史启祯
从事金属有机化学和物理无机化学领域的研究工作。
个性化签名
- 姓名:史启祯
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学术头衔:
博士生导师
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学科领域:
应用数学
- 研究兴趣:从事金属有机化学和物理无机化学领域的研究工作。
史启祯,男, 1935年生,教授,博士生导师。1958年毕业于兰州大学,1994年5月开始在西北大学任教。1981、1987、和1991年三次在美国西北大学从事合作研究。现任西北大学学术委员会委员,校教学指导委员会副主任委员,西北大学物理无机化学学科带头人,陕西省物理无机重点实验室学术委员会主任,教育部科学技术委员会化学部学部委员。曾任兰州大学党委副书记,西北大学物理无机化学研究所所长,陕西省物理无机化学重点实验室主任,《分子催化》、《化学应用与研究》和《无机化学学报》杂志编委,中国化学会理事,中国化学会无机化学专业委员会副主任委员,教育部化学教学指导委员会委员和应用化学与化工基础教学指导组副组长。被授予陕西省有突出贡献专家称号和优秀博士生导师。
科研和受奖 从事金属有机化学和物理无机化学领域的研究工作,先后主持7项国家自然科学基金研究项目,其中包括一项重点项目子课题和两项由中、美两国国家基金委共同支持的国际合作项目. 在国内外杂志上发表学术论文290余篇。其中《SCI》源杂志160余篇。是国内最早研究无机-金属有机反应动力学的领头人之一,关于空敏化合物V(CO)6取代反应动力学的研究在国际上首次提供了17电子与18电子配合物相对取代活性的比较,首次提出通过异腈桥实现内层电子转移的可能性,相关论文被引用600余次。合作专著《热分析动力学》(科学出版社,2001)。1991 年获国家教委科技进步二等奖,1995 年获甘肃省科技进步二等奖, 2001 年获陕西省科技进步二等奖。
教学和受奖 主编国家面向21世纪课程教材《无机化学与化学分析》(高教社)及国家“八五”重点教材《无机化学与化学分析实验》(高教社),翻译出版《无机化学》(高教社)等国外精品教材和教学参考书4部。1999年获陕西省高校优秀教学成果特等奖(排名1),2001年获国家优秀教学成果二等奖(排名1),2003年被评为陕西省教学名师和国家级教学名师。
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史启祯
,-0001,():
-1年11月30日
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史启祯, Jian-Kun Shen, † Yi-Ci Gao, † Qi-Zhen Shi, *, † and Fred Basolo*'‡
Organometallics 1989, 8, 2144-2147,-0001,():
-1年11月30日
Reported are rates of reaction and activation parameters for CO substitution by PPh3 of M(CO)5 (M=Fe, Ru, Os) in the presence of (CH3)3NO. The reactions follow a second-order rate law, being first-order in concentrations of M(CO)5 and of (CH3)3NO but zero-order in PPh3 concentration. The reaction rates show an approximate overall fourfold increase in the order Fe<Ru<Os. This contrasts the roughly 40-fold decrease in rate in the order Fe>Ru> Os for M3(CO)12. An attempt is made to account for the relative reaction rates of the M(CO)5 compounds and for why the order differs from that of the corresponding metal carbonyl clusters.
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史启祯, Yi-Ci Gao, † Qi-Zhen Shi, *† David L. Kershner, ‡ and Fred Basolo*‡
Inorg. Chem. 1988, 27, 188-191,-0001,():
-1年11月30日
Kinetic data are reported for the reactions of Mo(CO)5L (where L1=P(c-Hx)3, P(n-Bu)3, NMe3, py, PPh3, AsPh3, P(OEt)3, or P(OMe)3) with L in the presence of Me3NO to form cis-Mo(CO)4L2. The rates of reactions are second order: first order in Mo(CO)5L concentration, first order in Me3NO concentration, and zero order in L concentration. For ligand L with cone angles less than 135*, the rates of reaction increase with increasing stretching frequency of the CO bands in the IR. This supports the proposed mechanism, which involves attack by the O atom of Me3NO on a C of a CO cis to L in Mo(CO)sL. For L=PPh3 or AsPh3, the reactions are faster than expected on the basis of their vco values, and this is discussed in terms of steric effects.
