31P-NMR Spectroscopy

Organophosphate Ester Hydraulic Fluids. Absorption rates of TOCP were measured in chickens after subcutaneous injection by measuring the apparent disappearance of TOCP from the site of injection with 31P NMR spectroscopy (Carrington et al. 1988). Five chickens were injected with single,... 

The highly hindered disilene 2 did not react with white phosphorus, even under forcing conditions. With disilene 3, which is more hindered than 1 but less so than 2, the reaction with P4 was more complicated. It proceeded slowly, producing small amounts of both stereoisomers of the bicyclobutane compounds 70 and 70. The major product, however, was a more complex compound containing four phosphorus and four silicon atoms, also obtained as a mixture of two stereoisomers. Two-dimensional 31P NMR spectroscopy established the probable structures to be 71.98... 

Reaction between IrHCl2(PPh3)2 and Hg(o-tolyl)2 yields the red complex (45), in which the Ir—Hg bond has been confirmed by 31P—199Hg coupling in 31P NMR spectroscopy. Addition of CO and I2 gives [Ir(o-tolyl) Hg(o-tolyl) Cl(CO)(PPh3)2] and [Ir(o-tolyl)Cl(HgI)(PPh3)2], respectively.54... 

The reactions of (105) are summarized in reaction Scheme 14. In all cases the products were identified by JH and 31P NMR spectroscopy.556... 

The hexanuclear Ir111 complex [L IrCl2cp 6], in which L is based on the amino glycoside neomycin B (249), has been characterized by IR, 13C, and 31P NMR spectroscopy, and by FAB Ms419 The in vivo antitumor and antitrypanosomal effects of [IrY4Cl2]1 complexes,... 

The study of rapid, intermolecular ligand exchange between square-planar complexes trans-Ir(CO)L2X (X = C1 or Me, L - PPh3, P(p-tolyl)3, or PMePh2) by variable-temperature 31P NMR spectroscopy indicates that the reaction proceeds through dissociation of phosphine from the metal center and a subsequent associative substitution with other complexes 559,560 Ligand exchange between square-planar Ir and Pt complexes is slow. 

While extensive CO ligand loss can be induced in the gas phase in aqueous solution, 1 - 3 are moderately soluble and stable for days. No signs of hydrolysis or decomposition were observed by 31P NMR spectroscopy. The logPo/w values of 1 - 3 were determined (see Table 1). 

When either 7 or 8 were applied as catalysts for the hydration of 1-hexyne, neither hexanal nor 2-hexanone were detected. Intriguingly, however, because we monitored the reactions carefully by H and 31P NMR spectroscopy, we realized that both 7 and 8 were converted cleanly to another species. Repeating the reactions of 7 or 8 with 1-hexyne on larger scale in the absence of added water led to isolation of metallacycles 9 and 10, which were fully identified by NMR spectroscopy, and ultimately, by X-ray diffraction. 

P NMR spectroscopy is an excellent sensor of structural changes that occur along the reaction pathway [29], especially when monitoring the tightness of binding of the cofactor. 

The P-nitroso phosphine oxide 406 behaves as an N-O heterodienophile and reacts with the 1,3-diene part of the molecule in a cycloaddition reaction to form the 2,4 ,5,6,7,8-hexahydro-8-phenyl-[l,2]azaphosphorino[l,6-3][l,2]oxa-zine 8-oxide 407 containing an stereogenic cyclic phosphorus atom (Scheme 64). 31P NMR spectroscopy shows one single peak indicating the formation of only one diastereomer <2002JOG6174>. 

The study of [4.4.0] ring systems has resulted primarily from the study of various other aspects of phosphorus chemistry. An investigation into the effect of nitrogen donor action on the increase in coordination at phosphorus in a series of oxyphosphoranes led Holmes and co-workers <1998IC4945> to compounds 24 and 25. The compounds were fully characterized by NMR spectroscopy and X-ray diffraction. Compound 24 was heated for 30 min at 140°C in an NMR tube. The reaction was followed by 31P NMR spectroscopy which indicated that conversion to a phosphorane 26 and a small amount of phosphate had taken place (Equation 4). The pentaoxyphosphorane 25 was successfully produced via an oxidative addition reaction between the diol 27 and triphenyl phosphate in the presence... 

The system (23)/SnCl2, an active intermediate in the catalytic hydroformylation of 1-hexene, has been investigated by 31P NMR spectroscopy and two species are observed at low temperature, in equilibrium with the starting Pt complex (23). One is complex (27), and the other is a species which does not show Sn-P coupling and which has been tentatively attributed to a complex having chloride ions bridging the Pt and Sn metal centers. Formation of the complex (27) does not occur when EtOH is added to the CD2C12 or acetone solutions.91... 

It is evident that the silica support influences the catalytic performance and it is important to understand the details of the processes involved. For the sol-gel material it was shown by 31P NMR spectroscopy that the immobilised cationic complex completely transforms to the neutral rhodium-hydride species under a CO/H2 atmosphere (Scheme 3.3). On dried silica, however, this conversion might not be complete since the dried support is more acidic [32], It is therefore very likely that the neutral and cationic rhodium complexes co-exist on the silica support. 31P NMR measurements on homogeneous rhodium complexes have shown that a simple protonation indeed converts the neutral rhodium hydride species into the cationic complex. 

In vivo H- and 31P-NMR spectroscopy can be used to assess the concentration of clinically relevant compounds... 

Chiral bis-phosphine acylplatinum complex 210 with a strong acid such as TfOH serves as an effective enantio-selective catalyst for aldol-type reactions of aldehydes with ketene silyl acetals (Equation (127)).486 The presence of water and oxygen in the catalyst preparation step is required to obtain the highly enantioselective catalyst. The intermediacy of a C-bound platinum enolate was suggested by IR and 31P NMR spectroscopies. 

Much of the kinetic data have been obtained with the specific components written in Eq. (4), after which determinations were extended to the generalized compounds RC5H4NO and PR3 to characterize the specific electronic and steric effects of substituents. It was easy to demonstrate that the reaction went to completion by applying 1H- and 31P-NMR spectroscopies. Indeed, the reaction took place so rapidly with the concentrations used (44 mM of each reagent and ImM of catalyst 1) that product formation was complete before the first NMR spectrum could be recorded. 

---