Lanthanide-induced contact shifts in polyglycoldimethylethers

Tot-on

%-on

Lutterm Ho. 51, pp 4865 - 4866, 1971. LANTHANIDE-INDUCED

CONTACT

A.

M.

SHIFTS

PAltadin~twl~

Prora.

IN POLYGLYCOLDIMETHYLETHERS

and J. Smid* State University of New

Grotans

Chemistry Department.

College of Forestry Syracuse, New York 13210

York

USA

and

Department

E. de Boer Physical Chemistry, University Nymegen, The Netherlands

of

naoired in W

(Reoeiredin USA 12 Ootober 1971, Complexation

of polyglycoldlmethylethers

CH3(CH2CH20),CH3

with

sodium

is known

of

glyme

the

to result

protons

interpreted

in

for

protons,

the

certain

CH2

aromatic

in strong The

(1,2).

terms

of

a Fermi

each

(glymes)

downfield

ion

nuclear

the

general

such

as

magnetic

to

mechanism,

representing

of

salts

amounting

contact

peak

for publication16 November1971)

radical

shifts,

of Nymegen,

coronene

resonance

as much

produce

as 12

ppm

a first

a combination

of

formula

two

shifts and

order

spectrum

or more

CH2

groups. The in

the

large

presence

methanato) these

lanthanide

n ranging

number

and

of

nmr

shifts

and

reagents

quantities

nmr

experiments

the

the

glyme

added

molar

ratio

many

such

induced

us

(some

of

them

a Varian

of

lanthanide

look

partially of

A60A

compounds

tris(dipivaloat mixtures

glymes.

M solution

on

organic

as

to

polyfunctional

to a 0.15

recorded

for

complexes

(3-9)

with of

spectra

reported

lanthanide

-praseodymium

1 to 6 were

the

recently

paramagnetic

shift

small from

in CC14,

In

the

actual

deuterated)

a lanthanide

was

with

complex

spectrometer.

to glyme

of

In a

varied

from

to 4.0 The

the

of

europium

experiments,

0.2

proton

two

spectra terminal

absorptions rapid

of

each

exchange

concentration

CH3

the

groups,

glyme-Eu and

representing

spectrum, of

1:l

the

1:l

and

further

two plots

adduct

adducts

to

CH2

reveal

downfield

groups.

of

the

that

total

* Author

to whom

correspondence

should

be

4863

a series

Addition

proton

of

a sharp

addressed

shifts glyme

peak

of well

of more versus are

representing resolved

glyme the

linear

yields

ratio and

of

passing

a the

No. 51

4w

through of

the

the

glyme

It is number

For

singlet. four

that

the

glyme

four

well

resolved

Apparently,

the

far

from

removed

two

the

spectrum

refers

to

two

with

the

of

1:l

a glyme

number

glyme

and

groups

center

the

mixture

essentially

the

atoms

the

all

one

molecule.

Using

the

glyme)

of

two

CH2

peaks

6/Eu(dpm)3

nmr

(the

in

CH2...CH2

in addition

representing

of

of

a glyme

a singlet,

mixture

a combination

4 one

while

5/Eu(dpm)3

of oxygen

representing

triplets,

triplets CH2

M of

the

each

mixture

3 shows

at 0.15

Eu(dpm)3.

triplets,

a similar

Glyme

that

to the

interesting

exhibits

groups.

implying

is bound

following

clearly

of

origin,

is

spectrum

to

the

CH3

absorption

are

glyme

an

4 as

a

consists

group.

equally example:

CH30CH2CH20CH2CB20CH2CH20CH3

(3)(2) the

C 1 protons

and

C(3)

yield

will

give Glymes

protons.

only The

These

compounds

since

the

CH2

with

deuterated

glyme

4

obtained

with

observation

CH3

two

the

C(2)

for

glyme

the

CH3,

(C3)

and

interesting

(20

cps

of

are

expected

oxygen

chemical

praseodymium

3.2

protons 5, with C(1)

and

terminal

prepared

the

for and the

the

atoms

1.7

are

of

(dpm)3

the are

shift

for

the

(glyme

C(2)

3 or

5)

for

also

C(2 ) protons, groups.

Pr/Eu and

the

Pr/Eu

protons.

These

1.9 data

a triplet

chemical for

to a

shifts

the

were

asymmetrically

Pr). I, all

in pure The

the

ratio

ratios

and

1.7

suggest

being for

Results

For

protons. is

are

3.0

for

the

only

1.9

for

behavior

is observed

2.9,

and

the

that

being

striking

glyme

A similar ratios

values

glyme.

most

various shift

However,

shift

assignments:

5 absorptions,

from

a doublet

included.

the

only

the

in Table

for

peak

glyme

changed

protons

ratio

C(3)

4 and

on

with

glyme

protons.

the

in

further

CH30~H2~~20~~2~~20~H2CH20CH3.

are

listed

4 complexes

respective

CH2 (C4)

up

for

glyme

effects

separation

shifts

C(1)

all group

splitting

Pr/Eu

and

assign

shifts

lanthanide-glyme

and

were

isotope

peak

chemical

concerns

I:1

group

number

to a CD2

absorption

respective the

to

adjacent

some CH3

to

glymes

sufficient

protons

the

relative

the

odd

triplets

(CH30CH2C~20~H2CH2)20

were

Also,

The

an

deuterated

(CH30CH2~~20~~2~~2)20,

found,

with

(2)(3)

while

triplets.

following

singlet.