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史启祯, Jian-Kun Shen, † Yian-Long Shi, † Yi-Ci Gao, † Qi-Zhen Shi, *† and Fred Basolo*‡
J. Am. Chem. SOC. 1988, 110, 2414-2418,-0001,():
-1年11月30日
Reported are the rates of reaction and activation parameters for CO substitution reactions of M3(CO)12 (M=Fe, Ru, Os) with L (L = PPh3, P(OPh)3, AsPh3) in the presence of (CH3)3NO. In aprotic solvents the reactions are too fast to follow by conventional spectroscopy, but the rates decrease with added protonic solvents. Reactions are readily monitored at room temperature in the mixed solvent CHC13-C2H5OH (v/v, 2:1), and the rates of reaction are inversely proportional to the concentration of C2H5OH. It is suggested that this is due to hydrogen bonding to give (CH3)3NO…HOC2H5, which is unreactive compared with the very reactive free (CH3)3NO at these reaction conditions. The rates of formation of M3(CO)llL are first-order in concentrations of metal cluster and of (CH3)3NO but zero-order in concentration of L. This suggests a mechanism that involves a nucleophilic attack of the O atom of (CH3)3NO on the C atom of a CO, accompanied by oxidation of CO to CO2. Since CO2 is a good leaving group, its departure from the metal clusters affords the active intermediates M3(CO)II. These then rapidly react with entering ligands to form the monosubstituted products M3(CO)11. The rates of reaction decrease in the order F3(CO)12>Ru3(CO)12>Os3(CO)12, and an attempt is made to account for the observed relative rates.
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史启祯, Yan-Lung Shi, Yi-Ci Gao, and Qi-Zhen Shi*, David L. Kershner and Fred Basolo*
OrganometaUics 1987, 6, 1528-1531,-0001,():
-1年11月30日
Detailed kinetic data are reported for the reactions of M(CO)6 (where M=Cr, Mo, and W) with Me3NO, in the absence and in the presence of triphenylphosphine (PPha). The rates of reaction are first-order in concentrations of M(CO)6 and of Me3NO but zero-order in PPh8 concentration. The rates of reaction decrease in the order W>Mo>Cr. A mechanism is proposed which involves attack on a carbonyl carbon with the formation of coordinatively unsaturated intermediates of the type M(CO)5, which then rapidly react with an entering ligand. Compared with other nucleophiles reported to react by carbonyl attach in M(CO)6 substrates, Me3NO is a strong nucleophile. Qualitatively, the nucleophilic strengths decrease in the order MeLi>Me3NO>PhCH2MgBr>>N3->NCO->NCS->C1->Br->I-.
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【期刊论文】Origin of the Exceptional Reactivity of Vanadium Pentacarbonyl Nitrosyl
史启祯, QI-ZHEN SHI, THOMAS G. RICHMOND, WILLIAM C. TROGLER, ** and FRED BASOLO*
Inorg. Chem. 1984, 23, 957-960,-0001,():
-1年11月30日
The complex V(CO)5(NO) undergoes substitution of CO at or below 0℃ by L=PMe3, PPh3, P(O-i-Pr)3, P(OMe)3, and NEt3 to yield V(CO)4L(NO). Substitution proceeds according to a two-term rate law: -d[V(CO)5(NO)]/dt=kl[V(CO)5(NO)]+k2[V(CO)5(NO)] [L]. For the extremely weak NEt3 nucleophile, the substitution reaction occurs only via the k1 path. Substitution of a second CO ligand to afford V(CO)3(PMe3)2(NO) proceeds solely by a dissociative pathway and is 106 times slower than loss of CO from V(CO)5(NO) at 25℃. The thermal instability of V(CO)5(NO) results from facile CO dissociation at room temperature, which occurs faster than in any other first-row-metal carbonyl or carbonyl nitrosyl. This remarkable reactivity of V(CO)5(NO) may be attributed to a trans effect from the NO ligand. Ground-state SCF-Xa-DV calculations have been performed for V(CO)5(NO) and compared with those for V(CO)6. In V(CO)5(NO), the fully occupied r-bonding t2s orbitals split into b2(dxy) and e(dxz,yz) orbitals. The e level, which can π-bond to NO, is preferentially stabilized, and the NO π-orbital contribution is 4-5 times that of the axial CO ligand. This superior 7r-acceptor character of NO also leads to the purple color of V(CO)5(NO). One-electron transitions from the b2(dxy) and e(dxz,yz) levels into a low-lying empty NO π* orbital are calculated at 2.29 and 2.52 eV and observed experimentally at 2.23 and 3.14 eV, respectively.
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史启祯, Thomas G. Richmond, Qi-Zhen Shi, William C. Trogler, *t and Fred Basolo*
J. Am Chem, Soc. 1984, 106, 76-80,-0001,():
-1年11月30日
Vanadium hexacarbonyl readily disproportionates upon treatment with oxygen and nitrogen Lewis bases. The reaction is first order with respect to Lewis base and V(CO)6. Nucleophilic attack on the metal center appears to be the rate-determining step. Second-order rate constants in dichloromethane decrease in the series py>Et3N>MeCN>MeOH>acetone>THF>2,5-Me2THF>DME>MeNO2>EhO, with a factor of 104 separating the first and last members of this group. Activation parameters for disproportionation by THF are in accord with an associative mechanism: △H*=14.2±1.2 kcal/mol and △S*=-21.5±4.2 cal/mol.deg. The structure of the disproportionation product is also dependent on the nature of the Lewis base. For Et20, the bridging isocarbonyl complex [V(Et20)4] [O-C-V(CO)5]2 can be isolated from CH2C12-Et20 solution. For stronger oxygen and nitrogen bases (B), [V(B)6] [V(CO)6]2 is the final product. In the case of B = pyridine, a bridging isocarbonyl intermediate can be detected as a kinetic product of the disproportionation process. This intermediate reacts with additional pyridine to afford [V(B)6] [V(CO)6]2. The observation of an isocarbonyl-bridged intermediate suggests that electron transfer may take place through an isocarbonyl ligand. Phosphine-substituted derivatives of V(CO)6 undergo disproportionation much more slowly than V(CO)6, although the rate-limiting step also appears to be CO substitution by the Lewis base. For example, disproportionation of V(CO)5P(n-Bu)3 induced by CH3CN is five orders of magnitude slower than that of V(CO)6.
