- Email: [email protected]
Photochemical reactions of transition-metal dinitrogen compounds in the presence of carbon monoxide
INORG.
NUCL.
CHEM.
LETTERS
PHOTOCHEMICAL
Vol. 8,
pp. 529-532,
REACTIONS
COMPOUNDS
1972.
Pergamon Press.
OF T R A N S I T I O N - M E T A L
Printed in Great Britain.
DINITROGEN
IN T H E P R E S E N C E OF C A R B O N M O N O X I D E D o n a l d J. D a r e n s b o u r g
Department
of C h e m i s t r y ,
State University
Buffalo,
New York
of N e w Y o r k
at B u f f a l o
14214
(Received 1 March 1972)
It is w e l l k n o w n t h a t t r a n s i t i o n - m e t a l readily
undergo photolysis
monoxide
ligand.
However,
on transition-metal dinitrogen
compounds
of Re(I),
photochemical
containing
studies
the i s o e l e c t r o n i c
far b e e n reported.
studying
the p h o t o c h e m i s t r y
Fe(II),
excess c a r b o n m o n o x i d e
compounds
in loss of the c a r b o n
no a n a l o g o u s
ligand h a v e thus
We have been complexes
resulting
carbonyl
Os(II)
and Mo(O)
and our r e s u l t s
of the d i n i t r o g e n
in the p r e s e n c e
are the
following:
(i)
R e C I ( N 2) (PMe2Ph) 4
+
CO
hv ~r cis ReCI(CO) 2 ( P M e 2 P h ) 3
(2)
F e H 2 ( N 2) (PEtPh2) 3
+
CO
hv ~
Fe(CO) 4 ( P E t P h 2 ) + trans
(3)
OsCI2(N2) (PEt2Ph) 3
+
CO
of
hv ~
Fe(CO) 3 (PEtPh2)2
OsCl 2 (CO) (PEt2Ph) 3
+ cis and t r a n s OsCl 2 (CO)2(PEt2Ph)2 (4)
trans M o ( N 2)2 ( P h 2 P C H 2 C H 2 P P h 2 ) 2
+
CO
hv
+ eis Mo (CO) 2 (Ph2PCH2CH2PPh2) 2 The s t a r t i n g m a t e r i a l s procedures.
1
Reactions
were carried
a pyrex vessel maintained Carbon monoxide was
were prepared
according
to p u b l i s h e d
out in t e t r a h y d r o f u r a n
b e l o w 20 ° b y m e a n s o f a w a t e r
slowly b u b b l e d
529
through
the s o l u t i o n
in
condenser. during
530
TRAN~TIOI'q-METAL DINITROGEN COMPOUNDS
the irradiation process.
Vol. 8, No. 6
The light source was a Hanovia 550 watt
mercury lamp and was externally placed about 25 cm from the reaction vessel. For ReCI(N2)(PMe2Ph) 4 100% conversion to the cis ReCI (CO)2 (Me2PhP) 3 complex was achieved after 1 hour of irradiation.
Samples taken at several time intervals during an irradia-
tion period of 2~ 5 hours showed only the production of the cisReCI(CO)2(PMe2Ph)3 product° tral properties 8.18
(t), 8.25(t)
This product has physical and spec-
(m.p. 153-155 ° , VCO at 1933 and 1836 cm -I, T(CH3) , and 8.79(d))
identical with those reported by
Shaw 2 for cis ReCI (CO) 2 (PMe2Ph) 3 obtained by treatment of merReCI3(PMe2Ph) 3 with sodium amalgam and carbon monoxide.
The
experiment was repeated in the presence of N 2 instead of carbon monoxide resulting in only a slight decomposition of starting material with no production of the analogous bis-dinitrogen rhenium complex. Irradiation of Fell2 (N2) (PEtPh2) 3 for 0.5 hours led to the formation of the yellow complexes Fe(CO)4(PEtPh2) Fe(CO) 3(PEtPh2) 2 in about a i:i ratio.
and trans
These complexes were
identified by their infrared spectra in hexane solution in the carbonyl stretching region;
Fe(CO)4(PEtPh2) (VCO at 2051(AI),
1977(AI),
and 1943, 1936cm-l(E mode split)), trans Fe(CO) 3-
(PEtPh2)2
(VCO at 1887 and 1879cm -I(E mode split)).
