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New Imido-Bridged Transition Metal Clusters [(C5H5)4Ti4(NSnMe3)4] [Co11(PPh3)3(NPh)12] [Ni11Br6(NtBu)8] and [Li(thf)4]4[Cu24(NPh)14].

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Bucteria (Eds: J. M. Olson, J. G. Ormerod, J. Amesz, E. Stdckebrandt, H. G.
Truper), Plenum, New York, 1988, pp. 23-34: d) T. Nozaaa, M. Suzuki, S .
Kanno, S . Shirai, Chem. Lett. 1990.1805-1808, e)T. Nozaaa, M. Suzuki. K.
Ohtomo. Y Morishita. H. Konomi, M. T. Madigan, ihrd. 1991, 164; f) K.
Uehara. J. M Olson, Plrotosynth. Res. 1992,33.251-257, g) K. Matsuura, M.
Hirota. K. Shimada, M. Mimuro, Photochem. Photohrol. 1993.57. 92-97; h)
T.Nozawa. K. Ohtomo. M. Suzuki. M. Morishita. M T Madigan, Bull. Chem.
Sor Jpn. 1993.66. 231; I) H. Sato, K. Uehara. T. Ishii. Y Ozaki, Eiochennstr~
1995. 34. 7854-7860; j) T. Oba, T. Watanabe, M. Mimuro. M Kobaydshi, S .
Yoshida, Phorochem. Photohiol. 1996, 63. 639-648.
T.S . Balaban, A. R. Holzwarth, K. Schaffner. unpublished results.
K. M. Smith, D. J. Simpson, J Am. Chem. Soc. 1985, 107,4946-4954.
H. Tamraki, M. Amakawa, Y Shimono, R. Tanikaga. A. R . Holzwarth, K.
Schaffner, Photochem. Photohiol. 1996, 63, 92- 99.
H. Scheer in Chloroplrjll.s(Ed.: H Scheer), CRC Press, Boca Raton. FL, 1991,
P- 4
Satisfactory analytical data have been obtained for all new compounds.
After elution with aqueous methanol from the HPLC column and evaporation
of the solvents, a sharp blue-shifted peak at 622 nm is visible in the
dichloromethane solutions of 6a-Zn diluted with hexane. This peak is removed
after washing with brine a dichloromethane extract of 6a-Ln. We tentatively
assign this peak to a methanol-bridged dimeric species.
For 6a-Zn and 6b-Zn in dichloromethane solution the ester C=O band is at
1733cm-'. that of the aldehyde at 1664cm-I. and a chlorin mode at
1606 cm-! Upon addition of methanol the ester C = O band remains unshifted, whereas the aldehyde C = O appears at 3657 f 2cm-I. probably due to
hydrogen bonding to methanol. When dichloromethane solutions are diluted
with hexane. the ester C = O band is slightly shifted to larger wavenumhers
(1738 c m - I ) . whereas the aldehyde carbony[ band is strongly shifted to lower
frequencies [broad band at 1640cm.' for the more soluble (13's)epimer]
This is reminiscent of the strongly down-shifted 131-carbonyl vibration in
BChl c aggregates and chlorosomes [9 b]. We correspondingl) assign this latter
band to the aldehyde carbonyl group strongly hydrogen-bonded to a hydroxy
group, which simultaneously coordinates with a zinc atom.
The proportion of red-shifted oligomers is slightly greater on aggregation in
pentane than for that in hexane and heptane. Furthermore, the amount is also
determined by the concentration of the CH,CI, stock solution: the higher this
concentration, the more aggregated species are formed, as i\ expected from a
cooperative process for the self-assembly. This has been shown for BChl c
oligomers (predominantly tetramers. cooperativity of 3.6) [ I Sj
Solutions of 5a-Zn and 5b-Zn in hexane tend to form deposits upon standing.
albeit without a red shift in absorption of the supernatant.
For a first example of a functional unit based on the self-organized assembly
of zinc chlorins coupled to a metal-free bacteriochlorin as energy acceptor: H
Tamiaki, T. Miyatake, R. Tanikaga, A. R. Holzwarth. K. Schaffner, Angex..
