Silver Dimer, Tetramer, Polymer, and Network Structures with the

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4906

Organometallics 2010, 29, 4906–4913 DOI: 10.1021/om1001556

Silver Dimer, Tetramer, Polymer, and Network Structures with the Stannylene Stanna-closo-dodecaborate† Hartmut Schubert and Lars Wesemann* Institut f€ ur Anorganische Chemie der Universit€ at T€ ubingen Auf der Morgenstelle 18, 72076 T€ ubingen, Germany Received February 25, 2010

The reaction of the tin nucleophile stanna-closo-dodecaborate [SnB11H11]2- with silver electrophiles resulted in the formation of silver-tin complexes. Depending on the respective co-ligands, a dimer, a tetramer, a polymer, and a three-dimensional network structure were characterized. With bipyridine and phenanthroline, dimeric complexes exhibiting very short Ag-Ag interatomic distances were isolated. With t-BuNC and pyridine, tetranuclear clusters showing tetrahedral geometry were crystallized. From the reaction of the silver salt [Et4N]8[Ag4(SnB11H11)6] with the bridging ligand 1,4-diisocyanobenzene (DIB) a linear polymeric coordination compound was formed, and a three-dimensional network structure was the product from the reaction of 1,4diisocyanobenzene with the silver salt [Me4N][Ag(SnB11H11)]. The coordination compounds were characterized by X-ray crystal structure analysis and elemental analysis. In the case of the threedimensional network material {[Me4N]4[Ag4(SnB11H11)4(DIB)6/2]}n (12) a single crystal to single crystal solvent exchange was found.

Introduction The coordination chemistry of coinage metal electrophiles with heavy main group element ligands often results in the formation of clusters.1-7 The influence of the electronic and steric effects of these main group element ligands on the size of the clusters is still an attractive field of research. We investigated the coordination chemistry of heteroborates and especially of clusters with four element donor sites such as the dianionic stanna-closo-dodecaborate [SnB11H11]2- 8-15 and germa-closo-dodecaborate [GeB11H11]2-.16 In reaction with the metals of the nickel triad we found square-planar and octahedral coordination with the transition metals in † Part of the Dietmar Seyferth Festschrift. *Corresponding author. E-mail: [email protected]. (1) Spiekermann, A.; Hoffmann, S. D.; F€assler, T. F.; Krossing, I.; Preiss, U. Angew. Chem., Int. Ed. 2007, 46, 5310. (2) Spiekermann, A.; Hoffmann, S. D.; Kraus, F.; F€assler, T. F. Angew. Chem., Int. Ed. 2007, 46, 1638. (3) Schenk, C.; Schnepf, A. Angew. Chem., Int. Ed. 2007, 46, 5314. (4) Bumbu, O.; Ceamanos, C.; Crespo, O.; Gimeno, M. C.; Laguna, A.; Silvestru, C.; Villacampa, M. D. Inorg. Chem. 2007, 46, 11457. (5) Fenske, D.; Rothenberger, A.; Wieber, S. Eur. J. Inorg. Chem. 2007, 648. (6) Sevillano, P.; Fuhr, O.; Kattannek, M.; Nava, P.; Hampe, O.; Lebedkin, S.; Ahlrichs, R.; Fenske, D.; Kappes, M. Angew. Chem., Int. Ed. 2006, 45, 3702. (7) Olkowska-Oetzel, J.; Sevillano, P.; Eichh€ ofer, A.; Fenske, D. Eur. J. Inorg. Chem. 2004, 1100. (8) Marx, T.; Wesemann, L.; Dehnen, S.; Patenburg, I. Chem.-Eur. J. 2001, 7, 3025. (9) Wesemann, L.; Hagen, S.; Marx, T.; Patenburg, I.; Nobis, M.; Driessen-H€ olscher, B. Eur. J. Inorg. Chem. 2002, 2261. (10) Marx, T.; Mosel, B.; Patenburg, I.; Hagen, S.; Schulze, H.; Wesemann, L. Chem.-Eur. J. 2003, 9, 4472. (11) Wesemann, L. Z. Anorg. Allg. Chem. 2004, 630, 1349. (12) G€ adt, T.; Wesemann, L. Organometallics 2007, 26, 2474.

