Efficient Synthesis of New Stable 1,4-diionic Organosulfurs and Corresponding Mesoionic Compounds from <i>N</i>-Heterocyclic Ylides

<div><p></p><p>N-Phenacyl heterocyclic salts such as isoquinolinium, quinolinium, and pyridinium bromide react quickly with benzoyl isothiocyanate in the present of triethylamine to produce 1,4-diionic organosulfur derivatives. Cyclization and dehydrogenation of 1,4-diionic organosulfurs gave thiazoloisoquinolinium, quinolinium, or pyridinium benzimidates.</p> <p> <i>[Supplementary materials are available for this article. Go to the publisher's online edition of <i>Phosphorus, Sulfur, and Silicon and the Related Elements</i> for the following free supplemental files: Figures.]</i>.</p> </div

Chiral Thiahelicene-Based Alkyl Phosphine–Borane Complexes: Synthesis, X‑ray Characterization, and Theoretical and Experimental Investigations of Optical Properties

Chiral helical-based phosphanes are challenging and promising ligands, with a great potential for the generation of both organic and organometallic catalysts. We report here the preparation of novel chiral thiahelicene-based alkyl phosphanes, isolated and characterized as air-stable borane adducts, and the investigation of their experimental and theoretical (chir)­optical properties. X-ray characterization of a mono- and a disubstituted derivative as a racemic mixture has been performed, which confirms the influence of the number and nature of substituents on the flexibility of the helix. In addition, the absolute configuration inferred from CD spectra of the two enantiomers of a diborane complex has been established from X-ray analysis. State-of-the-art quantum chemical calculations of vibrationally resolved spectra allow, for the first time, for an unambiguous assignment of the experimentally observed peaks in linear absorption and circular dichroism spectra to excited electronic states of this class of thiahelicene phosphorus derivatives

Group 10 Metal Complexes with Chelating Macrocyclic Dicarbene Ligands Bearing a 2,6-Lutidinyl Bridge: Synthesis, Reactivity, and Catalytic Activity

Palladium­(II) and platinum­(II) complexes of the title ligands have been prepared; the two carbene moieties of the ligand coordinate to the metal in <i>cis</i> fashion, while the bridging pyridyl group remains outside the metal coordination sphere but close to the metal center. In this peculiar situation, the pyridyl group can assist the oxidation of the metal center to the +IV oxidation state upon coordination to the metal in the product. Furthermore, the pyridyl group is found to promote the catalytic role of the palladium­(II) complexes in copper- and amine-free Sonogashira reactions

Group 10 Metal Complexes with Chelating Macrocyclic Dicarbene Ligands Bearing a 2,6-Lutidinyl Bridge: Synthesis, Reactivity, and Catalytic Activity

Palladium­(II) and platinum­(II) complexes of the title ligands have been prepared; the two carbene moieties of the ligand coordinate to the metal in <i>cis</i> fashion, while the bridging pyridyl group remains outside the metal coordination sphere but close to the metal center. In this peculiar situation, the pyridyl group can assist the oxidation of the metal center to the +IV oxidation state upon coordination to the metal in the product. Furthermore, the pyridyl group is found to promote the catalytic role of the palladium­(II) complexes in copper- and amine-free Sonogashira reactions

Varför måste vi vila?

Syftet med detta examensarbete har varit att undersöka vilan för de större barnen, vilken betydelse har den för barnen och vad anser pedagogerna att vilan har för funktion. Avsikten har också varit att studera om barnen får vara delaktiga och påverka sin vila med innehåll och uppbyggnad. Bakgrunden till att vi valde att göra studien är för att det är ett ämne som sällan diskuteras utan sker oftast bara på rutin inom förskolan. Studiens tidigare forskning fokuserar på områdena barnperspektiv och barns perspektiv och delaktighet och inflytande. Genom intervjuer med både pedagoger och barn samt observationer på två olika förskolor har vi fått en inblick i hur vilostunden anses ha för funktion för barn och pedagoger samt hur den är uppbyggd med innehåll och miljö. Slutresultatet av vår studie är att vilan för det mesta är en rutinsituation efter lunch och innehållet varieras med till exempel böcker, cd-sagor och massage. Pedagogernas syn på vila handlar först och främst om att barnen behöver en stunds avkoppling och varva ner från vardagens stress. Barnen ges möjlighet till att använda sina erfarenheter och fantasi när de skapar egna bilder av böckernas och cd-sagornas innehåll. Pedagogerna anser också att vilans innehåll kan väcka barnens nyfikenhet och intresse av läs-och skrivförståelse. Barnens tankar och erfarenheter om vilans funktion är för dem förknippat med en stunds avkoppling efter lunchen för att maten ska sjunka ner. Både pedagoger och barn upplever att det finns möjlighet till delaktighet och inflytande under vilan

