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1、Organometallics 金属有机化学,1. Introduction（引论）,1.1 Historical Development and Current Trends in Organometallic Chemistry (在金属有机化学领域的历史发展和当前趋势) 1760 The cradle(摇篮) of organometallic chemistry is a Paris military pharmacy(制药厂). It is there Cadet(军校学员) works on sympathetic inks（隐显墨水）based on cobalt salts.
2、For their preparation, cobalt mineral which contain arsenic(砷) was used.,As2O3 + 4CH3COOK - “Cadets Fuming(发烟的) liquid” Contains cacodyloxide(卡可基氧) (CH3)2As2O (maldorous 恶臭的） First organometallic compound(化合物). 1827 Zeises salt NaPtCl3C2H4 First olefin(烯烃) complex(络合物、配合物),1840 R. W. Bunsen continue
3、s the study of cacodyl compounds which he names “alkarsines”. The weakness of As-As bond in molecules of the type R2As-AsR2 led to a profusion(丰富) of derivatives(衍生物) like (CH3)2AsCN whose taste is checked by Bunsen. 1849 E. Frankland, student of Bunsen, attepts the preparation of an “ethyl radical”
4、(乙基自由基). (cacodyl as well was taken to be a radical).,1852 Frankland prepares the important alkylmercury (烷基汞) compounds: 2CH3X + 2Na/Hg (CH3)2Hg + 2NaX Additionally: (C2H5)4Sn, (CH3)3B (1860). In the following years, alkyl transfer reactions using R2Hg and R2Zn serve in the synthesis of numerous ma
5、in-group organometallics. Frankland also introduced the concept of valency(“combining power”) and the term organometallic.,1852 K. J. Koning and M. E. Schweizer in Zurich first prepare (C2H5)4Pb from ethyliodide and Na/Pb alloy. In a similar manner, they also obtain (C2H5)4Sb and (C2H5)3Bi. 1859 W.
6、Hallwachs and A. Schafarik generate alkylaluminum iodides: 2Al + 3RI R2AlI + RAlI2 1863 C. Friedel and J. M. Crafts prepare Organochlorosilane: SiCl4 + m/2ZnR2 RmSiCl4-m + m/2ZnCl2,1866 J. A. Wanklyn develops a method for the synthesis of halide-free magnesium alkyls: (C2H5)2Hg + Mg (C2H5)2Mg + Hg 1
7、868 M. P. Schutzenberger obtains Pt(CO)Cl22, first metal carbony(羰基) complex. D. I. Mendeleev uses organometallic compounds as test cases for his periodic table. Example:,1890 L. Mond: Ni(CO)4, first binary(二元的) metal carbonyl, used in a commercial(商业的) process for refining nickel. Mond is the found
8、er of the English company ICI (Imperial Chemical Industries) as well as a renowned collector and patron(恩主) of the arts. 1899 P. Barbier replaces Mg for Zn in reactions with alkyl iodides:,Explored in more detail by Barbiers student V. Grignard (Nobel prize 1912 shared with P. Sabatier. Although les
9、s sensitive than ZnR2, RMgX is more potent(强有力的) alkyl group transfer reagent. 1901 L. F. S. Kipping prepares (C6H5)2SiO, suspects its high molecularity, and calls the material diphenylsilicone.,1909 W. J. Pope: formation of (CH3)3PtI, first s-organotransition-metal compound. 1909 P. Ehrlich (invent
10、er of chemotherapy化学疗法, Nobel prize 1908) introduces Salvarsan(洒尔佛散) for the treatment of syphilis(梅毒).,1917 W. Schlenk: Lithium alkyls via (通过) transalkylation(烷基转移). 2Li + R2Hg 2LiR + Hg 2EtLi + Me2Hg 2MeLi + Et2Hg 1919 F. Hein from CrCl3 and PhMgBr synthesizes polyphenylchromium compounds, now kn
11、own to be sandwich(三明治) complexes.,1922 T. Midgley and T. A. Boyd introduces Pb(C2H5)4 as an antiknock additive in gasoline. 1928 W. Hieber inaugurates(开始) his systematic study of metal carbonyls: Fe(CO)5 + H2NCH2CH2NH2 (H2NCH2CH2NH2)Fe(CO)3 + 2CO Fe(CO)5 + X2 Fe(CO)4X2 + CO,1929 F. A. Paneth genera
12、tes alkyl radicals through PbR4 pyrolysis(热解), radical identification by means of their ability to cause the transport of a metallic mirror. Paneth thus reaches a goal set by Frankland in 1849. 1930 K. Ziegler encourages more extensive use of organolithium compounds in synthesis by developing a simp
