Quantitative NMR in synthetic and combinatorial chemistry

Integrated standardization concept for Angelica botanicals using quantitative NMR

“…Expressing the accuracy for each qHNMR method as the % deviation from the concentration by weight (=100%) resulted in 100.1 ± 5.7% for the IS method (precision 94.3%), 98.7 ± 5.8% for the ES method (precision 94.2%), and 103.8 ± 14.8% for relying on the CC method (precision 85.2%). Compared with previous qHNMR reports [31,42,43], the present study found lower achievable accuracy and precision. This was mainly attributed to the complex nature of the analyzed plant extracts and fractions, which required a reduction in the size of the integral regions (ROIs) below the aforementioned 5ω̄ 1/2 threshold which has been proposed for the qHNMR of primary reference standards.…”

Integrated standardization concept for Angelica botanicals using quantitative NMR

“…Expressing the accuracy for each qHNMR method as the % deviation from the concentration by weight (=100%) resulted in 100.1 ± 5.7% for the IS method (precision 94.3%), 98.7 ± 5.8% for the ES method (precision 94.2%), and 103.8 ± 14.8% for relying on the CC method (precision 85.2%). Compared with previous qHNMR reports [31,42,43], the present study found lower achievable accuracy and precision. This was mainly attributed to the complex nature of the analyzed plant extracts and fractions, which required a reduction in the size of the integral regions (ROIs) below the aforementioned 5ω̄ 1/2 threshold which has been proposed for the qHNMR of primary reference standards.…”

Automatic Analysis of Quantitative NMR Data of Pharmaceutical Compound Libraries

“…Again, it is seen that the algorithm works well when using well-defined test samples. The triplicate values from both tables confirm what has already been reported, that NMR is accurate and precise. , …”

Mapping catalyst activation, turnover speciation and deactivation in Rh/PPh 3 -catalysed olefin hydroformylation

“…More detailed analysis using a D 1 of 35 seconds showed the existence of both linear and branched acyl isomers of Q (Figure S12). As can be seen from the 31 P{ 1 H} NMR profiles shown in Figure 8 a noticeable amount of triphenylphosphine oxide was also formed during the reaction, as also seen in all other experiments with this catalytic system (see below). Control reactions in thoroughly deoxygenated and sealed sample tubes showed this to be an intrinsic feature of the catalysis, and not due to traces of oxygen being present within or penetrating the flow system over time.…”

“…Interestingly, when only one equivalent PPh 3 was used in the reaction no Rh-H species were observed during catalysis, and the only catalyst intermediate detected by 31 P{ 1 H} FlowNMR was the mono-phosphine acyl complex Q (Fig. S8 †) identified previously.…”

“…When two or more equivalents of PPh Interestingly, when only one equivalent PPh 3 was used in the reaction no Rh-H species were observed during catalysis, and the only catalyst intermediate detected by 31 P{ 1 H} FlowNMR was the mono-phosphine acyl complex Q (Figure S8) identified previously. 28 When the syngas composition was changed from 1:1 to 3:1 H 2 /CO at the same total pressure in an experiment using six equivalents of PPh 3 the catalysis was ~30 % faster (Figure 6), reflecting the positive reaction order in H 2 which effects the turnover-limiting hydrogenolysis.…”

Integrated standardization concept for Angelica botanicals using quantitative NMR

“…Expressing the accuracy for each qHNMR method as the % deviation from the concentration by weight (=100%) resulted in 100.1 ± 5.7% for the IS method (precision 94.3%), 98.7 ± 5.8% for the ES method (precision 94.2%), and 103.8 ± 14.8% for relying on the CC method (precision 85.2%). Compared with previous qHNMR reports [31,42,43], the present study found lower achievable accuracy and precision. This was mainly attributed to the complex nature of the analyzed plant extracts and fractions, which required a reduction in the size of the integral regions (ROIs) below the aforementioned 5ω̄ 1/2 threshold which has been proposed for the qHNMR of primary reference standards.…”

Automatic Analysis of Quantitative NMR Data of Pharmaceutical Compound Libraries

“…Again, it is seen that the algorithm works well when using well-defined test samples. The triplicate values from both tables confirm what has already been reported, that NMR is accurate and precise. , …”