Reactions of the Unsaturated Hydroxo Complex [W₂Cp₂(OH)(μ-PPh₂)₂(CO)]BF₄ with Mono- and Bidentate Ligands Having E–H bonds (E = O, S, N)

The title compound reacted with CO at room temperature in the presence of excess HBF₄·OEt₂ to yield a mixture of the electron-precise complexes [W₂Cp₂(μ-PPh₂)₂(CO)₄]­(BF₄)₂ and [W₂Cp₂(μ-PPh₂)₂(CO)₃(OH₂)]­(BF₄)₂, with the aquo ligand in the latter complex being easily displaced by simple donors such as acetonitrile. Reaction of the title complex with simple acidic molecules such as HSPh or HBr took place rapidly with elimination of H₂O to give the 32-electron cations [W₂Cp₂(Z)­(μ-PPh₂)₂(CO)]⁺ [Z = Br, SPh (W–W = 2.8076(9) Å)], which were reversibly carbonylated to give the electron-precise derivatives [W₂Cp₂(μ-Z)­(μ-PPh₂)₂(CO)₂]⁺. Reaction with hydrogen sulfide likely proceeded analogously, but also involved fast cleavage of the second S–H bond to give the sulfido hydride cation [W₂Cp₂(μ-H)­(μ-PPh₂)₂(S)­(CO)]⁺. Deprotonation of the latter cation with 1,8-diazabicycloundec-7-ene (DBU) in the presence of excess H₂S gave a mixture of the corresponding sulfido and disulfido complexes [W₂Cp₂(μ-PPh₂)₂(S)­(CO)] and [W₂Cp₂(κ²-S₂)­(μ-PPh₂)₂(CO)]. Reactions of [W₂Cp₂(OH)­(μ-PPh₂)₂(CO)]­BF₄ with several bidentate ligands (L₂H) having weakly acidic H atoms (L₂ = SC₅H₄N, SC₆H₄NH₂, NHC­(S)­Ph) gave the unsaturated chelate derivatives [W₂Cp₂(κ²-L₂)­(μ-PPh₂)₂(CO)]­BF₄. The N–H bonds in the latter cations could be further deprotonated with strong bases (DBU or NaOH) to give neutral derivatives displaying either chelate (<i>N</i>,<i>S</i>-SC₆H₄NH) or imido-like terminal ligands (<i>N</i>-NC­(S)­Ph), respectively. The related chelate complex [W₂Cp₂(<i>O,O′</i>-OC₆H₄O)­(μ-PPh₂)₂(CO)] (W–W = 2.836(1) Å) was obtained in high yield from the reaction of the thiolato complex [W₂Cp₂(SPh)­(μ-PPh₂)₂(CO)]­BF₄ with catechol in the presence of DBU

Hierarchy of Supramolecular Arrangements and Building Blocks: Inverted Paradigm of Crystal Engineering in the Unprecedented Metal Coordination of Methylene Blue

