紫外激光诱导C60与M(CO)6(M=Cr,Mo, W)的配位反应

研究了用紫外激光(355 nm)诱导C_(60)与金属羰基化合物M(CO)_6(M＝Cr；Mo，W)的配位反应，合成了具有C_(4υ)对称性的配位络合物(η~2－C_(60))M(CO)_5，并初步讨论了C_(60)与M(CO)_6反应的动力学过程．     

含膦配体的羰基钼(0)和钨(0)化合物的改进合成，反应及催化活性

MoCl_5或WCl_6与锌粉及适当的膦配体和CO在常压常温进行反应,合成了含膦配体的羰基钼和钨的化合物(Ph_2PR)_nM(CO)_(6-n)(M=Mo,W;R=Me,Et,n-Pr,Ph;n=2,3)。用该方法也成功地将M(CO)_5(M=Mo,W)单元负载到含膦的高分子链上,化合物(Ph_2PEt)_2Mo(CO)_4与HgCl_2反应得到含Mo-Hg键的化合物。用(Ph_3P)_2Mo(CO)_4和(Ph_3P)_2Ni(CO)_2二元催化体系,在适当温度和压力下对甲醇羰基化反应进行了初步研究,得到了醋酸和醋酸甲酯。该催化过程对甲醇的转化率可达92％,对醋酸和醋酸甲酯的选择性可达68％。     

M3（CO）12（M=Fe,Ru,Os）的氧原子转移反应动力学

近期研究表明,M(CO)_6(M=Cr,Mo,W)与Me_3NO作用是缔合反应,Me_3NO中氧原子亲核进攻羰基碳,使其以CO_2的形式脱离金属原子,由此产生的活性中间体M(CO)_5与外来配体快速反应生成M(CO)_5L。有关金属原子簇羰基配合物的类似反应动力学研究尚未见报道。原子簇配合物可能表现出与单核配合物不同的反应性质,并且是有效的均相催化剂,进一步了解其与Me_3NO的反应性质颇有意义。本文报道在Me_3NO存在下M_3(CO)_(12)的CO取代反应(1)的研究结果(M=Fe,Ru,Os)。     

亚硝酰基配合物——Ⅱ.(η~5-C_5H_5)M(CO)_2NO和(η~5-C_5H_5)M(μ_3-NH)(μ_2-NO)(μ_2-CO)Fe_2(CO)_6(M=Mo或W)的合成、表征和晶体结构

在四氢呋喃-甲醇介质中将环戊二烯基三羰基金属(钼或钨)氯化物与等摩尔羰基亚硝酰基钠盐在室温反应,产物经柱色谱分离和纯化得:橙色固体(η~5-C_5H_5)M(CO)_2NO、紫色固体[(η~5-C_5H_5)M(CO)_3]_2和黑色固体(η~5-C_5H_5)M(μ_3-NH)(μ_2-NO)(μ_2-CO)Fe_2(CO)_6(M=Mo或W)各两种.其中,后者是具有新颖结构的簇合物,分子中含有亚硝酰基(NO)被还原得到的亚胺基(μ_3-NH)配体.本文报道了它们的合成、表征和两种配合物X射线晶体结构研究的结果.     

钌羰其原子簇催化雷伯法反应的促进效应

钌羰基原子簇Ru_3(CO)_12催化C_2H_4和CO/H_2O的反应速度,显著地受溶剂、Ⅵ族金属羰基化合物M(CO)(M=Cr,Mo,W)、金属卤化物和碱金属阳离子的影响,这些促进效应的顺序为:THF→MeOH>+W(CO)_6>+I~->K~+>Cs~+,在碱性的MeOH/HO溶液中,主要产物是2-甲基戊烯醛,其它的产物包括丙醛,1,1-二甲氧基丙烷,二乙基酮和正丙醇,讨论了上述各种促进效应的原因和可能的反应机理。     

Mo(CO)5L的氧原子转移反应动力学和机理研究

近期我们报道了M(CO)_2(M=Cr,Mo,W)与Me_2NO反应的动力学研究结果。 本文报道在CH_2Cl_2,-CH_2CN(体积比1:1)混合溶剂中,三甲胺氧化物存在下的二取代反应: Mo(CO)_5L Me_3NO L→顺-Mo(CO)_4L_2 Me_3N CO_3 (1)式中L=P(c-hx)_3,P(n-Bu)_3,NMe_3Pyr,PPh_3,AsPh_3,P(OEt)和P(OMe)_3,在金属原子不变的情况下对配体的电子效应(以Mo(CO)_5L的羰基伸缩振动频率表现出来)和立体效应做探讨。     