(l)(l)

a singlet,

it

3.0

penultimate is not

2.9

for

CU2

always

No. 51

4065 Table

Proton

NMR

Shifts

at

40°C,

measured

with

ccl4

of

Glyme

relative

4 and

to

respect

to

the

Chemical

5 Adducts

of

Shifts

of

Non

of

Paramagnetic

Concentration

TMS).

Mixture

Glyme

I

CH3

C(1)

Eu(dpm)3

and

Complexed

Pr(dpm)3

Glyme

Complex:0.15

-567

-521

1253

-1215

Eu/G4

= 1:l

-253

-385

-617

-562

Eu/G4

= 1:2

-124

-212

-318

-282

Pr/G4

= 1:0.2

1541

2120

2065

2011

Pi-/G4 = 1:l

763

1251

1200

977

P-r/G4 = 1:2

373

635

599

497

-465

Eu/G5

= 1:l

-208

-256

-335

-519

Pr/G5

= I:1

604

767

965

965

another

convert

proton

lanthanide

complex

Our

tentative

conclusion

the

outer

oxygen

two

connecting This in

these

apparently

addition

for

the

The

combined

CH3 to

Eu

or

Pr

protons the

the

same

is

found

of

the

in

as

in

or

they

Pr

close

for

the

simultaneous

compound

found

for

in 1,2

shift

ratios

and

those

meta

about

l/5

derivative of

that

is of

concentration

two

the

paramagnetic

shift of

on

shift

found

these

for

of

two

these

the

ortho

dimethoxyethane,

compound.

Also,

ion. protons,

are

downfield

the

Pr

complex.

protons.

glyme

oxygen

meta-dimethoxybenzene. with

Eu(dpm)3

while

the

and, 1,2

at

0.15

M,

to

CH 2 groups

for

mixture

dependent

(8,9).

the

CH

shifted

shift

amounts

dimethoxyethane

atoms The

are 3

the

for

predominantly

direction

binding

ortho

a 1:l

to

809

factor

chelated

kinds

opposite

low

of

is

into

ratio

contact

Both

the

behavior

shift

bringing

Fermi

in

complex

proximity

shift. are

one

ion

chain,

to

the

ortho

Eu

glyme

dipolar

but

evidence

the

for

a constant

a considerable

expected

lead

the

atoms

in

adduct,

extent

of

obtained

applying

that

oxygen

effects

Supporting to

atoms

two

Eu-glyme

by is

results

to

shifts

M. C(4)

= 1:0.2

to

(both

C(3)

C(2)

Eu/G4

justified

in

for to

only

is much

4866

No. 51

stronger

bound

than

to Eu(dpm)3

ethers

with

one

oxygen

atom,

including

tetrahydrofuran. The CH2

nmr

groups

a rapid

patterns

equally

on

opposite

between

complexed

exceeds

unity,

work

to

their

compare

(GM

gratefully

of

ends

of

15965)

by

of

and/or when

of

found

this

the

glyme

reagent

shifts

the

glyme

between

the

research

by

are

radical

the

-OCH2CH

(See

O-

observed

Table

I).

in progress

National (GP

2

ratio (not

anion

Foundation

suggest

exchange

glyme

protons

systems the

Science

to

of

molecule)

lanthanide/glyme

binds

for

National

identical

the

chelating

that

the

an intermolecular

complex shift

of

the

center

Also,

interesting with

(e.g.,

lanthanide

chain

further

support

and

the

paramagnetic

these

- The

the

the

molecules.

behavior

Acknowledgment.

adducts

exchange

an even on

glyme from

a second

Additional

the

removed

glyme

causing

DME),

Health

far

intramolecular

moieties

for

of

in order

shift

reagents.

Institutes 26350)

of

is

acknowledged.

REFERENCES

1.

E.

de Boer,

A.

M.

Grotens

and

.I. Smid,

.I. Amer.

A. M.

Grotens

and

3.

Chem.

Chem.

Sot.,

92,

4742

(1970). 2.

E.

de Boer,

3.

c. c. Hinckley,

M. R.

Klotz

and

Smid,

F. Patil,

Comm.,

1035

3. Amer.

(1970).

Chem.

Sot.,

2,

2417

M.

Staniforth,

(1971). 4.

J. Briggs, 9749

Comm., 5:

P.

G. H.

sot.,

Q,

6.

.I. K. M.

7.

P.

F. A.

Hart,

G. P. Moss

and

L.

Chem.

(1970).

Demarco,

v.

Frost,

T. K.

5737

R.

B. Lewis

and

E. Wenkert,

J. Amer.

Chem.

(1970).

Sanders

Belanger,

Elzey,

and

D.

H. Williams,

C. Freppel,

D.

Tizane

J. Amer. and

J.

Chem.

Sot.,

C. Richer,

93,

Chem.

641

Comm.,

(1971). 266

(1971). 8.

C. Beaute,

9.

D.

R.

4419

Grump, (19 JO).

2. M. Wolkowski J. K. M.

and

Sanders

N. and

Thoai,

Tetrahedron

D. H. Williams,

Letters, Tetrahedron

817

(1971).

Letters,