Dennis Lee Johnson

29Si NMR spectra of metal carbonyl silanes by the selective population transfer method

Abstract Utilization of the novel Selective Population Transfer (SPT) technique for the first NMR observation of 29Si nuclei directly bound to transition metals is reported. Four metal carbonyl trimethylsilanes ((CH3)3SiMn(CO)5, (CH3)3SiRe(CO)5, (CH3)3SiCo(CO)4, and (CH3)3SiFe(CO)2(C5H5)) have been studied and their chemical shifts and coupling constants obtained. These data are compared with existing 29Si NMR spectra of more conventional (CH3)3SiX compounds and 119Sn NMR spectra of homologous (CH3)3Snmetal complexes.

A convenient preparation of metal carbonyl monoanions by trialkylborohydride cleavage of metal carbonyl dimers; observation and reactions of a bimetallic manganese-formyl intermediate

Commercially available Li(C2H5)3BH rapidly and quantitatively cleaves [Mn(CO)5]2, [Co(CO)4]2, and [(C5H5)Mo(CO)3]2 in THF at room temperature to the corresponding transition metal monoanions. [(C5H5)Fe(CO)2]2 can be cleaved in hexamethylphosphorous triamide (HMPA) or by use of K((unsec)-C4H9)3BH. The mechanism postulated for Li[Mn(CO)5] formation (Scheme I) is supported by the direct observation of a manganese-formyl intermediate ((un4)) and rate data. ((un4)) acts as a hydride donor toward CH3SO3F, Fe(CO)5, and HMn(CO)5.

Simplified in situ syntheses of anhydrous pentacarbonylhydromanganese

Three rapid, convenient procedures are reported for the in situ preparation of anhydrous HMn(CO)/sub 5/ in tetrahydrofuran (THF). Protonation of Li(Mn(CO)/sub 5/) in situ previously prepared by the reaction of Mn/sub 2/(CO)/sub 10/ with Li(C/sub 2/H/sub 5/)BH in THF yielded HMn(CO)/sub 5/ which was contaminated by (C/sub 2/H/sub 5/) from the preparation and by Li/sup +/CF/sub 3/SO/sub 3//sup -/ from the protonation reaction by trifluormethanesulfonic acid (CF/sub 3/SO/sub 3/H). HMn(CO)/sub 5/ free from (C/sub 2/H/sub 5/)/sub 3/B can be prepared by volatilizing the (C/sub 2/H/sub 5/)/sub 3/B along with the solvent, or alternately, the (Mn(CO))/sup -/ can be isolated as its crystalline ..mu..-nitrido-bis-(triphenylphosphorous) salt. The in situ synthesis of HMn(CO)/sub 5/ free from ionic byproducts was accomplished by the solvolysis in methanol of (CH/sub 3/)/sub 3/Si(Mn(CO)/sub 5/).

Measurement of adenosine triphosphate and 2,3-diphosphoglycerate in stored blood with 31P nuclear magnetic resonance spectroscopy

Conditions for blood storage are chosen to assure adequate levels of adenosine triphosphate (ATP) and 2,3-diphosphoglycerate (2,3-DPG). Because of the invasive nature of the techniques, biochemical assays are not routinely used to measure levels of these compounds in stored blood. However, 31P NMR spectroscopy measures phosphorylated intermediates in intact cells and could be used without disruption of the storage pack. We compared levels of ATP and 2,3-DPG measured by 31P spectroscopy and standard enzyme-linked biochemical assays in whole blood (WB) and packed red blood cells (PRBCs) at weekly intervals during a 35-day storage period. NMR demonstrated a marked decrease in 2,3-DPG and an increase in inorganic phosphate after the first week of storage. No significant differences in ATP concentrations were seen in WB during the storage period, but a significant decrease in ATP in PRBCs was documented. There was good agreement in levels of ATP and 2,3-DPG measured by NMR and biochemical techniques. 31P NMR spectroscopy is a noninvasive technique for measuring ATP and 2,3-DPG which has a potential use in quality assurance of stored blood.