3
88
T. Hosokawa et al.rJournal of Organometallic Chemistry 551 (1998) 387–389
four amides L . The four amides coordinate to Cu atom
Ž .
via their carbonyl groups, forming a square plane. The
bond lengths between Cu and the amide oxygen atoms
wCu
1 –O 1 , 1.934 4 1 –O 2 , 1.958 4
Ž . Ž . Ž . Ž . Ž . Ž .
A˚ ; Cu A˚ x are
normal w10,11x.
As for complex 2, no crystals suitable for X-ray
analysis were obtained; however, the following observa-
tions indicate that the complex 2 is a Pd–Cu het-
erometallic complex bearing an O atom derived from
O2. i The reaction of complex 2 with 1-decene under
Ž .
an inert atmosphere gives 2-decanone smoothly, and
simple calculation shows that ;90% of the O atom
3
contained in 2 is transfered into the alkene.
ii The IR
Ž .
y1
spectrum of complex 2 shows a band at ;570 cm
due to nCu – O absorption w12x, and X-ray signals of Cu
Fig. 1. ORTEP drawing of a part of polymeric complex 1 with
and Pd were detected by EDS
Spectroscopy
The formation of complex 1 is viewed as the follow-
ing sequence. CuCl reacts with O to form Cl–Cu–
O–O–Cu–Cl which disproportionates to CuCl L
Ž
Energy Dispersive X-ray
adopted atom numbering scheme. Hydrogen atoms on carbon atoms
.
.
were omitted for clarity. Selected bond length Ž A˚ . and angles Ž8. with
esds in parenthesis: Cu-ClŽ1. 2.916Ž2., PdŽ1.–ClŽ1. 2.279Ž2., PdŽ1.–
X
ClŽ2. 2.257Ž2., PdŽ1.–ClŽ3. 2.328Ž2., PdŽ1.–ClŽ3 . 2.326Ž2., Cu–
i
Ž .
2
OŽ1. 1.934Ž4., Cu–OŽ2. 1.958Ž4.; CuClŽ1.–PdŽ1. 116.96Ž6., ClŽ1.–
PdŽ1.–ClŽ2. 91.84Ž6., ClŽ2.–PdŽ1.–ClŽ3. 90.58Ž6., ClŽ3.–PdŽ1.–
Ž . Ž
L
2
n
sDMF
by wCusOx w13–16x.
with two PdCl to afford one unit of the complex 1
.
and a copper oxo species formally represented
ii .n Žns4 combines
Eq.
... In the reaction with HMPA, the disproportionation
mentioned here is also presumed to take place, afford-
ing w
HMPA.2 and m -oxo com-
plex
The m -oxo complex 4 is formed by assembly of 4
X
X
ClŽ3 . 85.91Ž6., ClŽ3 .–PdŽ1.–ClŽ1. 91.69Ž6., OŽ1.–Cu–ClŽ1.
3.9Ž1., OŽ2.–Cu–ClŽ1. 93.7Ž1., OŽ1.–Cu–OŽ2. 91.7Ž2..
Ž
.
CuCl2
Ž
L
.
9
Ž
2
Ž
2
contain an O atom derived from O2
infra
Eq. 2
Ž Ž .. Žvide
Ž
Ž
PdCl2
.
2CuCl
Ž
3
x Ž .
n
.
.
2
4
PdCl2 . ŽCuO. ŽHMPA. Ž . Ž .
4 as shown in Eq. 3 .
6 4 4
O2
PdCl2
Ž
MeCN.2 qCuClqDMF
™
4
ClCH CH Cl
L–CusO LsHMPA and 6 PdCl . In the reaction
w x Ž .
2
2
2
with DMF, similar assembly could result in the forma-
tion of as shown in Eq.
PdCl2 . ŽCuO. ŽDMF.z
Ž
PdCl2 .2 CuCl2
CuO
DMF. z
The ORTEP drawing of 1
Ž
DMF.4 n
Ž
1
.
q
Ž
PdCl2 . x
Ž
2
Ž .
x
y
Ž
.
y
Ž
Ž
2
.