[η~5-Bz_5C_5(CO)_nM]_2的合成及结构

本文通过η~5-Bz_5C_5MNa与氧化偶联试剂Fe_2(SO_4)_3/HOAc/H_2O的反应合成了含η~5-五苄基环戊二烯基配体的两个金属-金属单键化合物[η~5-Bz_5C_5(CO)_3M]_2(1:M=Mo;2:M=W),产率分别为45％和19％。1在沸腾的甲苯中可进一步脱羰而以98％的产率生成金属-金属三键化合物[η~5-Bz_5C_5(CO)_2Mo]_2(3)。1～3的结构均经碳氢分析,IR,~1H NMR和MS鉴定。3的结构尚被单晶X射线衍射分析确证。该晶体属单斜晶系,空间群P2_1/c,晶体学数据:。α=1.1335(5),b=1.3823(4),c=2.1655(6)nm;β=102.33(3)°;V=3.315(2)nm~3;Z=2;D_x=1.34g/cm~3;F(000)=1380。     

以2-(1-吡唑基甲基)吡啶类化合物为配体的羰基钼、钨衍生物的合成及结构

合成了2-[1-(3-叔丁基)吡唑基甲基]吡啶(CH2(Py)(3-ButPz)),并研究了羰基钼(钨)与该配体及其类似物2-(1-吡唑基甲基)吡啶(CH2(Py)(Pz))和2-[1-(3,5-二甲基)吡唑基甲基]吡啶(CH2(Py)(3,5-Me2Pz))的反应,合成了6个含双齿螯合的2-(1-吡唑基甲基)吡啶类配体的四羰基金属衍生物CH2(Py)(3-ButPz)M(CO)4,CH2(Py)(Pz)M(CO)4和CH2(Py)(3,5-Me2Pz)M(CO)4(M=Mo或W)。当用SnCl4处理CH2(Py)(3,5-Me2Pz)M(CO)4时,Sn-Cl键对金属中心发生氧化加成得到2个杂双核金属有机化合物CH2(Py)(3,5-Me2Pz)M(CO)3(Cl)SnCl3。所有新化合物均通过了红外和核磁的表征,CH2(Py)(3-ButPz)W(CO)4和CH2(Py)(3,5-Me2Pz)W(CO)3(Cl)SnCl3的结构还得到了X-射线单晶衍射的确证。用循环伏安法测定了四羰基金属衍生物的电化学性质。     

羟甲基功能化吡唑金属羰基化合物的合成及催化性质

研究了3(5)-羟甲基-5(3)-甲基吡唑(L~1),4-羟甲基吡唑(L2)及双(3-羟甲基-5-甲基吡唑)甲烷(L3)与羰基钨(钼)的反应,合成了一系列以单齿及双齿氮配位的羰基金属衍生物LW(CO)5(L=L1或L2)和L3M(CO)4(M=Mo或W)。通过核磁、红外及X射线单晶衍射分析,对这些化合物进行了详细的结构表征。结果表明,这些化合物往往通过O-H…O,N-H…O及O-H…OC-M等氢键作用,形成一维或二维金属有机超分子结构。并且依赖于配体中羟甲基所处的不同位置,这些金属有机超分子表现出明显不同的结构特征。初步的催化活性测试表明,这些新化合物在苯乙炔三聚反应中具有明显的催化活性。     

基于1-(2-吡啶甲基)-1,2,4-三唑的金属有机化合物的合成及反应研究(英文)

合成了1-(2-吡啶甲基)-1,2,4-三唑(L)并研究了其与有机锡和羰基钼(钨)的配位反应,合成了通过三唑4位氮原子以单齿形式配位的有机锡衍生物L2SnR2Cl2(R=Me,n-Bu或Ph)和羰基金属配合物LM(CO)5(M=Mo或W),以及N,N螯合双齿配位的四羰基金属配合物LM(CO)4。当用氯化苄处理L时,制得了相应的三唑盐,该盐用氧化银处理后与M(CO)5THF或M(CO)4(NHC5H10)2(NHC5H10为哌啶)反应,得到了基于三唑的氮杂环卡宾衍生物L′M(CO)5和L′M(CO)4(L′=1-(2-吡啶甲基)-4-苄基-1,2,4-三唑-5-碳烯)。X-射线单晶衍射分析表明,在L′M(CO)5中氮杂环卡宾配体L′表现为通过卡宾碳配位的单齿配体;而在L′M(CO)4中,L′表现为通过卡宾碳和吡啶氮原子配位的螯合[C,N]双齿配体。     

Phosphinsubstituierte chelatliganden: XIII. Photochemische substitution von metallhexacarbonylen mit phosphinothioformamid-liganden

Neutral complexes with mono- and di-coordinated phosphinothioformamide ligands are obtained by photochemical substitution of the metal hexacarbonyls M(CO)₆ (M = Cr, Mo, W) in tetrahydrofuran or cyclohexane solution. The photosubstitution requires specific conditions due to the pronounced thermal and photolytic lability of the new compounds.     

