31-p nmr spectroscopy

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By

MUHAMMAD AKRAM

PhD Chemistry

Worthy Teacher : Dr. UZMA YUNUS

(Associate Professor)

Allama Iqbal Open University Islamabad

Presentation Layout

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Introduction to 31P NMR Spectroscopy

Chemical Shifts , Coupling Constants

Coupling other Nuclei

Applications

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Phosporus-31 nuclear magnetic resonance is an analytical

technique used to identify phosphorus-containing compounds,

such as organic compounds and metal complexes.

Phosphorus -31 nuclear magnetic resonance (31P NMR)

conceptually same as (1H NMR).

31P is one of the most important nuclei for NMR spectroscopy

due to its nuclear spin of 1/2, high gyromagnetic ratio ( 17.235

M Hz T-1 ) and has100% natural isotopic abundance.

Introduction of 31P NMR Spectroscopy

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I Atomic Mass Atomic Number Nuclei

Half-integer Odd Odd 1 1H(½), 31

15P(½)

Half-integer Odd Even 136 C(½), 73

32Ge(9/2)

Integer Even Odd 147 N(1), 2

1 H(1)

Zero Even Even 12 6 C(0), 16

8 O(0), 3216S(0)

Table 1.1 A quick guide as to whether an isotope has zero, half-integer, or integer nuclear spin

Nuclei with I = 1/2 are called dipolar nuclei. They appear to be

spherical, with a uniform charge distribution over the entire surface.

Since the nucleus appears to be spherical, it disturbs a probing

electromagnetic field independent of direction. The result is a

strong, sharp NMR signal. 31P is a dipolar nucleus.

Nuclei with I > 1/2 are called quadrupolar nuclei. They have a non-

spherical charge distribution, and rise to non-spherical

electric and magnetic fields. They have a quadruple moment.


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Nucleus Natural

Abundance

[%]

Magnetic Moment

μ [μ N]

Magnetogyric Ratio

γ[107 rad T−1 s−1]

NMR frequency

MHz

Standard

1H 99.985 4.83724 26.7519 100.000000 TMS

13C 1.108 1.2166 6.7283 25.145004 TMS

15N 0.37 −0.4903 −2.712 10.136783 MeNO2,

[NO3

19F 100 4.5532 25.181 94.094003 CCl3F

9Si 4.70 −0.96174 −5.3188 19.867184 TMS

31P 100 1.9602 10.841 40.480737 85%

H3PO4

From Table, it can be seen that the magnetogyric ratio for phosphorus is

about 2.5 times smaller than that for hydrogen.

The required radiofrequency is therefore also about 2.5 times smaller than that of

the spectrometer. For a 400 MHz NMR spectrometer, that would calculate to

approximately 161 MHz


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Normally chemical shifts in 31P NMR is typically reported relative

to 85% phosphoric acid ( δ = 0 ppm) which is used as external

standard due its reactivity.

They are also sensitive to temperature (and pressure). Reference

standard for 31P-NMR spectroscopy is 85% H3 PO4(external),

meaning that a sealed ampule containing 85% aqueous

H3 PO4 submerged in a NMR tube filled with D2O is measured and

stored on the NMR spectrometer’s hard drive as a reference.

Standard in 31P NMR Spectroscopy

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200 150 100 50 0 -50 -100 RPH2

R2PH

R3P

R2PX

P(NR)3

P(OR)3

P(SR)3

PX3

P(OR)2X

CPX2

CPXN

O=PX3

O=P(OR)X2

O=P(OR)2X

O=P(OR)3

S=P(OR)3

O=P(R)(OR)

S=P(R))(OR)

O=P(R)(OH)

(RO)2POH

200 150 100 50 0 -50 -100 ( δ ppm)

.Chemical shift range of different type of phosphorus compounds

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The range of 31P chemical shifts in diamagnetic compounds covers some

2000 ppm, and is thus one order of magnitude larger than that of carbon, and two

orders of magnitude larger than proton.

The upfield end in 31P –NMR is due to white phosphorus P4 at δP= −527 to −488

ppm, depending on solvent and water content of the sample.

Chemical shift values of Phosphorus resonance also dependence upon the bond

angle, electronegativity of the substituent's and the p-bonding character of the

substituent's .

From 13C-NMR, we know that an olefin resonates downfield from an alkane,

and an acetylene is found in between, but closer to the alkane. This is explained

by diamagnetic anisotropy and the behavior of P-C, P=C, and P≡C bonds also

same.