13、ler way of preparation. PhCH2OMe + 2Li PhCH2Li + MeOLi (ether cleavage) H. Gilman: RX + 2Li RLi + LiX (procedure used today),1931 W. Hieber prepares Fe(CO)4H2, first transition-metal hydride(负氢离子) complex. 1938 O. Roelen discovers hydroformylation (加氢甲酰化、羰基化)(the oxo process).,1939 W. Reppe starts w
14、ork on the transition-metal catalyzed reactions of acetylene(乙炔).,1943 E. G. Rochow: Cu-Cat.,300 2CH3Cl + Si - (CH3)2SiCl2 + This “direct synthesis” triggers large scale production and use of silicones. Preliminary work by R. Muller (Radebeul near Dresden) was interrupted by the Second World War. 19
15、51 P. Pauson (GB) and S. A. Miller (USA) obtain ferrocene(二茂铁) (C5H5)2Fe, first sandwich complex.,1953 G. Wittig discovers the reaction reaction bearing his name.,1955 E. O. Fischer: rational synthesis of bis(benzene)chromium (C6H6)2Cr. 1955 K. Ziegler, G. Natta: polyolefins(聚烯烃) from ethylene and p
16、ropylene, respectively, in a low pressure process employing mixed metal catalysts (transition-metal halide/ AlR3). 1956 H. C. Brown: hydroborane(氢硅烷). 1959 J. Smodt, W. Hafner: preparation of (C3H5)PdCl2, installation(建立) of the field of p-allyl transition-metal complexes.,1959 R. Crigee stabilizati
17、on(稳定) of cyclobutadiene(环丁二烯) by complexation in (C4Me4)NiCl22 veryfying a prediction by H. C. Longuet-Higgins and L. Orgel (1956)。 1960 M. F. Hawthorne: carboranes(碳硅烷). 1961 L. Vaska: (PPh3)2Ir(CO)Cl reversibly(可逆地) binds O2. 1963 Nobel prize to K. Ziegler and G. Natta. 1964 E. O. Fischer: (CO)5W
18、C(OMe)Me, first carbene(卡宾) complex.,1965 G. Wilkinson, R. S. Coffey: (PPh3)3RhCl acts as a homogeneous(均相的) catalyst in the hydrogenation of alkenes(烯烃). 1968 A. Streitwieser: preparation of uranocene(二茂铀), (C8H8)2U. 1969 P. L. Timms: synthesis of organotransition-metal complexes by means of metal-
19、atom ligand(配体)-vapor cocondensation(共缩合). 1970 G. Wilkinson: kinetically inert transition-metal alkyls through blockage(阻断) of b-elemination(消除).,1972 H. Werner: (C5H3)3Ni2+, first triple-decker(三层) sandwich complex. 1973 E. O. Fischer ICO4CrCR, first carbyne(卡拜) complex. 1973 Nobel prize to E. O.
20、Fischer and G Wilkinson. 1976 Nobel prize to W. N. Lipscomb: theoretical and experimental clarification of structure and bonding in boranes.,1979 Nobel prize to H. C. Brown and G. Wittig: application of organoboranes and methylenephosporanes, respectively, in organic synthesis. 1981 R. West (1,3,5-M
21、e3C6H2)4Si2, first stable compound with =Si=Si= double bond. 1981 Nobel prize to R. Hoffman and K. Fukui: semiempirical(半经验的) MO-concept in a unified discussion of structure and reactivity of inorganic, organic and organometallic molecules, isolobal analogies(等叶类比).,1983 R. G. Bergman, W. A. G. Grah
22、am: intermolecular reactions of organotransition-metal compounds with alkanes (C-H activation) Problems: 1. What was the first organometallic compound? Who prepared it? 2. What was the first olefin complex? 3. In what year did P. Ehrlich won Nobel prize and what was his invention?,4. What was K. Zie
23、gler and G. Nattas major discovery? 5. What was G. Wilkinsons discovery? 6. What did W. N. Lipscomb win Nobel prize for? 7. For what did G. Wittig win Nobel prize? 8. What were R. Hoffman and K. Fukui awarded Nobel prize for? 9. What project R. G. Bergman and W. A. G. Graham work for?,1.2 Classifica
24、tion of Organometallic Compounds Organometallic compounds are diffined as materials which possess direct, more or less polar bonds Md+ - Cd- between metal and carbon atoms.,The designation of s-, p-, d-bond,1.3 Energy, Polarity and Reactivity of M-C Bond It is important to distinguish between thermo
25、dynamic(热力学) (stable, unstable) and kinetic(动力学) (inert, labile) 1.3.1 Stability of Main-group Organometallics Compared with the strengths of M-N, M-O and M-Halogen(卤素) bond, M-C bonds must be deemed weak.,Generalizations M-C bond energies cover a wide range Compound (CH3)3B (CH3)3As (CH3)3Bi E(M-C)
