Metal syntheses with

Azomethinium ylids, N-metalated -, syntheses with - 43, 904 Azonia-Cope rearrangement-Mannich cyclization 41, 938, 982 lif-Azonine ring, 2,3,4,5,8,9-hexa-hydro-, 5-aryl-, N-protected 44, 579 Azoxy compds. 44, 18 Azulen-2-ones, hydro- 43, 640 Azulen-4-ones, perhydro-l-methylene-43, 955... 

Li and coworkers have proposed a new mechanism that assumes different nanotube to nanowire transitions for different melting point metals. As mentioned earlier, the morphology of sputtered base electrodes are annular, and the authors assume that all metals synthesized with this base electrode morphology initially form tubes, and depending on the conditions, some materials... 

Ullman reaction The synthesis of diaryls by the condensation of aromatic halides with themselves or other aromatic halides, with the concomitant removal of halogens by a metal, e.g. copper powder thus bromobenzene gives diphenyl. The reaction may be extended to the preparation of diaryl ethers and diaryl thio-ethers by coupling a metal phenolate with an aryl halide. 

The first step in designing a precursor synthesis is to pick precursor molecules that, when combined in organic solvents, yield the bulk crystalline solid. For metals, a usual approach is to react metal salts with reducing agents to produce bulk metals. The main challenge is to find appropriate metal salts that are soluble in an organic phase. 

Miscellaneous Reactions. Sodium bisulfite adds to acetaldehyde to form a white crystalline addition compound, insoluble in ethyl alcohol and ether. This bisulfite addition compound is frequendy used to isolate and purify acetaldehyde, which may be regenerated with dilute acid. Hydrocyanic acid adds to acetaldehyde in the presence of an alkaU catalyst to form cyanohydrin the cyanohydrin may also be prepared from sodium cyanide and the bisulfite addition compound. Acrylonittile [107-13-1] (qv) can be made from acetaldehyde and hydrocyanic acid by heating the cyanohydrin that is formed to 600—700°C (77). Alanine [302-72-7] can be prepared by the reaction of an ammonium salt and an alkaU metal cyanide with acetaldehyde this is a general method for the preparation of a-amino acids called the Strecker amino acids synthesis. Grignard reagents add readily to acetaldehyde, the final product being a secondary alcohol. Thioacetaldehyde [2765-04-0] is formed by reaction of acetaldehyde with hydrogen sulfide thioacetaldehyde polymerizes readily to the trimer. 

Pyran, 4-arylimino- C NMR, 3, 585 Pyran, 4-arylimino-2,6-dimethyl-synthesis, 3, 762 Pyran, 2-aryloxytetrahydro-X-ray studies, 3, 621 Pyran, 4-benzyl-isomerization, 3, 666 Pyran, 3-bromodihydro-synthesis, 3, 769 Pyran, -bromodihydro-halogen-metal exchange with t-butyllithium, 1, 474 Pyran, 2-bromotetrahydro- H NMR, 3, 579... 

Dimethyl-l,2,2,3-tetramethyl-A -1,2,5-azasilaboroline with [Fe2(CO)9] gives sandwich 62 and sandwich 63 (82AGE207, 82CB738) with Cp)Co(C2H4)2]. With [Ni(CDT)] or in a vapor phase with metallic nickel, sandwich 64 (M =Ni) is formed. The vapor-phase synthesis with iron gives 64 (M = Fe). In all these sandwiches, 62-64, the j " -coordination of the heterocyclic ligand is realized. 

Basically the same methods known from the synthesis of classical metal-silyl complexes can also be applied to the preparation of low valent Si compounds. The procedures given here are summarized with the focus on silylene complexes These are a) reactions of appropriate metal anions with halosilanes, which are the most important methods for the formation of M-Si bonds. Alternatively, silyl... 

Two commonly used synthetic methodologies for the synthesis of transition metal complexes with substituted cyclopentadienyl ligands are important. One is based on the functionalization at the ring periphery of Cp or Cp metal complexes and the other consists of the classical reaction of a suitable substituted cyclopentadienyl anion equivalent and a transition metal halide or carbonyl complex. However, a third strategy of creating a specifically substituted cyclopentadienyl ligand from smaller carbon units such as alkylidynes and alkynes within the coordination sphere is emerging and will probably find wider application [22]. 

The third area is the synthesis and characterization of aryldiazenido complexes of transition metals. In 1964 King and Bisnette isolated the first metal complex with an aryldiazenido ligand. The interest of organometallic chemists was concentrated mainly on the isolation and characterization of stable aryldiazenido complexes and not on potential metastable intermediates involved in metal-catalyzed dediazonia-tions. The situation is different, however, for metal complexes with alkyl-diazenido ligands. Complexes with aryl- and alkyldiazenido ligands are the subject of Chapter 10 in the forthcoming second book (Zollinger, 1995). 