Fell2 (N2) (PEtPh2) 3 has been shown to react with carbon monoxide thermally to produce Fell2 (CO) (PEtPh2) 3 lb.
RuH2 (N2) (PEtPh2) 3
similarly reacts thermally with carbon monoxide to produce RuH 2 (CO) (PEtPh 2) 33.
Presumably,
Fell2 (CO) (PEtPh2) 3 is an inter-
Vol. 8, No. 6
mediate
TRANSITION-METAL DINITROGEN COMPOUNDS
in the photochemical
was independently carbon monoxide
reaction described
found to undergo photolysis
leading to products
from the dinitrogen
species.
workers 4 have observed with carbon monoxide
531
in eq. 2 since it
in the presence
identical
of
to those obtained
In a related process Chatt and co-
that OsH2CI2(PEt2Ph) 3 reacts thermally
quantitatively
displacing
dihydrogen
to
produce OsCl 2 (CO) (PEt2Ph) 3 and OsCl 2 (CO)2 (PEt2Ph)2" mer OsCI 2 (CO) (PEt2Ph) 3 (isomer II)5 and cis and trans OsCl 2 (CO) 2 (PEtPh) 2 were produced by irradiation OsCI2(N2) (PEt2Ph) 3 for 0.7 hours
of
in the presence of excess carbon
monoxide. The photochemical
reaction of the trans Mo(N2) 2-
(Ph2PCH2CH2PPh2) 2 complex with carbon monoxide pale y e l l o w dicarbonyl
gave the known
complex cis Mo(CO) 2(Ph2PCH2CH2PPh2)2
(VCO in CHCI 3 at 1850 and 1782cm -I)
in approximately
50~ conver-
sion after 15 min. with no trace of starting material Recently,
this same reaction has been
at ambiet temperatures
found to proceed
over a 4 day period. 7
to note that in both the photochemical dicarbonyl
form.
bis-dinitrogen
An additional
obtained
complex
orange-red
and thermal
from the photolysis.
plex in solution
Further
for an additional
VCO in the complex to 1812cm -I. similar to the reddish-orange
is isolated
product
thermally
reactions while
the the
as the trans
(VCO at 1869cm -I) was irradiation
0.5 hours
This product
complex
remaining.
It is interesting
complex obtained has the cis configuration,
corresponding
6
of this com-
caused
a shift in
is proposed
empirically
to be
formulated
as
532
TRANSITION-METAL DINITROGEN COMPOUNDS
Mo(CO) (PPh3)2(VCO
at 1820 or 1800
Mo(N2) (PPh3) 2 and c a r b o n The above analysis,
i.r.,
monoxide
complexes and
cm -I)
IH n.moro
obtained
thermally.
have been
Vol. 8, No. 6
from
7
characterized
by
elemental
for
financial
spectra°
Acknowledgements The
author
assistance, n.m.r,
thanks
and Dr.
the R e s e a r c h
Mo Y.
Corporation
Darensbourg
for d e t e r m i n i n g
the IH
spectra.
References io
(a) J. Chatt, 687,
J. R. Dilworth,
Acta,
2243
P. G i a n n o c c a r o ,
5,
(c) J. Chatt, (A),
J. Leigh,
Chem.
Comm. 3
(1969).
(b) M. Aresta, Chim.
and G.
203
M.
Rossi,
and A.
Sacco,
Inorg.
Jo Chem.
Soc.
(1971).
Go J. Leigh,
and R. Lo
Richards~
(1970) o
(d) J. C h a t t
and A. G. Wedd,
Jo O r g a n o m e t a l .
Chem.•
27,
C15
(1971) o 2.
P. G.
Douglas
3.
Wo
Knoth,
4.
J. Chatt,
H.
(A), 895
D.
and B. L. J. Amer.
J. Chem.
Soc.,
94•
Soc. 104
(A) ~ 1491
(1969).
(1972).
and R. L. Richards~
Jo Chemo
Soc.
(1971).
D. J. D a r e n s b o u r g 3
6.
J. C h a t t
7.
M.
944, ii0
Chem.
P. M e l v i l l e ,
5.
Hidai,
Shaw,
and H.
Inorg.
R. Watson,
K. T o m i n a r i , (1972).
Chem.,
l_~0j 2399
J. Chem.
(1971).