Ž .
2
4
2 .
Ž .
2
Ž
Fig. 1 shows a poly-
.
0
2
PdCl2
Ž
MeCN.2 qCuClqHMPA
™
meric structure which consists of alternative units of
CuCl2 and dimeric PdCl . The Cu and
Pd units are linked by m-Cl atoms, and this structural
ClCH CH Cl
2
2
L
Ž .4 ŽLsDMF.
2
Ž
PdCl2 .2 CuCl2
Ž
HMPA.2 n
Ž
3
.
q
Ž
PdCl2 .6
feature is fundamentally the same as that of
Ž
CuO. ŽDMF.4 Ž
4
.
3
Ž .
4
wŽ
PdCl2
w9x. Although the bond distance of Cu
Cl , 2.916
x is slightly longer than that of
PdCl2 CuCl2 2-pyrrolidinone
wCu–Cl
x, the distance is within the sum of van der
Waals radius of Cu and Pd. In addition, the bond length
of Cl –Pd –Pd , 2.279
is normal wCl
A˚ ;
Cu–Cl –Pd , 116.96
8x. Therefore, the complex 1
2CuCl2 2-pyrrolidinone
. Ž . x reported previously
4
n
In order to examine whether the heterometallic com-
plex obtained acts as a catalyst for the oxidation shown
1 –Cl 1 1 –
Ž . Ž . wCuŽ .
Ž
1
.
2
Ž .
w
Ž
2
.
Ž
.
x
1 ,
Ž .
2
4 n
.823
Ž
1
.
3
The O2 uptake in the reaction of Eq. Ž2. is dependent on the
amount of DMF used. When DMF is used in more than 10-fold
Ž
1
.
1
Ž
1
.
1
Ž
1
.
Ž
1
.
Ž
2
.
excess per CuCl PdrCus1 , the O uptake becomes nearly con-
Ž
.
2
Ž
.
Ž
.
Ž
6
.
stant. For example, ;2.6 ml Ž;0.1 mmol. of O was consumed per
2
0
.5 mmol of CuCl under the conditions using PdCl ŽCH CN. Ž0.5
mmol., CuCl Ž0.5 mmol., and DMF Ž10 mmol. in ClCH CH Cl Ž5
can be said to be bimetallic. The Cu atom is on a
crystallographic center of symmetry and is arranged in
tetragonal bipyramidal structure by two m-Cl atoms and
2 3 2
2
2
ml. at 358C under O2 for 2 h. This reaction gave 0.065 g of complex
and 0.084 g of complex 1. When the complex 2 Ž0.065 g. obtained
2
was reacted with 1-decene Ž1 mmol, 0.19 ml. under argon atmo-
sphere Ž2 h, ClCH CH Cl–DMF., 0.18 mmol of 2-decanone was
2
2
formed Žglc analysis with n-tridecane as internal standard.. If O2
molecules absorbed Ž;0.1 mmol. in Eq. Ž2. are all incorporated into
0.065 g of 2, the O atom transfer from 2 to the alkene can be
calculated to be ;90%.
Purification of complex 2 is difficult because of its insolubility
into various solvents. From several elemental analyses of 2, its
composition appears to be around xs4, ys5, and zs6.
2
Crystallographic Data for 1: C12 H28 N O Pd CuCl , mws
4
4
2
6
7
81.44, dark brown crystal Ž0.3=0.3=0.3 mm., monoclinic, space
group C2rc ŽNo. 15., as20.095Ž5., bs9.182Ž4., cs16.647Ž3. A˚ ,
3
y3
4
b s116.81Ž1.8, Vs2741Ž1. A˚ , Zs4, D s1.89 g cm . The
calc
structure was refined to Rs3.8% and R s3.5% for 2528 reflec-
w
tions.