COMMUNICATION
DOI: 10.1002/chem.200900867
1,2,4-Diazaphospholide Complexes of Tin(II): From Nitride Stannylene to
Stannylenated Ammonium Ions
Chengfu Pi,[a, b] Jos Elguero,[c] Li Wan,[a] Ibon Alkorta,*[c] Wenjun Zheng,*[a]
Linhong Weng,[a] Zhenxia Chen,[a] and Limin Wu*[b]
Dedicated to Professor Herbert W. Roesky
The transamination of tin amide, Sn[NACHTUNGRE(SiMe3)2]2, generally allows the preparation of the corresponding stannylenes
in high yields and purity, employing a variety of ligand systems.[1–4] The ready cleavage of Sn N bonds makes this an
attractive method for the synthesis of related stannylenes,
probably because of the greatly enhanced reactivity of the
Sn N bond when compared with the Si N bond.[5] Although
tris(triorganostannyl)amine NACHTUNGRE(SnR3)3 (R = organic ligand)[6]
has been used as the N ligand or nitrogen source for the
preparation of many metal complexes[7] and recently as a
Lewis base for the synthesis of metal-coordinate onium
ions[8] EACHTUNGRE(SnMe3)4 + (E = N,[8d] P[8f]), tris(organostannylenyl)ACHTUNGREamine NACHTUNGRE(SnR)3 has not yet been reported, presumably due
to the highly reactive tin(II) species. Herein, we present the
synthesis and crystal structures of a nitride tetrastannylene
and a stannylenated ammonium ion stabilized by a samarium tetradiazaphospholido counterion that incorporates the
1,2,4-diazaphospholide ligand.[9] The former compound may
be viewed as an adduct of tris(organostannylenyl)amine NACHTUNGRE(SnR)3 with SnR2, and its formation involves a surprising
complete cleavage of the Si N bond of Sn[NACHTUNGRE(SiMe3)2]2.
The reaction of Sn[NACHTUNGRE(SiMe3)2]2[10] with 3,5-di-tert-butyl1,2,4-diazaphosphole (H[3,5-tBu2dp];[11] 1) in n-hexane afforded [{h1:h1ACHTUNGRE(N,N)-tBu2dp}{h1(N)-tBu2dp}2ACHTUNGRE(m3-Sn)2ACHTUNGRE(m4-N)ACHTUNGRE(m3Sn)2ACHTUNGRE{h1:h1ACHTUNGRE(N,N)-tBu2dp}2] (2) as air- and moisture-sensitive
orange crystals in 55 % yield (Scheme 1).[12] The structure
[a] Dr. C. Pi, Dipl.-Chem. L. Wan, Prof. Dr. W. Zheng, L. Weng, Z. Chen
Department of Chemistry, Fudan University
Handan Road 220
Shanghai 200433 (China)
Fax: (+ 86) 21-6564-2408
E-mail: [email protected]
[b] Dr. C. Pi, Prof. Dr. L. Wu
Laboratory of Advanced Materials, Fudan University
Handan Road 220
Shanghai 200433 (China)
Fax: (+ 86) 21-5566-4033
E-mail: [email protected]
[c] Prof. Dr. J. Elguero, Prof. Dr. I. Alkorta
Instituto de Qumia Mdica, CSIC
Juan de la Cierva 3
28006 Madrid (Spain)
Fax: (+ 34) 91-5644-853
E-mail: [email protected]
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.200900867.
Chem. Eur. J. 2009, 15, 6581 – 6585
Scheme 1. The preparation of complexes 2 and 3.
elucidation of 2 revealed a neutral monomeric species with
four tin atoms, five [3,5-tBu2dp] ligands, and one tetrametal-coordinate nitride ion (N3 ; Figure 1).[13, 14] The four
metal atoms are arranged in a slightly distorted tetrahedron
core and have a common center (N(6)) from which the distance to each tin atom is 2.147(2) . Each tin is three-coordinate, being bound to two [3,5-tBu2dp] ligands and one m4-
2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
6581
but the short Sn N bond lengths (2.148(2) ) within the
core relative to those at the sphere of the core (average Sn
N 2.306(3) ) are notable. The roughly equivalent Sn N(6)
bond lengths suggest a probably high degree of delocalization in the Sn4N(6) core. Here, the structures of tris(triACHTUNGREmethylstannyl)amine (NACHTUNGRE(SnMe3)3) with a trigonal planar arrangement of the tin atoms around the nitrogen center in
the gas phase[18a] and tris(dimethyhalostannyl)amine ([XACHTUNGRE(CH3)2Sn]3N; X = Cl, Br, I) with a planar Sn3N skeleton stabilized by bridging halides[18b,c] are worth noting.