Mapping catalyst activation, turnover speciation and deactivation in Rh/PPh 3 -catalysed olefin hydroformylation

“…More detailed analysis using a D 1 of 35 seconds showed the existence of both linear and branched acyl isomers of Q (Figure S12). As can be seen from the 31 P{ 1 H} NMR profiles shown in Figure 8 a noticeable amount of triphenylphosphine oxide was also formed during the reaction, as also seen in all other experiments with this catalytic system (see below). Control reactions in thoroughly deoxygenated and sealed sample tubes showed this to be an intrinsic feature of the catalysis, and not due to traces of oxygen being present within or penetrating the flow system over time.…”

“…Interestingly, when only one equivalent PPh 3 was used in the reaction no Rh-H species were observed during catalysis, and the only catalyst intermediate detected by 31 P{ 1 H} FlowNMR was the mono-phosphine acyl complex Q (Fig. S8 †) identified previously.…”

“…When two or more equivalents of PPh Interestingly, when only one equivalent PPh 3 was used in the reaction no Rh-H species were observed during catalysis, and the only catalyst intermediate detected by 31 P{ 1 H} FlowNMR was the mono-phosphine acyl complex Q (Figure S8) identified previously. 28 When the syngas composition was changed from 1:1 to 3:1 H 2 /CO at the same total pressure in an experiment using six equivalents of PPh 3 the catalysis was ~30 % faster (Figure 6), reflecting the positive reaction order in H 2 which effects the turnover-limiting hydrogenolysis.…”

Integrated standardization concept for Angelica botanicals using quantitative NMR

“…Expressing the accuracy for each qHNMR method as the % deviation from the concentration by weight (=100%) resulted in 100.1 ± 5.7% for the IS method (precision 94.3%), 98.7 ± 5.8% for the ES method (precision 94.2%), and 103.8 ± 14.8% for relying on the CC method (precision 85.2%). Compared with previous qHNMR reports [31,42,43], the present study found lower achievable accuracy and precision. This was mainly attributed to the complex nature of the analyzed plant extracts and fractions, which required a reduction in the size of the integral regions (ROIs) below the aforementioned 5ω̄ 1/2 threshold which has been proposed for the qHNMR of primary reference standards.…”

Automatic Analysis of Quantitative NMR Data of Pharmaceutical Compound Libraries

“…Again, it is seen that the algorithm works well when using well-defined test samples. The triplicate values from both tables confirm what has already been reported, that NMR is accurate and precise. , …”

Mapping catalyst activation, turnover speciation and deactivation in Rh/PPh 3 -catalysed olefin hydroformylation

“…More detailed analysis using a D 1 of 35 seconds showed the existence of both linear and branched acyl isomers of Q (Figure S12). As can be seen from the 31 P{ 1 H} NMR profiles shown in Figure 8 a noticeable amount of triphenylphosphine oxide was also formed during the reaction, as also seen in all other experiments with this catalytic system (see below). Control reactions in thoroughly deoxygenated and sealed sample tubes showed this to be an intrinsic feature of the catalysis, and not due to traces of oxygen being present within or penetrating the flow system over time.…”

“…Interestingly, when only one equivalent PPh 3 was used in the reaction no Rh-H species were observed during catalysis, and the only catalyst intermediate detected by 31 P{ 1 H} FlowNMR was the mono-phosphine acyl complex Q (Fig. S8 †) identified previously.…”

“…When two or more equivalents of PPh Interestingly, when only one equivalent PPh 3 was used in the reaction no Rh-H species were observed during catalysis, and the only catalyst intermediate detected by 31 P{ 1 H} FlowNMR was the mono-phosphine acyl complex Q (Figure S8) identified previously. 28 When the syngas composition was changed from 1:1 to 3:1 H 2 /CO at the same total pressure in an experiment using six equivalents of PPh 3 the catalysis was ~30 % faster (Figure 6), reflecting the positive reaction order in H 2 which effects the turnover-limiting hydrogenolysis.…”