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1.
Aino J. Karhu Juho Jämsä J. Mikko Rautiainen Raija Oilunkaniemi Tristram Chivers Risto S. Laitinen 《无机化学与普通化学杂志》2017,643(7):495-500
The reaction of tBuNH2 with a mixture of SeCl2 and SeOCl2 in a 6:2:1 molar ratio produces the novel selenium‐nitrogen chain ClSeN(tBu)Se(O)Cl ( 4 ), in which the selenium atoms are in two different oxidation states, SeII and SeIV. The crystal structure of 4 is compared with that of the related SeII/SeII system ClSeN(tBu)SeCl ( 1 ) and differences are attributed to hyperconjugative effects. The energetics of the formation of 4 via two different routes are elucidated by PBE0/def2‐TZVPP calculations. 相似文献
2.
Sari M. Kunnari Raija Oilunkaniemi Risto S. Laitinen Markku Ahlgren 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(10):o610-o611
The novel title tetraselenacalix[4]arene, C16H8S4Se4 or [(C4H2S)Se]4, has a centrosymmetric cyclic molecular structure with approximate C2h molecular symmetry. The four thienyl rings are joined together by Se bridges and exhibit a syn–syn–anti–anti arrangement around the molecule. The lattice consists of skewed stacks of molecules, with chalcogen–chalcogen close contacts binding the stacks together, forming a two‐dimensional network of molecules. 相似文献
3.
Veli-Matti Mukkala Pivi Liitti Ilkka Hemmil Harri Takalo Cristina Matachescu Jouko Kankare 《Helvetica chimica acta》1996,79(1):295-306
The synthesis of novel thiazole-containing complexing agents and their luminescence properties with EuIII and TbIII ions are reported. One of these terpyridine analogues was also tested as an EuIII labelling reagent, and its luminescence properties as an antibody conjugate were studied. 相似文献
4.
In situ reaction mechanism studies on the atomic layer deposition of Al2O3 from (CH3)2AlCl and water
Reaction mechanisms between dimethylaluminum chloride and deuterated water in the atomic layer deposition (ALD) of Al2O3 were studied at 150-400 degrees C using a quartz crystal microbalance (QCM) and a quadrupole mass spectrometer (QMS). The observed reaction byproducts were DCl and CH3D. QMS showed that about one-third of the chlorine, and half of the methyl ligands were released during the (CH3)2AlCl pulse. The growth rate deduced from the QMS and QCM data was in qualitative agreement with the previously published growth rate from ALD film growth experiments. 相似文献
5.
The reactions of tellurium tetrahalides and triphenylphosphine in tetrahydrofuran have been carried out under ambient conditions and afford [(Ph(3)PO)(2)H](2)[Te(2)X(10)] [X = Cl (1), Br (2)] and [(Ph(3)PO)(3)(OH(3)])(2)[TeI(6)] (4). The X-ray structures of 1 and 2 show that they are isostructural and contain discrete [Te(2)X(10)](2-) anions exhibiting octahedral coordination around both tellurium atoms with one shared edge and [Ph(3)POH...OPPh(3)](+) cations that show strong hydrogen bonds (the O...O distances are 2.399 and 2.404 A for 1 and 2, respectively). The compound 4 is built up with discrete octahedral hexaiodotellurate anions and [(Ph(3)PO)(3)(OH(3))](+) cations. The reaction of TeBr(4) and PPh(3) also results in the formation of formally zwitterionic Ph(3)PO(CH(2))(4)TeBr(4) (3). This reaction involves an unprecedented THF ring opening in which the oxygen atom becomes bonded to the phosphorus atom of triphenylphosphine and the carbon atom at the other end of the five-atomic chain becomes bonded to the tellurium atom of TeBr(4). The ring opening of the solvent THF is also taking place in the reaction involving tellurium tetraiodide, as indicated by the formation of C(4)H(8)TeI(2) (5). The reaction may initially lead to Ph(3)PI(2) that reacts with THF yielding Ph(3)PO and ICH(2)(CH(2))(2)CH(2)I. The latter species reacts with elemental tellurium producing 5. Depending on the conditions upon crystallization, two polymorphs of C(4)H(8)TeI(2) (5a and 5b) are observed. While the molecular structures of the two forms are virtually identical, their packing and intermolecular contacts are different. Two further minor products (6a and 6b) were isolated in the reaction of TeI(4) and PPh(3): Both are formally 1:1 adducts of 5 and TeI(4), but they differ considerably in their structures. 6a can be formulated as [C(4)H(8)TeI(+)](2)[Te(2)I(10)(2-)] and 6b as [C(4)H(8)TeI(+)](2)(TeI(3)(+))(2)(I(-))(4). The latter compound exhibits framework similar to that of the tetramers in gamma- and delta-TeI(4). 相似文献
6.
