Catalytic polymerization of acetylene in the presence of n5-C5H5-M-(CO)3 R (M=Mo,W;R=CH3-,C2H5-) has been studied.The results show that these complexes possess catalytic activities for the polymerization and copolymer...Catalytic polymerization of acetylene in the presence of n5-C5H5-M-(CO)3 R (M=Mo,W;R=CH3-,C2H5-) has been studied.The results show that these complexes possess catalytic activities for the polymerization and copolymerization of monosubstituted acetylene.The catalytic mechanism has been preliminarily discussed.It is suggested that the active species be metal-car-bene.In our previous publications we reported the synthesis of some new Fischer's molybdenum and tungsten-carbene complexes and catalytic activity for alkyne polymerization.The results show that the activity of Fischer's molybdenum-carbene is higher than that of tungsten.The catalytic polymerization of alkyne by M-σ-c bond-containing complexes of molybdenum and tungsten has not been reported yet in literature.Therefore,four M-σ-C bondontaining complexes of molybdenum and tungsten were synthesized by using the method reported in the literature,and catalyst polymerization of alkyne by these complexes was examined.展开更多
The reaction of W（CO）6 with pyOSNa （C5H4NOSNa） and Et4NCl in MeCN affords a new tungsten（0）complex [Et4N][W（pyS）（CO）4] 1 （Mr = 536.29）. The crystal and molecular structures have been determined by X-ray si...The reaction of W（CO）6 with pyOSNa （C5H4NOSNa） and Et4NCl in MeCN affords a new tungsten（0）complex [Et4N][W（pyS）（CO）4] 1 （Mr = 536.29）. The crystal and molecular structures have been determined by X-ray single-crystal diffraction. Complex 1 crystallizes in the orthorhombic system, space group P212121 with α= 8.2429（5）, b = 9.1045（4）, c = 26.8851（14） A, β= 90.00°, V=2017.66（18） A3^, Z = 4, Dc = 1.765 g/cm^3, μ= 58.51 cm^-1, F（000） = 1048, the final R = 0.0204 and wR = 0.0400 for 4432 observed reflections with I 〉 2σ（I）. X-ray structure analysis revealed that the molecule is acentric and has large first=order hyperpolarizability （7.2 × 10^-30 esu）, so it could be an IR second=order nonlinear optical candidate material.展开更多
The colored associated compounds of phosphomolybdotungstate and arsenomolybdotungstate with crystal violet are introduced. Their main characters have been studied. These two associated compounds may be used to determi...The colored associated compounds of phosphomolybdotungstate and arsenomolybdotungstate with crystal violet are introduced. Their main characters have been studied. These two associated compounds may be used to determine low tungsten with fairly high sensitivity and selectivity. Their strong point is that the interference of molybdenum can be overcome. In the presence of polyvinyl alcohol, tungsten can be determined directly in the aqueous solution.展开更多
Reaction of benzyl chloride with η5-CH3COC5H4W(CO)2Na formed in situ from η6-CH3CO C6H4Na and W(CO)2 gives η6-CH3COC6H4W(CO)3CH2C5H5.The single crystal structure of the product was determined by X-ray diffraction m...Reaction of benzyl chloride with η5-CH3COC5H4W(CO)2Na formed in situ from η6-CH3CO C6H4Na and W(CO)2 gives η6-CH3COC6H4W(CO)3CH2C5H5.The single crystal structure of the product was determined by X-ray diffraction method. It crystallizes in the triclinlc space group P1 with unit cell parameters a= 10.199(5),b=12.116(7), c=14.207(6)A;a=69.47(5),β=72. 38(3),γ= 85.89(4);V= 1569. 9A3, Dc= 1.98 g/cm2; Z=4. Least-square refinement led to final R value of 0. 0539 and Rw value of 0. 0553, based on 3548 independent observed reflections.展开更多
A new compound Sr6Sn2Nb8O30 was found in the ternary system of SrO-SnO2-Nb2O5. The transparent colorless crystal with needle-like shape can be grown by flux method. The crystal structure of new compound was determined...A new compound Sr6Sn2Nb8O30 was found in the ternary system of SrO-SnO2-Nb2O5. The transparent colorless crystal with needle-like shape can be grown by flux method. The crystal structure of new compound was determined by X-ray diffraction, and its belongs to tungsten bronze structure. Sr6Sn2Nb8O30 crystallizes in orthorhombic system with unit cell parameters a= 17. 579 (DA,6= 17. 509(DA,c=7. 7880(5)A,Z = 4 and space group Cmm2.展开更多