Chem. 1996, 108, 810-812; Angen. Chem. Inr. Ed Engl. 1996, 35, 772-774.
assemblyfi51 to large aggregates (Fig. 3) may involve selective
stereocombinations that suffice to exert diastereoselective controls.
Addition of methanol, (which competes for ligation with
zinc), to solutions of 6a-Zn, 6b-Zn, and (6a-Zn + 6b-Zn) disintegrated all aggregates and formed homogeneous solutions of
= 653 nm, see inset in Figure 2 ) .
Neither 5a-Zn15b-Zn nor 7a-Zni7b-Zn in which one of the
functional groups at either C 3' or C 13' is derivatized, exhibited
any red shift in absorption in the wavelength region above
653 nm upon dilution of their CH,CI, solutions with hexane.
This is in accordance with an earlier observation by Smith
et a1.18] and confirms the binding roles of the 3I-aldehyde and
the 13l-hydroxy groups (Fig. I), as postulated previously for
the original arrangement of the functions in 1-3.[231Furthermore, it provides independent evidence (in addition to
FT-IRi2'') against the postulates that the C 13l ketone[14c1
the C 17' ester['411carbonyl groups coordinate directly with
magnesium in BChl c aggregation.
Based on the structural conditions for the formation of
chlorosomal type aggregates, as now defined by the two classes
of metallochlorins (1 -3 and 6a-Zn/6b-Zn) it should be possible
to synthesize different macrocycles capable of similar selfassembly, and using them to design photoactive functional units
by coupling to appropriate energy traps.["]
Received: July 25, 1996 [Z 9383 IE]
German version: Angen. Chem. 1996, 108, 3019-3021
Keywords: aggregates . chlorins . chlorosomes self-assembly
[l] H Tamiaki. A R. H Holzwarth. K. Schaffner. J Photochem. Photohrol. E
Eiul. 1992, 15. 355-360: H. Amakawa, Y Shimono. R. Tanikaga, A . R .
Holzwarth, K. Schaffner. Photochem. Photohiol. 1996, 63, 92 -99.
[2] a) H. Tamiaki. S. 'l'akeuchi, R. Tanikaga, S. T. Balaban. A R. Holzwarth, K .
Schaffner. C/iom Lett. 1994. 401 -402; b) T. S . Balaban, H. Tamiaki. A. R.
Holraarth. K. Schaffner. unpublished results.
[3] a ) K. M. Smith. D. A. Goff, J. Fajer. K . M. Barkigia, J Am. Chem. Soc. 1983,
IO5, 1674 - 1676: b ) A. R. Holzwarth. K. Schaffner. Photosvnth. Res. 1994.41.
[4] H Tainiaki. S Miyata. Y. Kureishi. R. Tanikaga, Gtruhedron 1996,52, 12421 12432
[ S ] For analogies between magnesium and zinc chlorins, see Ref. [8].
[6] a ) M I Bystrova. I. N Mal'gosheva, A. A. Krasnovskii. Mol. Eiol. Engl.
Trun.d 1979, /.?. 440-451; b) A. R. Holzwarth. K. Griebenow, K. Schaffner.
J Phutiii~lr~wi.
Pliorohiol. A C/7em. 1992. 65. 61 -71, and references therein.
[7] a ) Recent reviews. R. E. Blankenship, J. M. Olson, M. Miller in Anorjgenic
Euctcriu (Eds.: R E. Blankenship. M. T. Madigan, C. E.
Bauer). Kluwei-, Dordrecht. 1995, pp. 399-435, b) see also T. S . Balaban,
A. R. Holzwarth. K. Schaffner, G:J. Boender, H. J. M. de Groot, Eiochernistrj
1995. 34. I 5 25Y - I5 266. and references therein.
[XI K. M Smith. L A Kehres. J. Fajer, J Am. Chem. Soc. 1983, 105, 1387-1389.
[9] a) P. Hildebrandt. H. Tamiaki, A. R . Holzwarth, K. Schaffner, J Phys. Chem.
1994. 98. 2192 2197, b) J. Chiefari, F. Fages. K. Griebenow, N. Griebenow,
T. S Balaban. A R. Holrwarth. K. Schaffner, rhrd. 1995, 1357-1365.
[lo] a ) D L Worce\ter. T. J. Michalski, J. J. Katz, Proc Nut/ Acud. Sci.U S A 1986.
