Aurophilicity-Triggered Assembly of Novel Cyclic Penta- and Hexanuclear Gold(I) Complexes with Rigid Anionic NHC-Type Ligands

The products of the reaction between <i>N</i>,<i>N</i>′-diphosphanylimidazol-2-ylidene (<b>P–C–P</b>) and gold­(I) precursors depend on the nature of the anions associated with the latter. In contrast to the reported reaction with [Au­(tht)₂(OTf)], the use of [AuCl­(tht)] led to the new hexanuclear complex <b>1</b>, which features a Au₆(μ₃-<b>P–C</b>,κ<i>C</i>,κ<i>N</i>,κ<i>P</i>)₃ skeleton. The reaction of lithium imidazolide (<b>P–C–Li</b>) and [AuCl­(tht)] also afforded <b>1</b>, together with an unusual salt of the general formula [Au₅Cl­(μ₃-<b>P–C</b>-κ<i>P</i>,κ<i>C</i>,κ<i>N</i>)₃]₂[AuCl₂]₂ (<b>2</b>), which contains [Au₅(μ₃-<b>P–C</b>-κ<i>P</i>,κ<i>C</i>,κ<i>N</i>)]⁺ subunits. In the solid state, one of these Au₅ cations is associated with an [AuCl₂]⁻ anion, while two other cations interact through their unique dicoordinated N–Au–N center with a [AuCl₂]⁻ anion, with the charge of the resulting monocation being compensated for by another [AuCl₂]⁻ anion to give a Au₁₂ salt. Remarkably, the latter displays seven different bonding types at Au^I: C–Au–C, N–Au–N, P–Au–P, Cl–Au–Cl, C–Au–N, P–Au–Cl, and Au···Au

<i>N</i>‑Phosphanyl- and <i>N</i>,<i>N</i>′‑Diphosphanyl-Substituted N‑Heterocyclic Carbene Chromium Complexes: Synthesis, Structures, and Catalytic Ethylene Oligomerization

The chromium­(II) complexes [CrCl₂(^{<i><b>t</b></i><b>‑Bu</b>}<b>NHC,P</b>-κ<i>C</i>)₂] (<b>1</b>), [CrCl₂(^<b>Mes</b><b>NHC,P</b>-κ<i>C</i>)₂] (<b>2</b>), [CrCl₂(^<b>Dipp</b><b>NHC,P</b>-κ<i>C</i>)₂] (<b>3</b>), and [CrCl₂(<b>P,NHC,P</b>-κ<i>C</i>)₂] (<b>4</b>) containing the <i>N</i>-phosphanyl- or <i>N,N</i>′-diphosphanyl-substituted N-heterocyclic carbene (NHC) hybrid ligands ^{<i><b>t</b></i><b>‑Bu</b>}<b>NHC,P</b> (1-(di-<i>tert</i>-butylphosphino)-3-<i>tert</i>-butylimidazol-2-ylidene), ^<b>Mes</b><b>NHC,P</b> (1-(di-<i>tert</i>-butylphosphino)-3-mesitylimidazol-2-ylidene), ^<b>Dipp</b><b>NHC,P</b> (1-(di-<i>tert</i>-butylphosphino)-3-(2,6-diisopropylphenyl)­imidazol-2-ylidene), and <b>P,NHC,P</b> (1,3-bis­(di-<i>tert</i>-butylphosphino)­imidazol-2-ylidene), respectively, were prepared from Cr^II ([CrCl₂(thf)₂]) or Cr^III ([CrCl₃(thf)₃] or [Cr­(Me)­Cl₂(thf)₃]) precursors. The solid-state structures of these four complexes show square-planar Cr^II centers, with two trans chloride and two monodentate C_NHC donors. Alkylation of <b>3</b> and <b>4</b> with [Mg­(benzyl)₂(thf)₂] led to the formation of the σ complexes [Cr­(benzyl)₃(^<b>Dipp</b><b>NHC,P</b>-κ<i>C</i>,κ<i>P</i>)] (<b>5</b>) and [Cr­(benzyl)₃(<b>P,NHC,P</b>-κ<i>C</i>,κ<i>P</i>)] (<b>6</b>), respectively, with five-coordinate distorted-square-pyramidal Cr^III coordination, comprising a chelating ligand through the C_NHC and one P donor and three benzyl groups. These complexes were used as precatalysts in ethylene oligomerization, and it was found that the nature of the cocatalyst used and the metal oxidation state have a remarkable influence on the catalytic properties. The Cr^III/MAO systems displayed superior catalytic performance (TOF values up to 16320 mol of C₂H₄/((mol of Cr) h) for <b>6</b>) and gave mostly oligomers. Interestingly, the oligomers obtained with complex <b>3</b> were almost exclusively 1-hexene and 1-butene when the reaction was initiated at 30 °C. The overall activities and selectivities were also affected by the initial reaction temperature and the nature of the solvent. With AlEtCl₂ (EADC) as cocatalyst, polyethylene was predominately formed

Novel Di- and Trinuclear Palladium Complexes Supported by <i>N</i>,<i>N</i>′‑Diphosphanyl NHC Ligands and <i>N</i>,<i>N</i>′‑Diphosphanylimidazolium Palladium, Gold, and Mixed-Metal Copper–Gold Complexes