The real Willamson synthesis with metallic sodium and sodium chloroacetate is only used for the preparation of pure ether carboxylates for analysis purposes or to obtain physicochemical measurements [229]. 

T. L. Ho, Reduction of organic compounds with low-valent species of Group IV B, V B and VIB metals. Synthesis 1979, 1. 

For a review, see Rylander, P.N. Organic Synthesis with Noble Metal Catalysts, Academic Press NY, 1973, p. 1. 

Dihydro-l,2-azaborolyl sandwich complexes, available by metal-vapor synthesis ( 6.5.3.3), can be prepared in a greater variety by reaction of metal halides with azaborolyl anions, e.g. " ° ... 

Since metals react with B only at > 700°C, and since alkali-metal borides are thermally unstable, the preparation of these borides by direct synthesis can be carried out at high T only with an excess of metal in sealed containers. 

Reactions of metal halides with polysulfide dianions are useful methods for the synthesis of polysulfido complexes of main group elements and transition metals. In most of these reactions, similarly to other methods, the chain lengths and coordination types of the polysulfide ligands depend on the other ligands coordinated to the metal, on the ratio between the metal and sulfur, on the reaction temperature, and other parameters. 

Scheme 20 Synthesis of group 13 polysulfido complexes by the reaction of the corresponding metal halides with polysulfide dianions...

The mechanism of the condensation in Part D probably involves thioformylation of the metallated isocyanoacetate followed by intramolecular 1,1-addition of the tautomeric enethiol to the isonitrile. This thi2izole synthesis is analogous to the formation of oxazoles from acylation of metallated isonitriles with acid chlorides or anhydrides. " Interestingly, ethyl formate does not react with isocyanoacetate under the conditions of this procedure. Ethyl and methyl isocyanoacetate have been prepared in a similar manner by dehydration of the corresponding N-formylglycine esters with phosgene and trichloromethyl chloroformate, respectively. The phosphoryl chloride method described here was provided to the submitters by Professor U. Schollkopf and is based on the procedure of Bohme and Fuchs. The preparation of O-ethyl thioformate in Part C was developed from a report by Ohno, Koi/.uma, and Tsuchihaski. " ... 

The synthesis of quaternary thiospinels, like Ag2FeSn3Sg [5], Ag2MnSn3Sg [6], and Cu2NiSn3Sg [7], has been achieved by reacting metals along with sulfur powder in an evacuated silica tube. Pure phases of these compounds were obtained at 750 °C, 670 °C and 750 °C respectively. 

R. G. Herman et al. (8) studied these catalyst systems In great detail and suggested a Cu-fl solution In ZnO as active phase where Cu- - non-dlssoclatlvely chemisorbs and activates CO and ZnO activates H2. In the range of 15 to 85Z CuO In the catalyst, up to 16% Cu+1 became dissolved In the ZnO (9) and Cu+1 has been widely accepted as active site (10). Recently, however, Raney Cu-Zn catalysts have been shown to be very active methanol synthesis catalysts (11). The active component for these Raney catalysts was found to be metallic Cu with an activity maximum at 97 wt% Cu (12). 

Two principle strategies have been employed for the synthesis of siloxide-containing molecular precursors. The first involves a silanolysis, or condensation, reaction of the Si - OH groups with a metal amido, alkyl, hahde, or alkoxide complex. The second method involves salt metathesis reactions of an alkali metal siloxide with a metal hahde. Much of our work has been focused on formation of tris(tert-butoxy)siloxide derivatives of the early transition metals and main group elements. The largely imexplored regions of the periodic table include the lanthanides and later transition metals. 

Abstract This review is a summary of supported metal clusters with nearly molecular properties. These clusters are formed hy adsorption or sirnface-mediated synthesis of metal carbonyl clusters, some of which may he decarhonylated with the metal frame essentially intact. The decarhonylated clusters are bonded to oxide or zeolite supports by metal-oxygen bonds, typically with distances of 2.1-2.2 A they are typically not free of ligands other than the support, and on oxide surfaces they are preferentially bonded at defect sites. The catalytic activities of supported metal clusters incorporating only a few atoms are distinct from those of larger particles that may approximate bulk metals. 

Byers, P.K, Carr, N. and Stone, F.G.A. (1990) Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 106. Synthesis and reactions of the alkylidyne complexes [M ( CR)(CO)2 (C6F5)AuC(pz)3 j (M = W or Mo, R — alkyl or aryl, pz — pyrazol-l-yl) crystal structure of pjC PtAu(C6F5)( l3-CMe)(CO)2(PMe2Ph)2 (C6F5)AuC(pz)3 ]. Journal of the Chemical Society, Dalton Transactions, (12), 3701—3708. 

---