R3.3791 3795. b) D. L Worcester, T. J. Michalski. M. K. Bowman, J. J. Katz,
Mut Rcs SICS1 mp. Proc. 1990. 1 7 4 ~157- 161
[l I] The formation of tubular inverted micelles from chlorophyll u , which possesses
a 3-binyl instead o f a 3-( I-hydroxyethyl) group, is mediated by water molecules
[lo]. 21sascertained in X-ray structure analyses by H. C. Chow, R. Serlin. C. E.
Strouse. J A m Chrm. Soc 1975. Y7. 7230-7237; R. Serlin. H. C. Chow, C. E.
Strouse. ;bid 1975. 97. 7237-7242; C. Kratky, J. D. Dunitz, Actu Crystullogr.
Sc2i.r. 8 1975. 31. 1586-1589.
[12] L. A. Staehelin. J. R Golecki, R. C. Fuller. G. Drews. Arch. Mikrohrol 1978.
I19.269 277.
[13] The bonding in Fig 1 is a n extension of the model initially advocated by Smith
et al. [XI. None of numerous other proposals [10a, 141 of the organization of
such ag.gregates has been found by molecular modeling [3 b, 151 t o afford tubular arrangements of appropriate diameters.
[14] a ) D. C Brune. T Nozawa. R. E. Blankenship, Erochemi.stry 1987, 26, 8644X652. b) D. f ' Brune, G H. King. R. E. Blankenship in Phuru.r)nthrtic
Lighiirorr~wmySi:rrmis (Eds.: H. Scheer, S . Schneider), Walter de Gruyter.
Berlin. 1988. pp. 141 - 151: c) M. Lutz, G. van Brake1 in Green Photosynthetic
A n w w Chew. l n t . Ed. Engl. 1996, 35, No. 23/24
New Imido-Bridged Transition Metal Clusters:
[(C,H,),Ti,(NSnMe,),I 9
[Nil1Br6(NtBu)811 and
[Li(thf)4]4[Cu24(NPh) i41**
Andrea Decker, Dieter Fenske,* and Klaus Maczek
Dedicated to Professor Rudolf Taube
on the occasion of his 65th birthday
Transition metal compounds with nitrogen-containing ligands usually form, with few exceptions, mononuclear compounds.[' - 31 Recently Dehnicke et al, for example, described
the synthesis of N-containing cluster compounds such as
[Cu,(NPMe,),(0,CCH3),1. [Cu,Cl,(NPMe,),]+. and [Cu,Br,(NPMe,),]+,[4-61 in which the phosphane imine groups act as
bridging ligands. These compounds were the first N-bridged
clusters of electron-rich transition metals to be synthesized.
Prof. Dr. D. Fenske, Dr. A. Decker, Dr. K. Maczek
lnstitut fur Anorganische Chemie der Universitit
Engesserstrasse, Geb.-Nr. 30.45, D-76128 Karlsruhe (Germany)
Telefax: Int. code +(721)661921
This work was supported by the Deutsche Forschungsgemeinschaft
0 VCH Verlugsgesellschaft mhH. D-69451
Wernlzeim, 1996
0570-0833i9613523-2863 3 I S 00+ ,254
Herein we report that imido-bridged transition metal clusters
can also be synthesized. The synthetic strategy is based on the
reaction of chlorotransition metal phosphane complexes with
stannylamines; the elimination of trimethylchlorostannane
leads to the formation of nitrogen-bridged clusters.
The Ti, cluster 1 can be isolated as brown crystals in a low
yield (20%) from the reaction of ICpTiCI,(PEt,),] (Cp = C,H,)
with tris(trimethy1stannyI)amine [Eq. (a)].
Since 1 contains four SnMe, ligands, there are four reactive
N-Sn bonds. which are potential centers for further reaction to
form links between Ti,N, heterocubane units. However, reactions with transition metal and main group element halide compounds have so far proved unsuccessful.
