Complexes lithium

Li+ required for efficacy by increasing its bioavailability and possibly to reduce some of the unpleasant side effects sometimes experienced with this drug. The toxicity of such ionophores and kinetics of ion complexa-tion, both association and dissociation, are obviously important factors under consideration in this field of research. 

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Ca.ta.lysts, A small amount of quinoline promotes the formation of rigid foams (qv) from diols and unsaturated dicarboxyhc acids (100). Acrolein and methacrolein 1,4-addition polymerisation is catalysed by lithium complexes of quinoline (101). Organic bases, including quinoline, promote the dehydrogenation of unbranched alkanes to unbranched alkenes using platinum on sodium mordenite (102). The peracetic acid epoxidation of a wide range of alkenes is catalysed by 8-hydroxyquinoline (103). Hydroformylation catalysts have been improved using 2-quinolone [59-31-4] (104) (see Catalysis). 

A series of lithium complexes have been utilized as synthons in the preparation of aminoborane complexes. (/V-Tlthiomethy1amino)dimethy1horane is used as a reagent for the preparation of borylarnino(arnino)boranes and diborylamines (50). Lithium benzyl-/ f/-butylamide reacts with BCl to yield the bisaminoborane [91573-50-1] shown in equation 16 (51). 

Scheme 10.10 and if Coordination modes for the [RSNR ] anion in solvated lithium complexes... 

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. ... 

Oxalamidinate anions represent the most simple type of bis(amidinate) ligands in which two amidinate units are directly connected via a central C-C bond. Oxalamidinate complexes of d-transition metals have recently received increasing attention for their efficient catalytic activity in olefin polymerization reactions. Almost all the oxalamidinate ligands have been synthesized by deprotonation of the corresponding oxalic amidines [pathway (a) in Scheme 190]. More recently, it was found that carbodiimides, RN = C=NR, can be reductively coupled with metallic lithium into the oxalamidinate dianions [(RN)2C-C(NR)2] [route (c)J which are clearly useful for the preparation of dinuclear oxalamidinate complexes. The lithium complex obtained this way from N,N -di(p-tolyl)carbodiimide was crystallized from pyridine/pentane and... 

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 complex bearing a r 1 1 -[ 1,2,4]diazaphospholide ligand, [(ri1 ri1-dp)-(ji-Li) (DME)]2 (DME= 1,2-dimethoxyethane) was first reported by Gudat and coworkers [43], Lithium [l,2,4]diazaphospholide further binds to two M(CO)5 fragments by coordination via the lone pair of the P and one N atom. Formation of mononuclear P-coordinated complexes as intermediates is supported by indication of more efficient M—>L back donation for P- than for IV-bound fragment by X-ray and spectroscopic studies. 

Figure 95 The structure of the the calcium-lithium complex CaLi3(oepg)(THF)3 181.

Compared to the wealth of data concerning the solid- and solution-state structures of lithium (di)organophosphides, reports of heavier alkali metal analogues are sparse. Indeed, the first crystallographic study of a homometallic heavier alkali metal (di)organophosphide complex was reported only in 1990 (67) and the majority of such complexes have been reported in the past 3 years. Interest in these complexes stems mainly from their enhanced reactivity in comparison to equivalent lithium complexes, which is particularly useful for the synthesis of alkaline earth, lanthanide, and actinide organophosphide complexes. 

The 1-t-butylphospholane sulfide intermediate to TangPhos was also used to prepare the P,N ligands 48 by reacting the lithium complex with C02 and then oxazoline formation with a range of chiral amino alcohols [69b, 74]. The Ir complexes of these ligands have been successfully used in the reduction of / -methylcinnamic esters (80-99% ee) and methylstilbene derivatives (75-95% ee), a particularly challenging class of unfunctionalized olefins [4 c]. 

Scheme 4-24. Gallium-lithium complex-catalyzed ring opening.

Enantioselective addition of R2Zn to aldehydes. Corey and Hannon2 have prepared the diamino benzylic alcohol 1 from (S)-proline and (lS,2R)-( + )-ephed-rine and report that the chelated lithium salt of 1 is an effective catalyst for enantioselective addition of diethylzinc to aromatic aldehydes. Thus benzaldehyde can be converted into (S)-( - )-3 with 95% ee, via an intermediate tridentate lithium complex such as 2 formed from 1. Similar reactions, but catalyzed by diastereomers of 1, show that the chirality of addition of dialkylzincs to aldehydes is controlled by the chirality of the benzylic alcohol center of 1. 

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... 

A tricyclic aromatic system closely related to borole, 9-boratafluorene, might be expected to form ( -coordinated transition metal sandwich complexes, but so far only the lithium complex has been characterized.19 Monohapto aluminum adducts of neutral 9-borafluorene, in which A1 is bound only to the boron atom, have been prepared.20... 

The central feature of the mechanism is the 3-cuprio(III) enolate Cpop, of an open, dimeric nature, as shown by comparison of theory with experimentation involving NMR and KIEs [80, 81]. This species serves as the direct precursor to the product (Scheme 10.5, top box). In this critical CPop complex, copper/olefin (soft/soft) and a lithium/carbonyl (hard/hard) interactions are present. The open complex may be formed directly, by way of an open cluster (bottom left of Scheme 10.5), or by complexation of a closed cluster with the enone (CPcl). Experiments have shown that the enone/lithium complex (top left of Scheme 10.11) is a deadend species [60, 74]. 

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