The 1H NMR spectrum ([D6]benzene, 25 8C) of 2 displays
two resonances at d = 1.33 (br) and 1.36 ppm (s) for the CH3
groups of the terminal and bridging ligands, respectively. In
the 31P{1H} NMR spectrum ([D6]benzene, 25 8C), the observed three resonances at d = 89.7 (br), 86.6 (s), and
81.6 ppm (br), which are shifted downfield relative to the
corresponding signals of H[3,5-tBu2dp] (31Pd = 65.4 ppm)[11]
and K[3,5-tBu2dp] (31Pd = 50.65 ppm),[9a] demonstrate the
electron-withdrawing character of the metal ion. The two
minor weak resonances at d = 97.1 (s) and 83.2 ppm (s) indicate the possible dissociation of 2.[19] The width of the resonances suggests dynamic behavior that was probed by variable-temperature 31P{1H} NMR in [D8]toluene (Figure 2). At
Figure 1. Top: Molecular structure of 2 (thermal ellipsoids set at 30 %
probability, tBu groups are omitted for clarity). Selected bond lengths
[] and angles [8]: Sn(1) N(6) 2.148(2), Sn(2) N(6) 2.147(2), Sn(1) N(1)
2.241(3), Sn(1) N(4) 2.292(3), Sn(2) N(5) 2.314(3), Sn(2) N(3) 2.376(3);
N(6)-Sn(1)-N(1) 86.68(7), N(6)-Sn(1)-N(4) 95.25(11), N(1)-Sn(1)-N(4)
92.52(10), N(6)-Sn(2)-N(5) 89.10(9), N(6)-Sn(2)-N(3) 82.64(8), N(5)Sn(2)-N(3) 86.40(10), Sn(2A)-N(6)-Sn(2) 107.59(15), Sn(2A)-N(6)Sn(1A) 106.390(19), Sn(2)-N(6)-Sn(1A) 112.285(19), Sn(2A)-N(6)-Sn(1)
112.285(19),
Sn(2)-N(6)-Sn(1)
106.390(19),
Sn(1A)-N(6)-Sn(1)
111.90(15). Symmetry code: A x + 2, y, z + 3=2 ; x + 1, y, z + 3=2 .
Bottom: The Sn4N core in 2.
nitride ion,[13] and thus forms a nitrogen-centered tetrastannylene pentadiazaphospholido polyhedron with Sn···Sn interactions (average Sn···Sn: 3.530 ).[15] The Sn···Sn distance
observed in this case is even significantly shorter than the
Sn Sn bond length found in the complex [Sn{2,4,6-C6H2ACHTUNGRE(CF3)3}2]2 (3.639(1) ).[15b] Taking into account an isolated
[Sn(h1-3,5-tBu2dp)2] species,[16] complex 2 may be viewed as
a Lewis acid–Lewis base adduct of tris((1,2,4-diazaphosholACHTUNGREido)stannylenyl) amine N[Sn(3,5-tBu2dp)]3 with a [Sn(3,5tBu2dp)2] unit. The geometry at the Sn atom exhibits exclusively distorted pyramidal geometry with the sum of angles
at Sn(1) being 274.448 (258.158 at Sn(2)), which suggests
that the stabilization of 2 is largely due to intramolecular
contacts between the vacant p orbital at the tin atom (sp2)
with the free electron pairs of the neighboring nitrogen
atoms of the [3,5-tBu2dp] ligands or the nitride ion (Lewis
pair). The bond lengths of Sn(1) N(1) (2.241(3) ) and
Sn(1) N(6) (2.148(2) ) are close to the Sn N lengths
(SnII N 2.200(3)–2.333(3) ) associated with the imidotin
[Sn7ACHTUNGRE(2-NR)8]·n THF (R = pyrimidinyl, 5-methylpyridinyl),[17]
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Figure 2. The variable-temperature
[D8]toluene (*: unidentified).