Chemical Shift Values in 31P NMR Spectroscopy

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Tertiary phosphanes (PMe3 , PEt3, PPrn3 , PBun

3, and PBut3 ) showing the continuous

downfield shift as the length of the alkyl chain increases.

The last phosphane in the series, PBut3 , should show an additional contribution for steric

effect. The actual chemical shift values are δP = −62 ppm, δP = −20 ppm, δP = −33 ppm,

δP =−33 ppm, and δP =63ppm, meaning that from going to methyl to n-propyl, the chemical

shift difference is Δδ= −13 ppm upfield, and not downfield as expected.

Chemical shift difference between n-propyl and n-butyl (Δδ = 0 ppm), PBut3,is

Δδ =83ppm downfield from PEt3 , and thus in the expected region, if one takes the

observed chemical shift difference between PMe3 and PEt3 (Δδ = 42 ppm downfield) as

representative

Dependence of 31P-NMR chemical shifts on the number of hydrogen substituent's

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At the upfield end, white phosphorus P4 resonates at δP = −488 ppm. This is readily

explained by an electron rich cluster structure with P-P-P angles of 60°.

Coordination to a transition metal causes a reduction in electron density on phosphorus, as

a P4 lone pair is used to create a donor bond.

Coordinating the phosphane PMe3 to a transition metal again results in the expected

downfield shift of Δδ = 107 ppm, since the phosphorus lone pair is utilized for the donor

bond, resulting in a decrease of electron density on phosphorus.

Similarly, substitution of a phosphorus atom by an isolobal transition metal fragment

causes a downfield shift, as electron density is transferred from the electron rich

phosphorus atoms to the “poorer” transition metal. In general, negative coordination

shifts are possible.

The 31P chemical shift range for phosphorus

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However, when we form covalent bonds between phosphorus and the metal, the picture

changes. Looking at [Cp2 Hf(PCy2 )2 ], we see two different phosphorus resonances at

δP = 270.2 ppm and d P = −15.3 ppm, respectively.

We note that the two phosphorus atoms are trigonalplanar and tetrahedrally coordinated,

and suspect that they are part of a P = Hf double and a P-Hf single bond, respectively.

The two 31P-NMR signals in [Cp2 Hf(PCy2 )2 ]

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31P-NMR chemical shift values for phosphorus carbon multiple bonds

Normally five membered heteroaromatic ring systems ( i.e. pyrrole ) are electron rich, and the corresponding

six membered (pyridine) ones are electron poor. The 1,3,5-triphosphabenzene resonates at δP = 232.6 ppm,

considerably downfield from the benzazaphosphole at d P = 69.8 ppm, as expected.

Interestingly, the 3,4 diphosphinidene-cyclobutene, featuring a conjugated, non-aromatic π-electron system with

resonance structures, has a P chemical shift of δP = 147.0 ppm midway between the two. The analog to

1,3,5-triphosphabenzene is stable, and shows P resonances at δP = 93.6 and 336.8 ppm.

These 31P chemical shifts are evidence for the folded roof-like structure of the compound, featuring a

tertiary phosphane phosphorus atom at δP = 93.6 ppm, and an isolated P=C at δP = 336.8ppm, respectively.

In 13C-NMR, chemical shift of benzene at δP = 128 ppm with that of the cyclopentadienide ligand Cp− at

δP = 118–136 ppm, depending on the cationic metal that it binds to. In 31P-NMR, 1,3,5-triphosphabenzene with a P

resonate at δP = 232.6 ppm, and 1,3,6 triphosphafulvenide anion, the relevant P atoms resonating at δP = 216, 223 ppm.

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The influence of coordination to a Lewis acid on the 31P chemical shift

Two phosphanes for comparison, PMe3 and PPh3, and note that the downfield shift for PPh3

upon coordination ranges from Δδ = 21–40 ppm, and that for PMe3 is in an even narrower

band of Δδ = 46–60 ppm.

In each case, the actual downfield shift depends on the Lewis base. Factors are the geometry

around the metal (cis or trans), and the substituent's on phosphorus (P+ or PPh2 + ).

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Phosphorus PCl3 PCl2F PClF2 PF3

Trihalides

δ P [ppm] 220 224 176 97

Phosphorus PI3 PBr3 PCl3 PF3 P(CN)3

Trihalides

δ P [ppm] 178 227 218 97 −136

O = PBr3 O = PCl3 O = PF3

δ P [ppm] −102.9 2 −35.5

The 31P chemical shift values for selected phosphorus trihalides

The explanation is a π-bonding interaction

(hyper conjugation) between the fluorine lone

pair and phosphorus, resulting in an increase of

electron density on phosphorus, and thus an

upfield shift in the phosphorus resonance.

