Element Halides

The trichlorides and tribromides of arsenic and of antimony react with [Fe(A -C5H5)(CO)2l2 by insertion of MXg, or of MXa+ arising from the self-ionization 2MXs MXa+ + MX4 , into the iron-iron bond. Indium(i), as InaBri, inserts into carbon-bromine and into carbon-iodine bonds, and into metal-metal and metal-halide bonds as in Mn2(CO)io, MnCl(CO)6, or AuCKPPhg).  

Hsieh and M. J. Mays, Inorg. Nuclear Chem. Letters, 1971, 7, 223. 

Oxygen,—[Os(H)(NO)a(PPh3)a]+ reacts with oxygen to form [Os(OH)-(NO)2(PPh3)2]+, apparently by an insertion reaction, with the consequent hydroperoxo-intermediate [Os(OOH)(NO)a(PPhs)2]+, for which there is a precedent in the chemistry of the [Co(H)(CN)5] - anion. A preliminary communication concerning the insertion of oxygen into the cobalt-carbon bond of cobaloximes (29) to produce (30), wherein R = H, Me, or OH and 

or a halogen, promises a later report on a study of the mechanism of this reaction.  

Metals.—The stereochemical course of the reaction between substituted cyclopropanes (31) and platinum(n) chloride, which could give (32) or (33), characterized as their pyridine adducts (34), depends on the balance 

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The product of reaction of BRj" with element halides depends on the electropositivity of the element. Halides of the electropositive elements tend to form the corresponding M(BH4)jc,... 

Reactions Beginning with Trivalent Group 13 Element Halides... 

Reactions Beginning with Group 13 Elements and Reduced Group 13 Element Halides 368... 

Reactions of Trivalent Group 13 Element Halides and Metal Carbonyl Monoanions Leading to Metal Cluster Products... 

In the reaction of group 13 element halides with metal carbonyl dianions, the analysis is more complex than observed for the reactions with metal monoanions. Upon addition of metal dianions to EX3 or REX3, either one or two halide ions may be eliminated. When only one halide ion is eliminated per added metal dianion, the complexes may still be viewed as E3+ derivatives (Equations (33)-(36)).19 This may be controlled to some extent by the stoichiometry of the reaction. Comparison of Equations (33)19 and (34)19 shows that the electron demand at the main group element can be satisfied by coordination either to an electron-rich metal center 26 or formation of a halide bridge 27. Ligand-stabilized forms may also be prepared in this fashion (Equation (36)).19... 

Examples of the reactions of metal dianions with group 13 element halides that lead to elimination of two halide ions and formation of the formally reduced species are given in Equations (37)—(39).3S>—44... 

Fig. 2.1-22. Some reactions of the BsHj anion with organyl element halides.

Methyl-1,2,4-diazaphosphole (6) is metallated by butyllithium selectively in the 5-position <87JOM(3l9)49>. From the subsequent reaction with an electrophilic element halide, 5-methyl-, 5-stannyl-, and 5-boryldiazaphospholes (7) are obtained <87JOM(3l9)49,87TH 422-01 >. Catalytic amounts of potassium t-butoxide in acetonitrile-i/j effect an H/D-exchange, fast in the 5-position and slow in the 3-position of 1-phenyl-1,2,4-diazaphosphole <87JOM(3l9)49>. 

R)C2B4H5] ions and appropriate main group element halides, have structures containing central main group elements in the 4+ oxidation states similar to the bis-dicarbollide silicon sandwich compound. The structure of the silicon sandwich compound 0 0-[ (CH3)3Si 2C2B4H4]2Si is shown in Figure 27. 

ZIEGLER-NATTA POLYMERIZATION. Polymerization of vinyl monomers under mild conditions using aluminum alkyls and TiCL lor other transition element halide) catalyst to give a stereoregulated, or tactic, polymer. These polymers, in which the stereochemistry of the chain is not random have very useful physical properties. 

Other examples of Si—C(Cp) bond cleavage reactions deal with pentamethylcyclopen-tadienyl (Cp ) substituted silicon compounds. Scheme 11 shows a collection of different kinds of reactions with (pentamethylcyclopentadienyl)trimethylsilane as the substrate. Nucleophilic as well as electrophilic attack is the basis for Si—C(Cp) bond fission97. Reactions with various element halides involved in pentamethylcyclopentadienyl transfer are very useful in synthetic chemistry88-91 (see also Sections II.B and HE). 

Metal carbonyl monoanions, with trivalent Group 13 element halides, 3, 347, 3, 357 Metal carbynes, Fe-containing, 6, 325 Metal-catalyzed cycloadditions, alkenyl- and alkynylboron compounds, 9, 180 Metal cation receptors characteristics, 12, 466 ferrocene-based, 12, 466 Pt- and Au-based receptors, 12, 471 types, 12, 473 Metal chalcogenides... 

NLO properties, 12, 771 overview, 12, 755-780 in polymer main chain, 12, 388 from trivalent Group 13 element halides, 3, 357 Metal complexes... 

Ziegler catalysis involves rapid polymerization of ethylene and a-ole-fins with the aid of catalysts based on transition-element compounds, normally formed by reaction of a transition-element halide or alkoxide or alkyl or aryl derivative with a main-group element alkyl or alkyl halide (1,2). Catalysts of this type operate at low pressures (up to 30 atm), but often at 8-10 atm, and, in special cases, even under reduced pressure, and at temperatures up to 120°C, but often as low as 20-50°C. Approximately 2,200,000 tons of polyethylene and 2,900,000 tons of polypropylene are produced per year with the aid of such catalysts. The polyeth-... 

The first cyclopentadienyl n complexes of phosphorus, arsenic, and antimony have been characterized only recently. The salt-like species LXXXV-LXXXVII containing a cationic n complex are prepared via halide ion abstraction from pentamethylcyclopentadienyl element halides according to Eq. (47) (248-250). 

The products formed during a reaction of an allenic stannane with a Lewis acidic element halide have been less investigated. One example is the propargyltrichloroger-mane (HC=CCH2GeCl3), which can be prepared from the starting material GeCLt and H2C=C=CHSnBu3 at 40 °C. Even if the latter is absolutely pure, a mixture of products... 

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