31
P NMR
spectrum
of
2
in
60 8C, three sharp resonances were preliminarily assigned
to the three h1,h1-bridging (signals a and c) and two h1-terminal (signal b) ligands according to their intensities (a:b:c
2:2:1), which is in agreement with the structure in the
solid state. The signals coalesce at about 40 8C, and above
this temperature the new coordination mode of the ligand is
indicated, as demonstrated by a new shoulder (signal d, d =
87.2 ppm) which is almost identical to that found for [Sn(h13,5-tBu2dp)2].[16] At 80 8C, an additional new broad signal (e)
appeared at d = 84.9 ppm, but remained indistinct. These
suggest that 2 is fluxional on the NMR time-scale, probably
involving a rapid exchange between the terminal and the
bridging coordination mode. The 13C{1H} NMR spectrum
([D6]benzene, 25 8C) displays the three sets of sharp doublets for the carbon atoms of the heterocycles at d = 189.77
(d, 1JACHTUNGRE(C,P) = 240.0 Hz, PCN), 195.86 (d, 1JACHTUNGRE(C,P) = 225.5 Hz,
PCN), and 197.16 ppm (d, 1JACHTUNGRE(C,P) = 230.5 Hz, PCN), which
2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2009, 15, 6581 – 6585
1,2,4-Diazaphospholide Complexes of Tin(II)
is consistent with three different coordinated rings in 2. The
119
Sn NMR resonances (d = 126.98 (s), 170.32 ppm (s)) in
[D8]toluene were assigned to two different environments for
the metals in the solution and were only observed at low
temperatures ( 60 8C).
The nitride ion found in 2 apparently arises from the NACHTUNGRE(SiMe3)2 group, but the mechanism of its formation is currently not clear. The cleavage of Si N bonds involving NACHTUNGRE(SiMe3)2 is known,[20] but none of them gives a controlled nitride ion, which is probably related to the nature of the
ligand.[9]
The success of the transition metal–tin complexes[21] has
attracted both theoretical[22a] and experimental interests in
lanthanide–tin compounds,[22] although the examples are relatively rare. The electron lone pair on the Sn atom within
the [Sn(3,5-tBu2dp)2] unit in 2 was expected to be reactive
toward a Lewis acid and eliminate N[Sn(3,5-tBu2dp)]3. On
treatment of 2 with one or even two equivalents of samarium 1,2,4-diazaphospholide [Sm(3,5-tBu2dp)3][23] in toluene,
only the unexpected complex [NACHTUNGRE{(m3-Sn)(h1:h1-tBu2dp)}4] +
[Sm(h2-tBu2dp)4] (3) was isolated after workup as colorless
crystals in 65 % yield (Scheme 1).
The X-ray structure analysis of 3 revealed a stannylenated
ammonium ion stabilized by a samarium tetradiazaphospholido anion (Figure 3).[13, 14] The cationic moiety adopts a
Figure 3. Molecular structure of 3 (thermal ellipsoids set at 30 % probability, tBu groups are omitted for clarity). Selected bond lengths [] and
angles [8]: Sn(1) N(9) 2.151(4), Sn(1) N(3) 2.241(4), Sn(1) N(1)
2.263(4), Sn(2) N(9) 2.150(4), Sn(3) N(9) 2.140(4), Sn(4) N(9) 2.164(4),
Sm(1) N(12) 2.426(4), Sm(1) N(13) 2.435(4); Sn(3)-N(9)-Sn(2)
116.26(17), Sn(3)-N(9)-Sn(1) 106.53(15), Sn(2)-N(9)-Sn(1) 106.54(15),
Sn(3)-N(9)-Sn(4) 105.97(15), Sn(2)-N(9)-Sn(4) 107.15(15), Sn(1)-N(9)Sn(4) 114.71(16), N(12)-Sm(1)-N(13) 32.82(13); sum of the angles at
each Sn atom: Sn(1) 262.46(14)8, Sn(2) 262.80(14)8, Sn(3) 261.23(14)8,
Sn(4) 261.32(14)8; average Sn···Sn distance 3.51 .
