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151.
Structures of New SeII and TeII Complexes Containing 2,2-Dicyanethylene-1,1-dithiolate, 2,2-Dicyanethylene-1,1-thioselenolate, and 2,2-Dicyanethylene-1,1-diselenolate (NBu4)2{Se[S2C?C(CN)2]2} ( I ), (AsPh4)2 · {Te[SSeC?C(CN)2]2} ( II ), and (NBu4)2{Te[Se2C?C(CN)2]2} ( III ) containing the bidentate chelate ligands 2,2-dicyanethylene-1,1-dithiolate i-mnt , 2,2-dicyanethylene-1,1-thioselenolate i-mnts , and 2,2-dicyanethylene-1,1-diselenolate i-mns have been prepared and characterized by X-ray structure analysis. The central units consist of [M(X? X)2E2]2? (M = Se, Te; X? X = ligand; E = lone-pair) with fourfold coordinated SeII and TeII, respectively. The complex anions [Se(i-mnt)2E2]2? as well as [Te(i-mnts)2E2]2? show a trapezoide distortion with d(Se? S) = 2.276(5); 2.287(5); 2.803(5); 2.789(5) Å and d(Te? Se) = 2.611(2); 2.617(3); d(Te? S) = 2.889(5); 2.935(4) Å. In III there are centrosymmetric complex anions [Te(i-mns)2E2]2? with nearly identical Te? Se-bond-lengths: 2.674(3) and 2.692(2) Å. These Te? Se bonds are elongated compared to usual Te? Se bonds. 相似文献
152.
J. Ty Redd Jerald S. Bradshaw Peter Huszthy Reed M. Izatt 《Journal of inclusion phenomena and macrocyclic chemistry》1997,29(3-4):301-308
Pyrimidino-crown ethers were prepared in 30-50% yields by reactingthe ditosylate derivative of the appropriate oligoethylene glycol with4-methoxy-5-methyl-2,6-pyrimidinedimethanol under basic conditions. A newmacrocyclic ligand containing a proton-ionizable pyrimidone subcyclic unitwas prepared in 88% yield by treating the appropriatepyrimidino-crown ether with 5 M NaOH in 50% (v/v) aqueous methanol.Preliminary complexation properties of some of these new compounds werestudied using various NMR spectral techniques. Good enantiomeric recognitionwas exhibited by a chiral pyrimidino-crown ether for the enantiomers of1-(-naphthyl)ethylammonium perchlorate. 相似文献
153.
Some new complexes between thecis-4,4′-dinitrodibenzo-18-crown-6 and rare earth chlorides LnCl3 (Ln=Nd, Gd, Yb) were synthesized in acetonitrile. Ligandcis-4,4′-dinitrodibenzo-18-crown-6 and its complexes were identified by infrared spectroscopy, X-ray diffraction and thermal
analysis (TG and DTA). Acis-trans isomerisation of the complexed ligand is observed about 148°C when heating the rare earth complex.
相似文献
154.
Absorption spectra of the photoexcited (2-C60)Pd(PPh3)2 complex in benzene were obtained by picosecond and nanosecond laser photolysis. The spectra are compared with those observed for photoexcited states of fullerene C60 and charge-transfer states of C60 complexes with ternary amines. The relaxation kinetics of excited (2-C60)Pd(PPh3)2 complex has three components with characteristic lifetimes 1 = 43 ps, 2 = 1500 ps, and 3 = 1.17 s. The results are discussed in terms of the four-level scheme of the excited complex.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1163–1166, May, 1996. 相似文献
155.
Yannick Ortin Paul O'Donohue Helge Müller-Bunz Anthony R. Manning 《Journal of organometallic chemistry》2004,689(9):1657-1664
Treatment of the aldehyde (η4-C4Ph4)Co(η5-C5H4-CHO) (4b) with tert-butyllithium or phenyllithium yields the secondary alcohols (η4-C4Ph4)Co(η5-C5H4-CH(R)OH), where R=tert-butyl (5) or phenyl (6). Protonation of 5 and 6 at −80 °C furnishes the deep purple, cobalt-stabilized cations, 7 and 8, respectively, both of which exhibit restricted rotation about the external C5H4-CHR+ linkage on the NMR time-scale. These data indicate a minimum value for the barrier to rotation of 15 kcal mol−1, but it is certainly much higher, indicating a considerable degree of C-C double bond character. X-ray crystal structures of 4b, 5 and also of the ketone (η4-C4Ph4)Co(η5-C5H4-C(O)CH3 (4a) are reported. The secondary alcohol 5 exhibits disorder in the solid state because of the presence of diastereomers as a consequence of the stereogenic center at the α-carbon and the clockwise or anticlockwise propeller orientations of the tetraphenylcyclobutadiene ligand. 相似文献
156.
