Preparation of a heterodifunctional ligand possessing both phosphine and cyclopentadienide functionality

Journal of OrganometaUic Chemistry, 184 (1980) C44-c48 0 33lsevierSequoia SA., Lausann e--printed in The Netheriands

Preliminary Comnunication PREPARATION OF A HETERODIFUNCTIONAL LIGAND POSSESSING BOTH PHOSPHINE AND CYCLOPENTADIENIDE FUNCTIONALITY Neil E. Schore* and Savithri Sundar Department of Chemistry, University of California, California 95616 (U.S.A.) (Received

September

5th)

Davis,

1979)

Sumnary

The difunctional ligand (C6H5),PCH,CH,Si(CH,)z@ 0

prepared

in three

steps

via

vinyldimethylchlorosilane.

taining

pairs

followed Ligand

and deprotonation.

photolytic

of different

addition

transition

(1)

is

readily

of diphenylphosphine

by reaction

1 is of value

Li*

with

lithium

to

cyclopentadienide

in the construction

of molecules

con-

metals indirectly linked but not metal-

metal bonded.

Several resulting

recent

from the

organic

fragments

equivalent

have revealed

interaction (1) _

intriguing

of more than

The construction

and unusual

one metal

center

of difunctional

chemistry

with

ligands

reactive having

non-

sites for metal complexation provides an entry into systems that

may be useful physical

reports

for

modeling

and chemical

We here

report

such chemistry

interactions

and,

in general,

of non-bonded

the convenient

preparation

but proximal

salt

possessing

a free,

metal

the centers.

of [dimethyl-

(2-diphenylphosphinoethyl)silyl]cyclopentadienyllithium, cyclopentadienide

studying

remote

(c6H5)EPCH2CH2Si (CH3)B@

l_, an isolable phosphine,

and well-suited

Li+

1 for

use in the

metal 1igand

centers

preparation (2).

of dinuclear

In earlier

work

coinpounds containing

(3)

we carried

out the

indirectly synthesis

linked of the

related

~dimethyl(diphen~lphosphinoRlethyl)silyl]cyc~opentadienyllithium..(C6H6)~-

PCH$i (CH~)~CSH~L~

.+

and demonstrated

its

capabilities

as a difunctional

ligand

c45

for

selective

Fe(I1) the

attachment

and Zr(IV)

latter,

to two different

and phosphine-linked

however,

requires

the

phosphinomethyllithium-TMEDA dry box,

and the

removal

scale

impurities

A benzene (20% excess)

resultant ether,

prepared

solvent

and

white, cooled

solvent,

is obtained lithium

the

by removal Treatment deposit

neutral

petroleum

The synthesis

stages

best

carried

out

The syn-

in the synthesis. and is well

suited

and chlorodimethylvinylsilane

in a stoppered

silane

lamp)

are

is

is

carried

removed

treated

supernatant

quartz

under

with

tube_

out vacuum

a little

collected.

at

(5).

dry

After

25°C

for

The

petroleum

removal

of

chlorosilane

solution

1 which

completely

which with

with

one equivalent

under nitrogen

cyclopentadienylsilane trituration

with

is

petroleum

butyllithium

solidifies

after

2, of

instantaneously

separated

from LiCl

ether,

and filtration.

gives

rise

trituration

to a gumny with

SCHEME I

CH2=CHSi(CH3)2C1

hu

@

(C6H5)2PCH2CH2Si(CH,)2C1

C6”6 2

1)

for

ligand.

in tetrahydrofuran

resultant

t

in a

on complete

ether.

(C6H5J2PH

of

of the diphenyl-

dependent

difficulties

useful

of this

of THF in vacua,

of impure

these

highly

ring-bonded

of chlorodimethyl(2-diphenylphosphinoethyl)silane,

Treatment

of the

various

mixture

and the

cyclopentadienide

produces

is

medium-pressure

unreacted

to -4O”C,

(6).

at

under nitrogen

semi-solid

a 54%.yield

a procedure

product

e.g.

and isolation

of diphenylphosphine

(450W Hanovia

and

(4),

metals,

and Fe(O).