slightly distorted tetrahedron with four tin atoms, four [3,5tBu2dp] ligands, and one tetra-metal-coordinate nitrido ion
(N3 ).[13] The arrangement of the atoms and the bond
lengths of Sn N(9) within the core (2.150(4) ), are quite
similar to those found in 2 despite one of the ligands being
removed, which is to some extent a reflection of the stability
of Sn4N(9) core. The tetrahedral structure of the ammonium
ion is obviously in obedience to the van’t Hoff model established for analogous carbon compounds and reflects the
close (isoelectronic) relationship between the NH4 + ion and
Chem. Eur. J. 2009, 15, 6581 – 6585
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the CH4 molecule.[24] The coordination sphere around the
samarium in the anion [Sm(h2ACHTUNGRE(N,N)-tBu2dp)4] possesses a
distorted tetrahedral geometry, assuming that the centers of
the N N bonds of the [3,5-tBu2dp] ligands are treated as
monodentate donors. The Sm(1) N(12) bond length
(2.426(4) ) and the N(12)-Sm-N(13) angle (32.82(13)8) are
comparable to those found in [Sm{h2ACHTUNGRE(N,N)-Ph2dp}3ACHTUNGRE(THF)3]
(Sm(1) N(1) 2.431(3) , N(3)-Sm(1)-N(4) 32.31(11)8).[9c]
The 1H NMR spectrum ([D8]toluene/[D8]THF, 25 8C) of 3
is rather complicated, and displays two sets of resonances at
d = 1.26 ppm (s, 72 H) for the CH3 groups of the anion and
at d = 0.96 (s, 3 H), 1.34 (s, 12 H), 1.38 (s, 6 H), and 2.06 ppm
(s, 51 H) for the CH3 groups of the cation. In the variabletemperature 31P{1H} NMR spectra ([D8]toluene/[D8]THF),[12]
the resonance at d = 105.65 ppm (s) for the anionic moiety is
temperature independent whereas the resonances for the
cation (d = 96.5 (s), 93.2 (s), 83.0 (s), and 77.6 ppm (s) at
60 8C) were shifted towards the resonance at d = 93.2 ppm
upon going from low to high temperatures. At about 0 8C
the signals coalesced, and above this temperature a new resonance appeared at d = 91.2 ppm. The intensity of this signal
increases gradually with the temperature. At 80 8C only two
major sharp resonances (d = 91.2 and 92.7 ppm (1:3)) were
observed and represent the nonequivalent ligands in solution, probably due to the effects of the anion. These observations suggest that the coordination of the ligands in 3 is
also an indication of the rapid exchange between the terminal and bridging position. Unfortunately, all attempts to observe 119Sn NMR spectra in [D8]toluene/[D8]THF were in
vain, even at low temperatures ( 60 8C).
While the reported metal-coordinate onium ions are exclusively stabilized by classic anions, such as BACHTUNGRE(C6F5)4 ,
OSO2CF3 , and BF4 ,[8] cations stabilized by an organometalate group are rare.[25] The isolation of 3 rather than the expected amine is probably due to the strong acidity of
[Sm(3,5-tBu2dp)3] or to the delocalization of the Sn4N(6)
core.
All attempts to obtain 15N NMR spectra of compounds 2
in [D8]toluene and 3 in [D8]toluene/[D8]THF failed due to
the fluxional processes present in solution. Therefore, we
decided to carry out theoretical calculations on complexes 2
and 3 (cation only). We removed the tert-butyl groups (complex 2’ and cation 3’) and optimized the structures by using
Dixons DGDZVP basis set because of the presence of tin
atoms.[26] Starting from the X-ray geometries, we obtained
two minima with symmetries of C2 (2’) and D2d (3’), the natures of which were confirmed by frequency calculations. By
using these geometries and the GIAO approximation,[27] we
calculated the corresponding 31P absolute shieldings (s,
ppm). To transform these values into chemical shifts (d,
ppm) we calculated, at the same level, the absolute shieldings of seven compounds (including three 1,2,4-diazaphospholes): (d, ppm) = (250 8) (0.860.02), n = 7, R2 = 0.997.[12]
With this equation we estimated the chemical shifts of 2’
(d = 82.4 (1P), 87.5 (2P), and 94.6 ppm (2P); weighted average 89.3 ppm) and 3’ (d = 99.5 ppm (4P)). These values
should be compared with 2 at 60 8C (d = 79.3 (2P), 84.0
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I. Alkorta, W. Zheng, L. Wu et al.