Tetraazaadamantane derivatives of group VI metal carbonyls

Summary Tetraazaadamantane (taad) reacts with group VI metal hexacarbonyls to give mononuclear (taad)M(CO)₅ (M=Cr, Mo and W) derivatives. Mixed ligand metal tricarbonyls,cis- (L-L)(taad)M(CO)₃ (L-L=o-phenanthroline or 2,2-bipyridine; M=Cr and Mo) have also been synthesised. Bromine or iodine reacts with (taad)M(CO)₅ (M=Cr and Mo) to give [(taad)M(CO)₅X]⁺X^– (X=Br or I). Nitrosyl chloride reacts with (taad)M(CO)₅ at room temperature to yieldmer- (taad)M(CO)₃NOCl while with the mixed (L-L)(taad)-Mo(CO)₃ complex, a mixture of (L-L)Mo(NO)₂Cl₂ and (L-L)Mo(CO)₂NOCl was obtained. An analogous reaction with (L-L)(taad)Cr(CO)₃, gave only (L-L)Cr(NO)₂Cl₂ derivatives. The products have been characterised by elemental analysis, i.r. spectra, conductivity data and magnetic measurements.     

Preparation and characterization of unique inorganic-organic hybrid mesoporous materials incorporating arenetricarbonyl complexes [-C6H4M(CO)3-] (M = Cr, Mo)

Unique inorganic-organic hybrid mesoporous materials incorporating arenetricarbonyl complexes [-C6H4M(CO)3-] (M = Cr, Mo) within their mesoporous frameworks have been successfully prepared by a simple CVD treatment of the phenylene-bridged organosilica mesoporous materials with metal hexacarbonyls [M(CO)6] (M = Cr, Mo). FT-IR and UV-vis investigations revealed that the arenetricarbonyl complexes exist stably even at temperatures above 473 K under vacuum.     

Darstellung und Eigenschaften von Komplexen des Typs cis-(RCN)3M(CO)3 (M = Cr,M, W)

Metal complexes of the type cis-(RCN)₃M(CO)₃ (M = Cr, Mo, W) have been prepared by different methods starting with M(CO)₆ or, more conveniently, with substituted derivatives of the metal hexacarbonyls. Infrared spectroscopic studies indicate that the strength of the nitrile-to-metal bond in cis-(RCN)₃M(CO)₃ is only sligthly influenced by the R group. The chromium compounds cis-(RCN)₃Cr(CO)₃ may be used as starting materials for the preparation of hexaalkylborazine-chromium-tricarbonyls.     

Syntheses and characterizations of group 6 metal cyanotrihydroborate complexes

The anions, [M(CO)_6-n(NCBH₃)_n]ⁿ⁻ (n=2, M=Cr(1); n=3, M=Cr(2), Mo(3), W(4)), were prepared either from the reactions of sodium cyanotrihydroborate with group 6 transition metal hexacarbonyls, M(CO)₆ (M=Cr, Mo, W), or through the reactions of M(CO)₃(CH₃CN)₃ (M=Cr, W) with sodium cyanotrihydroborate. The cyanotrihydroborate ligand bonds to the metal through a nitrogen atom, which was confirmed by the Infrared, proton and boron NMR spectroscopies. Crystal structures of the above complexes were determined by single crystal X-ray diffraction analyses. A cis configuration is found in 1. Molecular structures of 2, 3, and 4 are similar and a facial configuration is observed.     

Binuclear biscarbene complexes of furan

Carbene complexes of chromium and tungsten with a bridging furan substituent were synthesized from lithiated furan precursors and metal hexacarbonyls. The binuclear biscarbene complexes [(CO)5M{C(OEt)-C4H2O-C(OEt)}M'(CO)5](M = M'= Cr (3), W (4)) were obtained as well as the corresponding monocarbene complexes [M{C(OEt)-C(4)H3O}(CO)5](M = Cr (1), W (2)). A method of protecting the carbene moiety during the metal acylate stage was used to increase not only the yields of the binuclear Fischer biscarbene complexes 3 and 4 but to establish a method to synthesize analogous mixed heterobinuclear carbene complexes (M = W, M'= Cr (5)) in high yields. The binuclear biscarbene complexes 3 and 5 were reacted with 3-hexyne and yielded the corresponding benzannulated monocarbene complexes [M{C(OEt)-C14H17O3}(CO)5](M = Cr (6), W(7)). Complex 5 reacted regioselectively with the benzannulation reaction occurring at the chromium-carbene centre. The major products from refluxing 3 in the presence of [Pd(PPh3)4] were a monocarbene-ester complex [Cr{C(OEt)-C4H2O-C(O)OEt}(CO)5](8), the 2,5-diester of furan (9) and a carbene-carbene coupled olefin EtOC(O)-C4H2O-C(OEt)=C(OEt)-C4H2O-C(O)OEt (10). X-Ray structure analysis of 4 and 6 confirmed the molecular structures of the compounds in the solid state and aspects of electron conjugation between the transition metals and the furan substituents in the carbene ligands were investigated.     