The system W Ⅵ H 2O 2 has good selectivity for methoxyacetone in oxidation of 1 methoxy 2 propanol. The effects of acid and base additives on selectivity for methoxyacetone were studied. The results showed that the a...The system W Ⅵ H 2O 2 has good selectivity for methoxyacetone in oxidation of 1 methoxy 2 propanol. The effects of acid and base additives on selectivity for methoxyacetone were studied. The results showed that the acid additive, i.e. NaHSO 4, was favorable to Na 2WO 4 H 2O 2 system, while the base additive NEt 3 was favorable to other tungsten compounds. A 71 2% of yield of methoxyacetone with 98 9% of selectivity for methoxyacetone was obtained in Na 2WO 4 H 2O 2 NaHSO 4 MeCOMe oxidation system.展开更多
文摘Catalytic polymerization of acetylene in the presence of n5-C5H5-M-(CO)3 R (M=Mo,W;R=CH3-,C2H5-) has been studied.The results show that these complexes possess catalytic activities for the polymerization and copolymerization of monosubstituted acetylene.The catalytic mechanism has been preliminarily discussed.It is suggested that the active species be metal-car-bene.In our previous publications we reported the synthesis of some new Fischer's molybdenum and tungsten-carbene complexes and catalytic activity for alkyne polymerization.The results show that the activity of Fischer's molybdenum-carbene is higher than that of tungsten.The catalytic polymerization of alkyne by M-σ-c bond-containing complexes of molybdenum and tungsten has not been reported yet in literature.Therefore,four M-σ-C bondontaining complexes of molybdenum and tungsten were synthesized by using the method reported in the literature,and catalyst polymerization of alkyne by these complexes was examined.
基金This research was supported by NNSFC (No. 01008) and SKLSC (No. 980148-2)
文摘The reaction of W（CO）6 with pyOSNa （C5H4NOSNa） and Et4NCl in MeCN affords a new tungsten（0）complex [Et4N][W（pyS）（CO）4] 1 （Mr = 536.29）. The crystal and molecular structures have been determined by X-ray single-crystal diffraction. Complex 1 crystallizes in the orthorhombic system, space group P212121 with α= 8.2429（5）, b = 9.1045（4）, c = 26.8851（14） A, β= 90.00°, V=2017.66（18） A3^, Z = 4, Dc = 1.765 g/cm^3, μ= 58.51 cm^-1, F（000） = 1048, the final R = 0.0204 and wR = 0.0400 for 4432 observed reflections with I 〉 2σ（I）. X-ray structure analysis revealed that the molecule is acentric and has large first=order hyperpolarizability （7.2 × 10^-30 esu）, so it could be an IR second=order nonlinear optical candidate material.
文摘The colored associated compounds of phosphomolybdotungstate and arsenomolybdotungstate with crystal violet are introduced. Their main characters have been studied. These two associated compounds may be used to determine low tungsten with fairly high sensitivity and selectivity. Their strong point is that the interference of molybdenum can be overcome. In the presence of polyvinyl alcohol, tungsten can be determined directly in the aqueous solution.
文摘Reaction of benzyl chloride with η5-CH3COC5H4W(CO)2Na formed in situ from η6-CH3CO C6H4Na and W(CO)2 gives η6-CH3COC6H4W(CO)3CH2C5H5.The single crystal structure of the product was determined by X-ray diffraction method. It crystallizes in the triclinlc space group P1 with unit cell parameters a= 10.199(5),b=12.116(7), c=14.207(6)A;a=69.47(5),β=72. 38(3),γ= 85.89(4);V= 1569. 9A3, Dc= 1.98 g/cm2; Z=4. Least-square refinement led to final R value of 0. 0539 and Rw value of 0. 0553, based on 3548 independent observed reflections.
基金Funded by International Centre for Diffraction Data(ICDD).
文摘A new compound Sr6Sn2Nb8O30 was found in the ternary system of SrO-SnO2-Nb2O5. The transparent colorless crystal with needle-like shape can be grown by flux method. The crystal structure of new compound was determined by X-ray diffraction, and its belongs to tungsten bronze structure. Sr6Sn2Nb8O30 crystallizes in orthorhombic system with unit cell parameters a= 17. 579 (DA,6= 17. 509(DA,c=7. 7880(5)A,Z = 4 and space group Cmm2.
文摘The system W Ⅵ H 2O 2 has good selectivity for methoxyacetone in oxidation of 1 methoxy 2 propanol. The effects of acid and base additives on selectivity for methoxyacetone were studied. The results showed that the acid additive, i.e. NaHSO 4, was favorable to Na 2WO 4 H 2O 2 system, while the base additive NEt 3 was favorable to other tungsten compounds. A 71 2% of yield of methoxyacetone with 98 9% of selectivity for methoxyacetone was obtained in Na 2WO 4 H 2O 2 NaHSO 4 MeCOMe oxidation system.