(2P), and d = 96.8 ppm (1P)); weighted average 88.2 ppm)
and 3 at + 80 8C (d = 91.2 (3P), 92.7 ppm (1P); weighted
average d = 91.6 ppm). The agreement is fairly good if the
absence of tert-butyl groups in the calculations, which affects
not only the chemical shifts but also the conformations of
the 1,2,4-diazaphospholide ligands, is taken into account. In
conclusion, although both complexes are fluxional in solution, complex 2 maintains a structure similar to the solid
state whereas 3 is transformed into a much less symmetric
structure, probably with a broken N Sn bond.
In summary, we have prepared two novel complexes of nitride tetrastannylene and stannylenated ammonium ion stabilized by a samarium tetradiazaphospholido counterion,
elucidated by DFT calculation at GIAO/DGDZVP level by
using the Gaussian 03 software.[29] It is expected that the reaction of M[EACHTUNGRE(SiMe3)2]2 (M = Ge, Sn; E = N, P, As) and 3,5di-tert-butyl-1,2,4-diazaphosphole will be a general reaction
and will be applicable to the preparation of a wide variety
of [(3,5-tBu2dp)M]3E[M(3,5-tBu2dp)2] species and their related onium ions. Work is proceeding along these lines.
Experimental Section
Complex 2: Sn[NACHTUNGRE(SiMe3)3]2 (0.879 g, 2.0 mmol) in hexane (30 mL) was
added by syringe to a solution of H[3,5-tBu2dp][11] (0.595 g, 3.0 mmol) in
hexane (30 mL) at RT. After the solution had been stirred for 12 h at RT,
the solvent was removed under reduced pressure. The resulting residue
was dissolved in warm hexane (50 mL) and then immediately filtered
through Celite. The solution was concentrated to give 2·hexane as orange
crystals after several days at RT (0.43 g, 55 % based on Sn). Mp > 258 8C
(decomp.); 1H NMR ([D6]benzene, 25 8C): d = 1.36 (s, 36 H; CH3]), 1.33
(br, 54 H; CH3); 13C{1H} NMR ([D6]benzene, 25 8C): d = 197.16 (d, 1JACHTUNGRE(C,P) = 230.5 Hz, PCN), 195.86 (d, 1JACHTUNGRE(C,P) = 225.5 Hz, PCN), 189.77 (d,
1
JACHTUNGRE(C,P) = 240.0 Hz, PCN), 36.07 (d, 2JACHTUNGRE(C,P) = 68.5 Hz, CCH3), 33.65 (d, 2JACHTUNGRE(C,P) = 35.0 Hz, CCH3), 33.5 (d, overlapped, CCH3), 32.32 (br, CH3),
31.93 (s, CH3), 31.05 ppm (s, CH3); 31P{1H} NMR ([D6]benzene, 25 8C):
d = 97.1 (s), 89.7 (br), 86.6 (s), 83.2 (s), 81.6 ppm (br); 119Sn NMR
([D8]toluene, 60 8C): d = 126.98 (s), 170.32 ppm (s); IR (Nujol mull):
ũ = 1573 (w), 1362 (m), 1301 (w), 1261 (m), 1200 (w), 1146 (w), 1096 (s),
1018 (m), 798 (w), 779 (w), 721 (w), 688 cm 1 (w); elemental analysis
calcd (%) for C50H90N11P5Sn4 : C 40.72, H 6.15, N 10.45; found: C 40.43,
H 6.10, N 10.38.