157.
A series of novel bidentate pyrazolone based Schiff base ligands were synthesized by interaction of 4-benzoyl-3-methyl-1-(4′-methylphenyl)-2-pyrazolin-5-one with various aromatic amines like aniline, o-,m-,p-chloroaniline and o-,m-,p-toluidine in a ethanolic medium. All of these ligands have been characterized on the basis of elemental analysis, IR and 1H NMR data. The molecular geometries of five of these ligands have been determined by single crystal X-ray study. Crystallographic study reveals that these ligands exist in the amine-one tautomeric form in the solid state. NMR study also suggests the existence of the amine-one form in solution at room temperature. Ab initio calculations for representative ligand HL1 has been carried out to know the coordination site of the ligand. Novel vanadium Schiff base complexes of these ligands with general formula [OV(L1–7)2(H2O)] have been prepared by interaction of aqueous solution of vanadyl sulfate pentahydrate with DMF solution of the appropriate ligands. The resulting complexes have been characterized on the basis of elemental analysis, vanadium determination, molar conductance and magnetic measurements, thermo gravimetric analysis, infrared and electronic spectral studies. Suitable distorted octahedral structures have been proposed for these complexes. 相似文献
158.
Native non‐covalently bonded protein‐protein and protein‐substrate complexes are of great interest and have been extensively studied by electrospray ionization mass spectrometry (ESI‐MS). Multiply charged protein homomultimeric complexes are shown to form by ESI‐MS. This study addresses factors that can artificially induce the formation of multiply charged protein homomultimeric complexes. Cytochrome c (Cyt c) and ubiquitin, which are monomers in solution, were found to generate (Cyt c)mn+ by electrospray ionization (ESI). The homomultimeric complexes were not limited to dimeric complexes but include also multiply charged trimers, tetramers, and pentamers. The observation of these homomultimeric complexes has never been revealed from a Cyt c solution at the concentration as low as 10 μM. Increasing the concentration of Cyt c enhanced the formation of (Cyt c)mn+ as expected; however, the protein concentration does not affect the relative intensities of monomeric and dimeric complexes. Additionally the enrichment of NH4OH also promotes the formation of (Cyt c)mn+. Notably, source collision‐induced dissociations (source‐CID) of (Cyt c)mn+ alter the charge state distribution (CSD) and may lead to an incorrect interpretation of Cyt c conformations. Hence, extra care should be taken when using CSD to interpret the conformation of a protein derived from ESI‐MS. 相似文献
159.
Khoroshen'kov G. V. Fag A. A. Bochkarev M. N. Dechert S. Schumann H. 《Russian Chemical Bulletin》2003,52(8):1715-1719
The reactions of LnI2 (Ln = Nd (1) or Dy (2)) with cyclopentadiene (CpH) in THF at 0 °C afforded the CpLnI2(THF)3 complexes in 65—67% yields. The reaction of thulium diiodide (3) with an excess of CpH at 60 °C produced CpTmI2(THF)3, Cp2TmI(THF)2, and TmI3(THF)3 in 21, 58, and 63% yields, respectively. The reactions of 1 and 2 with pentamethylcyclopentadiene (Cp*H) in THF were accompanied by disproportionation giving rise to the Cp*2LnI(THF)2 and LnI3(THF)
x
complexes. Neodymium triiodide was isolated in the ionic form [NdI2(THF)5]+[NdI4(THF)2]–. Its structure and the structure of CpTmI2(THF)3 were established by X-ray diffraction analysis. 相似文献
160.
Sandrine Bouquillon Ulla Létinois-Halbes Jacques Muzart 《Journal of organometallic chemistry》2003,687(2):377-383
The reaction between palladium acetate, (−)-ephedrine and potassium acetate led to bis-chelate complex Pd[OCH(Ph)NH(Me)]2 whose the trans-structure is obtained from calculations. The use of this complex to catalyze either the 1,4-hydrogenation of (E)-2-benzyliden-1-tetralone or Heck reaction of phenyl iodide with 3-methyl-3-buten-2-ol led to a low enantiomeric excess. 相似文献