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史启祯, Qi-Zhen Shi, Thomas G. Richmond, William C. Trogler, *† and Fred Basolo*
J. Am. Chem. Soc. 1984. 106. 71-76,-0001,():
-1年11月30日
Carbon monoxide substitution in the metal radical V(CO)6 proceeds at or below room temperature to form monosubstitution products V(CO)5L (L=phosphine or phosphite). The substitution occurs solely by a second-order process according to a rate law that is first order in both V(CO)6 and phosphorus nucleophile. The rate of reaction is strongly dependent on the basicity and size of the ligand. Activation parameters further support the associative nature of the reaction: P(n-Bu)3, △H*=7.6 4±0.4 kcal/mol, △S*=-25.2±1.7cal/mol.deg; P(OMe)3, △H*=10.9±0.2kcal/mol, △S*=-22.6±0.8cal/mol.deg; PPh3, △H*=10.0±0.4kcal/mol, △S*=-27.8±1.6cal/mol.deg. The rate of substitution of V(CO)6 by PPh3 is unchanged under 1 atm of carbon monoxide or in the presence of [V(CO)6]-. The carbon monoxide substitution reactions of V(CO)sL with additional L also proceed by an associative mechanism with the rate of substitution approximately three orders of magnitude slower than for V(CO)6. The disubstituted product adopts the cis stereochemistry with small phosphorus donor ligands or with chelating phosphines. For L=P(OMe)3, activation parameters were determined: △H*=13.2±0.4kcal/mol, △S*=-27.6±1.8 cal/mol.deg. Phosphine exchange reactions of V(CO)sL were also observed indicating that, in addition to carbon monoxide, phosphine ligands on vanadium are substitution labile. Nucleophilic attack of P(n-Bu)3 at V(CO)5[P(n-Bu)3] is l05 times slower than that at V(CO)6, presumably because the increased electron density on the metal hinders nucleophilic attack. Quantitative comparisons between the 17-electron complex V(CO)6 and its 18-electron analogue Cr(CO)6 indicate that associative carbon monoxide substitution takes place 1010 times faster in the vanadium system.
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【期刊论文】Kinetics and Mechanism of Ligand Substitution in Iron Tricarbonyl 1,4-Diazabutadiene Complexes
史启祯, Qi-Zhen Shi, la Thomas G. Richmond, lb William C. Trogler, *b and Fred Basolo*lb
Organornetallics 1982, 1, 1033-1037,-0001,():
-1年11月30日
When aryl groups are substituents in the 1,4-positions of the diazabutadiene (DAB) ligand,2 substitution of carbon monoxide by PMes in Fe(CO)s(DAB) takes place solely by a second-order process. The rate law is first order in both Fe(CO)s(DAB) and PMes. Activation parameters for the 4-fluorophenyl derivative in toluene support the associative nature of this reaction: △H*=13.6±1.0kcal/mol; △S*=-34.8±3.2 eu. Carbon monoxide replacement rates depend on the nature of the nucleophile, and increase in the series PPh3<P(OMe)3<P(n-Bu)3<PMe3. This rate also increases when the π-acceptor ability of the DAB ligand increases. When bulky tert-butyl groups are the substituents in the 1,4-positions of the DAB ligand, steric interactions become important in the six-coordinate transition state. Nucleophilic attack on this complex results in loss of the DAB ligand to give Fe(CO)3(PMe3)2. This reaction obeys a two-term rate law involving both associative (△H*=20.4±0.8kcal/mol and △S*=-18.2±2.0 eu) and dissociative (△H*=25.0±1.0kcal/mol and △S*=-8.0±3,0 eu) pathways. Factors which facilitate nucleophilic attack on iron in these coordinately saturated metallacycles and in the related Fe(CO)3(N4Me2) complex are discussed.
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【期刊论文】Mechanism of Carbon Monoxide Substitution in a Metal Radical: Vanadium Hexacarbonyl
史启祯, Qi-Zhen Shi, la Thomas G. Richmond, tlb William C. Trogler, *lb and Fred Basolo*lb
J. Am. Chem. SOC1.9 82, 104, 4032-4034,-0001,():
-1年11月30日
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