Complex 3: Toluene (30 mL) was added by syringe to a Schlenk flask
that contained 2 (0.390 g, 0.25 mmol) and [Sm(3,5-tBu2dp)3][23] (0.186 g,
0.25 mmol). The reaction mixture was stirred at RT for 12 h, then the solution was filtered through Celite. The filtrate was reduced under
vacuum until a white precipitate appeared. The suspension was warmed
up and the clear solution slowly cooled down to RT to afford 3 as colorless crystals (0.36 g, 65 % based on Sm). Mp > 303 8C (decomp.);
1
H NMR ([D8]toluene/[D8]THF, 25 8C): d = 1.26 (s, 72 H; CH3), 2.06 (s,
51 H; CH3), 1.38 (s, 6 H; CH3), 1.34 (s, 12 H; CH3), 0.96 ppm (s, 3 H);
13
C{1H} NMR ([D8]toluene/[D8]THF, 25 8C): d = 28.09 (s, CH3), 28.13 (s,
CH3), 29.14 (s, CH3), 30.56 (s, CH3), 32.34 (s, CH3), 33.87 (d, 2JACHTUNGRE(C,P) =
70.5 Hz, CCH3), 34.09 (s, 2JACHTUNGRE(C,P) = 25.0 Hz, CCH3), 34.52 (s, 2JACHTUNGRE(C,P) =
28.5 Hz, CCH3), 36.39 (s, 2JACHTUNGRE(C,P) = 68.5 Hz, CCH3), 37.67 (s, 2JACHTUNGRE(C,P) =
68.5 Hz, CCH3), 190.78 (d, 1JACHTUNGRE(C,P) = 223.5 Hz, PCN), 197.42 ppm (d, 1JACHTUNGRE(C,P) = 231.5 Hz, PCN); 31P{1H} NMR ([D8]toluene/[D8]THF, 25 8C): d =
105.6 (s), 92.6 (s), 89.7 ppm (br); IR (Nujol mull): ũ = 593 (w), 1395 (m),
1359 (s), 1315 (w), 1263 (m), 1219 (m), 1127 (w), 1097 (vs), 1053 (w),
1019 (m), 801 (m), 696 (s), 682 cm 1 (m); elemental analysis calcd (%)
for C80H144N17P8SmSn4 : C 43.34, H 6.55, N 10.74; found: C 43.02, H 6.49,
N 10.67.
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Acknowledgements
W.Z. is thankful to the National Natural Science Foundation of China
(Grant no. 20872017) and the Shanghai Leading Academic Discipline
Project (Grant no. B108). C.-F.P. is thankful to the Shanghai Science
Postdoctoral Foundation and to Prof. D. Y. Zhao for helpful discussions.
I.A. and J.E. are thankful to the Ministerio de Educacin y Ciencia (Project no. CTQ2007-61901/BQU-01/BQU) and Comunidad Autnoma de
Madrid (Project MADRISOLAR, reference S-0505/PPQ/0225). Thanks
are given to the CTI (CSIC) for allocation of computer time.
Keywords: ammonium
ions
·
density
calculations · heterocycles · onium ions · tin
functional
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2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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1,2,4-Diazaphospholide Complexes of Tin(II)
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[12] See the Supporting Information.
[13] Although it is difficult to distinguish a nitride ion from an oxide
(phosphide) anion in a crystal structure analysis, the presence of the
latter can be largely excluded because the assumption of an O2
(P3 ) ion in place of the N3 ion would not result in a neutral charge
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31
P{1H} NMR spectrum) for this divalent tin compound.
[14] Crystallographic data[28] for 2·hexane: formula C56H104N11P5Sn4 ; Mr =
1156.11; T = 293 K; crystal system orthorhombic; space group
C222(1); a = 14.718(5), b = 24.080(9), c = 20.149(7) ; a = b = g = 908;
V = 7141(4) 3 ; Z = 4; 1calcd = 1.452 g cm 3 ; crystal size 0.18 0.15 0.10 mm3 ; FACHTUNGRE(000) = 3168; mACHTUNGRE(MoKa) = 1.536 mm 1; 1.62 q 26.018;
7004 independent reflections (Rint = 0.0296); GOF = 0.982; final R indices were R1 = 0.0243 [I > 2s(I)] and wR2 = 0.0533 (all data); residual electron density 0.549/ 0.276 e 3. Crystallographic data for 3:
formula C80H144N17P8SmSn4 ; Mr = 2216.99; T = 293 K; crystal system
monoclinic; space group P21/c; a = 13.370(5), b = 26.470(9), c =
30.022(10) ; a = g = 908, b = 90.653(5)8; V = 10 624(6) 3 ; Z = 4;
1calcd = 1.386 g cm 3 ; crystal size 0.25 0.12 0.10 mm3 ; FACHTUNGRE(000) = 4500;
mACHTUNGRE(MoKa) = 1.636 mm 1; 1.52 q 25.018; 18 676 independent reflections (Rint = 0.0454); GOF = 0.898; final R indices were R1 = 0.0397
[I > 2s(I)] and wR2 = 0.0790 (all data); residual electron density
0.707/ 0.431 e 3. MoKa radiation (l = 0.71073). CCDC-713387 (2)
and -713388 (3) contain the supplementary crystallographic data for
this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
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C20H36N4P2Sn; Mr = 513.16; crystal system orthorhombic; space
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2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Received: April 2, 2009
Published online: June 4, 2009
www.chemeurj.org
6585