Chemiluminescence of organometallic compounds in reactions with the free radical galvinoxyl

Chemiluminescence (CL) is observed in reactions of the free radical galvinoxyl (RO^•) with PhMgBr, PhMnCl, PhTi(BuⁱO)₃, and sodium naphthalenide or sodium anthracenide during their oxidation with air and in reactions of RO^• with the initial organometallic compounds. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 611–612, March, 1997.     

Evidence for single electron transfer in the reactions of organometallic compounds with 2,3,3-trimethyl-2-butyl peroxybenzoate

Utilization of a triptoxy radical probe in the reactions of organometallic compounds with 2,3,3-trimethyl-2-butyl peroxybenzoate indicates that the radical character of the reaction decreases in the order $\text{n}$-BuLi > $\text{n}$-BuMgCl > PhMgBr.     

Nucleophilic and organometallic displacement reactions of allylic compounds: stereo-and regiochemistry

Allylic alcohols, esters, halides and related compounds have been of mechanistic and synthetic interest for years. This Report focuses on the stereo- and regiochemical aspects of three reaction types: the S_N2' reaction (bimolecular nucleophilic substitution with allylic rearrangement); displacement reactions effected by organometallic reagents; the conversion of allylic alcohols into halides.     

金属有机化合物催化的环化反应新进展

综述了近年来金属有机化合物催化的环化反应在合成碳20环及杂环化合物中的应用。     

金属有机化学中的绿色化学反应进展

着重综述了金属有机化学领域中所涉及的与绿色化学概念有关的一些化学反应,如水相反应、超临界流体及离子液体中的反应、固态反应、原子经济性及过渡金属催化的有机反应。     

Hydrogen binding property of Co- and Ni-based organometallic compounds

The binding property of hydrogen on organometallic compounds consisting of Co, and Ni transition metal atoms bound to C _m H _m rings (m = 4, 5) is studied through density functional theory calculation. CoC _m H _m and NiC _m H _m complexes can store up to 3.49 wt% hydrogen with an average binding energy of about 1.3 eV. The adsorption characteristics of hydrogen to organometallic compounds are investigated by analyzing vibrational spectra of CoC₄H₄(H₂) _n and NiC₄H₄(H₂) _n (n = 0, 1, 2). The kinetic stability of these hydrogen-covered organometallic complexes is assured by analyzing the energy gap between the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals. It is also discussed the application of 18-electron rule in predicting maximum number of hydrogen molecules that could be adsorbed by these organometallic compounds.     

IR laser pyrolysis and the isotopic labelling of organometallic compounds

A homogeneous gas phase pyrolysis technique involving SF₆ sensitization and a continuous wave (CW) CO₂ laser, is described for preparing small quantities (～ 100 mg) of organometallic compounds. Several reactions have been successfully carried out and the synthesis of Os(CO)₅ from H₂Os(CO)₄ and CO is discussed in detail. With IR laser pyrolysis, room temperature reactors and sub-atmospheric pressures can be used for reactions which normally require high pressures and temperatures.     

Molecular complexing as the initial stage of some reactions of organometallic compounds

Complexing of molecular oxygen with arylmercury compounds and phenyl derivatives of Group IV and V elements has been studied by electronic spectroscopy. The type of complexing appeared to depend on the nature of the central heteroatom in the organometallic compounds.The chemical model for the reaction of R₂Hg (R = Et, n-Pr, n-Bu, Ph) with CCl₄ indicates that the complex R₂Hg · L (L = molecular oxygen, aromatic compound) is formed in the initial stage of the interaction. By studying the influence of π-donors on this process the correlation between the yield of alkylmercuric chloride and the donor properties of the ligand has been determined.     

Photochromism of organometallic compounds with structural rearrangement

This article introduces photochromic properties together with structures of organometallic compounds that undergo photo-induced structural rearrangement. The aim of this review is to survey the research on photochromism by using organometallics which possess by their own nature the properties responsible for the photochromism such as bonding and structural fluxionality, electronic state fluctuation, and photochemically active characteristic in both solution and the solid state. Therefore, the organometallics which include the well-characterized organic photochromic moieties, considered to be derivatives of such kinds of organic photochromic compounds, are excluded in this article. Mono-, di-, and poly-nuclear organometallic compounds are presented based on the reaction types such as linkage isomerization, haptotropic rearrangement, and reorganization of metal–ligand and/or metal–metal bonds. Very recently, the crystalline-state photochromism is becoming an attractive field of photochromic chemistry. As a demonstrative example, the photochromism of organometallic rhodium dinuclear complexes having a dithionite ligand (μ-O₂SSO₂), which shows 100% reversible interconversion in the crystalline-state and have been developed in the authors’ laboratory, will be discussed.     

