And pbme2i2 hydroxyllic or water containing solvents

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Unformatted text preview: 6.7pm, AI-C of the type R2MX; indeed, T1 gives air-stable non-hydrolysing ionic derivatives of the type is 197.6pm (close to the value for the terminal AI-C in A12Me6, p. 259) and the A1 atom [TlRzIX, where X = halogen, CN, NO3, $SO4, is 57pm above the N4 plane. A further notable etc. For example, the ion [TlMez]+ is stable in feature is the great stability of the A1-C bond: the aqueous solution, and is linear like the isoeleccompound can be recrystallized unchanged from tronic HgMe;! and [PbMe2I2+. hydroxyllic or water-containing solvents and does GaR3 can be prepared by alkylating Ga with not decompose even when heated to 300°C in an HgRz or by the action of RMgBr or AIR3 on GaC13. They are low-melting, mobile, flammable inert atmosphere. Heterocyclic and cluster organoaluminium liquids. The corresponding In and T1 compounds compounds containing various sequences of are similar but tend to have higher mps and bps; e.g. AI-N bonds are discussed on p. 265. Compound Organometallic compounds of Ga, In and TI Organometallic compounds of Ga, In and T1 have been less studied than their A1 analogues. The trialkyls do not dimerize and there is a general tendency to diminishing thermal stability with increasing atomic weight of M. There is also 79 V . L. GOEDKEN,. ITO a nd T. ITO, J . Chem. Soc., Chem. H C ~ m m ~ n .453-5 (1984). 1, MP BP Compound MP BP GaMe3 InMe3 TIMe3 16" 56" 88.4 136" 38.5" 147" (extrap) - GSt3 InEt, TlEt3 -82" 143" - 84/12 mmHg -63" 192" (extrap) The triphenyl analogues are also monomeric in solution but tend to associate into chain structures in the crysta11ine State as a resu1t Of weak intermolecular M . . .C interactions: GaPh3 mp 37.3.6 Organometallic compounds 166", InPh3 mp 208", TlPh3 mp 170". For Ga and In compounds the primary M-C bonds can be cleaved by HX, X2 or MX3 to give reactive halogen-bridged dimers (R2MX)2. This contrasts with the unreactive ionic compounds of T1 mentioned above, which can be prepared by suitable Grignard reactions: TlX3 + 2RMgX - [ TlRdX + 2MgX2 As in the case of organoaluminium compounds, unusual stereochemistries can be imposed by suitable design of ligands. Thus, reaction of GaCl3 with 3,3',3''-nitrilotris(propylrnagnesium chloride), [N{(CH2),MgC1}3], yields colourless t crystals of [ Ga(CH2)3N]in which intramolecular N+Ga coordination stabilizes a planar trigonal monopyramidal geometry about Ga as shown schematically in Fig. 7.20(a).@') Because of steric constraints, the Ga-N distance of 209.5pm is about 7% longer than the sum of the covalent radii (195 pm), although not so long as in Me3GaNMe3 (220pm). Long bonds are also a feature of the unique 6-coordinate complex of InMe3 with the heterocyclic triazine ligand (Pr'NCH2)3. The air-sensitive adduct, [Me31n{q3-(Pr"CH2)3}], can be prepared by 263 direct reaction of the donor and acceptor in ether solution, and is the first example of a tridentate cyclotriazine complex; it is also the first...
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This note was uploaded on 10/12/2012 for the course CHEMISTRY CHM1040 taught by Professor Jhon during the Spring '12 term at Florida A&M.

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