Lithium complexes compounds

In the presence of N,N,N, N",N"-pentamethyldiethylenetriamine ( = PMDETA), monomeric lithium complexes of bulky formamidinate ligands can be isolated. The compounds (Scheme 12) comprise a Li(PMDETA) center coordinated by a bulky formamidinate in either the E-syn- or E-anti-isomeric form. Two of the structures display coordination of the pendant amidinate imine, and can therefore be considered the first examples of if. r -C = N,N metal amidinate coordination. ... 

Treatment of UCI4 with the lithium complex obtained from dicyclohexylcar-bodiimide followed by crystallization from pyridine afforded a dinuclear uranium(rV) oxalamidinate complex in the form of dark green crystals in 94% yield (Scheme 191). The same compound could also be obtained by first reducing UCI4 to LiUCli (or UQs+LiCl) followed by reductive dimerization of di(cyclo-hexyl)carbodiimide as shown in Scheme 191. The molecular structure of this first oxalamidinato complex of an actinide element is depicted in Figure 31. ° ... 

Lithium cobalt dioxide, uses, 7 24 It Lithium complex greases, 15 243 Lithium compounds, 20 598-599. See also Organolithium compounds inorganic, 15 136-142 uses for, 15 134 Lithium cyanide, 8 194 Lithium 5—alumina, 2 406t... 

There are numerous compounds of lithium. Its atoms combine with many other elements to form a variety of compound molecules. Some form as single oxidation states, with one lithium cation combining with one anion (+1 combines with —1), and the more complex compounds involve two positive lithium cations combining with two negative anions (+2 combines with -2). Some examples follow ... 

III. LITHIUM COMPLEXES OF UNSATURATED HYDROCARBONS A. The Li(C2H2)i,2 and LI2C2H2 Compounds... 

The chelate formation in lithium complexes 17 or 20 contributes to stabilization. Enhancement of kinetic acidity arises from the formation of pre-complexes 16 and 19, respectively. Here, already a dipole is induced and, in addition, proton exchange can proceed intramolecularly via a five- or six-membered ring. Despite these favourable features, the acidity of alkyl carbamates 15 is lower than those of the 1-proton in butane n-BuLi does not lead to deprotonation. In order to suppress carbonyl attack, a branched amino residue NR2 such as diisopropylamino (in Cb) or 2,2,4,4-tetramethyl-l,3-oxazolidin-3-yl (in Cby) is essential. A study on the carbenoid nature of compounds 17 was undertaken by Boche and coworkers. ... 

Hay and co-workers reported that the Mn increased linearly with conversion at a molar ratio of 1 2. However, at high ratios of n-BuLi to TMEDA, the initiator became only 50% efficient. This finding is rather surprising as the addition of TMEDA to alkyllithium compounds enhanced the rate of the polymerization and without TMEDA, at Hay s polymerization temperature, no polymerization of the 1,3-butadiene took place. The explanation advanced by these authors was that the allylic lithium complex of polybutadiene is complexed with two TMEDA molecules and that complex 11 is the propagating species. 

The crystal structure of the fluorcnylpotassium-TMEDA complex (compound XlXa in Fig. 3) has been solved by Stucky et al. (45). The coordination sphere of the potassium atom is made up of two tertiary amines and two unsaturated groups instead of two tertiary amines and one unsaturated organic group as found for the lithium atom in the fluorenyllithium complex VI (12). 

Tlic CH3 CHa CHj - is a primary carbon. Tints the ring must be in the copper lithium complex. This means we need compound A and CH CHjCHal (a permitted starting material). 

While lithium tetrahydridoaluminate(l -) is used extensively as a reducing agent,1 relatively little is known about the utility of amine and/or amino complexes (compounds of the general formulas H3A1(NR3) and H3 A1-... 

The reaction of ZrCl4 with two equivalents of the lithium allyl compound (tBuMe2SiCH)2CHIi-TMEDA in toluene yielded the reduced complex [(lBuMe2... 

Other investigations of the properties of aqueous solutions have been made by various experimenters.1 Bonnefoi2 has prepared complex compounds of lithium bromide and ammonia analogous to those formed by the chloride (p. 62). 

The reaction of phosphorus trichloride with tgrt-bufylamine was reported to give a dicoordinate phosph(III)azene Bu N=P-NHBu which can be deprotonated to the [Bu NPNBu ] anion. The crystal structure ofK[Bu NPNBu ] has been determined. The anion has also been found in a gallium and a lithium complex. In monomeric form, the [RN P NMes] anion can be obtained when R = mesityl (Mes = 2,4,6-Me3C6H2), tert-butyl and 1-adamantanyl, as dimeric lithium ring compounds (3) ... 

Chiefly through the work of Jonas and co-workers ( ) mixed-metal organometallic complexes also are known that involve interactions of lithium atoms with unsaturated r-bonded hydrocarbon ligands (olefin, cyclopentadienyl, arene, etc.). While reviews already are available 88, S9), we include examples for comparison purposes. The lithium complexes in this section show increasing complexity and diversity both in the geometries around the lithium atoms and in the degree and type of interactions involved. The common feature in these compounds is the interaction of a lithium atom with a hydrocarbon ligand which is n... 

The quasi-complex compounds, as well as the complexes discussed above, led us into a domain which was nearly terra incognita at that time, namely, the substituted (j3-chloro, j8-alkyl, )3-keto) vinyl organometallics. Thus, the simplest of metal vinyls became the objective of our work, and the vinyl, isopropenyl, propenyl, and styryl derivatives of elements such as Hg, B, Tl, Ge, Sn, Si, P, As, Sb, and Bi were studied in collaboration with Freidlina and Borisov. Apart from the procedures mentioned in Section V, vinyl-lithium and vinyl Grignard compounds were used for the synthesis. Note that the highest valence alkenyl derivatives of the type RjSb were reported by us (181-205). 

Besides the well-known Grignard compounds, other magnesium, aluminium, lithium, and copper-lithium organometaliic compounds have been used as reagents — most recently, ate complexes of aluminium have been introduced. 

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