Synthesis and application of new organometallic compounds of silicon and germanium in chemical radioprotection

Several organosilicon and organogermanium compounds possessing radioprotective activity have been synthesized. In this paper, we describe the preparation and study of the pharmacological properties of new organometallic compounds such as metallathiazolidines and metalladithioacetals derived from 1‐[N‐(2‐mercaptoethyl)‐­2‐aminoethyl] ‐ 2 ‐ (1‐naphthylmethyl) ‐2‐ imidazoline and 1‐[N‐(2‐mercaptopropyl)‐2‐aminoethyl]‐2‐(1‐naphthylmethyl)‐2‐imidazoline. We have noted a decrease in the toxicity and a rather important increase in the radioprotective activity of these new organometallic derivatives in comparison with the starting organic compounds. Copyright © 1999 John Wiley & Sons, Ltd.     

双核钼/钨金属键有机化合物的反应化学研究

着重总结了我们研究组近几年来对M-M(M=Mo,W)金属单键化合物(η^5-RC5H4)2M2(CO)6,M=M金属双键化合物(η^5-RC5H4)2M2(CO)2(μ-EPh)2(E=S,Se,Te)及M≡M金属三键化合物(η^5-RC5H4)2M2(CO)4的反应化学所取得的系列成果。该系列成果清楚地表明这三类典型的金属键有机化合物可分别同多种无机、有机以及金属有机试剂发生涉及金属键加成、金属键断裂以及金属键上配体的消除和环戊二烯基配体上有机官能团的转化等一系列有趣反应。这些反应不仅有重要理论意义而且被广泛地用在新型金属有机和原子簇化合物的合成上。     

Mechanochemical tools in the synthesis of organometallic compounds

In response to rising environmental concerns, chemistry is experiencing a considerable change in both concepts and practices to adopt more efficient and sustainable technologies. One of the alternative technologies that offer many advantages over the conventional solution-based techniques is mechanochemistry which utilizes mechanical energy to induce chemical reactions. Despite the fact that mechanochemistry has reached high significance in the creation of advanced materials, such as alloys, ceramics, electrode materials, and nanocomposites, in the field of small molecule synthesis its potential remains largely untapped. This review highlights the opportunities and prospects of different mechanochemical tools in the synthesis of organometallic compounds, including transition metal complexes with N-heterocyclic carbene, arene, and cyclopentadienyl ligands, monometallacyclic and pincer derivatives, as well as main group metal compounds (e.g., allyl complexes and the Grignard reagents). Many important organometallic transformations such as C–H bond metalation, transmetalation, and oxidative addition can be successfully implemented under mechanochemical conditions in a highly productive and energy-saving manner. Furthermore, the postmodification of metal-containing species upon grinding or milling is shown to be a powerful route to both new discrete metal complexes and different supramolecular architectures (metal-containing organic cages, macrocylces, networks).     

Preparation,stability and reactivity of fluorinated vinyl organometallic compounds

In contrast to the low stability of the fluorinated vinylic lithium or magnesium reagents, the analogous vinylic cadmium, zinc, copper, and silver reagents have been found to exhibit excellent stability. These organometallic substrates are readily prepared from the corresponding vinylic iodides or $\text{via}$ methathesis reaction. Stereochemical integrity is preserved in all organometallic-forming reactions as well as in all

subsequent chemical transformations of these reagents. In some cases (M = Cd), the $\text{bis}$-reagent can be isolated as a stable solid.A variety of chain-extension and/or functionalization reactions of these stable organometallic compounds will be presented and discussed.     

Accumulation and toxic effect of organometallic compounds on algae

This paper reports toxic effects and bioaccumulation factors of organometallic compounds, mainly organotin species, on algae. We selected two species of microalgae as test algae: one was Scenedesmus obliquus as a representative of fresh-water algae, the other Dunaliella salina and Dunaliella viridis, to represent commonly mixed algae which exist abundantly in Tianjin Harbor, People's Republic of China. For comparison, Chlorella vulgaris was also used in this study. The toxic effect of ten organometallic compounds on the freshwater alga, S. obliquus, was investigated. The ten compounds were (as chlorides) tributyltin (TBT); triphenyltin (TPT); trimethyltin (TMT); dibutyltin (DBT); diphenyltin (DPT); dimethyltin (DMT); trimethyl-lead acetate (TML); dimethyl-arsine (DMA) and two new mixed-alkyltin pesticides, dicyclohexylmethylitin acetate (Cy₂MTA) and dicyclohexylmethyltin isobutyrate (Cy₂MTB). The order of toxicity of these compounds in fresh-water algae, S. obliquus, was TBT>TPT>DBT> Cy₂MTA=TML> Cy₂MTB>DPT>TMT>DMA>DMT, according to 96 h EC₅₀ values attained. The ten toxicants were divided into three groups according to the sequence of their toxicities; (a) TBT, TPT; (b) DBT, Cy₂MTA, TML, Cy₂MTB; (c) DPT, TMT, DMA, DMT. In each group the EC₅₀ values of each compound were quite similar. The difference of EC₅₀ values between two vicinal groups was approximately one order of magnitude. The bioconcentration factor (BCF) of TBT and TPT compared with water in the freshwater alga S. obliquus was >3.32 × 10⁵ and 1.14 × 10⁵, respectively. The BCF of the marine mixed algae was >3.48 × 10⁵. The marine microalga, Chlorella vulgaris, was adaptable to TBT at lower concentration. TBT at high concentration only inhibited the growth of S. obliquus, but it could cause chlorosis anddisintegration of D. salina and D. viridis. Resistance to toxicity of algae against TBT appears in order as follows: C. vulgaris>S. obliquus>D. salina and D. viridis. TBT was metabolized by algae to a less toxic product, DBT. The existence of algal cells accelerated the concentration reduction of TBT. The toxic mechanism of TBT was also studied.     