The reaction of the trinuclear complex [Ag₃(μ₃-<b>PC</b>_<b>NHC</b><b>P</b>,κ<i>P</i>,κ<i>C</i>_NHC,κ<i>P</i>)₂]­(OTf)₃ (<b>Ag3</b>; <b>PC</b>_<b>NHC</b><b>P</b> = <i>N</i>,<i>N</i>′-bis­(di-<i>tert</i>-butylphosphanyl)­imidazol-2-ylidene) with [Pd­(dba)₂] afforded the trinuclear palladium complex [Pd₃(μ₃-<b>PC</b>_<b>NHC</b><b>P</b>,κ<i>P</i>,κ<i>C</i>_NHC,κ<i>P</i>)₂]­(OTf)₂ (<b>Pd3</b>) and the dinuclear palladium­(I) complex [Pd₂(μ₂-<b>PC</b>_<b>NHC</b><b>P</b>,κ<i>P</i>,κ<i>C</i>_NHC,κ<i>P</i>)₂]­(OTf)₂ (<b>Pd2</b>). The assignment of the oxidation state of the metals in the mixed-valence <b>Pd3</b> chain as Pd⁰–Pd^II–Pd⁰ was based on the reactivity of the complex with 2,6-dimethylphenyl isocyanide and density functional theory calculations. Reaction of <b>PC</b>_<b>NHC</b><b>P</b> with [PdMe₂(tmeda)] afforded the palladium­(II) complex [PdMe₂(<b>PC</b>_<b>NHC</b><b>P</b>,κ<i>P</i>,κ<i>C</i>_NHC)] (<b>Pd-Me2</b>), with <b>PC</b>_<b>NHC</b><b>P</b> acting as a bidentate ligand. The reaction of <b>PC</b>_<b>NHC</b><b>P</b> with [Pd­(dba)₂] led to a dinuclear palladium(0) complex [Pd₂(μ₂-<b>PC</b>_<b>NHC</b><b>P</b>,κ<i>P</i>,κ<i>C</i>_NHC,κ<i>P</i>)]­(dba) (<b>Pd2-dba</b>); attempted replacement of the remaining dba by <b>PC</b>_<b>NHC</b><b>P</b> failed. The imidazolium triflate <b>PCHP</b>, precursor to <b>PC</b>_<b>NHC</b><b>P</b>, was reacted with [Pd₂(dba)₃]·CHCl₃ to give the (2 + 2) metalla-mesocyclic cationic palladium(0) complex [Pd₂(μ₂-<b>PCHP</b>,κ<i>P</i>,κ<i>P</i>)₂] (<b>PCHP-Pd2</b>), which resisted further deprotonation of the imidazolium cation. In contrast, <b>PCHP</b> reacted with [AuCl­(tht)] to give [Au₂Cl₂(μ₂-<b>PCHP</b>,κ<i>P</i>,κ<i>P</i>)] (<b>PCHP-Au2</b>), in which one Au–Cl moiety is bound to each P donor. Further reaction of <b>PCHP-Au2</b> with [Au­{N­(SiMe₃)₂}­(PPh₃)] afforded a mixture of the trinuclear [Au₃(μ₃-<b>PC</b>_<b>NHC</b><b>P</b>,κ<i>P</i>,κ<i>C</i>_NHC,κ<i>P</i>)₂]­(OTf)₃ (<b>Au3</b>) and [AuCl­(PPh₃)], while reaction with [CuMes]₅, where Mes = 2,4,6-trimethylphenyl, resulted in a novel, centrosymmetric, heterometallic complex [Au₂Mes₂(Cu₄Cl₄)­(<b>PCHP</b>,κ<i>P</i>,κ<i>P</i>)₂] (<b>PCHP-AuCu</b>) featuring a new <b>PCHP-AuMes</b> metalloligand bridging a Cu···Cu diagonal of a Cu₄Cl₄ cubane via the P and AuMes functionalities

Additional file 12: of Identification of genes regulating ovary differentiation after pollination in hazel by comparative transcriptome analysis

Table S12. FPKM values of DEGs encoding constituents of the floral quartet model (FQM). (XLSX 10 kb

Additional file 5: of Identification of genes regulating ovary differentiation after pollination in hazel by comparative transcriptome analysis

Table S5. DEGs in T-vs-FO paired comparisons. (XLS 3651 kb

Additional file 4: of Identification of genes regulating ovary differentiation after pollination in hazel by comparative transcriptome analysis

Table S4. DEGs in S-vs-T paired comparisons. (XLS 3850 kb

Additional file 7: of Identification of genes regulating ovary differentiation after pollination in hazel by comparative transcriptome analysis

Table S7. KEGG pathway enrichment analysis of DEGs identified in S-vs-T paired comparisons. (XLSX 22 kb

Additional file 1: of Identification of genes regulating ovary differentiation after pollination in hazel by comparative transcriptome analysis

Table S1. Primer sequences of selected unigenes in qRT-PCR. (XLSX 10 kb

Additional file 9: of Identification of genes regulating ovary differentiation after pollination in hazel by comparative transcriptome analysis

Table S9. Selected DEGs in auxin biosynthesis, transport, and signal transduction pathway. (XLSX 12 kb

Additional file 10: of Identification of genes regulating ovary differentiation after pollination in hazel by comparative transcriptome analysis

Table S10. FPKM values of all expressed transcripts. (XLS 7921 kb