Chloride ligand

Dimesitylimidazolium chloride with chromocene gives the carbene 32 (R = C1) (990M529). With phenylmagnesium chloride, 32 (R = C1) gives 32 (R = Ph), the product of substitution of the chloride ligand by phenyl radical. In chloroform, 32 (R = C1) gives the chromium(III) species 33. In contrast,... 

Dimesitylimidazolium chloride with nickelocene gives the carbene complex [(T) -Cp)NiCl(L)] (L= l,3-dimesitylimidazol-2-ylidene), in which the chloride ligand can be substituted by a methyl group by reacting the product with methyl-lithium (OOJOM(596)3). 

A chiral titanium complex with 3-cinnamoyl-l,3-oxazolidin-2-one was isolated by Jagensen et al. from a mixture of TiCl 2(0-i-Pr)2 with (2R,31 )-2,3-0-isopropyli-dene-l,l,4,4-tetraphenyl-l,2,3,4-butanetetrol, which is an isopropylidene acetal analog of Narasaka s TADDOL [48]. The structure of this complex was determined by X-ray structure analysis. It has the isopropylidene diol and the cinnamoyloxazolidi-none in the equatorial plane, with the two chloride ligands in apical (trans) position as depicted in the structure A, It seems from this structure that a pseudo-axial phenyl group of the chiral ligand seems to block one face of the coordinated cinnamoyloxazolidinone. On the other hand, after an NMR study of the complex in solution, Di Mare et al, and Seebach et al, reported that the above trans di-chloro complex A is a major component in the solution but went on to propose another minor complex B, with the two chlorides cis to each other, as the most reactive intermediate in this chiral titanium-catalyzed reaction [41b, 49], It has not yet been clearly confirmed whether or not the trans and/or the cis complex are real reactive intermediates (Scheme 1.60). 

An X-ray structure of the complex formed between 3-cinnamoyl-l,3-oxazohdin-2-one and a chiral TADDOL-Ti(IV) complex (see Chapters 1 and 6 by Hayashi and Gothelf, respectively) has been characterized [16]. The structure of this complex has the chiral TADDOLate and cinnamoyloxazohdinone ligands coordinated to titanium in the equatorial plane and the two chloride ligands in the axial plane and is similar to A in Fig. 8.8. The chiral discrimination was proposed to be due to... 

Salts of IrClg were used in the classic first ESR experiments to demonstrate delocalization of unpaired electrons onto the chloride ligand (Figure 2.1) the unpaired electron spends 30% or more of its time in ligand orbitals in this case [27],... 

A planar complex of the type [Pt(NH3)2Cl2] can exist in two forms depending upon the relative spatial orientation of the two chloride ligands. They can be at 90° to each other to give the cis form (1.1), or at 180° to give the trans isomer (1.2). 

Fig. 6.9 Differentiation of niobium atoms and outer chloride ligands in the cluster unit of Ti2Nb6Cli404 and [Tl5(Ti2Cl9)][(NbeCI,204)3(Ti3Cl4)2]. The numbers in the boxes are electrostatic charges calculated by the DFT method.

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