Base free lithium-organoaluminate and the gallium congener: potential precursors to heterometallic assemblies

The first examples of base free lithium-organoaluminate and the corresponding gallium compound [LM(Me)OLi]3 (M = Al (3), Ga (4); L = HC{C(Me)N-2,6-iPr2C6H3}2) have been prepared by the reaction of Li[N(SiMe3)2] with the corresponding metal hydroxides LM(Me)OH (M = Al (1), Ga(2)); the oxygen atom in the M-O-Li fragment exists as oxide ion and is involved in the central Li3O3 six-membered ring formation.     

Bed Bug Aggregation Pheromone Finally Identified

Bed bugs have become a global epidemic and current detection tools are poorly suited for routine surveillance. Despite intense research on bed bug aggregation behavior and the aggregation pheromone, which could be used as a chemical lure, the complete composition of this pheromone has thus far proven elusive. Here, we report that the bed bug aggregation pheromone comprises five volatile components (dimethyl disulfide, dimethyl trisulfide, (E)‐2‐hexenal, (E)‐2‐octenal, 2‐hexanone), which attract bed bugs to safe shelters, and one less‐volatile component (histamine), which causes their arrestment upon contact. In infested premises, a blend of all six components is highly effective at luring bed bugs into traps. The trapping of juvenile and adult bed bugs, with or without recent blood meals, provides strong evidence that this unique pheromone bait could become an effective and inexpensive tool for bed bug detection and potentially their control.     

Analysis of Solid-State Luminescence Emission Amplification at Substituted Anthracenes by Host–Guest Complex Formation

Small robust organic molecules showing solid-state luminescence are promising candidates for optoelectronic materials. Herein, we investigate a series of diphenylphosphanyl anthracenes [9-PPh₂-10-R-(C₁₄H₈)] and their sulfur oxidised analogues. The oxidation causes drastic changes in the molecular structure as the new orientation of the bulky (S)PPh₂ substituent induces a strong butterfly bent structure of the anthracene core, which triggers a strong bathochromic shift resulting in a green solid-state fluorescence. As the emission properties change only slightly upon aggregation the origin of the emission is attributed to a typical monomer fluorescence. The host–guest complexes of [9-(S)PPh₂-10-Ethyl-(C₁₄H₈)] with four basic arenes reveal an emission enhancement up to five-times higher quantum yields compared to the pure host. Less interchromophoric interactions and a restriction of intramolecular motion within the host molecules due to fixation by weak C−H⋅⋅⋅π interactions with the co-crystallised arene are responsible for that emission enhancement.     

A Neutral Three-Membered 2π Aromatic Disilaborirane and the Unique Conversion into a Four-Membered BSi2N-Ring

We report the design, synthesis, structure, bonding, and reaction of a neutral 2π aromatic three-membered disilaborirane. The disilaborirane is synthesized by a facile one-pot reductive dehalogenation of amidinato-silylene chloride and dibromoarylborane with potassium graphite. Despite the tetravalent arrangement of atoms around silicon, the three-membered silicon-boron-silicon ring is aromatic, as evidenced by NMR spectroscopy, nucleus independent chemical shift calculations, first-principles electronic structure studies using density functional theory (DFT) and natural bond orbital (NBO) based bonding analysis. Trimethylsilylnitrene, generated in situ, inserts in the Si−Si bond of disilaborirane to obtain a four-membered heterocycle 1-aza-2,3-disila-4-boretidine derivative. Both the heterocycles are fully characterized by X-ray crystallography.     

A stable cation of a CSi3P five-membered ring with a weakly coordinating chloride anion

Don't count on counterions: The cyclic five-membered CSi(3)P cation 1 is synthesized in the reaction of benzamidinato-stabilized chlorosilylene and methyl phosphaalkyne. The presence of four π?electrons in 1 means it can be considered as a formal, heavier analogue of the cyclopentadienyl cation. Surprisingly the small counteranion (Cl(-)) does not contribute to the ring stability.     

Adsorption and reaction of SO2 on clean and oxygen precovered Pd(100)--a combined HR-XPS and DF study

We studied the adsorption and reactivity of SO(2) on clean and oxygen precovered Pd(100) with high resolution X-ray photoelectron spectroscopy and density functional calculations. Upon adsorption at 120 K two different SO(2) species were detected, which were identified as upright-standing and flat-lying molecules by comparing the calculated core level shifts. In agreement with the relative stabilities determined by the calculations the intensities of the photoelectron spectra indicate that the majority species are upright-standing SO(2). Upon heating the quantitative analysis of the data indicates desorption of SO(3) and formation of atomic sulfur. On the oxygen precovered surface small amounts of SO(3) are formed already upon SO(2) adsorption at low temperatures. Upon heating stepwise oxidation of SO(2) to SO(3) and, eventually, to SO(4) is found. Two different SO(4) species were detected, which are assigned to SO(4) bound in the proximity of or remote from oxygen adatoms, according to core level shift estimates.     

Tunable plasmon coupling in distance-controlled gold nanoparticles

Plasmons are resonant excitations in metallic films and nanoparticles. For small enough static distances of metal nanoparticles, additional plasmon-coupled modes appear as a collective excitation between the nanoparticles. Here we show, by combining poly(N-isopropylacrylamide) micro- and nanospheres and Au nanoparticles, how to design a system that allows controllably and reversibly switching on and off, and tuning the plasmon-coupled mode.     

N‐Heterocyclic Carbene Adducts of Aluminium Triiodide

N‐Heterocyclic carbene adducts of aluminium triiodide, IMes · AlI₃ ( 1 ) and IPr · AlI₃ ( 2 ) (IMes = 1,3‐bis(2,4,6‐trimethylphenyl)imidazol‐2‐ylidene and IPr = 1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene) are reported. These adducts are available by the reaction of aluminium triiodide with the correspondingN‐heterocyclic carbene. Compounds 1 and 2 are soluble in hydrocarbon solvents, stable in inert atmosphere, and have been characterised by elemental analysis, NMR spectroscopy and single‐crystal X‐ray diffraction studies.