A novel three dimensional fluorinated gallium phosphate has been hydrothermally synthesized by using diethylenetriamine as an organic structure directing agent. X ray single crystal structure analysis indicates this c...A novel three dimensional fluorinated gallium phosphate has been hydrothermally synthesized by using diethylenetriamine as an organic structure directing agent. X ray single crystal structure analysis indicates this compound crystallizes in the orthorhombic space group Pbca, a =1.605 6(7) nm, b = 1 011 4 (4) nm, c =1.854 6(5) nm, V =3.011 6(19) nm 3, Z =4. The three dimensional framework based on linkage of corner sharing polyhedron PO 4, GaO 4F and GaO 4F 2 delimit ten ring channels along b axis in which the triply protonated amines are located serving as charge compensating vips and supporters.展开更多
Ga 3(PO 4) 4](H 3NCH 2CH 2) 2NH 2(abbr. to GaP 1) has been synthesized by a hydrothermal method. X ray crystal structure analysis indicates GaP 1 crystallizes in monoclinic, with space group C2/c , a =2 079 3(5) nm, b...Ga 3(PO 4) 4](H 3NCH 2CH 2) 2NH 2(abbr. to GaP 1) has been synthesized by a hydrothermal method. X ray crystal structure analysis indicates GaP 1 crystallizes in monoclinic, with space group C2/c , a =2 079 3(5) nm, b =1 194 2(2) nm, c =1 648 0(4) nm, β =117 064(14)°, V =3 644 2(13) nm 3, Z =6, D c=1 901 g/cm 3, I ≥2 σ(I )=2 274, R =0 055 6, R w=0 134 8. GaP 1 is characteristic of the intercalation of disordered fully protonated diethylenetriamine among two dimensional inorganic framework built up from PO 4, GaO 5 and GaO 6 primary structure units. The framework features 3 , 4 , 5 and 8 ring topological connectivity.展开更多
The tautomerization of H2NCH2C(OH)NH to H2NCH2CONH2 is an important step by way of Strecker synthesis for the production of glycine in the interstellar medium (ISM) with respect to the origin of amino acids on the ear...The tautomerization of H2NCH2C(OH)NH to H2NCH2CONH2 is an important step by way of Strecker synthesis for the production of glycine in the interstellar medium (ISM) with respect to the origin of amino acids on the early Earth.Our work indicates two mechanisms for the tautomerization to occur.k CVT/SCT (rate constant) is 45.6s-1 at 50 K,obtained with the small curvature tunneling (SCT) approximation and canonical variational transition state theory (CVT),to support one mechanism assisted by quantum tunneling in the ISM.Another mechanism is through the (H2O) 2-coupled proton transfer.In the (H2O)2 coupled reaction,two H2O molecules act as a catalyst to reduce the barrier energy by 23.7 kcal mol 1,and cooperatively let a proton pass a hydrogen-bonded bridge composed of H2NCH2C(OH)NH with (H2O)2.kTST is 8.08×10-4 s-1 at 100 K,calculated with TST kinetics,to demonstrate the mechanism.Therefore,the tautomerization is feasible in the ISM.H2NCH2C(OH)NH and H2NCH2CONH2 will be detected in the ISM and found in carbonaceous chondrites.The results present new evidence for the third theory on the origin of amino acids on the early Earth.展开更多
文摘A novel three dimensional fluorinated gallium phosphate has been hydrothermally synthesized by using diethylenetriamine as an organic structure directing agent. X ray single crystal structure analysis indicates this compound crystallizes in the orthorhombic space group Pbca, a =1.605 6(7) nm, b = 1 011 4 (4) nm, c =1.854 6(5) nm, V =3.011 6(19) nm 3, Z =4. The three dimensional framework based on linkage of corner sharing polyhedron PO 4, GaO 4F and GaO 4F 2 delimit ten ring channels along b axis in which the triply protonated amines are located serving as charge compensating vips and supporters.
文摘Ga 3(PO 4) 4](H 3NCH 2CH 2) 2NH 2(abbr. to GaP 1) has been synthesized by a hydrothermal method. X ray crystal structure analysis indicates GaP 1 crystallizes in monoclinic, with space group C2/c , a =2 079 3(5) nm, b =1 194 2(2) nm, c =1 648 0(4) nm, β =117 064(14)°, V =3 644 2(13) nm 3, Z =6, D c=1 901 g/cm 3, I ≥2 σ(I )=2 274, R =0 055 6, R w=0 134 8. GaP 1 is characteristic of the intercalation of disordered fully protonated diethylenetriamine among two dimensional inorganic framework built up from PO 4, GaO 5 and GaO 6 primary structure units. The framework features 3 , 4 , 5 and 8 ring topological connectivity.
基金supported by the One-Hundred-Talents Project of Chinese Academy of Sciences,and the Academic Talent Foundation of Yunnan Province,China (Grant No.2006PY01-29)
文摘The tautomerization of H2NCH2C(OH)NH to H2NCH2CONH2 is an important step by way of Strecker synthesis for the production of glycine in the interstellar medium (ISM) with respect to the origin of amino acids on the early Earth.Our work indicates two mechanisms for the tautomerization to occur.k CVT/SCT (rate constant) is 45.6s-1 at 50 K,obtained with the small curvature tunneling (SCT) approximation and canonical variational transition state theory (CVT),to support one mechanism assisted by quantum tunneling in the ISM.Another mechanism is through the (H2O) 2-coupled proton transfer.In the (H2O)2 coupled reaction,two H2O molecules act as a catalyst to reduce the barrier energy by 23.7 kcal mol 1,and cooperatively let a proton pass a hydrogen-bonded bridge composed of H2NCH2C(OH)NH with (H2O)2.kTST is 8.08×10-4 s-1 at 100 K,calculated with TST kinetics,to demonstrate the mechanism.Therefore,the tautomerization is feasible in the ISM.H2NCH2C(OH)NH and H2NCH2CONH2 will be detected in the ISM and found in carbonaceous chondrites.The results present new evidence for the third theory on the origin of amino acids on the early Earth.