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formal oxidation state 2 or 4.13 With ruthenium electrophiles the tin borate shows reversible coordination between tin and BH coordination modes.17,18 A surprising Au-Sn cluster formation was found in reaction of the tin nucleophile with gold and silver electrophiles (Chart 1).19-21 In the first example of this coinage metal chemistry we isolated with the [Ph3PAu]þ fragment a molecule showing the tin ligand in a bridging coordination mode between two gold atoms. The Au2Sn2 structure (type 1 in Chart 1) exhibits a very short interatomic distance of 2.63 A˚ between the gold atoms.19 Investigated by quantum chemical calculations, dispersive interactions between the four metals of the Au-Sn cluster core are responsible for the stabilization of this skeleton.19 The influence of the size of the phosphine coligand in this cluster formation was studied with the electrophiles [Ph3PAg]þ, [Et3PAg]þ, and [Me3PAg]þ. In this series a dimer, a trimer, and a tetramer were isolated (Chart 1).21 (13) Kirchmann, M.; Eichele, K.; Schappacher, F. M.; P€ ottgen, R.; Wesemann, L. Angew. Chem., Int. Ed. 2008, 47, 963. (14) Kirchmann, M.; Fleischhauer, S.; Wesemann, L. Organometallics 2008, 27, 2803. (15) Marx, T.; Wesemann, L.; Dehnen, S. Z. Anorg. Allg. Chem. 2001, 627, 1146. (16) Dimmer, J.-A.; Schubert, H.; Wesemann, L. Chem.-Eur. J. 2009, 15, 10613. (17) G€adt, T.; Grau, B.; Eichele, K.; Pantenburg, I.; Wesemann, L. Chem.-Eur. J. 2006, 12, 1036. (18) G€adt, T.; Wesemann, L. Dalton Trans. 2006, 328. (19) Hagen, S.; Pantenburg, I.; Weigend, F.; Wickleder, C.; Wesemann, L. Angew. Chem. 2003, 115, 1539. (20) Hagen, S.; Wesemann, L.; Pantenburg, I. Chem. Commun. 2005, 1013. (21) Hagen, S.; Schubert, H.; Maichle-M€ ossmer, C.; Pantenburg, I.; Weigend, F.; Wesemann, L. Inorg. Chem. 2007, 46, 6775. (22) For details of the crystal structures of 5, 6, and 9 see the Supporting Information. r 2010 American Chemical Society

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Chart 1. Series of Silver Tin Compounds [Ag2(SnB11H11)2(PPh3)2]2- (1), [Ag3(SnB11H11)3(PEt3)3]3- (2), and [Ag4(SnB11H11)4(PMe3)4]4- (3)a

For 1 and 2 the analogous gold complexes are also known (Sn0 = [SnB11H11]2-). a

Without a coordinating phosphine the silver cluster [Et4N]8[Ag4(SnB11H11)6] (4) (Figure 1) composed of four silver cations and six tin borate nucleophiles was isolated in good yield.21 So far we have characterized clusters with the coinage metals silver and gold carrying a phosphine as a coligand. In this publication we report on silver tin clusters with the stannylene stanna-closo-dodecaborate and co-ligands such as pyridine, bipyridine, and isonitriles. In these syntheses the salt [Et4N]8[Ag4(SnB11H11)6] (4) serves as a versatile starting material.

Figure 1. Silver-tin cluster 4 from the reaction of [Et4N]2[SnB11H11] with AgNO3. Scheme 1. Formation of the 2,20 -Bipyridine Complex [Et4N]2[{Ag(SnB11H11)bipy}2] (5)a

Results and Discussion Synthesis and Solid-State Structures. The cluster formation reaction between coinage metals and the stanna-closododecaborate ligand has been published so far only with phosphines as co-ligands and in one case without a coligand.19-21 Since we are very much interested in a general application of this reaction, we have investigated other coligands in this context. We started our investigations and reacted silver nitrate with the heteroborate reagent together with selected co-ligands such as isonitriles and pyridines. However from this one-pot procedure we were not able to isolate any defined product. With the silver-tin cluster [Et4N]8[Ag4(SnB11H11)6] (4) synthesized simply by mixing silver nitrate and the salt [Et4N]2[SnB11H11] we found a new versatile starting material for cluster syntheses.21 From the reaction of the silver salt [Et4N]8[Ag4(SnB11H11)6] purified by crystallization with 2,20 -bipyridine (bipy), 5,50 -dimethyl-2,20 -bipyridine (mbipy), and 1,100 -phenanthroline (phen) we have isolated three dinuclear silver complexes (5-7) with bridging tin ligands and chelating nitrogen ligands. The structures of the three dinuclear complexes were determined in the solid state by single-crystal structure analysis. In Figure 2 the molecular structure of the dianion of the phenanthroline complex 7 is shown, and in the Supporting Information the results of the crystal structure solutions of complex 5 and 6 are presented.22 The Ag-Ag distances in these complexes are in a close range of 2.6366(10) A˚ in [Et4N]2[{Ag(SnB11H11)bipy}2] (5), 2.6493(12) A˚ in [Et4N]2[{Ag(SnB11H11)mbipy}2] (6), and 2.6485(4) A˚ in [Et4N]2[{Ag(SnB11H11)phen}2] (7). These very short Ag-Ag interatomic distances are shorter than the comparable distance in the phosphine adduct [{Ag(SnB11H11)PPh3}2]2[2.7160(4) A˚] and the Ag-Ag distance in metallic silver [2.89 A˚].21 Furthermore, the found Ag-Ag contacts belong to