The reaction of PhN(SnMe,), with [CoCl,(PPh,),] led to
dark green crystals of 2 [Eq. (b)]. which tend to decompose very
quickly. The central metal framework in 2 consists of a planar
The results of the single-crystal X-ray structure analysis of 1
are shown in Figure 1.IgJ Compound 1 consists of a Ti,N, cluster with a heterocubane structure, in which the titanium atoms
Co, ring that is formed from the atoms Co 1 , C o 3, c o 4 , Co 6,
Co 7, and C o 9 (Fig. 2). Single Co atoms lie above and below the
Co, plane lie at distances of 118.6 pm (Co 10) and 122 pm
Fig. 1 Molecular structure of 1. Hydrogen atoms have been omitted for clarity.
Selected bond lengths [pm] and angles [;I: Til-Til' 277.9(4). Ti1 -T12' 268.6(3).
Ti2-Ti2 277.3(3), Ti1 -Ti2 278.5(3), Ti1 -- N1 197.0(9), Ti1 - N l ' 205 8(9).
Ti1 -N2 2064(8), Ti2 -N2 195.0(8). T i 2 - N 2 203.2(8); Nl-Til-N2 91.2(3).
Nl'-TiI-NZ 97.4(3). Ti2-Til-Til' 57 72(8). T12-Til-Tt2' 60 X6(8).
are each coordinated to an q,-Cp ligand, and the N atoms are
bound to SnMe, groups. Within the four-membered rings of the
cubane framework, the Ti-N-Ti and the N-Ti-N angles lie between 87.2-88.2' and 91.1 -92.3", respectiveiy. The Ti atoms in
1 are all formally in the oxidation state +III. Surprisingly this
complex shows diamagnetic behavior. This must be a result of
coupling between the d' spin centers.[81 Compound 1 has
52 valence electrons (VE) and therefore 8 VE less than expected
for a M, cluster with a tetrahedral structure.[7a1However,
1 is isoelectronic with [MXNPEt,], (X = CI, I). in which M,N,
heterocubane structures are also
On the other hand there are many heterocubane clusters for
which the noble gas rule (60 VE) is exceeded or not met. Extended Hiickel calculations show that a M, tetrahedral cluster with
52 VE should possess D,, symmetry with four longer and two
shorter M - M bonds.'8"] This is indeed found to be true for 1,
which has two short Ti-Ti bonds (268.3(3) pm) and four longer
Ti-Ti bonds (277.2-278.5(3) pm). Other titanium clusters with
the same number of valence electrons have already been reported. Examples include [Cp4Ti,Te,] and [CpkTi,S,] (Cp' =
iPrC,H,),[8al in which the Ti-Ti distances are significantly
longer (292.7-300.8 and 314.5-321.4 pm, respectively).
[Cp,*Ti,N,] (Cp* = C,Me,) is another compound with a Ti,N,
structural unit that has recently been reported;[8b1however, in
contrast to 1, this compound contains an undistorted Ti, tetrahedron (Ti-Ti 278.8 pm).
Q VCH Veriy~~~~seli.sschaf!
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Fig. 2. Molecular structure of 2 (C and H atoms omitted) Selected bond lengths
[pm]: Col --Co2 242.9(3), Col -Co3 258 4(3), Col -Cog 248 2j3). Col -ColO
272.4(3). COl -Col I 287.2(3). cO2-cO3 243.7(3). C03-cO4 247.3(3). CO3-cOlO
279.0(4). c o 3 - Call 282.5(3). c o 4 - c o 5 242.0(3), Co4-Co6 255.9(3), Co4-ColO
279.5(3). c 0 4 - C o i l 271.5(3), cO5-cO6 243.7(3), Co6-Co7 246.00). Co6-ColO
280.9(2), C06-Cotl 275.3(2), C07-Co8 243.6(3), C07-CO9 249.6(3). cO7-cOlO
275.9(3), Co7-Coll 277.4(3). Co8--Co9 245.4(3), Co9-ColO 276.9(2). c o g C o l l 276.8(3). C o l O - C o l l 239 8(3). Co-P 2207-221.3(5). p,-N- Co 175.4
178.3(10) )c,-N- Co 186.1-191.8(!0)
(Co 1 l ) , respectively. In addition, three alternate edges of the
Co, ring are pc,-bridgedby Co atoms (Co 2, Co 5, and C o 8). The
distances between the C o ring atoms and the pL,-bridgingC o
atoms, which lie in the plane of the ring, range between 242.9
and 245.4(3) pm. Within the Co, ring, the co3-co4, C06C o 7, and Co 1-Co 9 bonds are significantly shorter (246.0248.2(3) pm) than the Co4-Co6, c o 7 - c o 9 , and C o l - c o 3
bonds (249.6-258.4(3) pm). In contrast, the bond lengths to the
apical CO atoms in the Co, ring range from 271.5(3) to
287.2(3) pm. The Co 1 0 - C o l l bond length (239.8(3) pm) is
conspicuously short. N 3, N 7, and N 11 and N 4, N 7, and N 12
form the triangular faces of an almost undistorted trigonal
prism. Co 10 and C o 11 lie only 20 pm below the mean planes
defined by these nitrogen atoms, which is a consequence of the
short bond length between these two C o atoms. This unusual.
distorted trigonal-planar coordination of Co 10 and CO11
N-CO-N: C010: 358.5'; Co 11 : 357.0") is a result of the steric
shielding of the nitrogen-bound phenyl groups. The cluster
framework of 2 is also sterically shielded by the terminally
bound triphenylphosphane ligands at Co 2, Co 5,and C o 8, as
__B 15.110 + .25!0
Ang~ii..Chem. Int. Ed. Enpi 1996. 35. No. 23 24
well as by twelve phenylimido groups. These phenylimido
groups bind in two ways: there are six p,-imido bridges (N 1,
N 2, N 3, N 6, N9. and N 10) between the C o atoms in the periphery of the cluster (Co-p,-N 175.4-178.3(10) pm) and six
p3-imido groups ( N 3 , N4, N ? , N8, N11, and N12) that form
bridges between the two apical C o atoms (Co 20 and C o 11) and
the C o atoms in the Co, ring (Co-p3-N 186.1-191.8(10) pm).
Compound 2 contains a C o , , cluster, which possesses an
overall charge of + 24. Evidently, we are dealing with a mixedvalent cluster. A possible charge distribution would be nine
C o 2 + and two Co3' ions. In agreement with this proposal, 2 is
paramagnetic. Taking the coordination of the C o atoms into
consideration. i t is conceivable that the Co3+ ions can be assigned to Co 10 and Co 11
The low reactivity of the amine derivative in the reaction of
the stannylamine with transition metal halide complexes proved
to be problematic. Therefore, we investigated whether the use of
the significantly more reactive lithium amide would provide a
pathway to the formation of imido-bridged clusters of the d9
and d ' " transition metals.
In the previously known nitrogen-bridged compounds of
nickel, the Ni, cluster is the dominant structure motif.[8a. l o * ''I
The reaction of [NiBr,(dme)] with tBuNHLi afforded the N i , ,
cluster 3 [Eq. ( c ) ] .
[Ni, lBr6(p3-N~Bu)8]
Apart from the metal-metal interactions, the two Ni, pyramids are also connected by four p2-bromo bridges (Br 3- Br 6)
between Ni 3-Ni 11, Ni 8-Ni 11, Ni 2-Ni 9. and NI 4-Ni ? (NiBr 236.3(1)-240.9(1) pm). Irrespective of this there are eight
p,-tert-butylimido groups in 3; the Ni-N bond lengths range
from 184.9(7) pm to 194.2(7) pm. The six Br- and eight NtBuZligands lead to a formal oxidation state of + I I for all nickel
The reaction of CuBr with PhNLi, affords the copper cluster
4 with NPh bridging ligands [Eq. (d)] .[' 21 It is an orange colored
CuBr --L
[ L I ( ~ ~ ~ ) ~ ] ~ [ C U ~ ~ ( ~ ~ ~ - N P ~ ) ~ ( (d)
ionic compound, which consists of four [Li(thf),]+ions and one
[Cu2,(NPh),,l4- ion. Correspondingly, all Cu atoms are in the
oxidation state + I . The structure of the cluster anion (without
C atoms) with 7 symmetry is shown in Figure 4. The metal
The main building blocks of 3 consist of two square pyramids
of Ni atoms (Nil-Ni5, Ni6-Ni10) (Fig. 3). The apical Ni
atoms (Ni 1 and Ni 10) are coordinated to terminal bromo ligands (Br 1. Br2; Ni-Br 236.5-238.0 pm). The Ni-Ni distances
within the Ni, unit lie in the range 245.8(2)-259.2(13) pm, and
can be described as bonding interactions.['"] The two Ni pyramids are linked in several ways. Ni 11 acts as a bridge bridge
between N i 3 and Ni8, and the Ni-Ni distances are
240.2(2) pm. This distance is typical for a Ni-Ni bond.[', lo.lll
There is a further metal-metal contact between the two Ni,
pyramids from Ni5 to Ni6 (230.5(2) pm).
Fig 3 . Molecular structure of 3 (H atoms omitted). Selected bond lengths [prn]:
Nil -Ni 245 7 253 3(2). Ni2-Ni3 247 9(2), Ni3-Ni4 249.4(1). Ni2-Ni5 257.2(2).
Ni4-Ni5 255.4(1). N15-Ni6 230.5(2), Ni3-Nil1 240 O(2). Ni8-Nil1 240.2(2).
NilO-Ni 245.8-253 3 2 ) . Ni6-Ni7 259.211). Ni7-Nix 247.4(1), NiX--Ni9
249.2(2).Ni6-Ni9?543(1).Nl-N1 185.3-188.5(6),N2-Ni 184.9-185.2(5). N 3 N: 187.1 190.8(6). N4-NI 186 6-190.5(7), N 5 - N i 185.5-191.4(6). N6-Ni
183 7-188.5(6). N7-Ni 184.5-192.7(6). N8-Ni
184.9-193.7(6), Nil -Brl
*38.0(?). N: 10- Br? 216.W). Ni-Br3 236.3-238.3(2), Ni- Br4 235.9 -238.5(2).
Ni-Br5 240.0- 2 5 I . l ( l ) . NiLBr6 239 8-252 2(1).
Anoau. Chrn Int
121 Enpi. 1996. 35. N o . 23i24
Fig. 4 StructureoftheCu,,N,,cluster of4. Selected bond lengths[pm].Cul - ~ C u 2
265.2. Cul -Cu3 270.9. Cu2-Cu3 272.1. C U ~ - C U S
258.5. CUS C U 258.4
~ Cu6Cu7 255.1, Cu7-Cu8 257 1. Cu8-CuY 258.9. Cu4-Cu9 261 5. C u l O C u l l 250.4.
CulO-Cul2 252.8. C u l l - C u l 2 252.0. Cut-Cub 281.3, Cu? Cu7 278.8. Cu2Cu8 285.3, Cu3-CuY 281.9. Cu3-Cu7 281.4. Cu4- CulO 249.5. Cu5-Cull 251.6.
Cu6-Cu12'250.6,Cu7-CulO 251.0,CuX-Cull'251.7.Cu9-Cu12248.Y.
186.3-189.2. N2-CU 185.7-188.6, N 3 - c ~184 2-189.2. N4 CU 185 9-189.3.
NS-CU 193 3 -196.7, N 6 - c ~193.3-194.9. N 7 - c ~193.0-.195 5
framework of 4 is formed from three planar Cu, rings (Cu4Cu9, CulO-Cu12, and C u 1 0 - C u 1 2 , C u 4 - C u 9 ) and two
Cu, rings (Cu 1-Cu3, Cu 1'-Cu3'). These rings lie parallel to
one another with the two three-membered rings a t either end.
Thus, a Cu,, polyhedron is formed comprising Cu, and Cu,
faces. The Cu, faces are bridged by p,-phenylimido groups
(N 1 -N4, N 1'-N4') and half of the Cu, faces by p,-phenylimid o groups (N5-N7. N5'-N7'). All the Cu atoms, as is usual
for Cu' ions, are approximately linearly coordinated by the N
atoms of the NPh ligands (N-Cu-N 171.3-178.0'). The difference in the degree of bridging is also evident from the bond
lengths. Thus, the Cu-p,-N bond lengths are 184.2(5) and
189.3(6) pm, while, as expected, the Cu-pu,-N bond lengths are
longer (193.0(6) and 196.7(6) pm). The Cu-Cu distances lie
between 248.9(1) and 285.3(1) pm. Notably, the bond lengths
of the Cu, rings, 265.2-272.2 pm are significantly longer than
those found in the Cu, rings. The ring formed from Cu4-Cu9
contains Cu-Cu distances of between 257.1 and 261.5 pm. In
comparison, the six-membered ring containing the atoms
Cu 10-Cu 12 and Cu 10'-Cu 1 2 has much shorter Cu-Cu contacts (250.3-252.8 pm). The interactions between the Cu atoms
of the Cu, ring and between the Cu, ring (Cu 1 -Cu3) and the
Cu, ring (Cu4-Cu9) are weak (Cu-Cu 278.9-285.3 pm). In
VCH Vrrlu~,~~~e.sell.~chuft
mbH. D-69451 Wc.whefm.1996
0570-0833:96'3523-2865X 15.00+ 2 j 0
contrast the distances between the Cu, rings are significantly
shorter (Cu-Cu 248.9-252.9 pm). In this respect, it is more
meaningful to describe the structure of the cluster as a hexagonal prism derived from 18 Cu atoms that is linked to two Cu,
clusters through p,-bridging NPh ligands. The construction
principle of parallel hexagonal and triangular layers is observed
in other Cu clusters such as [Cu,,(PPh),(PPh,),]
Therefore one could describe the skeleton
of 4 as a [Cu,,E,] structure fragment that has been extended by
the insertion of two Cu, layers.
In contrast to other main group element bridged Cu clusters,
the Cu framework in 4 is not shielded by terminal ligands coordinated to copper, but by the phenyl groups of the imido bridging ligands (Fig. 5). No definite statement can be made about
Keywords: clusters imido ligands transition metal compounds
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b) P. Gomez-Sal, A. Martin, M Mena, C. Yelamos. J Chem. Soc. Chem.
Commun. 1995. 2185.
[9] X-ray crystal structure analysis: Stoe-STADI IV and Stoe-IPDS diffractometer. (Mo,, radiation); data collection and refinement (SHELX-76, SHELXS86 and SHELXL-93): 1 ' The compound crystallizes with two molecules of
hexane per formula unit: monoclinic. space group C2,c (no. 15); lattice
constants (230 K). a = 20.925(13). h = 11.327(8). c = 23.472(19)
/7 =
97.84(5)'. V = 5511.27 As;2 = 4; p(MoKJ = ?3.6cm-': 20,,, = 54 : 7952
reflections measured of which 5498 were independent; max. residual electron
density 1 . 8 7 e k ' ; 129 parameters (Sn, Ti, N, and C atoms of the methyl
groups anisotropic. C atoms of the C p groups disordered); R , = 0.084:
R, = 0.076. 2: The compound cryslallizes with five dimethoxyethane molecules per formula unit; triclinic. space group pi (no. 2); lattice constants
(160 K ) : (I = 15.893(8). h = 19 986(16). c = 21.739(13)
x = 97.63(4),
/{=102.54(3), ;.=107.43(3), V=7151.39A3; 2 = 2 ;p(MoK,)=13.2cm-':
?Urnax = 48'. 23630 reflections measured of which 20385 were independent:
max. residual electron density 1.56 e k 31479
; parameters (Co. P. N , and C
atoms of the phenyl groups anisotropic. The H atoms were calculated in idealized positions); R , = 0.081; R, = 0.076. 3: The compound crystallizes with
two dimethoxyethane molecules and one toluene molecule per formula unit:
monoclinic. space group C2:c (no 15): lattice constants (200 K):
I( = 24.547(3),
h =11.942(1). c = 48.483(7)A. /3 = 94.079(10) , V =
14176.23(2) A3; 2 = 8; p(MoKZ)= 61.8 c m - ' ; 20max= 50 ; 18916 reilections
measured of which 10127 were independent; max. residual electron density
1.27e.k', 613 parameters (Ni, Br, N.and C atoms of the cluster molecule
anisotropic. The H atoms were calculated in idealized positions ); R , = 0.084;
W R ,= 0.192. 4. The compound crystallizes with two T H F molecules per formula unit: monoclinic, space group P 2 , [ n (no. 14); lattice constants (190 K ) :
u = 19.474(4), h = 19841(5), ( ' = 26.343(6) A, (1 = 94.02(2)., P" 10154(4) A';
2 = 2 ; ~(Mo,,) = 27.84 c m - ' , 20mdx= 52 ; 44927 reflections measured of
which 17871 were independent; max. residual electron density 0 . 7 2 e k 3 , 790
parameters (Cu. N. and C atoms of the phenyl groups anisotropic. The H
atoms w'ere calculated in idealized positions); R , = 0.067. wR, = 0.184.
Further details of the crystal structure investigations may be obtained from
the Fachinformdtionszentrum Karlsruhe, 76344 Eggenstein-Leopoldshafen
(Germany) on quoting the depository numbers CSD-405340. CSD-405341.
CSD-405342, and CSD-405343.
[lo] H. F. Klein. S. Haller, H Konig, J. Am. Chem. So<. 1991. 113. 4673.
[ l l ] a ) S. Otsuka. A. Nakamura, T. Yoshida, hzorg. Chem. 1968. 7,261; h) J. Muller.
Chem. Ber. 1973. 106, 1122.
[12] D. Fenske, J. Ohmer. J. Hachgenei. K. Merzweiler, Angew. Chem. 1988, 100.
1300; Angiw. Chem Inr. Ed. Engl. 1988,27,1277;A. Eichhofer. D . Fenske, W.
Holstein. rhid. 1993, 105, 257 and 1993. 32, 1277; H. Krautscheid. D. Fenske.
G. Baum, M. Semmelmann, ihul. 1993, 105, 1364 and 1993, 32, 1302, D.
Fenske, J. Stcck. ihid. 1993, 105. 254 and 1993.32.238:S Dehnen. D. Fenske,
ihrd 1994, 1U6, 2369 and 1994, 33. 2287: D Fenske, W. Holstein. i h d 1994.
1U6, 1311 and 1994. 33, 1290.
Fig. 5. Molecular structure of 4 (H atoms omitted). Cu atoms are shown striped
and N atoms in black.
the results that have been obtained from preliminary reactions
of AgCl with PhNLi, . Interestingly, however, dark red solutions are formed, from which it has not yet been possible to
isolate a crystalline product. If the solvent is evaporated, a red
powder is afforded, the IR spectrum of which is very similar to
that of 4.
E-uperimental Procedure
1: PEt, (0.45 mL, 6 mmol) was added to a suspension of [CpTiCl,),] in toluene
(30 mL). The solution became clear. To this tris(trimethylstanny1)amine (1 mL.
3 mmol) was added, and the mixture was stirred at room temperature to give a dark
brown solution. The solvent was removed by evaporation and the residue redissolved in hexane and filtered, and the filtrate kept at -2S'C. Crystals of I (yield
20%) were isolated after a few days.
2: To a solution of [CoCI,(PPh,),] (4.1 g. 6.26mmol) in DME (100 mL).
bis(trimethylstannyl)phenylamine (1.75 mL, 6.28 mmol) was added. The reaction
mixture was heated to reflux for several days, which led to a black-brown solution.
Dark green crystals of 2 (yield 40%) were obtained after several days at -25 -C.
3: To a suspension of [NiBr,(dme)] (2 75 g, 6.9 mmol) in T H F (100 mL) at - 78 -C,
rBuNLiH (0.65 g, 8.3 mmol) was added. The reaction solution darkened at
about -40'C. The reaction mixture was allowed t o warm to room temperature.
and the solvent was removed by evaporation. The black residue was then stirred in
a mixture of hexaneitoluene ( 2 : 1) Some of the residue dissolved, and black rodlike
crystals of 3 (yield 60%) were obtained from this fraction after reduction of the
4: To a suspension of CuBr (2.67 g, 18.6 mmol) in T H F (100 mL). Bu,NH
(3.12 mL, 18.6 mmol) was added. The resulting clear solution was cooled in an ice
hath, and PhNLi, (1.95 g, 18.6 mmol) was added slowly. Orange crystals of 4 (yield
80%) were formed from the red brown solution after several days at room temperature.
Received' July 8. 1996 [Z93031E]
German version: AngeM.. Chem. 1996. 108,3025-3028
Verlagsgesellschafr mhH. 0-69451 Weinheim. 1996
057U-0833/96/3523-2866 S 15.00i 2510
AnRew. Chem. Int. Ed E n d 1996 35 N u 2<:24
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