Dimethyl-1,1’-ferrocene determination

Ferrocene-based aminophosphines are shown to be effective ligands in the Ru(II)- catalysed asymmetric hydrogenation of ketones. The enantioselectivity is mainly determined by the C-centred chirality of the ligands, but the planar chirality is also important, and (Rc,SFc)- or (Sc,Rfc)- is the matched combination of chiralities.334 Dimethyl oxalate is selectively hydrogenated to methyl glycolate with Ru(acac)3,... 

The reaction must be performed in a dry, oxygen-free environment although the product is not sensitive to air or moisture, the intermediate C5HJ is. Cyclopentadiene is added dropwise to a stirred slurry of KOH powder and 1,2-dimethoxyethane. A solution of FeCl2.4H20 in dimethyl sulphoxide (CH3)2SO is then added. The choice of solvents is determined by obvious considerations of solubility and miscibility, and chemical inertness towards the products and intermediates. Dimethyl sulphoxide is a fairly weakly-coordinating aprotic solvent, easily displaced by C5H from Fe(II). A mixture of aqueous HC1 and crushed ice is then added this neutralises the KOH (the ice absorbs the heat evolved) and causes the precipitation of ferrocene, which is (predictably) insoluble in water. The crude product is purified by sublimation. 

Mass spectrometry has proved extremely useful in determining the composition of various polyferrocene products such as those formed by trimerization of ferrocenylacetylenes (180), reactions of ferrocenyl-acetylenes with metal carbonyls (175), oxidative coupling of ferrocenyl polyacetylenes (179), and lithiation of ferrocene (186). The 1,12-dimethyl-[l,l]ferrocenophane (XC) shows a very strong molecular ion and fragments [M—Me]+ [M—2 Me]+ and the doubly charged species M2+, [M —Me]2+, and [M —2 Me]2+ (197). 

Organometallic and Coordination Compounds. - Crystallization of ferrocene and ruthenocene substituted in the 1- and T-positions by two nitronyl nitroxide radicals gave the new crystal phases p-1 (besides the known phase a-1, a-2, and a-2 whose structures were determined by X-ray analysis and were investigated by C and H NMR spectroscopy with MAS NMR. The solid state Sn CP MAS NMR spectra of a series of triaryltin chlorides of the form ArsSnCl have been acquired. The indirect spin-spin coupling constants (J( Sn- C1)), quadrupolar-dipolar shifts (6( Sn- Cl)), and the Sn chemical shift tensors were extracted. " Powders of the zinc and copper(II) dimethyl-(MDtc), diethyl-(EDtc), and morpholinedithiocarbamate (MfDtc) complexes quantitatively absorb hexamethyleneimine (Hmi) to produce the adducts... 

NMR spectroscopy was applied in the enantiomeric excess determination of (iV,iV-dimethyl-(2,2,2-trifluoro-l-phenylethyl)amine-C,A)palladium complexes of a-amino acids.Dunina et al. used NMR spectroscopy and a P -chiral phosphapalladacycle for the enantiomeric purity determination of a-amino acids. P NMR spectroscopy was also used in the enantiomeric excess determination of N,C o///5< -palladated complexes of P-chiral phosphines. A ferrocene-based reagent (i p,successfully designed for the chiral recognition of /3-hydroxyphosphines and the discrimination of ( )-bis(diphenylphosphino)-1,1 -binaphthyl. 

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