26、 365 229 141 kJ/mol strong medium weak The mean bond energy E(M-C) with a main-group decreases with the increasing atomic number.,Ionic binds are encountered if M is particularly electropositive and /or the carbanion(碳负离子) is especially stable. Examples: Na+C5H5-, K+CPh3-, Na+CCR- Muticenter(多中心) bo
27、nding (“electron deficient bond”) arises if the valence shell of M is less than half filled and the cation Mn+ is srongly polarizing (possesses a large charge/radius ration). Examples: (LiCH3)4, Be(CH3)2n, Al(CH3)32,1.3.2 Lability of Main-group Organometallics All organometallic materials are thermo
28、dynamically unstable with respect to oxidation to Mon, H2O and CO2. Nevertheless, large differences in the ease of handling of organometallics are encountered which may be traced back to differences in kinetic inertness. Example:,1.4 Concise introduction of nomenclature in organic compounds and meta
29、l complexes (有机化合物及其金属配合物的命名简介) 1.4.1 Nomenclature of organic compounds (有机化合物的命名),Names for the root designating carbon numbers in the backbone chain,C- numbers root C-numbers root One meth- two eth- Three prop- four but- Five pent- six hex- Seven hex- eight oct- Nine non- ten dec- Eleven undec- tw
30、elve dodec- Thirteen tridec- fourteen tetradec- Fifteen pentadec- twenty eicos- Twenty one heneicos- Twenty two docos- Thirty triacont-,Systematic names, common names and abbreviations for some groups,Group sys. name com. name abbrev. CH3- methyl Me CH3CH2- ethyl Et CH3(CH2)2- propyl Pr (CH3)2CH- 1-
31、methylethyl isopropyl i-Pr CH3(CH2)3- butyl Bu (CH3)3C- 1,1-dimethylethyl- ter-butyl t-Bu C6H5- phenyl Ph C6H5CH2- phenylmethyl- benzyl Bez,Names of common functional groups (常见官能团的名称),Formula Name Prefix Sufix RH Alkane alkyl- -ane RCH=CH2 Alkene vinyl- -ene RCCH Alkyne -yne ArH Arene phenyl- -benz
32、ene RX Alkyl halide halo- -halide ROH Alcohol hydroxo- -ol ROR Ether alkoxo- -ether RNH2 Amine amino- -amine R-SH mercaptan -thiol,Order of priority for selected functional groups (官能团的优先顺序),Functional group Group prefix Rank of priority Carboxylic acid 1 Ester 2 Acid chloride 3 Amide 4 Aldehyde oxo
33、- 5 Nitrile cyano- 6 Ketone oxo- 7 Alcohol hydroxy- 8 Amine amino- 9 Ether alkoxy- 10 Halogen fluoro-, chloro- 11 bromo-, iodo- -NO2 nitro- 12,Some examples of nomenclature (一些命名实例),1.4.2 Nomenclature of metal complexes Order of listing ions(列出离子的顺序): The cation(正离子) is named first, and then the ani
34、on(负离子). This is the usual practice when naming a salt. NaCl Sodium Chloride Cr(NH3)6(NO3)3 hexaamminechromium(III)nitrate K2PtCl6 Potassium hexachloroplatinate(IV),Nonionic complexes: Nonionic or molecular complexes are given a one-word name. Co(NH3)3(NO2)3 Trinitrotriamminecobalt(III) Cu(CH3COCHCO
35、CH3)2 Bis(acetylacetonato)copper(II) CH3COCH2COCH3 = acetylacetone (乙酰基丙酮),Names of ligands: Neutral ligands are named as the molecule; negative ligands end o; and positive ligands (of reare occurrence) end in ium. NH2CH2CH2NH2 ethylenediamine (C6H5)3P trphenylphosphine Cl- chloro CH3COO- acetato NH
36、2NH3+ hydrazinium(胫鎓) NH2NH2(胫，联氨),Two exceptions to this rule are water and ammonia. H2O aquo NH3 ammine(Note the spelling with two ms; this applies only to NH3; other amines are spelled with usual one m.) Cr(NH3)6(NO3)3 Hexaamminechromium(III)nitrate Cr(NH2CH2CH2NH2)3(NO3)3 Tris(ethylenediamine)ch
37、romium(III)nitrate,Order of ligands The ligands in a complex are named in the order (1) negative, (2) neutral, and (3) positive, without separation by hyphens. Within each of these categories(范畴) the groups are listed in order of increasing complexity. Pt(NH3)4(NO2)ClSO4 Chloronitrotetraammineplatin