Soc. • 4980
and Y. Uchida,
J. Amer.
(1961). Chem.
Soc.,
NUCL.
CHEM.
LETTERS
PHOTOCHEMICAL
Vol. 8,
pp. 529-532,
REACTIONS
COMPOUNDS
1972.
Pergamon Press.
OF T R A N S I T I O N - M E T A L
Printed in Great Britain.
DINITROGEN
IN T H E P R E S E N C E OF C A R B O N M O N O X I D E D o n a l d J. D a r e n s b o u r g
Department
of C h e m i s t r y ,
State University
Buffalo,
New York
of N e w Y o r k
at B u f f a l o
14214
(Received 1 March 1972)
It is w e l l k n o w n t h a t t r a n s i t i o n - m e t a l readily
undergo photolysis
monoxide
ligand.
However,
on transition-metal dinitrogen
compounds
of Re(I),
photochemical
containing
studies
the i s o e l e c t r o n i c
far b e e n reported.
studying
the p h o t o c h e m i s t r y
Fe(II),
excess c a r b o n m o n o x i d e
compounds
in loss of the c a r b o n
no a n a l o g o u s
ligand h a v e thus
We have been complexes
resulting
carbonyl
Os(II)
and Mo(O)
and our r e s u l t s
of the d i n i t r o g e n
in the p r e s e n c e
are the
following:
(i)
R e C I ( N 2) (PMe2Ph) 4
+
CO
hv ~r cis ReCI(CO) 2 ( P M e 2 P h ) 3
(2)
F e H 2 ( N 2) (PEtPh2) 3
+
CO
hv ~
Fe(CO) 4 ( P E t P h 2 ) + trans
(3)
OsCI2(N2) (PEt2Ph) 3
+
CO
of
hv ~
Fe(CO) 3 (PEtPh2)2
OsCl 2 (CO) (PEt2Ph) 3
+ cis and t r a n s OsCl 2 (CO)2(PEt2Ph)2 (4)
trans M o ( N 2)2 ( P h 2 P C H 2 C H 2 P P h 2 ) 2
+
CO
hv
+ eis Mo (CO) 2 (Ph2PCH2CH2PPh2) 2 The s t a r t i n g m a t e r i a l s procedures.
1
Reactions
were carried
a pyrex vessel maintained Carbon monoxide was
were prepared
according
to p u b l i s h e d
out in t e t r a h y d r o f u r a n
b e l o w 20 ° b y m e a n s o f a w a t e r
slowly b u b b l e d
529
through
the s o l u t i o n
in
condenser. during
530
TRAN~TIOI'q-METAL DINITROGEN COMPOUNDS
the irradiation process.
Vol. 8, No. 6
The light source was a Hanovia 550 watt
mercury lamp and was externally placed about 25 cm from the reaction vessel. For ReCI(N2)(PMe2Ph) 4 100% conversion to the cis ReCI (CO)2 (Me2PhP) 3 complex was achieved after 1 hour of irradiation.
Samples taken at several time intervals during an irradia-
tion period of 2~ 5 hours showed only the production of the cisReCI(CO)2(PMe2Ph)3 product° tral properties 8.18
(t), 8.25(t)
This product has physical and spec-
(m.p. 153-155 ° , VCO at 1933 and 1836 cm -I, T(CH3) , and 8.79(d))
identical with those reported by
Shaw 2 for cis ReCI (CO) 2 (PMe2Ph) 3 obtained by treatment of merReCI3(PMe2Ph) 3 with sodium amalgam and carbon monoxide.
The
experiment was repeated in the presence of N 2 instead of carbon monoxide resulting in only a slight decomposition of starting material with no production of the analogous bis-dinitrogen rhenium complex. Irradiation of Fell2 (N2) (PEtPh2) 3 for 0.5 hours led to the formation of the yellow complexes Fe(CO)4(PEtPh2) Fe(CO) 3(PEtPh2) 2 in about a i:i ratio.
and trans
These complexes were
identified by their infrared spectra in hexane solution in the carbonyl stretching region;
Fe(CO)4(PEtPh2) (VCO at 2051(AI),
1977(AI),
and 1943, 1936cm-l(E mode split)), trans Fe(CO) 3-
(PEtPh2)2
(VCO at 1887 and 1879cm -I(E mode split)).