Substituent's capable of π-bonding interactions

cause additional shifts: upfield for a donor

interaction, and downfield for an acceptor

interaction.

The influence of the halogen on the phosphorus resonance of the phosphorus trihalide

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Generally larger in magnitude than those in 1 H- or 13C-NMR spectroscopy, but they are

governed by the same principles. 1 J coupling constants of 1000 Hz are readily observed.

Coupling is facilitated through the s-bonds of the backbone. There is no pronounced

π-effect as the one observed for the chemical shift values, but there are examples for

which a limited π-effect is indeed observed.

As with the more common nuclei, 1 H and 13C, the phosphorus coupling constants

decrease with an increase of bonds between the coupling nuclei.

However, it is frequently observed that 3 JPX coupling constants are larger than 2 JPX

coupling constants. In the following we will examine the trends in the coupling

constants of phosphorus with the more common nuclei 1 H, 13C, and 31P.

The coupling constants in 31P-NMR spectroscopy

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As with other nuclei, n JPH coupling constants have a tendency to decrease when the value of n increases.

Although 1 JPH values are frequently in the range of 400–1000 Hz, the coupling constants drop rapidly

and are detectable for 4 JPH only in special circumstances.

JPH Coupling Constants value for 1 JPH increases with decreasing electron density on phosphorus. In the

series PH4 + , PH3 , and PH2 − , the 1 JPH coupling constants are 547 Hz, 189 Hz, and 139 Hz, respectively.

It appears that the influence of electron lone pairs on the 1 JPH coupling constant becomes smaller with

each lone pair. Δ 1 JPH for PH4 + /PH3 is 358 Hz, whereas for PH3 /PH2 − Δ, 1 JPH is only 50 Hz.

When the phosphorus binds to a σ-acceptor, such as a transition metal or a main group Lewis acid. As a

result, the electron density on P drops sharply and the 1 JPH coupling constant increases accordingly.

A good example is with PH3 , which has a 1 JPH =189 Hz as a free ligand, but a significantly larger one in

its complexes: 307 Hz in [Cr(CO)4 (PBu3 )(PH3 )], and 366 Hz in Me3 BPH3 , respectively.

Note: PF2 H (1 JPH = 181.7 Hz) has a smaller 1 JPH coupling constant than PH3 (1 JPH = 189 Hz) despite the

greater electronegativity of fluorine compared to hydrogen. The reason, of course is π-back-bonding

(hyperconjugation) observed in P-F, but not in P-H bonds, decreasing the effective electronegativity of F

towards P .

Similarily, the 1 JPH coupling constant increases with an increasing sum of the electronegativities of the

substituent's on phosphorus.: H < alkyl < aryl < OR < OPh. Note: The 1 JPH coupling constant increases

with decreasing steric bulk of the substituent's on phosphorus

Phosphorus coupling to Hydrogen

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In 2 JPH (H-A1-P) and 3 JPH ( H-A1-A1-P) commonly feature is a minimum of

the coupling constant around Θ = 90° with maxima at Θ = 0° and Θ = 180°,

respectively. Typically, the maximum at Θ = 180° is larger than at Θ = 0°.

The relationship between the magnitudes of 2 JPH (gem) and 3 JPH (cis and trans)

coupling constants is similar to that observed in JHH coupling constants.3 JPH (trans) is frequently larger than 3 JPH (cis), but 2 JPH (gem) can be larger than

3 JPH (trans).

The electron density on phosphorus has a pronounced effect on 2 JPH (gem) and3 JPH (cis). Coordination to a transition metal markedly increases both, whereas

electronegative substituent's on phosphorus effect only 3 JPH (cis) in a variable

manner.

The effect on 3 JPH (trans) is small, but nonetheless significant. The coupling

constants for 3 JPH (trans) are typically 10–30 Hz, 2 JPH (gem) up to 25 Hz, and3 JPH (cis) up to 15 Hz. Without electronegative substituent's on phosphorus, the

values for 2 JPH (gem) and 3 JPH (cis) remain well under 10 Hz.