Chemistry of organometallic compounds on silicon: the first step in film growth

The continuous decrease in size of electronic devices has reached a critical point at which the molecular-level understanding of chemical processes is imperative. Metal-containing films, an important part of every circuit, are currently deposited from a myriad of organometallic compounds, in order to control the first stages of film growth and ultimately produce an atomically defined interface. This article outlines recent molecular-level investigations on reactions of organometallic compounds with silicon surfaces. The role of surface structure and chemical state is placed in a framework of future challenges and opportunities for applications in electronics.     

水相金属有机化学

本文对近年来锡、锌、铋等介入下的水相金属有机化学作了综述。特别对水相Barbier 反应作了较详细的介绍, 同时也描述了一些典型的水相金属有机反应,如Immonium 阳离子的烷基化反应, α, β 不饱和化合物的共轭加成, 醇醛缩合反应及水溶性金属有机化合物的反应等。某些反应的机理也被讨论。     

Laser photodissociation of organometallic compounds on a cryosubstrate

The photodissociation dynamics of organometallic compounds (tetramethyltin, trimethylgallium, trimethylindium and dimethylzinc) adsorbed on a quartz substrate at 100 K have been studied by time-of-flight mass spectrometry, detecting mainly CH₃ photofragments. Shapes of the time-of-flight spectra depend on the flux of the dissociation laser at 193 nm and the thickness of multilayers of organometallic compounds. In thick layers, not only a low energy component but also a high energy component are observed in the time-of-flight spectrum of the CH₃ photofragments. In thin layers, relaxation processes take place so quickly that the product time-of-flight profiles are characterized by a Maxwell–Boltzmann temperature profile.     

Reactions of quinones with organometallic compounds: correlation analysis of substituent effects

The effects of substituents in lithium, magnesium, zinc, and cadmium organometallic compounds in their reactions with p-benzoquinone and 3,6-di-tert-butyl-o-benzoquinone on the ratio of addition and reduction products were considered. The reduction of quinones follows a homolytic mechanism of single electron transfer. The results of correlation analysis confirmed a suggestion that the addition to quinones followed a nucleophilic (heterolytic) mechanism.     

The reactions of transition metal chelates with organometallic compounds and their paramagnetic products. V—New possibilities in the generation of anion radicals by reactions of Grignard reagents and lithium alkyls in the presence of transition metal ions

In the reactions of Grignard reagents and n-butyllithium the presence of transition metals and complexing solvents facilitates the formation of anion radicals. High radical concentrations, observable for some days at laboratory temperature, and very well resolved e.s.r. spectra of the following structural types have been obtained using a relatively simple procedure: aromatic hydrocarbons, heteroaromatics, aldehydes, ketones, α-diketones, enolates of β-diketones, quinones, sulphones, sulphoxides, nitro-, nitroso- and azo-benzenes, cyano compounds and phosphine oxides. It is suggested that the transition metals, according to the type of reactants and the experimental conditions, mediate the transfer of one electron to the substrate in many reactions and stabilize the intermediate products as anion radicals. The variation of solvents and organometallic compounds modifies the reduction power of such systems and leads to the radical products in a different reduction state. The procedure described is advantageously employable in the generation of anion radicals, and the effect of transition metals which has been found may widen the scope of this phenomenon to many different applications.     

HPLC monitored synthesis of R2NCH2 substituted benzene derivatives used as (C,N)-ligands for organometallic compounds

2-(Diethylaminomethyl)phenyl bromide and 1,3-bis(dimethylaminomethyl)-benzene, useful ligands for the synthesis of hypervalent organometallic compounds, were prepared and characterized by NMR (¹H, ¹³C, 2D experiments) spectroscopy. Their synthesis was monitored by the HPLC method. The compounds were eluted on a Nucleosil 120 Si column (5 μm, 25×0.4 cm) with n-hexane at room temperature using a 1.0 ml/min flow-rate. The maximum values of absorbance for the studied compounds, excepting the diethylamine, were located in a narrow range around 212 nm, the wavelength used for their UV detection. The diethylamine was detected at 190 nm. The calibration curves are straight lines with correlation factors r>0.995. The HPLC data are in good agreement with those provided by NMR spectroscopy.