The aromatic methylene blue cation (MB⁺) shows unprecedented ligand behavior in the X-ray structures of the trigonal-planar (TP) complexes MBMCl₂ (M = Cu^I, Ag^I). The two isostructural compounds were exclusively synthesized by grinding together methylene blue chloride and MCl solids. Only in the case of AuCl did the technique lead to a different, yet isoformular, Au^I derivative with separated MB⁺ and AuCl₂^– counterions and no direct N–Au linkage. While the density functional theory (DFT) molecular modeling failed in reproducing the isolated Cu and Ag complexes, the solid-state program <i>CRYSTAL</i> satisfactorily provided for Cu the correct TP building block associated with a highly compact π stacking of the MB⁺ ligands. In this respect, the dispersion interactions, evaluated with the DFT functional, provide to the system an extra energy, which likely supports the unprecedented metal coordination of the MB⁺ cation. The feature seems governed by subtle chemical factors, such as, for instance, the selected metal ion of the coinage triad. Thus, the electronically consistent Au^I ion does not form the analogous TP building block because of a looser supramolecular arrangement. In conclusion, while a given crystalline design is generally fixed by the nature of the building block, a peculiarly efficient supramolecular packing may stabilize an otherwise unattainable metal complex

Reactions of the Tetrafluoroborate Complex [Mo₂Cp₂(κ²-F₂BF₂)(μ-PPh₂)₂(CO)]BF₄ with Mono- and Bidentate Ligands Having E–H bonds (E = O, S, Se, N, P)

The title compound reacted rapidly with CN^<i>t</i>Bu at room temperature by displacing the BF₄^– ligand and incorporating three molecules of isocyanide to yield the electron-precise complex [Mo₂Cp₂(μ-PPh₂)₂(CN^<i>t</i>Bu)₃(CO)]­(BF₄)₂, which was obtained as a mixture of cis and trans isomers. Reaction with several HER_<i>n</i> molecules (HER_<i>n</i> = HSPh, HSePh, H₂PCy) took place with formal elimination of HBF₄ and spontaneous carbonylation to give the electron-precise cations [Mo₂Cp₂(μ-ER_<i>n</i>)­(μ-PPh₂)₂(CO)₂]⁺. Reactions with several bidentate ligands (L₂H) having acidic E–H bonds (2-hydroxypyridine, 2-mercaptopyridine, cathecol, 2-aminophenol, and 2-aminothiophenol) proceeded analogously with deprotonation of these bonds with the preference E = S > O > N. The N,O-donor ligands yielded 32-electron chelate derivatives of the type [Mo₂Cp₂(<i>O,N</i>-L₂)­(μ-PPh₂)₂(CO)]­BF₄ (L₂ = OC₅H₄N, OC₆H₄NH₂), whereas the S,N-donors yielded 34-electron, S-bridged complexes [Mo₂Cp₂(μ-<i>S</i>:<i>S,N</i>-L₂)­(μ-PPh₂)₂(CO)]­BF₄ [L₂ = SC₅H₄N (Mo–Mo = 2.8895(8) Å), SC₆H₄NH₂]. However, reaction with catechol gave a monodentate derivative [Mo₂Cp₂(<i>O</i>-OC₆H₄OH)­(μ-PPh₂)₂(CO)]­BF₄. In contrast, reactions of the title complex with several carboxylic acids and related species (acetic, benzoic, and thioacetic acids, acetamide, thioacetamide, and sodium diethyldithiocarbamate) were insensitive to the nature of the donor atoms and gave in all cases 32-electron chelate derivatives of type [Mo₂Cp₂(κ²-L₂)­(μ-PPh₂)₂(CO)]­BF₄. All of the above cations having Mo-bound OH, NH, or NH₂ groups were easily deprotonated upon reaction with 1,8-diazabicycloundec-7-ene (DBU) or other bases to give neutral complexes which exhibited different coordination motifs depending on the donor atoms, including chelate complexes of the type [Mo₂Cp₂(κ²-L₂′)­(μ-PPh₂)₂(CO)] (L₂′ = OC₆H₄O, OC₆H₄NH), the bridged complexes [Mo₂Cp₂(μ-<i>S,N</i>:<i>S,N</i>-SC₆H₄NH)­(μ-PPh₂)₂] and [Mo₂Cp₂{μ-<i>S,N</i>-N­(S)­CMe}­(μ-PPh₂)₂], and the terminal acetylimido complex [Mo₂Cp₂{<i>N</i>-N­(O)­CMe}­(μ-PPh₂)₂(CO)]

Topologically Unique Heterometallic Cu^II/Li Coordination Polymers Self-Assembled from <i>N</i>,<i>N</i>-bis(2-Hydroxyethyl)-2-aminoethanesulfonic Acid Biobuffer: Versatile Catalyst Precursors for Mild Hydrocarboxylation of Alkanes to Carboxylic Acids

