Ligand amino-functionalized

Similarly (— )-trans-1,2-cyclohexanediaminetetraacetic acid (CDTA) also coordinates stereospecifically (25). In diaminocyclohexane, both amino groups must be equatorial (Fig. 8) since with the donor groups in the axial positions the ligand cannot function as a bidentate and trans- 1,2-cyclo-hexanediaminetetraacetic acid could not coordinate as a sexadentate. If the cyclohexane ring adopts the boat conformation ( 5 kcal/mole less stable than the chair conformer), the l structure (Fig. 8) is still the only one possible, as the ligand now will not coordinate at all six positions in the d configuration. 

The aldimine chelate ligands formed from the primary amino functions present showed a slight increase of enantioselectivity. Further enlargement of the li-... 

Vanadate reacts only very weakly with aliphatic amines such as ethylamine. As a consequence, reactions with aliphatic amines have not been extensively studied, but the information available suggests the reactions are analogous to those of alcohols. Additionally, there have been numerous studies of multidentate ligands where amino functionality is a critical component of vanadium ligation (Section 4.4). 

Figure 13.10 Reaction scheme for the stepwise preparation of multicomponent particle arrays by photolithography.72 Chemically patterned amino-functionalized surfaces were formed by selectively exposing the NVOC substrate by UV exposure. Multicomponent amino-functionalized nanocrystals were subsequently adsorbed via ligand exchange.

One of the most studied class of macrocyclic ligands in lanthanide coordination chemistry is without any doubt the molecules derived from cyclen, a 12-membered ring bearing four amino functions. In particular, its tetracarboxylic derivative H4DOTA (see Fig. 4.40) was synthesized in 1976 by a German chemist, H. Stetter from the University of Aachen,... 

Nonnally, the free ligand is employed in the synthesis of the various transition metal complexes of TIMEN [394-397] and thus the mononuclear complex is formed. It requires only little imagination to reahse that the amino function of the scaffold can be employed for a weak fourth coordination when the need arises. In the complexes of Ni(0) [396], Co(I)... 

The situation is completely different for the amino-substituted derivative II, where the HOMO refers to the rtpp-orbital (bj), whereas the HOMO-1 and HOMO-2 correspond to aj and b2 orbitals. This result has relevance for the coordination behavior of the C-amino-functionalized diphosphirenylium ion II toward the [W(CO)s] moiety. According to calculations at the B3LYP/DZ(P) level the 77 -complex is by 3.8 kcal moH more stable than the isomeric 7] -complex. Fixation of cation II to the metal carbonyl fragment in the 77 -mode leads to an elongation of the P-P bond from 2.11 to 2.31 A. In the complexed ligand CN and PC separations of 1.32 and 1.80 A are calculated <1999EJI1479>. 

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