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Novel Nickel- and Palladium-Complexes with Aminobis(imino)phosphorane Ligands for the Polymerization of Ethylene.

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metal compounds. As we discovered earlier, remarkable stereoselective effects can be achieved with bidentate ligands“].
We report here on novel nickel- and palladium-complexes
containing an aminobis(imino)phosphorane as chelate ligand.
The in-situ reaction of bis( 1,5-cyclooctadiene)nickel or bis(q3-ally1)nickel with the aminobis(imino)phosphorane (1) in
toluene yields a catalyst which polymerizes ethylene to
polyethylene at 70°C and 50 bar. Activities of 1000 mol ethylene per mol of nickel are achieved. The physical properties
of the short-chain branched polymer lie between those of
high-pressure polyethylene and “EPDM’. Catalysts of this
type are of interest because of their potential for the production of high-pressure polyethylenes.
In the stoichiometric reaction of bis(q3-ally1)nickel with
( I ) we isolated the complex (2), whose structure followed
from spectroscopic data (‘H-, T - ,and ”P-NMR, IR), the
mass spectrum ( M + with the expected isotopic ratio) and the
comparison of these data with those of the analogous palladium compound (3). The formation of (2) proceeds via an
unexpected ally1 rearrangement, which leads to a P-bonded
o-ally1 group.
(5) appear at increasingly high field on passing from (5c) to
(Sb) to (Sa), as required for increased T participation of the
system’s two heteroatomic lone pairs, the degree of overall
delocalization of the nitrogen-centered negative charge as assessed by the increasingly downfield shift of the directly adjacent quaternary carbon unit, i. e., C-9aI4I, is seen to implicate
the existence of an alternate sequence namely (5b)
(6 = 82.72) < (5a) (6 = 86.62) < (5c) (6 = 89.05)!
We are thus faced with an interesting situation whereby
the effectiveness of X in mobilizing the nitrogen-centered
negative charge increases in the order S < 0 <NMe for extended delocalization into the benzenoid moieties and in the
order 0 <NMe <S for overall but spacially limited participation. This apparent discrepancy, which was recently also
shown to obtain in the case of the related monoheterocarbanions (l)[’I,is best reasoned by the second-row nature of
sulfur and its consequent ability to stabilize an adjacent negative charge be it inductively or via direct expansion of its
“octet”.
Finally, it is notable that whereas the data presented in
this report relating to the “benzenoid” chemical shifts of (5)
clearly implicate, at least in the case of the diaza derivative
(5a), the presence of a substantially delocalized distinctly paratropic molecular periphery, the effect does not appear to be
as extensive as was recently observed with the monohetero
carbanionic relatives ( l ) [ ’ l . For obvious reasons the increased
electronegativity of the negatively charged center on passing
from (1) to (5) is believed to account for much of the observed differences.
SiMe3
I
(2). R l
Received: July 10, 1980 [Z 662 IE]
German version- Angew. Chem. 93, 1 1 I (1981)
= Xi;
(3), M = P d
The complex (2) contains a four-membered ring made up
of two nitrogen atoms, the nickel atom, and the phosphorus
atom. Four-membered rings of aminobis(imino)phosphoranes are well known[*], but so far not in combination with
transition metals. With respect to electron distribution and
bonding there exist resemblances to the phosphoniobis(methanide) derivatives described by Schrnidba~r[~1.
A sulfur
analog of (1) could recently be complexed as “P--=S side-on’’
ligand to platinum‘41.
In analogy to the synthesis of (2) we also reacted bis(q3-al1yl)palladium with (1) to give the remarkably stable complex
CAS Registry numbers:
(2). 122-39-4 (31,61057-05-4 (4aj, 20057-16-3 (4bj. 135-67-1; (4cj. 92-84-2; (Sa).
76069-02-8; (5b). 76069-03-9; (Scj 76069-04-0
[ I ] a) A. G. Anustassiou, H. S Kasmai, Angew. Chem. 92. 53 (1980): Angew.
Chem. Int. Ed. Engl. I Y , 43 (1980): b) A. C. Anasiussiou. H. S. Kasmai, M . R.
Saadein, Tetrahedron Lett. 1980, 3743.
[2J The sample remained qualitatively and quantitatively unchanged (NMR)
after 10 h exposure to ambient temperature.
131 The centers of both major and minor absorption manifolds consistently undergo 0.2 to 0.25 ppm upfield shifts on passing from (Sc) to (Sb) to (Saj.