38、um(IV)sulfate NH4Cr(NH3)2(NCS)4 Ammonium tetrathiocyanatodiamminechromate(III),Numerical prefixes The prefixes di-, tri-, tetra-, etc., are used before such simple expressions as bromo, nitro, and oxalato. Prefixes bis-, tris, tetrakis-, pentakis-, etc., are used before complex names (chiefly expres
39、sions containing the prefixes mono-, di-, tri-, etc., in the ligand name itself) such as ethylenediamine and trialkylphosphine. K3Al(C2O4)3 potassium trioxalatoaluminate(III) Co(en)2Cl22SO4 dichlorobis(ethylenediamine)cobalt(III)sulfate,Termination of names The ending for anionic(负离子的) complexes is
40、ate; alternatively, -ic if named as an acid. For cationic(正离子的) and neutral complexes the name of the metal is used without any characteristic ending. Ca2Fe(CN)6 Calcium hexacyanoferate(II) Fe(H2O)6SO4 Hexaaquoiron(II)sulfate,Oxidation states The oxidation state of the central atom is designated by
41、a Roman numeral in parentheses at the end of the name of the complex, without a space between the two. For a negative oxidation state a minus sign is used before the Roman numeral, and 0 is used for zero. NaCo(CO)4 Sodium tetracarbonylcobaltate(-I) K4Ni(CN)4 Potassium tetracyanonickelate(0),Bridging
42、 groups Ligands that bridge two centers of coordination are preceded by the Greek letter m, which is repeated before the name of each different kind of bridging group.,Point of attachment Whenever necessary, the point of attachment of a ligand is designated by placing the symbol (in italics) of the
43、element attached after the name of the group, with separation by hyphen. (NH4)3Cr(NCS)6 Ammonium hexathiocyanato-N-chromate(III) (NH4)2Pt(SCN)6 Ammoniu hexathiocyanato-S-platinate(IV) -SCN-, thiocyanato, -NCS-, isothiocyanato -NO2-, nitro, -ONO-, nitrito(亚硝基),Geometrical isomers Geometrical isomers
44、are generally named by the use of the term cis to designate adjacent (90o apart) positions and trans for opposite (180o apart) positions. It is occasionally necessary to use a number system to designate the position of each ligand.,Problems: 1.Write the formula for each of the following compounds: (
45、1) dibromotetraammineruthenium(III)nitrate. (2)chloroaquobis(ethylenediamine) rhodium(III)chloride. (3) calcium dioxalatodiamminecobaltate(III). (4) octaammine-m-amido-m-hydroxodicobalt(III)sulfate. (5) sodium dithiosulfato-S-argentate(I).,2. Name each of the following compounds: (1) Co(NH3)62(SO)3
46、(2) Co(NH3)4(NCS)ClNO3 (3) Pt(en)Cl4 (4) NH4Cr(NH3)2(NCS)4 (5) Na2K4Ni(CN)4,2. Main-Group Organometallics (主族金属有机化合物),2.1 Alkali organometallics 2.1.1 Organolithium compounds: (1) Preparation: Et2O CH3Br + 2Li CH3Li + LiBr 20 (direct synthesis) THF C5Me5H + n-BuLi C5Me5Li + n-BuH - 78 (metallation),
47、(2) Sructure and bonding Tend to form oligmeric(寡聚的) units in solution as well as in solid state. A classic example is the structure of solid methyllithium which is best described as cubic body-centered packing of (LiCH3)4 units. The latter consisting of Li4-tetrahedra with methyl groups caping the
48、triangular faces (E. Weiss, 1964) This type of heterocubane arrangement is encounted frequently for species of constitution (AB)4.,Schematic drawing of the unit (LiCH3)4,NMR spectroscopy of the less common nuclei Nuclei with the spin quantum number I = For small molecules, I = usually yield sharp re
49、sonance lines with half widths W1/2 (at the half height) between 1 and 10 Hz. Nuclei with spin quantum numbers I 1/2 These nuclei possess electric quadrupole moments(四极矩) (deviation of the distribution of nuclear charge from spherical symmetry) which can cause extremely short nuclear relaxation time and large half widths.,(3) Reactions of organolithium compounds a) Metallation and subsquent reactions R-Li