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11.
Aguilar JA Adams RW Duckett SB Green GG Kandiah R 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,208(1):49-57
A new family of NMR pulse sequences is reported for the recording of para-hydrogen enhanced NMR spectra. This Only Para-hydrogen SpectroscopY (OPSY) approach uses coherence selection to separate hyperpolarized signals from those of fully relaxed and thermally equilibrated protons. Sequence design, performance, practical aspects and applicability to other hyperpolarization techniques are discussed. 相似文献
12.
Adams CJ Baber RA Connelly NG Harding P Hayward OD Kandiah M Orpen AG 《Dalton transactions (Cambridge, England : 2003)》2006,(14):1749-1757
Deprotonation of mixtures of the triazene complexes [RhCl(CO)2(p-MeC6H4NNNHC6H4Me-p)] and [PdCl(eta(3)-C3H5)(p-MeC6H4NNNHC6H4Me-p)] or [PdCl2(PPh3)(p-MeC6H4NNNHC6H4Me-p)] with NEt3 gives the structurally characterised heterobinuclear triazenide-bridged species [(OC)2Rh(mu-p-MeC6H4NNNC6H4Me-p)2PdLL'] {LL' = eta(3)-C3H5 1 or Cl(PPh3) 2} which, in the presence of Me3NO, react with [NBu(n)4]I, [NBu(n)4]Br, [PPN]Cl or [NBu(n)4]NCS to give [(OC)XRh(mu-p-MeC6H4NNNC6H4Me-p)2PdCl(PPh3)]- (X = I 3-, Br 4-, Cl 5- or NCS 6-) and [NBu(n)4][(OC)XRh(mu-p-MeC6H4NNNC6H4Me-p)2Pd(eta(3)-C3H5)], (X = I 7- or Br 8-). The allyl complexes 7- and 8- undergo one-electron oxidation to the corresponding unstable neutral complexes 7 and 8 but, in the presence of the appropriate halide, oxidative substitution results in the stable paramagnetic complexes [NBu(n)4][X2Rh(mu-p-MeC6H4NNNC6H4Me-p)2Pd(eta(3)-C3H5)], (X = I 9- or Br 10-). X-Ray structural (9-), DFT and EPR spectroscopic studies are consistent with the unpaired electron of 9- and 10- localised primarily on the Rh(II) centre of the [RhPd]4+ core, which is susceptible to oxygen coordination at low temperature to give Rh(III)-bound superoxide. 相似文献
13.
Zhou R Aguilar JA Charlton A Duckett SB Elliott PI Kandiah R 《Dalton transactions (Cambridge, England : 2003)》2005,(23):3773-3779
The reactions of RhCl(PBz3)3 with H2 and pyridine or 4-methylpyridine yield RhCl(H)2(PBz3)2(py) and RhCl(H)2(PBz3)2(4-Me-py), respectively. These species undergo hydride site exchange via the loss of the pyridyl donor and formation of RhCl(H)2(PBz3)2 which contains equivalent hydride ligands; for the py system the activation free energy, deltaG++300, is 57.4 +/- 0.1 kJ mol(-1) while for 4-Me-py the value is 59.6 +/- 0.3 kJ mol(-1). These products only showed parahydrogen enhancement in the corresponding hydride resonances when a sacrificial substrate was added to promote hydrogen cycling. When RhCl(PPh3)3 was used as the precursor similar observations were made, while when RhCl(PCy3)2(C2H4) was examined, H2 addition led to the formation of the binuclear complex (H)2Rh(PCy3)2(micro-Cl)2Rh(H)2(PCy3)2 which was differentiated from RhCl(H)2(PCy3)2 on the basis of the similarity in diffusion coefficient (5.5 x 10(-9) m2 s(-1)) to that of (H)2Rh(PPh3)2(micro-Cl)2Rh(PPh3)2 (5.3 x 10(-9) m2 s(-1)). The detection of RhCl(H)2(PCy3)2(py) was facilitated when pyridine was added to a solution of RhCl(PCy3)2(C2H4) before the introduction of H2. During these reactions trace amounts of the double substitution products, RhCl(H)2(phosphine)(py)2, were also detected. 相似文献
14.
Newton KA Clench MR Deshmukh R Jeyaseelan K Strong PN 《Rapid communications in mass spectrometry : RCM》2007,21(21):3467-3476
The red scorpion, Mesobuthus tamulus, is found in two distinct biotopes within the Indian state of Maharastra-a tropical, sea-level biotope and a semi-arid biotope, up to 600 m. Scorpions from these two geographical areas show marked differences in toxicity. Using mass spectrometry, we have shown biotope-specific variation in the expression of peptides from scorpions collected from these two distinct areas. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) and reversed-phase liquid chromatography/electrospray ionisation mass spectrometry (LC/ESI-MS) were assessed as techniques for obtaining mass fingerprint data. On line LC/ESI-MS was judged to be the method of choice and unique biotope-specific mass fingerprints, with key diagnostic markers, were obtained. 相似文献
15.
Adams CJ Baber RA Connelly NG Harding P Hayward OD Kandiah M Orpen AG 《Dalton transactions (Cambridge, England : 2003)》2007,(13):1325-1333
The triazenide-bridged tetracarbonyls [(OC)(2)Rh(mu-p-MeC(6)H(4)NNNC(6)H(4)Me-p)(2)M(CO)(2)] (M = Rh or Ir) undergo oxidative addition of iodine across the dimetal centre, giving the [RhM](4+) complexes [I(OC)(2)Rh(mu-p-MeC(6)H(4)NNNC(6)H(4)Me-p)(2)M(CO)(2)I], structurally characterised for M = Ir. The anionic tricarbonyl iodide [I(OC)Rh(mu-p-MeC(6)H(4)NNNC(6)H(4)Me-p)(2)Rh(CO)(2)](-) forms [I(2)(OC)Rh(mu-p-MeC(6)H(4)NNNC(6)H(4)Me-p)(2)Rh(CO)I](-) by initial one-electron transfer whereas the analogous tricarbonyl phosphine complexes [(OC)(Ph(3)P)Rh(mu-p-MeC(6)H(4)NNNC(6)H(4)Me-p)(2)M(CO)(2)] (M = Rh or Ir) undergo bridge cleavage, giving mononuclear [Rh(p-MeC(6)H(4)NNNC(6)H(4)Me-p)I(2)(CO)(PPh(3))] and dimeric [I(OC){RNNN(R)C(O)}M(mu-I)(2)M{C(O)N(R)NNR}(CO)I] (M = Rh or Ir, R = C(6)H(4)Me-p) in which CO has been inserted into a metal-nitrogen bond. 相似文献