Cyclopentadienyl magnesium

Reaction of an alkyl (usually trimethyl) of Group-IIIb element (Al, Ga, In) with a hydride of a Group-Vb element (P, As, Sb) at 600-800°C and 1 atm. [4i][42] p. doping obtained from addition of diethyl zinc or bis(cyclopentadienyl) magnesium. 

The molar ratio of the III compound to the V compound is typically l/lO.t ] To obtain the desired semiconductor properties, dopants are added such as zinc (from diethyl zinc) or magnesium (from bis(cyclopentadienyl) magnesium) for p doping, and silicon (from silane) or selenium (from hydrogen selenide) for n doping. 

Bis[dicarbonyl(cyclopentadienyl)tributylphosphinemolybdenmn]-tetrakis (tetrahydrofuran)magnesium, 3913... 

Bis(i -benzene)molybdenum(0), 3514 Bis(cyeloetatetraene)uranium(0), 3708 Bis(cyclopentadienyl)bis(pentalluorophenyl)zirconium, 3830 Bis(cyclopentadienyldinitrosylchromium), 3275 Bis(cyclopentadienyl)hexalluoro-2-butynechromium, 3636 Bis(cyclopentadienyl)lead, 3294 Bis(cyclopentadienyl)magnesium, 3277 Bis(cyclopentadienyl)manganese, 3278 Bis(cyclopentadienyl)niobium tetrahydroborate, 3324... 

Bis(cyclopentadienyl)phenylvanadium, 3705 Bis(cyclopentadienyl)titanimn, 3295 Bis(cyclopentadienyl)titanium selenate, 3293 Bis(cyclopentadienyl)zirconium, 3296 Bis(dicarbonylcyclopentadienyliron)-bis(tetrahydrofuran)magnesium, 3835... 

Enantioselective conjugate addition [40] has become truly useful with the aid of dialkylzinc, cationic copper catalyst, and a chiral ligand (Eq. 1, see also Chapt. 7) [41]. Magnesium-based reagents have found use in quantitative fivefold arylation of Cgo (Eq. 10.2) [42] and threefold arylation of C70 [43], paving ways to new classes of cyclopentadienyl and indenyl ligands with unusual chemical properties. 

Hybrid scorpionate/cyclopentadienyl-Mg (63) and -Zn (64,65) complexes were structurally characterized and reported to catalyze the formation of PLAs with medium molecular weights and narrow polydispersities [85]. Among them, the magnesium complex 63 is much more active than the others, giving a polymerization of L-lactide in toluene at 90 °C with 97% conversion in 2.5 h. However, it takes 30 h for zinc complexes 64 and 65 to reach similar results under the same conditions. Some representative structures of magnesium and zinc complexes are summarized in Table 2 as they display closely related ROP activity of lactide, and often stmcrnrally similar ligand systems are employed to construct these initiators. 

Hung and R. W. Schurko, Solid-state Mg QCPMG NMR of bis(cyclopentadienyl) magnesium. Solid State Nucl. Magn. Reson., 2003, 24, 78-93. 

Soon after the first synthesis of bis(cyclopentadienyl)magnesium (56), its structure in the solid state, based on X-ray powder diffraction data, was reported . A more refined structure based on a single-crystal X-ray diffraction study was reported later . The structure in the solid state is isostructural with that of ferrocene. The two parallel... 

The substituted cyclopentadienylmagnesium compounds 62a and 62b have been prepared from the corresponding fulvenes (equation 8) and were structurahy characterized in the solid state by X-ray crystallography . The structures are, as expected, (tj -bonded cyclopentadienyl groups) for bis(cyclopentadienyl)magnesium compounds. 

The structure of cyclopentadienyl(neopentyl)magnesium (65) in the gas phase has been determined by gas-phase electron diffraction . The Mg—C bond distances of the rf-bonded cyclopentadienyl group are 2.328(7) A while the Mg—C bond distance of the neopentyl group was found to be 2.12(2) A. 

The tetramethylethanediyl-bridged, f-butyl-substituted bis-cyclopentadienyl complex Me4C2(3-f-BuC5H3)2Mg(THF) (129) is present in the solid state as a me o-diastere-oisomer. It has a structure in which both cyclopentadienyl groups are /7 -bonded to magnesium while only one THF molecule is coordinated to magnesium (Figure 62) . 

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