preparation

avoids

of this

solution

is

Irradiation h,

here

preparation

Ni(I1)

reagent

of final

of 1 described

large

48

purity

of non-ionic

thesis

transition

LiC5H5,

THF +

(C6H5)2PCK2CH2Si(CH3)2C5H4-Lif

2) nC4HgLi, pet.

ether

1

fresh

C46

Inasmuch as the latter overall

two steps

Both intermediate

silanes

with the neutral

well

(s,6H),

a.8

ether.

readily

FeCl2 in ether

at 25X,

rise

(m,2H),

to an oil

either

(br s,4H),

phosphine moieties

crystallizes

rise

excess

3.

of

The crude

itself,

indicative

with unreacted

FeC12.

on alumina I with benzene, upon standing

show similar

.I values P(C),H

to give

with a slight

ferrocene

the P-CH2-CH2-Si proton

comparable two- and three-bond

solvents

The

that are not only broadened

by chromatography

which slowly

as

(m,lOH).

81% of ferrocene

to the purified

of the free

for

Reaction

and slightly

in THF-d8 at 60.13

and 7.1-7.7

in appropriate

NMRabsorptions

relative

solid,

spectroscopical!y

absorptions

affords

2, _ and 3 (when pure) all

CaWleX RMRpatterns

to dimerize

in tetrahydrofuran,

characterized

systems.

exhibits

of 3 is effected

Compounds 1, _

5.93

example,

for

perhaps of complexation

giving

It is readily

metallocene

in position

Purification

under nitrogen

and water-sensitive

very soluble

with metal halides

a brown oil,

but shifted

air-

in the NMRit displays

to the corresponding

product,

solvents,

(m,2H), ~2.0

anion reacts

yellow

1 is a pale

in hydrocarbon

as chemically;

of 50% (Scheme I).

at room temperature

showing no tendency

the

solvent.

Cyclopentadienide

in diethyl

in yield,

is on the order

appear to be stable

silylcyclopentadiene

neat or in hydrocarbon

soluble

quantitative

of 1 based on diphenylphosphine

yield

insoluble

virtually

are

pairs systems,

under nitrogen

of characteristically consistent

seen in a variety

with the

of acyclic

compounds (8) _

Fe

6 In sumnary, ligand tive.complexation sition units

metals.

1 is a stable,

isolable

at the cyclopentadienide In all

in the purified

with the central

Si(CH3)2-CH2-CH2-P(C6HS)2

cases

thus far

complexes

reagent

function

investigated,

with a variety

for

selec-

of tran-

the remote phosphine

appear to be completely

metal and behave normally

suitable

in reactions

free

from interaction

aimed at complexation

(7).

c47

with a second metal large

atom.

scale makes it

this

type

systems,

by far

of which

Acknowledgements.

to the

Donors

of

the

currently

to thank

Petroleum

for

the

of 1 on a

of difunctional of a variety

under

investigation

ligands novel

of

of

dinuclear

in our laboratory.

L. H. Somner and W. K. Musker

is made to the

Research

support

and isolation

study

Drs.

Acknowledgement

the

Society,

for

are

We wish

discussions.

Chemical

the most accessible

and the most valuable several

helpful

The ease of preparation

Fund,

of this

Research

Corporation,

by the

administered

for

and

American

research.

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c48.. 6.

~.

_ Colorlck

oil i _iMR (C&$:

and 7.0r7.8 7.

8.

solid,

(m,4H,-CH2-Si), = 1_7Hz,4H

(m,8H,o-Ph)

..

Anal:

(rn.ZH)~~2.16.(111;

found:

C,69.41;

A.A.

R.H.

3.

Chem. 21,

Nf4R (C696):

(“AH,-(X$-P),

ea. .Cp),

C42H46P2Si2Fe : Bother-By,

mp 89-91°C.

2-13

splittings

Austral.

0.90.

ZH),

(n,lO~),

Orange crystal.line 0.92

60.17 -(s.~H)..

H,6.66;

Cox, J. 1197

3.,90 and.4.13

7.03-7.30

C,69.61;

(m,lZHJn-

H,6.76;

P,8.33:

(s,12H,CH3Si), (apparent

and p-Ph), Calcd.

triplets,

7.35-7.72 for

P.8_52%.

Phys.

(1968).

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Chem. 7&

1830 (1969);

M.J.

Gallagher,