141 An increase In the degree of amide ion delocalization ought to enhance the
double bond character of the link connecting -Nto C-9a with consequent
deshielding of the carbon center. Hence one’s expectation that increased amide ion delocalization should lead to a downfield shift of the C-9a resonance.
c21
n
Novel Nickel- and Palladium-Complexes with
Aminobis(imino)phosphoraneLigands for the
Polymerization of Ethylene[**]
c1
By Wilhelm Keim, Rolf Appel, Arnold Storeck,
Carl Kriiger, and Richard Goddard“]
c2
Few investigations have been carried out on the influence
of chelate ligands in homogeneous catalysis with transition
[‘I
C32
Prof. Dr. W. Keim [ ‘1, Dipl.-Chem. A. Storeck
Institut fur Technische Chemie und Petrochemie
der Technischen Hochschule
Worringer Weg 1, D-5100 Aachen (Germany)
Prof. Dr. R. Appel
Anorganisch-chemisches lnstitut der Universitat
D-5300 Bonn 1 (Germany)
Priv.-Doz. Dr. C. Kriiger. Dr. R. Goddard
Max-Planck-Institut fur Kohlenforschung
D-4330 Miilheim-Ruhr 1 (Germany)
[**I
This work was supported by the Deutsche Forschungsgemeinschaf~.
[ ‘1
Author to whom correspondence should be addressed.
116
0 Verlag Chemie, GmbH. 6940 Weinheim, 198f
Fig. 1 Molecular structure of complex (3) in the crystal. Cell data: a = 9.174 (I).
b= 17.745 (2). c = 18.900 (2)
p = 104.610 (7)”. space group P2,/c. Z = 4 with
= 1.24 gcm - I, R = 0.037, R , = 0.04.
A,
0570-0833/81/0101-0116
$ 02.50/0
Angew. Chem. Int. Ed. Engl. 20 (1981) No. 1
(3). The 'H-,
and "P-NMR spectra as well as the IR
spectrum corresponded to those of (2). The mass spectrum
shows the molecular ion with the expected ratio of isotopes.
A crystal structure analysis was carried out on (3) (Fig. 1).
The primary skeleton of the molecule is characterized by its
near C,(m) symmetry, the mirror plane running through
N3, P, Pd and C2 perpendicular to a planar ( k 0.03 A) fourmembered ring formed from Pd, P, N1 and N2. Only the arrangement of the trimethylsilyl groups at N1 and N2 do not
correspond to this symmetry. The terminal atom C6 of the
ally1 group is disordered. The phosphorus atom has approximate tetrahedral configuration. Like the Si-N bonds the
P-N bonds are of varying length. Thus, in the strainef fourmembered ring"] we find on average P-N=1.598 A, and
thus high multibonding*character. The length of the exocyclic P-N bond (1.685 A) in comparison with the sum of the
covalent radii of the two atoms (1.84 A) is likewise indicative
of multibonding character, albeit to a lesser extent. As complex ligand the R-N-PR2-N-R
group, like the isoelectronic phosphoniobis(methide) group (H2C-PRz-CH2)[61,
is to be regarded as a three-electron donor with analogous
geometry and bonding. Thus a 15-electron configuration is
present at the central palladium, like in the educt bis(q3al1yl)palladium.
The palladium complex (3) cannot catalyze the polymerization of ethylene. Dry (3) is air-stable for several days at
room temperature, but decomposes within hours at 50 "C.
Procedure
All operations must be carried out under argon.
(2): A solution of (I)[*](6.8 g, 0.019 mol) in toluene (15
em3) was added dropwise within 30 min at - 78 "C to a stirred suspension of bis(q'-allyl)nickel['~ (2.5 g, 0.018 mol) in
toluene (10 cm'). A reddish brown solution was formed. After standing for several days at - 78 "C, red-brown crystals
separated out (1.17 g); on concentration of the mother-liquor
and addition of a small amount of dichloromethane a further
3.1 g could be isolated. Total yield 4.27 g (47%) of (Z), m.p.
135 "C (dec.).
(3): (1) (5.5 g, 0.015 mol) was added dropwise within 3 min
at - 20 "C into a solution of bi~(q'-allyl)palladium[~~
(2.8 g,
0.015 ml) in toluene (20 cm'). After ca. 12 hours' stirring at
room temperature the solvent was removed in an oil-pump
vacuum and the residue taken up in 10 ml dichloromethane:
Yellowish-green crystals precipitated at - 15 "C. Yield: 3.53 g
(43%) (3), m. p. 95-96 "C (dec.).
Received: July 14, 1980 [ Z 649 I€]
German version: Angew. Chem. 93, 91 (1980)
[S] 0. J. Scherer, N. Kuhn, Chem. Ber. 107, 2123 (1974).
