Sulfide ligands

Additionally to the above reducing agents, ROH, Zn, Nal, A1I3, and M[BH4] (M = Li, Na) are used. In our opinion, the possibility of obtaining mixed-ligand sulfide-sulfoxide complexes 748 as a result of these syntheses is of the highest... 

Hydrometallation is catalyzed by Pd. Hydroboration of l-buten-2-methyl-3-yne (197) with catecholborane (198) gives the 1,4-adduct 199 with 84% selectivity. The ratio of Pd to phosphine (1 1.5) is important[l 10]. The vinyl sulfide 201 is prepared by a one-pot reaction of the thioalkyne 200 via a Pd-catalyzed hydroborution-coupling sequence using dppf as a ligand[l 11]. 

The red tetrathiomolybdate ion appears to be a principal participant in the biological Cu—Mo antagonism and is reactive toward other transition-metal ions to produce a wide variety of heteronuclear transition-metal sulfide complexes and clusters (13,14). For example, tetrathiomolybdate serves as a bidentate ligand for Co, forming Co(MoSTetrathiomolybdates and their mixed metal complexes are of interest as catalyst precursors for the hydrotreating of petroleum (qv) (15) and the hydroHquefaction of coal (see Coal conversion processes) (16). The intermediate forms MoOS Mo02S 2> MoO S have also been prepared (17). 

The copper(I) ion, electronic stmcture [Ar]3t/ , is diamagnetic and colorless. Certain compounds such as cuprous oxide [1317-39-1] or cuprous sulfide [22205-45 ] are iatensely colored, however, because of metal-to-ligand charge-transfer bands. Copper(I) is isoelectronic with ziac(II) and has similar stereochemistry. The preferred configuration is tetrahedral. Liaear and trigonal planar stmctures are not uncommon, ia part because the stereochemistry about the metal is determined by steric as well as electronic requirements of the ligands (see Coordination compounds). 

An achiral reagent cannot distinguish between these two faces. In a complex with a chiral reagent, however, the two (phantom ligand) electron pairs are in different (enantiotopic) environments. The two complexes are therefore diastereomeric and are formed and react at different rates. Two reaction systems that have been used successfully for enantioselective formation of sulfoxides are illustrated below. In the first example, the Ti(0-i-Pr)4-f-BuOOH-diethyl tartrate reagent is chiral by virtue of the presence of the chiral tartrate ester in the reactive complex. With simple aryl methyl sulfides, up to 90% enantiomeric purity of the product is obtained. 

MLTC bands, S, 575 NMR.5,574 Raman, 5, 575 stereochemistry, 5,538-572 stibine ligands, S, 584 sulfides, S, 584 sulfurdiimine reactivity, 2,194 sulfur dioxide, 5,584 sulfur ligands, 5,584 synthesis, 5,536-538... 

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