Phosphinomethanes: Synthesis and Reactivity - American Chemical

We have synthesized Me2PCH2PR2. (R=Ph, t-Bu),MeP(CH2PMe2)2. ,. P(CH2PMe2)3 and mixed Cl/t-Bu and Me/CH2SiMe3 diphos phinomethanes by various ...
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27 Phosphinomethanes: Synthesis and Reactivity H. H. KARSCH

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Technische Universität München, Anorganisch-chemisches Institut, Lichtenbergstrasse 4, D-8046 Garching, FRG

Diphosphinomethanes are distinguished by two nucleo­ philic centers close together and an additional elect r o p h i l i c s i t e (acidic H). Η—IN

E,E* = H , R ( M ) , 0 , S Ν = R" +

+

f

w

i Ε

Η

\ E»

We have synthesized Me PCH PR (R=Ph, t-Bu),MeP(CH PMe ) , P(CH PMe ) and mixed C l / t - B u and Me/CH SiMe diphos­ phinomethanes by various methods. Because of its s i m p l i c i t y and low steric require­ ments, we chose the methyl derivate Μe PCH ΡMe as model for these compounds. Examples for nucleophilic reactions of the phos­ phinomethanes are (1.): 2

2

2

2

2

2 3

2

2

ο

Ε

^

E

2

2

2

E (1)

Me PGH PMe 2

2

2

3

2

+

+

E=H Me ,t-Bu ,0,S.. +

f

Me PGH PMe 2

2

2

+ 2 Me^Gl

[Me PPMe GH PMe PMe ]Gl ( 2 ) 2

2

2

2

2

2 Me^PMeg + CH G1 2

2

2

Reaction (2) offers a new route to the preparation of Me PCH PMe , since the equilibrium may be shifted to the l e f t by hydrolysis of the s a l t . The ligand properties are very s i m i l a r to those of PMe i n electronic respects, but s t e r i c a l l y it i s much more favourable. Thus, whereas (PMe ) Fe is not known as an isolable complex, (2), (Me P) (Me PCH PMe )Fe i s a stable compound (no C-H-cleavage occurs!) The 2

2

2

3

3 5

3

3

2

2

0097-6156/81/0171-0l4l$05.00/0 © 1981 American Chemical Society In Phosphorus Chemistry; Quin, L., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

2

142

PHOSPHORUS CHEMISTRY

complex may be compared w i t h t h e i s o e l e c t r o n i c C o ( I ) and I\' i ( 11 ) -c omp 1 exe s, w h i c h are l e s s s t a b l e i n r e s p e c t t o p e n t a c o o r d i n a t i o n . The c a t i o n i c c o b a l t ( I ) - c o m p l e x C(rie P)(Me PCH PFie )2Go]Gl decomposes r a t h e r r a p i d l y i n THF, y i e l d i n g (Prie ) (i1e PCH PMe )GoGl and a n o v e l , p a r a ­ m a g n e t i c complex [(Ke^P)(Me PCH PFie )Go] PMe w h i c h c o n ­ t a i n s a unique C o - e n t i t y w i t h i n a t r i p l e - b r i d g i n g framework. Other r e c e n t l y i s o l a t e d ne^GE Pne -complexes c o n t a i n Gr(0),Fe(II),Οο(ΙΙ,ΙΙΐ) o r Ag 2+-moieties. The c o o r d i n a t i o n b e h a v i o u r o f MeP(CH PMe ) i s c o m p a r a b l e t o t h a t o f PMe , as i s shown i n r e a c t i o n (3)· 3

2

2

2

3

2

2

2

2

2

2

2

2

2

2

1 +

2

2

2

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2

2

2

E

3

, ,

M

( N e P \ P e + 2 MeP(CH£>Me ) -"[MePCCH^Me^^Fe" (3) No 4- o r 5- c o o r d i n a t e d Fe(0)-complex i s o b t a i n e d , C - H - c l e a v a g e of a P G H - g r o u p as i n t h e s t a r t i n g com­ p l e x [ c f . ( 6 ) ] b e i n g o b s e r v e d i n s t e a d . The r e s u l t i n g H - F e ( I I ) - c o m p l e x i s u n i q u e by i t s s t r u c t u r a l f e a t u r e s : one six-membered (FePCPGP) r i n g and a n o v e l m e t a l l a b i c y c l o - s y s t e m . I n c o n t r a s t , the l i t h i a t i o n of the f r e e l i g a n d o c c u r s a t t h e b r i d g i n g c a r b o n atom ( 4 ) : J