The facile aqueous medium reactions of copper­(II) nitrate with BES biobuffer [(HOCH₂CH₂)₂N­(CH₂CH₂SO₃H), hereinafter referred as H₃bes] in the presence of various benzenecarboxylic acids [benzoic (Hba), 3-hydroxybenzoic (Hhba), and 3,5-dihydroxybenzoic (Hdhba) acid] and lithium hydroxide gave rise to the self-assembly generation of three new heterometallic Cu^II/Li materials, [Li­(H₂O)₄]­[Cu₄(μ₂-Hbes)₄(μ₂-ba)]·H₂O (<b>1</b>) and [Cu₄(μ₃-Hbes)₄(L)­{Li­(H₂O)₂}]_n·3nH₂O {L = μ₂-hba (<b>2</b>) and μ₂-dhba (<b>3</b>)}. They were isolated as air-stable crystalline solids and fully characterized by infrared (IR) and UV–vis spectroscopy and electrospray ionization (ESI)-MS(±), elemental, thermal, and single-crystal X-ray diffraction analyses. The latter revealed that <b>1</b>–<b>3</b> have comparable packing patterns and unit cell parameters, being composed of similar [Cu₄(μ-Hbes)₄(μ-carboxylate)]⁻ cores and [Li­(H₂O)₄]⁺ cations (in <b>1</b>) or [μ-Li­(H₂O)₂]⁺ groups (in <b>2</b> and <b>3</b>), which are arranged into discrete 0D aggregates in <b>1</b> or infinite 3D noninterpenetrating metal–organic networks in <b>2</b> and <b>3</b>. The topological analysis of the coordination polymers <b>2</b> and <b>3</b> disclosed the trinodal 3,3,4-connected underlying nets with an unprecedented topology defined by the point symbol of (4.6.8)₄(4².6)₂(6².16².18²), further simplification of which resulted in the binodal 4,4-connected nets with the <b>pts</b> (PtS) topology. Apart from representing very rare examples of coordination compounds derived from H₃bes, <b>1</b>–<b>3</b> feature solubility in water and were applied as efficient and versatile catalyst precursors for the mild (60 °C) single-pot hydrocarboxylation, by CO and H₂O, of various gaseous, linear, and cyclic C_n (<i>n</i> = 2–9) alkanes into the corresponding C_n+1 carboxylic acids, in H₂O/MeCN medium under homogeneous conditions and in the presence of potassium peroxodisulfate. Total yields (based on alkane) of carboxylic acids up to 78% were achieved, which are remarkable in the field of alkane functionalization under mild conditions, especially for a C–C bond formation reaction in aqueous acid-solvent-free medium

Hierarchy of Supramolecular Arrangements and Building Blocks: Inverted Paradigm of Crystal Engineering in the Unprecedented Metal Coordination of Methylene Blue

The aromatic methylene blue cation (MB⁺) shows unprecedented ligand behavior in the X-ray structures of the trigonal-planar (TP) complexes MBMCl₂ (M = Cu^I, Ag^I). The two isostructural compounds were exclusively synthesized by grinding together methylene blue chloride and MCl solids. Only in the case of AuCl did the technique lead to a different, yet isoformular, Au^I derivative with separated MB⁺ and AuCl₂^– counterions and no direct N–Au linkage. While the density functional theory (DFT) molecular modeling failed in reproducing the isolated Cu and Ag complexes, the solid-state program <i>CRYSTAL</i> satisfactorily provided for Cu the correct TP building block associated with a highly compact π stacking of the MB⁺ ligands. In this respect, the dispersion interactions, evaluated with the DFT functional, provide to the system an extra energy, which likely supports the unprecedented metal coordination of the MB⁺ cation. The feature seems governed by subtle chemical factors, such as, for instance, the selected metal ion of the coinage triad. Thus, the electronically consistent Au^I ion does not form the analogous TP building block because of a looser supramolecular arrangement. In conclusion, while a given crystalline design is generally fixed by the nature of the building block, a peculiarly efficient supramolecular packing may stabilize an otherwise unattainable metal complex