The reaction of unsymmetrical phenylmethyltin dihydride (PhMeSnH2), phenylethyltin dihydride (PhEtSnH2), phenylbutyltin dihydride (PhBuSnH2) and butylmethyltin dihydride (BuMeSnH2) with biuret (HAL) proceeds...The reaction of unsymmetrical phenylmethyltin dihydride (PhMeSnH2), phenylethyltin dihydride (PhEtSnH2), phenylbutyltin dihydride (PhBuSnH2) and butylmethyltin dihydride (BuMeSnH2) with biuret (HAL) proceeds via SnH/NH dehydrocoupling to afford the corresponding tetra-coordinate cyclic products. The reactions in the molar ratios of 1 : 1, 2 : 1 and 1 : 2 have been studied. The yellow derivatives so isolated were soluble in polar solvents and insoluble in nonpolar solvents. It was found that 1 : 1 reaction went to completion while 2 : 1 and 1 : 2 did not go to completion. The derivatives had been characterized by elemental analysis and spectroscopic techniques viz. IR, ^1H NMR, ^13C NMR, ^119Sn NMR. DSC and TGA of the reaction products have also been studied. All the derivatives were thermally stable upto (1904- 10)℃ and degradation occurred after that.展开更多
With the WIEN2 k simulation code,ab initio calculations of electronic structure and of equilibrium properties for the superstoichiometric rare-earth dihydride GdH_(2.25)using the full-potential linearized augmented pl...With the WIEN2 k simulation code,ab initio calculations of electronic structure and of equilibrium properties for the superstoichiometric rare-earth dihydride GdH_(2.25)using the full-potential linearized augmented plane-wave(FP-LAPW)method within density functional theory(DFT)in generalized gradient approximation(GGA)were performed.The lattice parameter,bulk modulus,pressure derivative,density of states(DOS)and energy band structures were determined.The GGA-optimized lattice parameter agrees much better with the experimental findings than the local density approximation(LDA)one.The non-negligible electronic DOS at Fermi level confirms that GdH_(2.25)has a metallic character.The Fermi energy(E_(F))falls at a level where most of the states are rare-earth 5 d conduction states while negligible contributions of both interstitial(tetrahedral and octahedral)H s states are observed near EF.It is found that hybridization exists between s electronic orbital of both interstitial H atoms and d electronic orbitals of Gd.展开更多
We performed ab initio calculations of electronic structure and equilibrium properties for the rare earth superstoichiometric dihydride GdH2.25 (with the space group Pm-3m (No. 221)) using the full-potential linea...We performed ab initio calculations of electronic structure and equilibrium properties for the rare earth superstoichiometric dihydride GdH2.25 (with the space group Pm-3m (No. 221)) using the full-potential linearized augmented plane wave method (FP-LAPW) approach within the density functional theory (DFT) in the generalized gradient approximation (GGA) and local density approximation (LDA) as implemented in the WIEN2k simulation code at 0 K. The equilibrium properties were determined, the density of states, electronic density and the energy band structures were studied in details. It was concluded that the GGA optimized lattice parameter agreed much better with the experimental findings than the LDA one, The non negligible electronic density of states at the Fermi level confirmed that the GdH2.25 had a metallic character. The Fermi energy EF fell at a level where most of the states were rare-earth 5d-eg conduction states while negligible contributions of both interstitial (tetrahedral and octahedral) H s-states were observed near EF, From electronic density, the bonding between Gd and tetrahedral H atoms was of prominent covalency, while was ionic between Gd and octahedral H atoms.展开更多
The dihydride cluster H<sub>2</sub>O<sub>s<sub>3</sub></sub>(CO)<sub>10</sub> reacts with ethyne to give a cis-adduct [O<sub>s<sub>3</sub></sub&g...The dihydride cluster H<sub>2</sub>O<sub>s<sub>3</sub></sub>(CO)<sub>10</sub> reacts with ethyne to give a cis-adduct [O<sub>s<sub>3</sub></sub>H(μ,η<sup>2</sup>-CH=CH<sub>2</sub>)(CO)<sub>10</sub>]. The high deuterated cluster D<sub>2</sub>O<sub>s<sub>3</sub></sub>(CO)<sub>10</sub>, the reaction of D<sub>2</sub>O<sub>s<sub>3</sub></sub>(CO)<sub>10</sub>with ethyne C<sub>2</sub>H<sub>2</sub> to form the vinyl product cluster [O<sub>s<sub>3</sub></sub>D(μ, η<sup>2</sup>-CH=CHD)(CO)<sub>10</sub>], and thereaction of H<sub>2</sub>O<sub>s<sub>3</sub></sub>(CO)<sub>10</sub> with the deuterated ethyne C<sub>2</sub>D<sub>2</sub> to form [O<sub>s<sub>3</sub></sub>H(μ,η<sup>2</sup>-CD=CDH)(CO)<sub>10</sub>] have been reported primarily in this paper. The two cis-adducts undergo cis-trans-isomerization of μ,η<sup>2</sup>-vinyl ligands under a small amount of the nucleophile pyridine. Usingthe combination of deuteration and dynamic <sup>1</sup>H,<sup>2</sup>H NMR spectra, we report the experimen-tal evidence determined by the dynamic <sup>1</sup>H, <sup>2</sup>H NMR spectra, mechanism, and kinetic dataof the isomerization.展开更多
文摘The reaction of unsymmetrical phenylmethyltin dihydride (PhMeSnH2), phenylethyltin dihydride (PhEtSnH2), phenylbutyltin dihydride (PhBuSnH2) and butylmethyltin dihydride (BuMeSnH2) with biuret (HAL) proceeds via SnH/NH dehydrocoupling to afford the corresponding tetra-coordinate cyclic products. The reactions in the molar ratios of 1 : 1, 2 : 1 and 1 : 2 have been studied. The yellow derivatives so isolated were soluble in polar solvents and insoluble in nonpolar solvents. It was found that 1 : 1 reaction went to completion while 2 : 1 and 1 : 2 did not go to completion. The derivatives had been characterized by elemental analysis and spectroscopic techniques viz. IR, ^1H NMR, ^13C NMR, ^119Sn NMR. DSC and TGA of the reaction products have also been studied. All the derivatives were thermally stable upto (1904- 10)℃ and degradation occurred after that.
