Peak doubling in the nuclear magnetic resonance spectra of certain phosphorus esters

Jardine, R. V.; Gray, Alfred; Reesor, J.B.

doi:10.1139/v69-004

Cited by 8 publications

(2 citation statements)

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“…Jardine and co-workers conducted a study on organophosphorus esters that had an alkoxy substituent and a benzene ring and discovered that the alkoxy groups were either located above or below the phosphorus atom, which has a nearly tetrahedral shape (Jardine et al, 1969;Mentz et al, 1996). This indicates that the alkoxy groups can be either close to or far from the benzene ring, depending on the rotation around the P-O-C linkage.…”

Section: Synthesized Compounds and Their Physical Characteristicsmentioning

confidence: 99%

Synthesis, characterization, antimicrobial activities and computational studies of some carbamoyl phosphonates

Doherty,

Olasunkanmi,

Ogunkunle

et al. 2024

ijs

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Four carbamoyl phosphonates, namely diethyl p-tolylsulphonyl carbamoyl phosphonate (NA), dimethyl p-tolylsulphonyl carbamoyl phosphonate (NC), dimethyl p-tolyl carbamoyl phosphonate (ND) and dimethyl p-tolylsulphonylmethane carbamoyl phosphonate (NE) were synthesized and characterized using FTIR, 1H- and 13C-NMR. The products were screened in vitro for their growth-inhibitory activity against nine Gram-positive strains, three Gram-negative bacteria strains, and a fungus isolate. Some compounds exhibited broad-spectrum (in vitro) activity against the bacterial strains, and all showed activity against the only fungus used. It was observed that NC showed the highest overall activity against the microorganisms. Density functional theory (DFT) calculations conducted at ωB97XD/def2-TZVP level of theory corroborated the structural conformations of the molecules deduced from spectroscopic analyses. Predicted reactivity indices of the compounds also correlate fairly with the observed biological activities.

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Section: Synthesized Compounds and Their Physical Characteristicsmentioning

confidence: 99%

Synthesis, characterization, antimicrobial activities and computational studies of some carbamoyl phosphonates

Doherty,

Olasunkanmi,

Ogunkunle

et al. 2024

ijs

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“…Soman [ 1 ] ( O ‐pinacolyl methylphosphonofluoridate, CAS [96‐64‐0]) is one of the internationally banned chemical warfare (CW) agents, [ 2 ] which has been extensively studied by several methods. First, 1 H‐NMR spectrum of soman was published already 1969, [ 3 ] and in later studies, 1 H, 13 C‐{ 1 H}, 19 F, and 31 P NMR spectra with rather thorough chemical shift assignment along with their spin–spin coupling constants in several solvents have been published. [ 4 ] However, some details in soman NMR spectra have remained elusive, for example, pinacolyl group trimethyl proton resonance line width/shape.…”

Section: Introductionmentioning

confidence: 99%

NMR spectroscopic discrimination of the enantiomer pairs of soman and bispinacolyl‐methylphosphonate and detailed analysis of the pinacolyl group ¹H NMR resonances

Haapaniemi

2023

Magnetic Reson in Chemistry

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If a 1 H NMR FID measured from oman is manipulated with Gaussian windowing before Fourier transformation, nine protons' signals of pinacolyl group can show some shape depending on the solvent and temperature. How could those signals shape and separate soman isomers as well as conformers information be combined, or could they fit somehow? Molecular modeling results together with accurate iterative spectral analysis were also extended to bispinacolylmethylphoshonate (BPMP), which have two pinacolyl groups. As far as we know, this is the first complete 1 H, 13 C, and 31 P NMR spectral analysis of BPMP.

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Evidence from fluorine and proton NMR spectra for restricted rotation about the PO bond in some steroidal phosphorofluoridates

Cooper

Chittenden

1974

Org. Magn. Reson.

