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1,2-Diaminocyclohexane complexes

Another application of the free diamine as a ligand for asymmetric catalysis is the Michael reaction of cyclic p-keto esters with methyl vinyl ketone, which has been accomplished with a nickel(II)- (15,25)-1,2-diaminocyclohexane complex, with ee s up to91%(eq 11). ... [Pg.204]

The [Hg3(OH)2]4+ cation has a zigzag structure 78 the [Hg(OH)]+ cation, in its chlorate and bromate salts, is an infinite chain analogue (17).79 A related cyclic /x-hydroxo trimer (18) is found in a platinum(II)-diaminocyclohexane complex.69... [Pg.299]

Multidentate amine ligands react readily with palladium(II) halides to yield chelated products. Crystal structure determinations have been carried out for 1,2-diaminoethane complexes [PdCl2(en)], [Pd(en)2]Cl2 and [Pd(en)2][Pd(S203)2(en)]. A variety of 1,2-diaminoethane, 1,2-diaminocyclohexane and 1,3-diaminocyclohexane complexes have been prepared because their necessarily cis geometry makes them analogous to the antitumour platinum complexes. In contrast to compounds tram-[PdX2L2] these former complexes are claimed to have activity comparable with or greater than that of cisplatin. ... [Pg.5989]

Another platinum(IV) ammine complex studied as a possible anti-tumour compound is shown in Figure 3.101 [171] m-(l,2-diaminocyclohexane)tetra-chloroplatinum has undergone clinical trials but was found to be too neurotoxic. [Pg.253]

These different catalysts were first tested in the desymmetrization of the achiral triene 63 (Scheme 40). The best enantioselectivities (up to 39%) were obtained with complexes 60b and 61c-d bearing carbene ligands derived from 1,2-diphenyl-1,2-diaminoethane (R = Ph). ligands derived from 1,2-diaminocyclohexane gave poor enantioselectivities (< 9% ee). Replacement of the mesityl group in complex 60b by o-methyl- or o-isopropylphenyl groups (complexes 61c-d) slightly increases the enantioselectivity (from 13... [Pg.216]

One study has been made with a chelate complex, tran5-l,2-diaminocyclohexane-tetraaceatomanganate(III), which is either pentadentate or hexadentate, a water molecule occupying the sixth or seventh coordination position respectively, and hence chelation of the oxalate is very unlikely. The reaction is first-order both in oxidant and oxalate and is retarded by increase of acidity. The HC204 ion is, therefore, attacked more slowly than the 204 " ion but both forms are oxidised as follows... [Pg.397]

Methyltrioxorhenium(VII) (MTO) forms mono- or bis-complexes with di-Schiff bases being derivatives of various salicylaldehydes and fra s-l,2-diaminocyclohexane [37] 90... [Pg.164]

Fox et al.101-103 have studied the structure of Ni(II) complexes being derivatives of frans-l,2-diaminocyclohexane, using 1H NMR spectroscopy. Chemical shift differences (A<5) between di-Schiff base and its nickel (II) complexes observed for aromatic protons were attributed to the ring currents [40]. [Pg.168]

The NMR studies of di-Schiff bases Ni(II) complexes, derivatives (IR,2R)-l,2-diaminocyclohexane and 3- or 5-methoxysalicylaldehyde have been also presented by Szlyk et al.97... [Pg.169]

Szlyk et al.109 have studied the di-Schiff bases Zn(II) complexes, being derivatives of (7R/2R)-l,2-diaminocyclohexane and 5-bromo- or 5-chloro-salicylaldehydes by means of 1H and 13C NMR in CDCI3 and 13C CP MAS NMR spectra. [Pg.172]

In Sn(II) complexes, the tin atom was located above the di-Schiff base coordination plane, while in Sn(IV) complexes, it was coplanar with the imine coordination framework. The position of the metal was supported by X-ray data. For the compounds studied, the 119Sn chemical shift values varied from 501.4 to —1015.9 ppm. Increase in the coordination number from Sn(II) to Sn(IV) led to an increase in the tin shielding. The differences of up to 3.0 ppm between 5119Sn values for the complexes, being derivatives of R,R and S,S 1,2-diaminocyclohexane, were observed. [Pg.173]

A trons-[RuCl2(diphosphine)(l,2-diamine)] complex with (R,R)-Et-DuPhos and (R,R)-l,2-diaminocyclohexane as the ligand combination has been found to be effective for the hydrogenation of imine 143, with up to 94% ee being obtained under the standard basic conditions employed for this catalytic system [198]. Unfortunately, the optimum combination of chiral diphosphine and diamine was found to be substrate-dependent, with only 40% ee being obtained for 2-methylquinoxaline 144 with Et-DuPhos. [Pg.822]

The other alternative mechanisms discussed here, which are based on the formation of different types of complexes with the substrate, failed to accommodate additional observations, such as the conformational effects. Indeed, if any difference would be expected between the cis- and fra s-l,2-diaminocyclohexane in forming complexes with the substrate, that would be in favour of an increase in rate for the reaction with the trans-isomer, contrarily to the experimental observation. [Pg.1289]


See other pages where 1,2-Diaminocyclohexane complexes is mentioned: [Pg.241]    [Pg.9]    [Pg.19]    [Pg.180]    [Pg.59]    [Pg.241]    [Pg.9]    [Pg.19]    [Pg.180]    [Pg.59]    [Pg.232]    [Pg.57]    [Pg.317]    [Pg.50]    [Pg.207]    [Pg.215]    [Pg.254]    [Pg.126]    [Pg.117]    [Pg.164]    [Pg.165]    [Pg.347]    [Pg.349]    [Pg.164]    [Pg.112]    [Pg.461]    [Pg.543]    [Pg.813]    [Pg.123]    [Pg.395]    [Pg.95]    [Pg.306]    [Pg.241]    [Pg.320]    [Pg.220]    [Pg.157]   
See also in sourсe #XX -- [ Pg.9 ]




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