Bidentate ligands 2-aminopyridine

Table 3 4x4 ligand matrix of aminopyridine (4a-d)/isoquinolone (5a-d) derived self-assembled bidentate ligands in the [Rh]-catalyzed hydroformylation of l-octenea... 

Table 2.6 3x3 Ligand matrix of aminopyridine/isoquinolone derived self-assembled bidentate ligands in the Ru-catalyzed hydration of 1-nonyne.

Bidentate ligands bearing a NS donor set have been prepared from either 2-formyl-thio(seleno)-phenol (or derivatives) or heterocyclic thio(seleno)-aldehydes and different monoamines (or substituted monoamines)31 (11, X = S, Se). When the monoamine is 2-aminopyridine, the potentially tridentate N2S SB behaves as bidentate since pyridine is not involved in coordination.43... 

Aminopyridinato ligands are an important group of asymmetric A,A-bidentate ligands and derived from deprotonation of 2-aminopyridines. The flexibility of binding modes of aminopyridinato ligands can be explained by two resonance forms the amidopyridine and the aminopyridinato. The anionic function is localized at either... 

The reactions of TpRuCl(COD) with the bidentate ligands 2-aminopyridine (apy), 2-amino-4-picoKne (apic) and 2-(methylamino)pyridine (mapy) in the presence of terminal alkynes HC=CR (R = Ph, "Bu, CeHg) afford the cyclic aminocarbene complexes TpRuCl = C(CH2R)apy, TpRuCl = C(CH2R)apic) and TpRuCl = C(CH2R)mapy. This reaction proceeds most likely via the intermediacy of both a reactive TpRu complex containing a strained, and thus labile, k -KN -coordinated aminopyridine Ugand and a vinylidene intermediate. 

Pyridine-based N-containing ligands have been tested in order to extend the scope of the copper-catalyzed cyclopropanation reaction of olefins. Chelucci et al. [33] have carefully examined and reviewed [34] the efficiency of a number of chiral pyridine derivatives as bidentate Hgands (mainly 2,2 -bipyridines, 2,2 6, 2 -terpyridines, phenanthrolines and aminopyridine) in the copper-catalyzed cyclopropanation of styrene by ethyl diazoacetate. The corresponding copper complexes proved to be only moderately active and enantios-elective (ee up to 32% for a C2-symmetric bipyridine). The same authors prepared other chiral ligands with nitrogen donors such as 2,2 -bipyridines 21, 5,6-dihydro-1,10-phenanthrolines 22, and 1,10-phenanthrolines 23 (see Scheme 14) [35]. 

Selected examples of nickel(II) complexes with bidentate aminopyridines and related ligands are shown in Table 49. 

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