N,O ligand

Treatment of ZnMe2 with the thallium salt of a bis(pyrazolyl)hydroborate gave the methylzinc complex [BpZnMe] 104 in which zinc is three coordinate.162 This complex reacted with paraformaldehyde, Scheme 73, with the direct insertion of the CH20 moiety into the B-H bond to produce the methylzinc complex 105 (Figure 51), in which zinc is tetrahedrally surrounded by the methyl group and the newly formed N,N,O-ligand.163... 

Figure 80 N,O-Ligands used without an additional metal promoter in reactions of diorganozincs with aldehydes.

Linkage isomerism has been discussed for 0,S and N,O ligands both at Ru(II) and at Ru(III), with particular mention of relevance to redox reactions of DMSO complexes (31). 

A Lewis base ligand has been developed as the chiral catalyst. Dahmen, Brase and coworkers reported that the [2.2]paracyclophane-based chiral N,O-ligand 8 (2 mol%) affords (V-formylamine with 84-95% (equation 34)134. In this system, the phenyl transfer reaction also proceeds in a catalytic manner134b. 

Table 5 Pt—Pt Distances in Pt11—Pt11 Complexes with N.O Ligands and with -Pyridone Blue...

While there are no crystal structures of mononuclear Schiff base complexes of copper(I) (N—O ligands) available, these do occur as in the dimeric structure of... 

The majority of studies has involved aromatic N—O ligands, a selection of which is given by (9)-(13) together with abbreviations which will be used in referring to them. All of these offer scope for inclusion of substituents with a range of electronic characteristics. 

The known chemistry of Mn1" with nitrogen ligands, other than the macrocycles (Section 41.4.8), is still quite limited but see also the mixed N, O ligands, Section 41.4.7. Perhaps the tendency for Mn1" to disproportionate, in many ligand systems, is responsible for the failure to obtain [Mn N(SiMe3)2 3], when these species have been obtained84 for all other metals Scm to Fem. 

Table 50 Mn111 Compounds8 of Bidentate N—O Ligands of Type (227)...

Salicylaldehyde has been condensed with many primary amines to yield bidentate N—O ligands. Such ligands react with MnIU acetate dihydrate to give compounds of stoichiometries Mn(L)3 or Mn(L)2(X) (where HL = (227) X = Cl, Br, OH or OAc) examples are listed in Table 50. 

Again the only example seems to be [Os(NO)dppe2]" (see below) 243 the low vN 0 frequency of 1420 cm 1 would be consistent with the presence of a bent Os—N—O ligand, equivalent to a coordinated NO" group (a linear Os—N—O group would give an electron count of 20). 

Recent reports have described other neutral, singlecomponent Ni catalysts based on the N-O ligands... 

The majority of studies involve aromatic N O ligands, some common examples being pyridine W-oxide and methyl substituted derivatives (I04-I06). They are versatile ligands,... 

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