[91 a ) W. Keim. Dissertation, Technische Hochschule Aachen 1963; b) G. Wilke,
B. Bogdonouic, P. Hardf, P. Heimhach, W: Keim. M. Kroner, W Oherkirch,
K. Tanaka, E. Steinriicke, D. Walter, H. Zimmermann, Angew. Chem. 78, 157
(1966); Angew. Chem. Int. Ed. Engl. 5 , 151 (1966).
Synthesis of Multielectron Ligands for Transition
Metals uia Spiro[cyclopropane-l,1'-indene]~**~
By Karlheinz Berghus, Angelika Hamsen, A[fons Rensing,
Annegret Woltermann and Thomas Kauffmannl'l
Dedicated to Professor Wilhelm Klemm on the occasion
of his 85th birthday
We have recently shown that spiro[2.4]hepta-4,6-diene(1)
is highly suitable for the synthesis of multielectron ligands
for transition metals[']. As anticipated, analogous ligands e. g.
(4a), (Sa), (6a), and (6b) (Ind=3-indenyl) can be prepared
from spiro[cyclopropane-l,l '-indenel (3) by similar transformations[21.
Attempts to extend the donor capability of the compounds
obtained by addition of a cyclopentadienyl- or indenyl group
as five-electron donorI3l demonstrated the expected superiority of indene derivatives for this purpose. Thus, while the
reaction of ( 2 ~ ) with
" ~ 1,2-dibromoethane and sodamide led
to an (as yet) inseparable mixture of the isomers (2b) and
(2c), the corresponding reaction of the indene derivative
(4a)-+(46) and the comparable reactions (3) -+ (4c) and
(5a) -+ (Sb) gave single products.
\
/4h), 3 7@0
1) PhzArLi
2) O=CH-Ph
P
CAS Registry numbers:
( I ) , 5211 1-28-1; (2), 75949-58-5; (3). 75949-59-6; bis(q'-allyl)nickel, 12077-85-9;
his(~3)-allyl)palladium,
12240-87-8
( I f a) W . Keim, kl H. Kowaldf. R. Goddard, C. Krijger, Angew. Chem. 90, 493
(1978): Angew. Chem. Int. Ed. Engl. 17, 466 (1978); b) W. Keim, B. Hoflmann, R. Lodewick, M . Peuckert. G. Schmitt, 1. Mol. Catal. 6, 79 (1979).
121 a) R. Appel. M . Halstenberg, F. Knoll, Z. Naturforsch. B 32, 1030 (1977); b)
0. J . Scherer. W.Glussel, Chem. Ber. 1/0, 3874 (1977)
[3] H. Schmidhaur. Acc. Chem. Res. 8, 62 (1975).
141 0. J. Scherer. H. Jungmann, Angew. Chem. 91, 1020 (1979); Angew. Chem.
Int. Ed. Engl. 18, 953 (1979).
[5] E. Niecke. W Flick, S. Pohl, Angew. Chem. 88, 305 (1976); Angew. Chem.
Int. Ed. Engl. 15, 309 (1976).
161 a) H. H. Karsch, H. Schmidbaur, Chem. Ber. 107, 3684 (1974); b) H. H.
Karsch, H.-F. Klein, C. C Kreirer. H. Schmidbaur, ibid. 107, 3692 (1974); c)
D. J. Brauer, C. Kriiger, P. J. Roberts, Y.-H. Tsay, ibid. 107, 3706 (1974).
[7] a) B. Bogdanourc, Dissertation, Technische Hochschule Aachen 1962; b) G.
Wilke, B. Bogdanovid, Angew. Chem. 73, 756 (1961).
Angew Chem Int. Ed Engl. 20 11981) No. 1
(46) and ( 4 4 were coupled with a further 2-electron donor
group and by this means the potential 9-electron ligands (4e)
and (4d)l4]respectively, were obtained.
1'1
Prof. Dr. Th. Kauffmann, K. Berghus, A. Hamsen, DiplLChem. A Rensing. A. Woltermann
Organisch-Chemisches Institut der Universitat
Orleans-Ring 23. D-4400 Miinster (Germany)
[*'I Multielectron Ligands, Part 2. This work was supported by the Deutsche
Forschungsgemeinschah and the Fonds der Chemischen Industrie. Part 1:
111.
0 Verlag Chemie, GmbH, 6940 Weinheim, 1981
0570-0833/81/0101-0117
$ 02.50/0
2 17
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nickell, imine, palladium, aminobis, ethylene, phosphorane, novem, complexes, polymerization, ligand
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