Ligand periphery

The concept may be extended by additional coordination of weakly binding peripheral donor functions to the metal centre, as exemplified by the yttrium complex displayed in Fig. 5. The 2-fluorophenyl groups provide an "active" ligand periphery which stabilizes the highly acidic Y-center [12],... 

Two diastereomers of a vanadium Schiff base complex with a chiral vanadium centre plus three chiral centres in the ligand periphery. ] The constituents of the Schiff base are o-hydroxynaphthaldehyde and S-alanine the additional monodentate ligands are i ec-butanol and i ec-butanolate. 

C3-symmetrical tripodal ligands have been used to obtain amido complexes of family (86). If chiral substituents are present in the ligand periphery, some stereo discrimination is observed in the reaction with several chiral ketones and aldehydes. On the other hand, such systems can generate early-late heterobimetallics with metal-metal bonds (equation 41). Reaction of (91) with MeNC as well as the heteroallenes CO2, CS2, RNCO and RNCS led to insertion into the polar metal-metal bond. Tris (pyrazolyl) borate see Tris(pyrazolyI)borates) Zr and Hf complexes are other interesting examples of the type (86). In combination with MAO, they give promising results in ethylene and ethylene/hexene polymerizations. Substitution of these sterically crowded ligands allows adjustements of the environment of the active site to the... 

Homonuclear unbridged tm bonds exhibit a high reactivity towards insertion or addition reactions when the ligand periphery is sterically crowded. This results in a... 

Unique properties for polymers that include their thermal behavior, processability, and ability to assemble into ordered structures would offer potential for com-patibilizing nanocrystals, directing their assembly, and providing a mechanism for charge transports. The confirmation of theoretical predictions for spatial distribution for nanoparticles inside polymer hosts would depend on interactions between the ligand periphery and polymer environment (Skaff et al., 2008). 

Metal complexes bearing initiator functionalities in their ligand periphery may act as multifunctional metalloinitiators according to the core-first approach. This method is less sensitive to steric restrictions and the products can be easily purified from the unreacted monomer by precipitation. Limitations of the method include the difficulties concerning the synthesis of the metalloinitiator, which often bears sensitive functionalized ligands, and the compatibility problems of the metal complex with the polymerization reaction conditions. Furthermore, decomposition of the complex has to be avoided during... 

Since many metal complexes bind to DNA, those that show luminescence in fluid media have the potential to act as probes of biological structure. Such a feature is particularly useful if the luminescent probe is site specific on the DNA chain. Complexes that can be chemically modified at the ligand periphery, or whose photophysical properties are sensitive to medium effects, have the best potential for use in biological applications. 

Another family of phosphane ligands that contain a phosphine unit and stericaUy shielded nitrogen lone pairs in the ligand periphery are the so-called AZARYPHOS (aza-aryl-phosphane, L) ligands. The incorporation of these ligands into homoleptic ruthenium complexes [RuCp(L)2(MeCN)][PF6], either preformed [86] or generated in situ [87], provides catalysts for the anti-Markovnikov hydration of terminal... 

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