2

2

3

MeP(GH PMe ) 2

2

+ LiCHgPMe

2

_ ^

Li[Me PCHP(Me)CH PMe ] (4)

ρηβ

2

2

2

2

T h i s r e a c t i o n (4-) a l s o d e m o n s t r a t e s t h e enhanced a c i d i t y a c c o r d i n g t o t h e f o l l o w i n g sequence: Ï^PCHj < (R P) CH < (R P) CH 2

2

2

2

5

The m e t a l a t e d p h o s p h i n o m e t h a n e s L i [ C H _ ( P H e ) ] ( n = 1 - 3 ) r e p r e s e n t examples f o r a r a r e c l a s s o f com­ pounds, where two n u c l e o p h i l i c c e n t e r s , w h i c h may com­ pete f o r e l e c t r o p h i l e s , are l i n k e d t o g e t h e r d i r e c t l y . Me^-CC He P=GC: 3

n

2

n

2

We have shown ( j5 ), t h a t t h e r e a c t i o n s w i t h p r o c e e d v i a a t t a c k a t p h o s p h o r u s , e.g.(5)· Li[C(PMe ) ] + 3 2

5

2

[(Μβ5Ρ) σ]ι 3

THF -6o°C"

L (H)Fe(CH PMe ) 5

Kel

2

)•+

Iîel- £ e n t g n e _

2

Mel

(5)

J

L,(Me EtP)(H)FeI 2

L^(Me)FeI

(6)

T g V f e , L (Me)F^GH>Me ) L=PMe ° I n c o n t r a s t , lie I y i e l d s d i f f e r e n t p r o d u c t s i n t h e reac­ t i o n w i t h (He P)i Fe [ w h i c h e x i s t s i n e c u i l i b r i u m w i t h (HejP) (H)Fe(GHgPMeg) ( 2 ) ] , d e p e n d i n g on t h e r e a c t i o n c o n d i t i o n s , but i n n e i t h e r c a s e a t t a c k a t p h o s p h o r u s i s observed ( 6 ) . L^Pe

3

+ 2

U

3

3

f

3

In Phosphorus Chemistry; Quin, L., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

2

KARSCH

27.

143

Phosphinomethanes

W i t h d i o r g a n o c h l o r p h o s p h i n e s as e l e c t r o p h i l e s , G - a n d / o r P - a t t a c k may o c c u r , d e p e n d i n g on t h e s t e r i c b u l k o f t h e s u b s t i t u e n t s , ( f t ) , e.g. Li[CH PMe ] +

RjPGl

Li[CH(PMe ) ] +

R^Gl

2

2

Me2PGH PR 2

(7)

2

-(Me P) (R P)GH2

2

2

2

2

(8) R P-PMe =CH-PMe -

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2

Li[C(PMe ) 3 2

2

2

+ Me^PGl —

3

(9) • Me P-PMe *C(PMe ) — 2

2

2

1

2

T h i s y l i d , formed i n r e a c t i o n (9)> belongs t o a r a r e c l a s s o f compounds, d i s t i n g u i s h e d by t h r e e p h o s p h o r u s atoms a t t a c h e d t o a y l i d i c c a r b o n atom. T h e i r P-NMRd a t a a r e g i v e n i n T a b l e I . The p a r e n t compound o f t h i s t y p e may be o b t a i n e d a c c o r d i n g t o ( 1 0 ) b y 3 i n d e p e n ­ dent r o u t e s . 3 1

Li[C(PMe ) ] 2

5

Me P=C(PMe ) 5

+ Mel

>

2

-Me SiGl

Me5P=GH-PMe

3

2

LBuLi 2.Me PCl

-LiCl

PMe -PMe ~ 2

2

01 ( 1 0 )

Me^C

2

5 MejP=CH-PMe

2

+ 2 KfegPCl

dMe* -Me 8iGl 3

2

+

Me PGH PMe =C(PMe ) 2

Table

I:

R=

3 1

PMe

2

G£y?Me

2

0 2

2

2

MejP=C ( S i M e ) 3

2

2

P-NMR-data f o r RMe^=G(P Me ) ( C D H P ( \ ext.) B

*\

Me

GH

2

2

6

2

6f

3

J(P P )J(P P )J(P P ) A

B

A

R

B

R

123,4

+ 8,15

-43,20

+14,15

-33,96

-58,87

140,4

+13,06

-39,30

-57,63

138,8

+26,22

-48,83

213,6

12,2

46,5

7,6

85,5

These y l i d s may be l o o k e d a t a s t h e n e u t r a l c o u n t e r ­ p a r t s o f t h e diphosT^hinomethanides. Φ PR, Me P2

Η •\PMe

2

Me P" 2

-PMe

2

In Phosphorus Chemistry; Quin, L., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

144

PHOSPHORUS CHEMISTRY

I n f a c t , t h e y a c t as p o w e r f u l l i g a n d s i n m e t a l com­ p l e x e s , e . g . i n {(Me^P) CMe3PG(PMe ) ]Go} (PF ) . 3

Me*P

2

S=PMe

2

2

6

2

PMe,

9

I ^ 0 -

-PMe

Me P-

-PMe,

Me P5

2

2

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S

The mesomeric s t a b i l i s a t i o n i n t h i s s y s t e m ( A ) i s com­ p a r a b l e t o t h e d i - c a t i o n i c system (C) [see r e a c t i o n ( 5 ) 1 and t h e a n i o n i c s y s t e m ( Β ) , w h i c h my be o b t a i n e d according t o ( 1 1 ) . 2

5

(11)

[Me^P] C (Me PS) C]

(Me PS) GH + MejP=GH =s=z 2

2

3

The d i p h o s p h i n o m e t h a n e s s h o u l d a l s o be s u i t a b l e f o r p r e p a r i n g PCPCPC s i x - r i n g s y s t e m s f o r t h e f i r s t t i m e . I n f a c t , we o b t a i n e d a c o l o u r l e s s s o l i d f r o m r e a c t i o n (12), and f r o m t h e P-îîITR-spectrum we b e l i e v e , t h a t i t c o n t a i n s a s i x - r i n g - d i c a t i o n , a l o n g w i t h some p o l y ­ mer, f r o m w h i c h s e p a r a t i o n c o u l d n o t be a c h i e v e d , how­ ever . 5 1

MeP(CH PMe ) 2

2

Me PCH PMe i

The [

5 1

2

Me

+ CH^r

2

MeP(CH Cl)

2

2

(12)

CH,

'GH,

Me, Ρ

PMe,

(13)

GH,

2

i s o b t a i n e d from r e a c t i o n ( 1 3 ) .

same p r o d u c t

Ρ-1ΜΠΗ (CD OD HjPO*. e x t . ) : J PI: - 4 9 , 1 4 ; c S P : + 2 5 , 6 3 ; J ( P P ) = +

3

f

3 0 H z ] . We c o u l d n o t a c h i e v e f u r t h e r r e a c t i o n w i t h h e I and n e i t h e r w i t h rrieP(GH PMe ) ] I · [ Ρ-ΝΪΙΡ(θυ Οΰ,Η ΡΟ

3

3

contrast,

v

RP(CH SiMe ) (R=l ie, t-Bu) i s r e a d i l y c o n v e r t e d b y M e l t o t h e c o r r e s p o n d i n g phosphonium s a l t s . Prom t h e s e and r e l a t e d f i n d i n g s , we c o n c l u d e , t h a t the s i m p l i c i t y ( l o w s t e r i c r e q u i r e m e n t s ) , s y n t h e t i c u t i l i t y , and p o w e r f u l c o o r d i n a t i o n a b i l i t y o f s u b ­ s t i t u t e d p h o s p h i n o m e t h a n e s and t h e i r a n i o n s c r e a t e a wide p r o s p e r i n g f i e l d o f o r g a n o o h o s p h o r u s and c o o r d i ­ n a t i o n c h e m i s t r y t o be c u l t i v a t e d i n t h e f u t u r e . 2

3

2

1. 2.

Karsch,H.H. Z. Naturforsch. 1979, 34b, 31 Karsch,H.H. Inorg. Synth. VolXX, Wiley Interscience, New York, 1980;p.69 and refernces therein 3. Karsch,H.H. Z. Naturforsch. 1979,34b, 1178 4. Karsch,H.H. Z. Naturforsch. 1979,34b, 1171 R E C E I V E D July 7, 1981. In Phosphorus Chemistry; Quin, L., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.