[[Ag.sub.2][(dppe)[(3-benzyl-1,3-thiazolidine-2-thione).sub.2]].
The synthesized 3-benzyl-1,3-thiazolidine-2-thione ligands were reacted with silver nitrate and one of the following: (a) 1,2-bis(diphenylphosphino)methane (dppm), (b) 1,1-bis (diphenylphosphino)ferrocene (dppf), (c) 1,1-bis(diphenylphosphino)ethane (dppe), (d) triphenylphosphine (P[Ph.sub.3]), or (e) tri(o-tolyl)phosphine.
As for complex 3, there was a peak at [delta] 2.46 ppm corresponding to the four protons of the ethylene group in the dppe ligand.
As per the [sup.31]P{[sup.1]H} NMR data of complexes 2, 3, and 4, the singlet peaks can be ascribed to two chemically-equivalent P atoms each in dppf and dppe, as well as one in triphenylphosphine.
The top layer was then cannulated into the flask containing Ni(dppe)[Cl.sub.2] (0.02 g, 0.3 mol%, based on I) in 5.0 mL of DMA at room temperature and the resulting mixture was allowed to stir at ambient temperature for 24 h.
2,5Dibromo-3-hexylthiophene was readily prepared by a literature procedure: coupling of n-hexyl Grignard reagent with 3-bromothiophene in the presence of Ni(dppe)[Cl.sub.2], followed by bromination with NBS [14] Scheme 2).
With the resulting thienylzinc bromide, the subsequent polymerization was carried out using Ni(dppe)[Cl.sub.2]-catalyst, which was superior over other catalysts, especially in terms of regioregularity in the resultant polymer.
For this, the complexes of rhodium (I) [RhCl(dppe)], [RhCl(dppp)] y [RhCl(dppb)], where dppe = 1,2-bis(diphenylphosphino)ethane, dppp = 1,3-bis (diphenylphosphino)propane y dppb = 1,4-bis(diphenylphosphino)butane, were used as catalytic precursors in the hydrogenation of styrene, at different temperatures and hydrogen pressures, the products were analyzed by gas chromatography with mass selective detector (MSD) and flame ionization detector (FID), it has found that the best catalytic precursor was the rhodium complexe with dppe as ligand, the minor steric impediment that this ligand exerts over the coordination of olefin on the metal probably helps to improve the activity of that catalytic precursor.
(4) Entre los ligandos fosfina bidentados de importancia estan las difosfinas de formula general [Ph.sub.2]P--(C[H.sub.2])n-[PPh.sub.2] (Figura 1), y entre ellas las mas utilizadas han sido: dppm (1,1-bis(difenilfosfino)metano), n=1, dppe (1,2-bis(difenilfosfino)etano), n=2 dppp (1,3-bis(difenilfosfino)propano), n=3 dppb (1,4-bis(difenilfosfino)butano), n=4 dpp-p (1,5-bis(difenilfosfino)pentano), n=5.
En el presente trabajo se evaluo el efecto de los ligandos fosfina bidentados dppe, dppp y dppb sobre la actividad catalitica del rodio (I) en la hidrogenacion homogenea de estireno, empleando como precursores cataliticos los complejos [RhCl(dppe), [RhCl(dppp)] y [RhCl(dppb)].
Brandes and his colleagues wondered if other chemicals, similar to DPPE, would do the same thing.
This class of drug resembles DPPE and binds to the same intracellular histamine receptors.
