H11B11Sn2ꢀ) is thus evisaged for this particular coordination
environment.[23] Further examples are found with compounds
Keywords: coordination chemistry · hypercoordination ·
palladium · tin · transition-metal basicity
.
ꢀ
comprising a {TM SnE5} pattern, with TM being a Group 6
element.[24] According to the isolobal concept, these TM
centers appear less likely to act as lone-pair donors rather
than being acceptors for a stannylene or stannyl lone pair.
[2] a) R. Sowa, Jr., V. Zanotti, G. Facchin, R. J. Angelici, J. Am.
ꢀ
Although only a very limited number of examples for {TM
ꢀ
SnE5} and {TM SnE4} complexes were reported for electron-
rich TM centers,[5,6,18] the comparison of 1 and 2 has shown
[3] a) A. F. Hill, G. R. Owen, A. J. P. White, D. J. Williams, Angew.
Sircoglou, M. Mercy, N. Saffon, Y. Coppel, G. Bouhadir, L.
Bouhadir, W. Gu, M. Mercy, C.-H. Chen, B. M. Foxman, L.
Sircoglou, G. Bouhadir, N. Saffon, K. Miqueu, D. Bourissou,
ꢀ
that even in complexes of the general type {TM SnE4} (with
pentacoordinate tin), the interpretation as a metallastanna-
(IV)ocane-like compound might be appropriate. Thus, it
should be pointed out that other presumed stannylene
complexes of late TMs comprising a pentacoordinate tin
atom[25] might exhibit similar features (that is, tin in an
oxidation state of more than + II). As to seemingly simple
stannylene complexes, even compounds such as [Cl2Sn =
Fe(CO)4][26] (or derivatives thereof) might thus reveal sig-
!
nificant contributions of a [Cl2SnIV]2+ [FeꢀII(CO)4]2ꢀ form in
addition to the widely accepted interpretation as a [Cl2SnII]!
[Fe0(CO)4] stannylene complex, the former being also sup-
ported by the easy accessibility and stability of the dianion
[FeꢀII(CO)4]2ꢀ. The extension of this work to the applicability
of the ylene ligand model would include various ligands with
metalloid donor atoms, such as the related germylenes and
silylenes, and also alumylene, gallylene, arsine, and stibine
ligand systems, the lone-pair donor sites of which have the
potential of exhibiting a higher oxidation state (Al, Ga: + III
instead of + I; As, Sb: + V instead of + III), thus reverting
the formal roles of s-donor and s-acceptor.
Angew. Chem. Int. Ed. 2010, 49, 624 – 627; b) L. A. Truflandier,
[6] a) P. Gualco, T.-P. Lin, M. Sircoglou, M. Mercy, S. Ladeira, G.
Bouhadir, L. M. Pꢃrez, A. Amgoune, L. Maron, F. P. Gabbaꢀ, D.
Bourissou, Angew. Chem. 2009, 121, 10076 – 10079; Angew.
Mercy, S. Ladeira, Y. Coppel, L. Maron, A. Amgoune, D.
Experimental Section
1: A freshly prepared solution of potassium methimazolide, prepared
by addition of a KN(SiMe3)2 solution in toluene (0.5m, 4 mL) to a
solution of methimazole (0.23 g, 2.0 mmol) in THF (5 mL), was added
to a suspension of [PdCl2(PPh3)2] (0.70 g, 1.0 mmol) in THF (5 mL),
whereupon an orange-red solution was obtained. Upon gentle
heating, an orange precipitate formed. Solid [SnCl2(dioxane)][27]
(0.28 g, 1.0 mmol) was then added and the mixture was stirred to
give a clear red solution from which a pink precipitate separated
within five minutes. The solid thus obtained was filtered off, washed
with THF (5 mL), and extracted with dichloromethane. Removal of
the solvent afforded red crystals of 1 (0.66 g, 0.84 mmol, 84%).
[8] CCDC 798517 (1), 798518 (2), 798516 (3), and 798515
(4·2CHCl3)) 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.
Elemental
(784.58 gmolꢀ1): C 39.80, H 3.21, N 7.14; found: C 39.71, H 3.30,
N 7.14. 2: Ligand H2ONN (0.07 g, 0.32 mmol) and (0.25 g,
analysis (%)
calcd
for
C26H25Cl2N4PPdS2Sn
¯
R values with [I > 2s(I)]: 1: P1, a = 8.8002(2), b = 11.7182(2), c =
1
15.9093(3) ꢁ, a = 105.695(1), b = 94.980(1), g = 108.940(1)8,
R1 = 0.0197, wR2 = 0.0484. 2: Pbca, a = 17.7179(4), b =
0.32 mmol) were stirred in dichloromethane (10 mL), and triethyl-
amine (ca. 0.1 g, 0.99 mmol) was added, whereupon the red crystals of
1 dissolved and a yellow solution formed. Upon addition of ethanol
(15 mL), yellow crystals of 2 formed, which, upon evaporation of
some dichloromethane (ca. 5 mL), were separated by decantation,
washed with ethanol (5 mL), and dried in air. Yield: 0.28 g,
¯
16.0002(3), c = 25.8367(6) ꢁ, R1 = 0.0289, wR2 = 0.0590. 3: P1,
a = 7.5602(3), b = 11.6779(6), c = 12.3307(7) ꢁ, a = 81.511(2),
b = 89.378(2), g = 77.907(2)8, R1 = 0.0397, wR2 = 0.0662.
4·(CHCl3)2:
P21/c,
a = 8.5042(2),
b = 11.1156(3),
c =
15.8801(3) ꢁ, b = 91.616(1)8, R1 = 0.0244, wR2 = 0.0367.
0.30 mmol,
94%.
Elemental
analysis (%)
calcd
for
[9] a) V. N. Khrustalev, I. A. Portnyagin, M. S. Nechaev, S. S.
Schiemenz, K. Heinze, L. Zsolnai, O. Walter, A. Jacobi, A.
C37H34N7O2PPdS2Sn (928.89 gmolꢀ1): C 47.84, H 3.69, N 10.56;
found: C 47.47, H 3.92, N 10.19. Compounds 1 and 2 decompose
upon heating without melting. For 1H, 13C, 31P, and 119Sn NMR
spectroscopic data and details of computational analyses, see the
Supporting Information.
Received: December 16, 2010
Published online: April 14, 2011
[10] a) R.-D. Hoffmann, D. Kußmann, U. C. Rodewald, R. Pꢂttgen,
C. Rosenhahn, B. D. Mosel, Z. Naturforsch. B 1999, 54, 709 –
Angew. Chem. Int. Ed. 2011, 50, 4696 –4700
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim