfer the amido group at ambienttemperature. The bis(trimethylsilyl)amide complex (dtbpe)Rh–N(TMS)2reacts with CO2to form a carbamate complex thatdecomposes via loss of hexamethyldisiloxane to form a bis(μ-isocyanate)dimer, suggesting that silylamides may be useful nitrene-group andnitrogen-atom sources through selective N–Si bond cleavage. [ABSTRACT FROM AUTHOR]

The synthesis and metalation of twobis(phosphine)/dihydrosilylligands at rhodium(I) sources is reported. Irrespective of the substitutionat silicon (diaryl versus diamino), multiple Si–H activationsand chloride migration afford tridentate bis(phosphine)/chlorosilylcomplexes of Rh(I). For the diarylsilyl ligand, reaction with a cationicrhodium(I) triflate precursor gives the analogous triflatosilyl complex.The [P2Si]H2proligands and their Rh complexesprovide distinct opportunities for exploring metal/silicon cooperativereactivity. [ABSTRACT FROM AUTHOR]