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Abstract-The salient features of the l9F and lH NMR spectra of seven steroidal phosphorofluoridates are presented and evidence for restricted rotation, obtained from high temperature studies and deuteration experiments, is discussed.THE l9F NMR spectra of the steroidal phosphorofluoridates1 and phosphoramidofluoridatel shown in Table 1 fall into two categories. Compounds 1 to 4 show four signals for the fluorine nucleus whereas the others 5 to 7 give rise to two only. The four signals in 1 to 4 appear as a pair of doublets, the separation of each arm varying from 0.1 1 to 0.20 ppm (see 6 in Table 1). Typically, compound 4 has spectra displaying the following couplings to fluorine: (i) J(I,,F) 959 Hz; (ii) J(F,NMe2) 1.9 Hz (from IH spectrum).2 As a consequence of coupling between fluorine and the NMe,. protons the signals in the 19F spectrum are broadened slightly.On heating the phosphoramidofluoridate (4) in deuteriobenzene (or in DMSO-d,) from 23 "C to 82 "C the arms of each doublet in the ISF spectrum coalesce. The resulting singlets have the same chemical shift (relative to TFA) as the upfield arm of the room temperature doublet. Identical pairs of doublets are observed on cooling again.It seems most likely that two rotamers are present in compounds 1 to 4. To our knowledge this is the first reported example of restricted rotation in phosphorofluoridates which has been detected by I9F NMR. The chemical shift of the high temperature singlet coincides with one of the room temperature rotamers which suggests that on warming, one rotamer is converted to the other rather than formation of a third (new) rotamer. This explanation for the multiple fluorine signals implies that the proton bearing groups (OCH,, N(CH,),, OCH,CH,) may also be non-equivalent. Such nonequivalence has been discerned in the IH NMR spectra of the closely similar tertiary butylphosphonamidofluoridate,, several phosphine ~x i d e s ,~ phosphonate~~ and phosphonothioates.G However, no such proton non-equivalence is seen in the l H spectrum of 4 either at room temperature or in deuteriobenzene or DMSO-d6 at 8O"C, nor after addition of the chemical shift reagent Eu(fod),. If the assumption is made that effects which change the chemical shifts of fluorine signals produce proportionately the same change in the shifts of proton signals, such changes are more likely to be seen in the 19F spectrum than the IH spectrum owing to the greater frequency range (-150 ppm) over which resonance occurs for fluorine compared to that for protons (-10 ppm). Such an 'amplification factor' would enable the detection of smaller energy differences with fluorine than with proton nuclei.Examination of the l H N M R spectrum of N , Ndimethyl-2,2,4, 4-tetradeuterio-5a-cholestan-3/3-ylphosphoramidofluoridate (4-4) reveals a single coupling of 7 Hz between the 3u proton and phosphorus. If there are

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Peak doubling in the nuclear magnetic resonance spectra of certain phosphorus esters

Cited by 8 publications

References 1 publication

Synthesis, characterization, antimicrobial activities and computational studies of some carbamoyl phosphonates

Synthesis, characterization, antimicrobial activities and computational studies of some carbamoyl phosphonates

NMR spectroscopic discrimination of the enantiomer pairs of soman and bispinacolyl‐methylphosphonate and detailed analysis of the pinacolyl group ¹H NMR resonances

Evidence from fluorine and proton NMR spectra for restricted rotation about the PO bond in some steroidal phosphorofluoridates

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Peak doubling in the nuclear magnetic resonance spectra of certain phosphorus esters

Cited by 8 publications

References 1 publication

Synthesis, characterization, antimicrobial activities and computational studies of some carbamoyl phosphonates

Synthesis, characterization, antimicrobial activities and computational studies of some carbamoyl phosphonates

NMR spectroscopic discrimination of the enantiomer pairs of soman and bispinacolyl‐methylphosphonate and detailed analysis of the pinacolyl group 1H NMR resonances

Evidence from fluorine and proton NMR spectra for restricted rotation about the PO bond in some steroidal phosphorofluoridates

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NMR spectroscopic discrimination of the enantiomer pairs of soman and bispinacolyl‐methylphosphonate and detailed analysis of the pinacolyl group ¹H NMR resonances