Hofmann C Boll R Heitmann B Hauser G Dürr C Frerich A Weitnauer G Glaser SJ Bechthold A 《Chemistry & biology》2005,12(10):1137-1143
The oligosaccharide antibiotic avilamycin A is composed of a polyketide-derived dichloroisoeverninic acid moiety attached to a heptasaccharide chain consisting of six hexoses and one unusual pentose moiety. We describe the generation of mutant strains of the avilamycin producer defective in different sugar biosynthetic genes. Inactivation of two genes (aviD and aviE2) resulted in the breakdown of the avilamycin biosynthesis. In contrast, avilamycin production was not influenced in an aviP mutant. Inactivation of aviGT4 resulted in a mutant that accumulated a novel avilamycin derivative lacking the terminal eurekanate residue. Finally, AviE2 was expressed in Escherichia coli and the gene product was characterized biochemically. AviE2 was shown to convert UDP-D-glucuronic acid to UDP-D-xylose, indicating that the pentose residue of avilamycin A is derived from D-glucose and not from D-ribose. Here we report a UDP-D-glucuronic acid decarboxylase in actinomycetes. 相似文献
7.
[CoCl2{N,N′-Te2(NtBu)4}] (1) was obtained in good yields by the reaction of equimolar amounts of (tBu)NTe(μ-NtBu)2TeN(tBu) and CoCl2 in toluene under an argon atmosphere. The crystal structure of 1·CH2Cl2 showed that the dimeric tellurium diimide ligand is N,N′-chelated to cobalt. The related reaction of Se(NtBu)2 and CoCl2 affords a green product tentatively identified as a 1:1 adduct [CoCl2{N,N′-Se(NtBu)2}] (CHN analysis). However, recrystallization from thf produces the ion-separated complex [Co2(μ-Cl)3{N,N′-Se(NtBu)2}2(thf)2][CoCl3{NH2(tBu)}]·1½thf (2·1½thf), in which the monomeric selenium diimide ligand is N,N′-chelated to cobalt in the cation. A pathway for the formation of 2 from [CoCl2{N,N′-Se(NtBu)2}] in thf is proposed. 相似文献
8.
Aromatic Gd(III) and Y(III) chelates produce ligand-centered emissions during cathodic pulse polarization of oxide-covered
aluminum electrodes, while the corresponding Tb(III) chelates produce metal-centered5D4 →7Fj emissions. It was observed that a redox-inert paramagnetic heavy lanthanoid ion, Gd(III), seems to enhance strongly intersystem
crossing in the excited ligand and direct the deexcitation toward a triplet-state emission, while a lighter diamagnetic Y(III)
ion directs the photophysical processes toward a singlet-state emission of the ligand. The luminescence lifetime of Y(III)
chelates was too short to be measured with our apparatus, but the luminescence lifetime of Gd(III) chelates was between 20
and 70 μs. The mechanisms of the ECL processes are discussed in detail.
Preliminary results of electrogenerated triplet-state emission of one of the ligands used in this work have been published
in a letter elsewhere [9]. 相似文献
9.
Veli-Matti Mukkala Matti Helenius Ilka Hemmil Jouko Kankare Harri Takalo 《Helvetica chimica acta》1993,76(3):1361-1378
The synthesis and luminescence properties are reported for 20 different chelates composed of 2,2′:6′,2″-terpyridine as the energy-absorbing and donating group, EuIIIand TbIII as the emitting ions, methylenenitrilo(acetic acids) as the stabel chelate-forming moieties, and isothiocyanato or(4,6-dichloro-1,3,5-triazin-2-yl)amino groups as the activated moieties for coupling to biomolecules. 相似文献
10.
Harri Takalo Veli-Matti Mukkala Liisa Meri Juan Carlos Rodríguez-Ubis Rosa Sedano Olga Juanes Ernesto Brunet 《Helvetica chimica acta》1997,80(2):372-387
The synthesis of novel TbIII labels suitable for protein labelling are reported. Their luminescence properties as antibody conjugates were measured and compared to the results of corresponding TbIII chelates of the parent ligand structures. When the lowest triplet-state energy level of the parent donor ligand was over 23000 cm?1, i.e., the energy gap between the 5D4 level of TbIII and the lowest triplet-state energy level of the ligand exceeded 2600 cm?1, the label derivative with a long decay time (τ = 1.35–2.93 ms) and a high luminescence yield (?. Φ = 3770–4560) was found to be suitable for bioaffinity assays. 相似文献