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2,6,7-trioxa-1,4-

dicyclo[2.2.2.]OctanePhosphorus shifts at 90.0 ppm for Pά

and -67.0 ppm for Pβ


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(PhCH2 ) 2 PPh PhCH2 (Ph)2 P Ph3 P Ph4 P+ Ph3 P = O

1 JPC [Hz] 20.6 16.2 −12.5 88.4 104.4

2JPC [Hz] 19.8 18.9 19.6 10.9 9.8

3 JPC [Hz] 7.0 6.4 6.8 12.8 12.1

4JPC [Hz] 0.6 0.2 0.3 2.9 2.8

Coupling to Carbon

The coupling of phosphorus to carbon follows the general trends observed with other

nuclei. The magnitude of n J PC is dependent on the oxidation state and the

coordination number of phosphorus .The electronegativity of substituent's on

phosphorus also plays an important role.

The magnitude of 1JPC increases dramatically upon loss of the lone pair on phosphorus.3JPC becomes larger than 2 JPC upon loss of the lone pair on phosphorus. For methyl

phosphorus derivatives, the 1JPC coupling constant for compounds with phosphorus in the

oxidation state +III is generally found to be small or even negative, whereas the

corresponding 1 JPC coupling constant for phosphorus compounds where the phosphorus is in

the oxidation state +V is usually substantially larger and positive.

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Coordinated

1JPC

2 JPC

3 JPC 2 JPC

1JPC

3 JPC

n JPC

Free ligand

Influence of coordination on n JPC

Upon coordination to transition metals, the nJPC coupling constants in trialkyl phosphanes are

influenced differently. The 1JPC coupling constant increases substantially, the 2JPC coupling

constant decreases substantially, and the 3JPC coupling constant increases slightly. A typical

example is shown in Fig.

Coupling to Carbon

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Coupling to Hydrogen and Carbon

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Coupling to Phosphorus

JPP in organ phosphorus compounds cover a wide range of values , where as P2 Me41JPP = −180 Hz, this value drops to

1 JPP = −290 Hz for ButMePPMeBut , 1 JPP = −318 Hz for Me2 PPBut2 , and as low as 1 JPP = −451 Hz for P2But4 .

The corresponding doubly oxidized derivatives R2 (E)PP(E)R2 (E = O, S, Se) follow the same trend, but they can be

found to the left (larger coupling constants) from the non-oxidized analogues. P2 Me4 S2 has a coupling constant of1 JPP = −19 Hz, and {P(S) MeBut}2 a coupling constant of 1 JPP = −109 Hz.

• Finally, the monoxidized diphosphanes R2 (E)PPR2 (E = O, S, Se) have similar 1 JPP coupling constants to the

diphosphanes, indicating that one PALP is sufficient for the magnitude of the 1 JPP coupling constant. Note: Steric

crowding results in a decrease of the 1 JPP coupling constant in diphosphanes. Note: Lower electron density results in

an increase of 1 JPP constants in diphosphanes.

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The energy supply in cells is provided by molecules that contain phosphorus. Especially PCr

(Phosphocreatine) and ATP (Adenosine-Tri-Phosphate) carry the energy needed for most

processes in the brain and other organs. Magnetic Resonance Spectroscopy has the potential

to quantitatively detect these substances in living subjects noninvasively.

Spectra of some Phosphorus compounds

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Spectra of some Phosphorus compounds

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Pt Coupling to Phosphorus

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NMR Spectra of some other Nuclei having Phosphorus

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Applications: Monitoring the Reaction

Single signal at -4.40 ppm

corresponding to free

diphosphine ligand. After an

hour a new signal appear at

40.05 ppm , corresponding

to diphosphine nickel

complex. The downfield

peak grows as the reaction

proceeds relative to the up

field peak. No change is

observed between four and

five hours, suggesting the

conclusion of the reaction.

-4.40 ppm

40.05 ppm

Coskran J.K.; Verkade G.j. Inorganic. Chem. 1965, 4,1665.

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Applications: Determine the Epoxide content of carbon nonmaterial's

An Epoxide react with methyltrioxorhenium

to form a five membered ring. In the presence

of triphenyl phosphine (PPh3) , the catalyst is

regenerated, forming an alkene and triphenyl

phosphine oxide (OPPh3) the same reaction

can be applied to carbon nanostructures and

used to quantify the amount of Epoxide on

the nonmaterial's.

31 P spectrum of experiment before addition of Re complex (top)

and at the completion of experiment (bottom).

The integration of the two 31P signals is

used to quantify the amount of Epoxide

on the nanotube according to equation.

