Metal alkyls bridged

Bochmann M, Lancaster SJ (1995) Cationic group IV metal alkyl complexes and their role as olefin polymerization catalysts The formation of ethyl-bridged dinuclear and heterodinuclear zirconium and hafnium complex. J Org Chem 494 55-59... 

The mixed metal alkyl-amido base [BuNa(TMEDA)][TMP2Mg] (TMP = 2,2,6,6-tetramethylpiperidine) is capable of deprotonating furan selectively at its 2-position in THF as a solvent. The product obtained is a complex tris-furylmagnesiate, with the empirical formula [Na2(THF)3][2-furyl6Mg2(TMEDA)] (15) . An X-ray crystal-structure determination showed that in the solid state this compound exists as a coordination polymer of [Na2(THF)3][2-furyl6Mg2] units linked by bridging TMEDA molecules (Figure 16). 

Direct reaction of fulvenes with metal atoms appears to afford a useful synthetic route to alkyl-bridged metallocenes (122), e.g.,... 

On several occasions, a different model has been proposed to account for the bridge bonding in metal alkyls. In this model, it has been suggested that the bridge involved 2 atoms with an M—C—H—M interaction ... 

The tetradentate ligand forms monomeric square planar complexes. Synthetic and kinetic studies reveal that the coordinated mercapto group may be converted into the coordinated thioether function without breaking the metal-sulfur bond. The nucleophilic power of the coordinated mercapto group exceeds that of RSH, but depends on the metal atom. Bridging protects the sulfur atom from alkylation. In the case of nickel(ll), alkylation is accompanied by expansion of the coordination number of the nickel from 4 to 6. Ligand reactions have led to the synthesis of planar ligands completely cydized about the metal ion. 

The only apparent exception to this rule is the hydrido-bridged osmium cluster (/u-CHjX/u-H lOsalCOhol (75) (Table IV). The alkanediyl derivatives (type G) may even be distinguished from the closely related metal alkyls. The chemical shifts of the latter compounds typically cover the... 

Sulfur dioxide is capable of reacting with metal alkyl, aryl or u-allyl complexes in an insertion-type reaction to yield S-sulfinate (4), O-sulfinate (5) or 0,< -sulfinate complexes (6).13 It can also insert into the metal-metal bond in the cobalt complex (7) to give the S02-bridged complex (8).38... 

Alkylboronic esters, as catalysts, 9, 223 Alkyl-bridged compounds, transition metal-Group 13 alkyl combinations, 3, 271... 

Neopentylidenes, with titantium(IV), 4, 364 Neoplasia, Ti(IV) complex treatments, 4, 664 Nephrosteranic acid, via Ti(IV) complexes, 4, 406 Neutral alkyl-bridged compounds, transition metal-Group 13 alkyl combinations, 3, 271... 

Iminoacyls111. These are formed by isocyanide, RNC, insertions into MH, metal alkyl or -aryl bonds. Although if-C,N bonding is most common, bridging groups are known. 

The synthesis, structures, and reactions of silicon-substituted alkyl derivatives of metals from groups 1, 2, and 3 have been recently reviewed. A diverse range of structures has been discovered with the alkali metals. More recently, some additional structures and an important discussion of structural trends observed among the silicon-substituted alkyl derivatives of the alkali metals have also been published. " Tris(trimethylsilyl)methyl lithium forms a solvent-free dimer, as well as several ate complexes in the presence of bases (THF or TMEDA). In the alkyl-bridged dimer of tris(trimethylsilyl)methyl lithium (2), there are interactions between the C-H bonds of the silyl ligand and the lithium atoms (3) (Li to C distances of 254.1(7) and 246.6(6) pm). ... 

---