Fell2 (N2) (PEtPh2) 3 has been shown to react with carbon monoxide thermally to produce Fell2 (CO) (PEtPh2) 3 lb.
RuH2 (N2) (PEtPh2) 3
similarly reacts thermally with carbon monoxide to produce RuH 2 (CO) (PEtPh 2) 33.
Presumably,
Fell2 (CO) (PEtPh2) 3 is an inter-
Vol. 8, No. 6
mediate
TRANSITION-METAL DINITROGEN COMPOUNDS
in the photochemical
was independently carbon monoxide
reaction described
found to undergo photolysis
leading to products
from the dinitrogen
species.
workers 4 have observed with carbon monoxide
531
in eq. 2 since it
in the presence
identical
of
to those obtained
In a related process Chatt and co-
that OsH2CI2(PEt2Ph) 3 reacts thermally
quantitatively
displacing
dihydrogen
to
produce OsCl 2 (CO) (PEt2Ph) 3 and OsCl 2 (CO)2 (PEt2Ph)2" mer OsCI 2 (CO) (PEt2Ph) 3 (isomer II)5 and cis and trans OsCl 2 (CO) 2 (PEtPh) 2 were produced by irradiation OsCI2(N2) (PEt2Ph) 3 for 0.7 hours
of
in the presence of excess carbon
monoxide. The photochemical
reaction of the trans Mo(N2) 2-
(Ph2PCH2CH2PPh2) 2 complex with carbon monoxide pale y e l l o w dicarbonyl
gave the known
complex cis Mo(CO) 2(Ph2PCH2CH2PPh2)2
(VCO in CHCI 3 at 1850 and 1782cm -I)
in approximately
50~ conver-
sion after 15 min. with no trace of starting material Recently,
this same reaction has been
at ambiet temperatures
found to proceed
over a 4 day period. 7
to note that in both the photochemical dicarbonyl
form.
bis-dinitrogen
An additional
obtained
complex
orange-red
and thermal
from the photolysis.
plex in solution
Further
for an additional
VCO in the complex to 1812cm -I. similar to the reddish-orange
is isolated
product
thermally
reactions while
the the
as the trans
(VCO at 1869cm -I) was irradiation
0.5 hours
This product
complex
remaining.
It is interesting
complex obtained has the cis configuration,
corresponding
6
of this com-
caused
a shift in
is proposed
empirically
to be
formulated
as
532
TRANSITION-METAL DINITROGEN COMPOUNDS
Mo(CO) (PPh3)2(VCO
at 1820 or 1800
Mo(N2) (PPh3) 2 and c a r b o n The above analysis,
i.r.,
monoxide
complexes and
cm -I)
IH n.moro
obtained
thermally.
have been
Vol. 8, No. 6
from
7
characterized
by
elemental
for
financial
spectra°
Acknowledgements The
author
assistance, n.m.r,
thanks
and Dr.
the R e s e a r c h
Mo Y.
Corporation
Darensbourg
for d e t e r m i n i n g
the IH
spectra.
References io
(a) J. Chatt, 687,
J. R. Dilworth,
Acta,
2243
P. G i a n n o c c a r o ,
5,
(c) J. Chatt, (A),
J. Leigh,
Chem.
Comm. 3
(1969).
(b) M. Aresta, Chim.
and G.
203
M.
Rossi,
and A.
Sacco,
Inorg.
Jo Chem.
Soc.
(1971).
Go J. Leigh,
and R. Lo
Richards~
(1970) o
(d) J. C h a t t
and A. G. Wedd,
Jo O r g a n o m e t a l .
Chem.•
27,
C15
(1971) o 2.
P. G.
Douglas
3.
Wo
Knoth,
4.
J. Chatt,
H.
(A), 895
D.
and B. L. J. Amer.
J. Chem.
Soc.,
94•
Soc. 104
(A) ~ 1491
(1969).
(1972).
and R. L. Richards~
Jo Chemo
Soc.
(1971).
D. J. D a r e n s b o u r g 3
6.
J. C h a t t
7.
M.
944, ii0
Chem.
P. M e l v i l l e ,
5.
Hidai,
Shaw,
and H.
Inorg.
R. Watson,
K. T o m i n a r i , (1972).
Chem.,
l_~0j 2399
J. Chem.
(1971).
Soc. • 4980
and Y. Uchida,
J. Amer.
(1961). Chem.
Soc.,