Vacuum ultraviolet excitation spectra at ∼10 K have been recorded for [Formula: see text] transitions of Cs(2)NaYF(6):Ln(3+) (Ln = Nd, Sm, Eu, Tb, Ho, Er, Tm). In these high bandgap hosts the lanthanide ions occupy octahedral symmetry sites. The spectra comprise broad, structured bands and in most cases the individual vibronic structure is not resolved. Simulations of the relative intensities a...

Many methylotrophs, microorganisms that consume carbon compounds lacking carbon-carbon bonds, use two different systems to oxidize methanol for energy production and biomass accumulation. The MxaFI methanol dehydrogenase (MDH) contains calcium in its active site, while the XoxF enzyme contains a lanthanide in its active site. The genes encoding the MDH enzymes are differentially regulated by th...

Collision-induced dissociation (CID) rates are measured for a suite of lanthanide (plus yttrium) monoxide ions stored in a quadrupole ion trap. Yttrium, neodymium, and gadolinium oxides, having the same nominal dissociation energy (D0 ≈ 735 kJ mol−1) but different masses, provide an empirical correction of −1.2 s−1 amu−1 for the measured CID rates. The CID rate correction enables the correlatio...

The ability to tune color output of nanomaterials is very important for their applications in laser, optoelectronic device, color display and multiplexed biolabeling. Here we first propose a femtosecond pulse shaping technique to realize the up-conversion fluorescence tuning in lanthanide-doped nanocrystals dispersed in the glass. The multiple subpulse formation by a square phase modulation can...

The transition-metal-catalyzed amination of aryl halides has been the most powerful method for the formation of aryl amines over the past decades. Phenols are regarded as ideal alternatives to aryl halides as coupling partners in cross-couplings. An efficient palladium-catalyzed formal cross-coupling of phenols with various amines and anilines has now been developed. A variety of substituted ph...

A simple and mild catalytic coupling reaction of propargyl halides with organotitanium reagents is reported. The reaction of propargyl bromide with organo-titanium reagents mediated by NiCl2 (2 mol%) and PCy3 (4 mol%) in CH2Cl2 afforded coupling product allenes in good to excellent yields (up to 95%) at room temperature. However, NiCl2(PPh3)2 was the best catalyst for substituted propargyl hali...

This review reports some novel (or considerably improved) methods for the synthesis of aromatic iodides, (dichloroiodo)arenes, (diacetoxyiodo)arenes, iodylarenes and diaryliodonium salts, as well as some facile, oxidative anion metatheses in crude diaryliodonium halides and, for comparison, potassium halides. All these new results were obtained in our laboratory over the past decade (1990-2000)...

A new method for the preparation of S-trityl(i.e. triphenylmethyl) and S-diphenylmethyl-cysteines or -cysteine peptides involves treatment of cysteine or cysteine peptides with aralkylcarbinols in the presence of trifluoroacetic acid or hydrogen halides in acetic acid solution. The optimal conditions for the removal of these S-protecting aralkyl groups by trifluoroacetic acid or hydrogen halide...

Tri-isopropylsilyl thio-glycosides (TIPS S-glycosides) were synthesized through base promoted SN2 substitution of glycosyl halides with TIPS-SH or by Lewis acid promoted glycosylation of TIPS-SH with glycosyl acetates or p-methoxyphenyl glycosides. Various thioglycoside derivatives were obtained in high yields by one-pot fluoride-mediated de-silylation and thiol alkylation with alkyl halides or...

Transition-metal-free LiCl-promoted cross-coupling reactions of tetraphenyltin, trichlorophenyl-, dichlorodiphenyl-, and chlorotriphenylstannanes with aryl halides in DMF provided access to biaryls in good to high yields. Up to four phenyl groups were transferred from the organostannanes substrates. The aryls bearing electron-withdrawing groups in either halides or organotin substrates gave cou...