Verkade, G.J.; Quin D.L. Phosphorus -31-NMR Spectroscopy in seterochemical analysis. 1987.

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Applications

31P NMR spectra of the reaction products catalysed

by PhnI, PhnM and PhnJ. a, RPnTP from the reaction

of methylphosphonate and MgATP catalysed by PhnI

in the presence of PhnG, PhnH, and PhnL at pH 8.5.

The methylphosphonyl group is labelled as 1-Pn.

Inset, 31P–31P coupling of the triphosphate portion of

the RPnTP product (the ά, β and γ phosphoryl

groups).

b, The formation of PRPn from RPnTP in the

presence of PhnM. Inset, protoncoupled spectrum at

pH 8.5 showing the multiplet that corresponds to 1-Pn

and the triplet that corresponds to the 5-phosphate

(5P). Pi , inorganic phosphate.

c, The formation of PRcP from PRPn in the presence

of PhnJ at pH 6.8. Inset, proton-coupled spectrum

showing the formation of a new triplet that

corresponds to the 1,2-cyclic moiety of PRcP (1,2-

cP). The chemical shifts for the phosphate moiety at

the fifth carbon atom of PRcP and PRPn are

coincident with one another (3.4 ppm).

Reaction pathway for

the conversion of

methylphosphonate to

PRcP. The proteins

PhnG, PhnH, PhnI,

PhnJ, PhnL and PhnM

are required for this

transformation. The

role of PhnK is

unknown. PhnGHL

denotes PhnG, PhnH

and PhnL.

Siddhesh S. K.; , Howard J.; Frank M. R.; Intermediates in the transformation of phosphonates to phosphate by bacteria. Nature. 2011 , 480, 570- 573.

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1D 31P NMR spectra of NaOH/EDTA

extracts of soil-1, which is naturally high in

Fe. Spectra without (bold line) and with (thin

line) sulfide treatment are compared.

The region displayed corresponds to

phosphomonoesters and inorganic phosphate

(6.5 ppm). Spectra are scaled for easy

comparison.

Applications

Organic phosphorus (P)

compounds represent a major

component of soil P in many soils

and are key sources of P for

microbes and plants.

Solution NMR (nuclear magnetic

resonance spectroscopy) is a

powerful technique for

characterizing organic P species.

Overlap is often exacerbated by

the presence of paramagnetic

metal ions, even if they are in

complexes with EDTA following

NaOH/EDTA extraction

Johan V.; Andrea G. V. High-Resolution Characterization of Organic Phosphorus in Soil Extracts Using 2D 1 H−31P NMR Correlation Spectroscopy. Environ. Sci. Technol.

2012, 46, 3950−3956

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Applications

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Possible binding modes for 1·Zn2222 with PPi and ATP suggested by31P NMR data.

Fig. 31P NMR spectra (202 MHz) of ATP (10 mM) in the absence and presence of receptor 1·Zn2222 in D2O at 300

K. (a) [1·Zn2222] = 0. (b) [1·Zn2222] = 0.5 equiv. (c) [1·Zn2222] = 1 equiv. (d) [1·Zn2222] = 2 equiv.

Applications

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Enlarged portions of in vivo

proton-decoupled 31P-NMR

spectra of sycamore cells. (A)

Cells harvested after a 2-wk

preincubation in Mg2+ -free NM

and perfused with Mg2+-free

NM. Acquisition time, 4 h

(24,000 scans). The spectrum is

the sum of four successive

comparable 1-h spectra. Peak 1

was attributed to the γ-signal of

mitochondrial ATP, and the

broad peak 2 was attributed to

the β-signal of ADP pools

present in mitochondria and

cytosol.

(B) Spectrum accumulated 1 h after the addition of 1 mM MgSO4 to NM. Perfusion

conditions are as with standard NM. Acquisition time, 1 h (6,000 scans). Horizontal arrows

indicate the downfield shift (toward the left of the spectra) of the different ATP resonance

peaks after the addition of MgSO4 to NM. (Insets) Centered on γ-ATP at −6.2 ppm, portions

of PCA extract spectra prepared from cells incubated outside the magnet under the same

conditions. Acquisition time, 1 h (1,024 scans)

Elisabeth G.; Fabrice R.; Roland D.; Richard B. Interplay of Mg2+, ADP, and ATP in the cytosol and mitochondria: Unravelling the role of Mg2+ in cell respiration 19, 2014.

