Trinuclear complexes, formation

Chromium, (ri6-benzene)tricarbonyl-stereochemistry nomenclature, 1,131 Chromium complexes, 3,699-948 acetylacetone complex formation, 2,386 exchange reactions, 2,380 amidines, 2,276 bridging ligands, 2,198 chelating ligands, 2,203 anionic oxo halides, 3,944 applications, 6,1014 azo dyes, 6,41 biological effects, 3,947 carbamic acid, 2,450 paddlewheel structure, 2, 451 carboxylic acids, 2,438 trinuclear, 2, 441 carcinogenicity, 3, 947 corroles, 2, 874 crystal structures, 3, 702 cyanides, 3, 703 1,4-diaza-1,3-butadiene, 2,209 1,3-diketones... 

A variety of such ternary catalytic systems has been developed for diastereoselective carbon-carbon bond formations (Table). A Cp-substituted vanadium catalyst is superior to the unsubstituted one,3 whereas a reduced species generated from VOCl3 and a co-reductant is an excellent catalyst for the reductive coupling of aromatic aldehydes.4 A trinuclear complex derived from Cp2TiCl2 and MgBr2 is similarly effective for /-selective pinacol coupling.5 The observed /-selectivity may be explained by minimization of steric effects through anti-orientation of the bulky substituents in the intermediate. 

The formation of monomer and dimer of (salen)Co AIX3 complex can be confirmed by Al NMR. Monomer complex la show Al NMR chemical shift on 5=43.1 ppm line width =30.2 Hz and dimer complex lb 5=37.7 ppm line width =12.7 Hz. Further instrumental evidence may be viewed by UV-Vis spectrophotometer. The new synthesized complex showed absorption band at 370 nm. The characteristic absorption band of the precatalyst Co(salen) at 420 nm disappeared (Figure 1). It has long been known that oxygen atoms of the metal complexes of the SchifT bases are able to coordinate to the transition and group 13 metals to form bi- and trinuclear complex [9]. On these proofs the possible structure is shown in Scheme 1. 

Using sterically bulky groups in the ortho positions of the phenyl rings in ArNC(H)NHAr, such as Ar = 2,6-Me2-QH3, led to formation of dinudear and trinuclear complexes. This suggests that steric factors can prevent the formation... 

The synthesis and structural characterization of luminescent di- and tri-nuclear organopalla-dium complexes with rigid conjugated alkynyl-aryl bridges and preliminary experiments on the formation of the first generation metallodendrimer using the trinuclear complex as the backbone were reported.102... 

In the Rh-BINAP-catalyzed allyl amine isomerization step used in Takasago s Menthol process, the catalyst is inhibited by water through the formation of a hydroxyl-bridged rhodium trinuclear complex [ Rh(BINAP) i(/<2-0H)2]C104 [61]. 

The formation of trinuclear complexes 2 -Ag, 2 -Cu, 2 -Au shows the tendency of group 11 metal ions to form linear, two-coordinate complexes. As a result, the metal centers of these complexes are not situated in a well-protected cavity as planned. 

Mo, W) are very useful reagents in organometallic chemistry, in particular for the formation of metal-metal bonded complexes. This is illustrated below by the high-yield synthesis of a heterotrinuclear complex having a linear M— Pt—M core, Section C. The trinuclear complexes M—M —M react with tertiary phosphines3,4 to give heterotetranuclear clusters M2M 2( 7-C5H5)2 (CO)6(PR3)2 and details of the synthesis of two of these (M = Mo M = Pd, Pt) are presented in Section D. 

In 1959, the coordinated mercaptide ion in the gold(III) complex (4) was found to undergo rapid alkylation with methyl iodide and ethyl bromide (e.g. equation 3).9 The reaction has since been used to great effect particularly in nickel(II) (3-mercaptoamine complexes.10,11 It has been demonstrated by kinetic studies that alkylation occurs without dissociation of the sulfur atom from nickel. The binuclear nickel complex (5) underwent stepwise alkylation with methyl iodide, benzyl bromide and substituted benzyl chlorides in second order reactions (equation 4). Bridging sulfur atoms were unreactive, as would be expected. Relative rate data were consistent with SN2 attack of sulfur at the saturated carbon atoms of the alkyl halide. The mononuclear complex (6) yielded octahedral complexes on alkylation (equation 5), but the reaction was complicated by the independent reversible formation of the trinuclear complex (7). Further reactions of this type have been used to form new chelate rings (see Section 7.4.3.1). 

Chromium complexes acetylacetone complex formation, 386 exchange reactions, 380 amidines, 276 bridging ligands, 198 chelating ligands, 203 carbamic add, 450 paddlewheel structure, 451 carboxylic adds, 438 trinuclear, 441 oorroles, 874... 

At the same time, a transformation, similar to (3.272), with participation of ethyle-nediamine (en), PbO, NH4SCN, and 2-dimethylaminoethanol is accompanied by the formation (82%) of structurally characterized trinuclear complex Pb3(en)6(SCN)6 [678],... 

Considering the ease of formation of the trinuclear complex, it is somewhat surprising that a corresponding complex was not reported for the vanadiocitrate... 

The ligands with S2C donor atom sets have been found only in complexes and cannot be isolated in the free state. Sodium amalgam reduction of mononuclear [Ni(S4C3Me2)J leads to removal of benzenedithiolate and formation of trinuclear [Ni(p-S2C3Me2)]3 (Eq. 1) (10). The trinuclear complex shows cleavage and insertion reactions of interest as CO dehydrogenase model reactions (see below). Tetrahydrofurane = THF. 

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