Koordinationschemie funktioneller Phosphorylide. VII. Pentacarbonylmetall-Komplexe des Cyanmethylen-triphenyl-phosphorans, [Ph3PCH(CN)] · M(CO)5 (M = Cr,Mo, W)

Coordination Chemistry of Functional Phosphorus Ylides. VII. Pentacarbonylmetal Complexes of Cyanomethylene Triphenylphosphorane, [Ph₃P?CH(CN)] · M(CO)₅ (M = Cr, Mo, W) The pentacarbonyl complexes [Ph₃P?CH(CN)] · M(CO)₅ ( 1a –c) are obtained by reaction of the irradiated metal hexacarbonyls M(CO)₆ (M = Cr, Mo, W) with cyanomethylene triphenylphosphorane under exclusion of light. The IR and NMR spectra indicate N-coordination of the ligand, that means a nitrile complex. The chromium complex 1a crystallizes triclinic (space group P1 , Z = 2) with the lattice constant a = 1126.5(2), b = 1153.6(3), c = 951.4(3) pm; α = 103.47(3), β = 102.04(3), γ = 84.00(2)°. The linear array of the ligand atoms C7, C6, N forms an angle of 168.1(5)° with the metal-nitrogen bond. Significant bond distances are Cr? N = 206.2(6), N? C6 = 115.3(7), C6? C7 = 137.2(8) and P? C7 = 170.9(5) pm.     

Ligand-field excited states of metal hexacarbonyls

Over 35 years ago, the low-lying bands in the absorption spectra of metal hexacarbonyls were assigned to ligand-field (LF) excitations. Recent time-dependent density functional theory (TDDFT) calculations on M(CO)6 (M = Cr, Mo, W) are not in accord with this interpretation. Here we extend TDDFT calculations to the isoelectronic series V(CO)6-, Cr(CO)6, and Mn(CO)6+. By analyzing the trends in the energies of the various electronic excitations, we are able to fully assign the spectra of the complexes. In particular, we demonstrate that the LF excitation 1A1g -->1T1g is observed at 4.12 eV in the Mn(CO)6+ spectrum, but all LF features in the spectra of V(CO)6- and Cr(CO)6 are obscured by intense metal-to-ligand charge-transfer absorptions. Our results suggest that use of B3LYP as the exchange-correlation functional and inclusion of solvation effects through a continuum solvation model lead to the most accurate calculated transition energies.     

Syntheses and structures of methyltris(pyrazolyl)silane complexes of the group 6 metals

The methyltris(3,5-dimethylpyrazolyl)silane ligand, TpsMe2, was readily prepared by the metathesis reaction of methyltrichlorosilane with 3 equiv of lithium 3,5-dimethylpyrazolate. The octahedral tricarbonyl complexes (TpsMe2)M(CO)3 were synthesized either by ligand exchange with the labile nitrile adducts M(CO)3(NCR)3 (M = Cr, Mo, R = Me; M = W, R = Et) or thermally by direct substitution on the hexacarbonyls M(CO)6 (M = Cr, Mo). The three new complexes were characterized by a combination of analytical and spectroscopic techniques, including electrospray ionization mass spectrometry and single-crystal X-ray diffraction. They are all isostructural and display in the solid state the expected distorted octahedral geometries with facially coordinated tris(pyrazolyl)silane ligands. Crystallographic data were used to calculate the ligand cone angles (251-264 degrees) in (TpsMe2)M(CO)3 and also to estimate a value of 1.59 A for the covalent radius of octahedral W(0).     

Tungsten and molybdenum nitrosyl cations in fluorosulfonic acid

The tungsten and molybdenum hexacarbonyls, M(CO)(6) (M = W, Mo), dissolve in fluorosulfonic acid, HSO(3)F, to generate the tungsten and molybdenum carbonyl cations, [M(CO)(4)](2+)(solv), which are transformed, by exposure to an NO atmosphere, into the tungsten and molybdenum carbonyldinitrosyl cations, [M(CO)(NO)(2)](2+)(solv), respectively. These complexes have been characterized by NMR ((183)W, (13)C, and (15)N), IR, and Raman spectroscopy, and they are the first well-characterized metal nitrosyl cations in strong acids or superacids although the spectroscopic techniques do not address the number or coordination mode of the solvent molecules. Their formation suggests that strong acids and superacids can hopefully be used to generate a number of metal nitrosyl cations as they have been successfully used for preparing a series of metal carbonyl cations.