基金financially supported by the Algerian Ministry of Higher Education
文摘With the WIEN2 k simulation code,ab initio calculations of electronic structure and of equilibrium properties for the superstoichiometric rare-earth dihydride GdH_(2.25)using the full-potential linearized augmented plane-wave(FP-LAPW)method within density functional theory(DFT)in generalized gradient approximation(GGA)were performed.The lattice parameter,bulk modulus,pressure derivative,density of states(DOS)and energy band structures were determined.The GGA-optimized lattice parameter agrees much better with the experimental findings than the local density approximation(LDA)one.The non-negligible electronic DOS at Fermi level confirms that GdH_(2.25)has a metallic character.The Fermi energy(E_(F))falls at a level where most of the states are rare-earth 5 d conduction states while negligible contributions of both interstitial(tetrahedral and octahedral)H s states are observed near EF.It is found that hybridization exists between s electronic orbital of both interstitial H atoms and d electronic orbitals of Gd.
文摘We performed ab initio calculations of electronic structure and equilibrium properties for the rare earth superstoichiometric dihydride GdH2.25 (with the space group Pm-3m (No. 221)) using the full-potential linearized augmented plane wave method (FP-LAPW) approach within the density functional theory (DFT) in the generalized gradient approximation (GGA) and local density approximation (LDA) as implemented in the WIEN2k simulation code at 0 K. The equilibrium properties were determined, the density of states, electronic density and the energy band structures were studied in details. It was concluded that the GGA optimized lattice parameter agreed much better with the experimental findings than the LDA one, The non negligible electronic density of states at the Fermi level confirmed that the GdH2.25 had a metallic character. The Fermi energy EF fell at a level where most of the states were rare-earth 5d-eg conduction states while negligible contributions of both interstitial (tetrahedral and octahedral) H s-states were observed near EF, From electronic density, the bonding between Gd and tetrahedral H atoms was of prominent covalency, while was ionic between Gd and octahedral H atoms.
基金Project supported by the National Natural Science Foundation of China.
文摘The dihydride cluster H<sub>2</sub>O<sub>s<sub>3</sub></sub>(CO)<sub>10</sub> reacts with ethyne to give a cis-adduct [O<sub>s<sub>3</sub></sub>H(μ,η<sup>2</sup>-CH=CH<sub>2</sub>)(CO)<sub>10</sub>]. The high deuterated cluster D<sub>2</sub>O<sub>s<sub>3</sub></sub>(CO)<sub>10</sub>, the reaction of D<sub>2</sub>O<sub>s<sub>3</sub></sub>(CO)<sub>10</sub>with ethyne C<sub>2</sub>H<sub>2</sub> to form the vinyl product cluster [O<sub>s<sub>3</sub></sub>D(μ, η<sup>2</sup>-CH=CHD)(CO)<sub>10</sub>], and thereaction of H<sub>2</sub>O<sub>s<sub>3</sub></sub>(CO)<sub>10</sub> with the deuterated ethyne C<sub>2</sub>D<sub>2</sub> to form [O<sub>s<sub>3</sub></sub>H(μ,η<sup>2</sup>-CD=CDH)(CO)<sub>10</sub>] have been reported primarily in this paper. The two cis-adducts undergo cis-trans-isomerization of μ,η<sup>2</sup>-vinyl ligands under a small amount of the nucleophile pyridine. Usingthe combination of deuteration and dynamic <sup>1</sup>H,<sup>2</sup>H NMR spectra, we report the experimen-tal evidence determined by the dynamic <sup>1</sup>H, <sup>2</sup>H NMR spectra, mechanism, and kinetic dataof the isomerization.