Paramagnetism mixed-ligand complexes

Various thiourea ligands have been used in the synthesis of mixed ligand complexes. A series of complexes [NiQ2L2] (HQ = ethylacetoacetate, L = thiourea, allyl-, benzoyl-, methyl-, diphenyl-thiourea) have been prepared. The complexes are all paramagnetic (/i = 3.02-3.27/iB) and have been assigned tra 5-octahedral structures.1014... 

Pseudooctahedral coordination of rhenium(III) centers has also been found for mixed-ligand complexes with tertiary phosphines and A-heterocyclic thiols which coordinate as their neutral thione tautomers. A representative example with thiazoline-2-thiol (HSthiaz) has been characterized structurally. The paramagnetic complex [ReCl3(HSthiaz)2(PPh3)] (235) contains the HSthiaz ligands in trans position. ... 

The analogous uranium(III) compounds also show unusual reactivity patterns. For example, addition of COT to (Cp )3U yields a mixed metallocene dimer (18) bridged by a COT ligand in this reaction, the (Cp )3U complex has effectively acted as a formal three-electron reductant (equation 3)." A variety of substituted (Cp )3U complexes form adducts with CO and CNR (isocyanides) - these are rare examples of actinide metals with r-acidic ligands." Paramagnetic uranium alkyl complexes are active in a range of catalytic processes." ... 

It has also turned out mainly during our studies of mixed-ligand organo-ytterbium systems that many Yb3+-complexes present excellent conditions for the observation of their 1H-NMR spectra in spite of the strong paramagnetism of this f13-system.Previous... 

The detailed electronic configuration of a transition-metal ion (e.g. 5 = I, i, or i for a ion), orbital populations, and mixed ligand-field crossover complexes can be studied in detail. Electronic spin relaxation is known in paramagnetic ions. The pressure dependence may give additional information on the bonding-type and anisotropy of the crystal. 

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