Applications

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Applications

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Applications

A normal spectra of a forearm human muscle

displaying 6 pics and their variation during a rest -

exercise -recovery protocol. The major peaks of the

Phosphorus-MR spectrum are: phosphocreatine

(PCr), inorganic phosphates (Pi), phosphodiesters

(PDE), and the three peaks (α, β, γ) of ATP. The

chemical shift (in parts per million [ppm]) of the Pi

is used for calculation of intracellular, cytosolic pH.

Note the decrease of PCr concentration and the

increase of Pi concentration during exercise.

Mattei J.P.; Bendahan D .; Cozzone P. P-31 Magnetic Resonance Spectroscopy. A tool for diagnostic purposes and pathophysiological insights in muscle diseases. Reumatismo, 2004; 56(1):9-14

Mitochondrial Disorders.

Genetic and biochemical

heterogeneity. A majority of

these diseases include

neurological symptoms

besides.

Glycolytic Defects. painful

cramps, contractures, and with

progressive weakness.

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A) Fully relaxed 31P spectrum without

ST preparation (tsat = 0 s) (left) and 31P-

ST Spectrum with complete saturation

(arrow) of the γ-ATP resonance (tsat =

6.84 s) (right). B) Series of ST spectra at

different tsat. C) PCr signal intensity

fitted to Eq.2, (Pearson's product

moment correlation = 0.9992).

In order to estimate the pseudo first-order forward rate constant (kf) of the CK reaction, we

need to measure the phosphocreatine (PCr) signal while we saturate the γ-adenosine

triphosphate (γ-ATP) resonance for different durations (i.e. the progressive ST experiment)

Assuming a two-pool exchange system between PCr and γ-ATP and complete saturation of γ-

ATP, we can estimate the exchange rate between the two metabolites by solving the modified,

for chemical exchange, Bloch equation . To confirm the efficiency of our saturation pulses,

we acquired unlocalized 31P spectra in the entire volume of the lower leg muscles in all of our

volunteers.

Prodromos P. ; Ding X.; Gregory C.; Ravinder R. Three-dimensional Saturation Transfer31P-MRI in Muscles of the Lower Leg at 3.0 T Scientific Reports. 2014

ApplicationsApplications

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Static 31P spectra of DMPC (a–c) and VM (d–i)

membranes in the absence and presence of M2 at

303 K. (a, d, and g) Protein-free lipid bilayers. (b,

e, and h) M2TM-containing membranes. (c, f, and

i) M2(21–61)-containing membranes. The DMPC

spectra (a–c) and the VM spectra (d–f) were

measured on samples with Amt, whereas the VM

spectra (g, h, and i) were measured on samples

without Amt.

Applications

NMR Determination of Protein

Partitioning into Membrane

Domains with Different Curvatures

and Application to the Influenza

M2 Peptide. Many membrane

peptides and proteins cause

curvature to the phospholipid

bilayer as their mechanism of

action. Examples include viral

fusion proteins

The M2 protein of the influenza A.

Transmembrane (TM)

1,2-dimyristoyl-sn-glycero-3-phosphocholine bilayers.

(DMPC)

Tuo W.; Sarah D. C.; Mei H.NMR Determination of Protein Partitioning into Membrane Domains with Different Curvatures and

Application to the Influenza M2 Peptide. Biophysical Journal. 2012, 102(4) ,787–794

40

Applications

Single-voxel 1 H MRS and 31P MRSI

overlaid on MRI acquired from the second

patient during neoadjuvant chemotherapy. Not

only can the conventionally obtained

modulation in total choline (tCho) (spectra,

left) and tumor volume (indicated by the dotted

area) be observed, but also alterations in the

levels of phosphoethanolamine (PE), glycerol

phosphocholine (GPC), glycerol

phosphoethanolamine (GPE) and inorganic

phosphate (Pi) (spectra, right). Prior to

treatment, 31P resonances of PE, GPC, GPE and Pi were

restricted to the tumor area, whereas, after the

first dose of chemotherapy, mainly levels of Pi

remained detectable. As can be seen, these Pi

levels were not restricted to the tumor region,

but were similarly elevated in glandular tissue.

At the end of the last dose of chemotherapy, but

prior to surgery, the recurrence of phospholipid

levels was detected in the tumor.

Dennis W. J. K.; Bart B.D. 31P MRSI and 1 H MRS at 7 T: initial results in human breast cancer. NMR Biomed. 2011; 24: 1337–1342.

31-p nmr spectroscopy

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