a In analogy with the synthesis of compound 5 complexes with ligands 5,50 -dimethyl-2,20 -bipyridine (6) and 1,100 -phenanthroline (7) were isolated.

the group of the shortest values known in the literature.23-34 In [{Ag(SnB11H11)PEt3}3]3- we found, with 2.6326(10) A˚,21 an example with a shorter Ag-Ag distance, and in diaryltriazene- and amidinate-bridged dimers the Ag-Ag bond length is only a little bit longer.23-25 In the complexes 5-7 an interesting distortion in the solid state was detected: the plane through the nitrogen atoms is not perpendicular to the plane through the tin and silver atoms (Figure 2). Probably due to packing forces, the angle between the best planes through the nitrogen atoms and the four Sn and Ag atoms ranges from 65° to 76°. (23) Beck, J.; Str€ahle, J. Z. Naturforsch., B: Chem. Sci. 1986, 41, 4. (24) Hartmann, E.; Schmid, R.; Str€ahle, J. Z. Naturforsch., B: Chem. Sci. 1989, 44, 778. (25) Fenske, D.; Baum, G.; Zhu, A.; Dehnicke, K. Z. Naturforsch. B: Chem. Sci. 1990, 45, 1273. (26) Catalano, V. J.; Malwitz, M. A. Inorg. Chem. 2003, 42, 5483. (27) Garrison, J. C.; Simons, R. S.; Tessier, C. A.; Youngs, W. J. J. Organomet. Chem. 2003, 673, 1. (28) Wang, X.-J.; Langtepe, T.; Fenske, D.; Kang, B.-S. Z. Allg. Anorg. Chem. 2002, 628, 1158. (29) Bowmaker, G. A.; Harvey; Effendy, P. J.; Healy, P. C.; Skelton, B. W.; White, A. H. Dalton Trans. 1996, 2459. (30) Fenske, D.; Simon., S. Z. Anorg. Allg. Chem. 1996, 622, 45. (31) Papasergio, R. I.; Raston, C. L.; White, A. H. Dalton Trans. 1987, 3085. (32) Gorol, M.; M€ osch-Zanetti, N. C.; Roesky, H. W.; Noltemeyer, M.; Schmidt, H.-G. Chem. Commun. 2003, 46. (33) Papasergio, R. I.; Raston, C. L.; White, A. H. Chem. Commun. 1984, 612. (34) Findeis, B.; Gade, L. H.; Scoven, I. J.; McPartlin, M. Inorg. Chem. 1997, 36, 960.

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Figure 2. Diamond plot of the anion of [Et4N]2[{Ag(SnB11H11)phen}2] (7) in two projections. The cations have been omitted for clarity; ellipsoids are at 50% probability. Interatomic distances [A˚] and angles [deg]: Ag1-Ag2 2.6485(4), Ag1-Sn1 2.7909(4), Ag1-Sn2 2.7671(4), Ag2-Sn1 2.7201(4), Ag2-Sn2 2.7891(4), Ag1-N3 2.315(3), Ag1-N4 2.339(3), Ag2-N1 2.314(3), Ag2-N2 2.308(3), Ag1-Sn1-Ag2 57.430(10), Ag1-Sn2-Ag2 56.935(9), Sn1-Ag1-Sn2 121.013(12), Sn1-Ag2-Sn2 122.833(13). Angles between the best planes through the nitrogen atoms and the Sn2Ag2 square: bipy 76°, mbipy 65°, phen 74°. Scheme 2. Formation of the Tetranuclear Pyridine Adduct [Et3MeN]4[{Ag(SnB11H11)py}4] (8)a

a

Clusters without boron atoms.

Scheme 3. Formation of the Tetranuclear Isonitrile Adduct [Et4N]4[{Ag(SnB11H11)(t-BuNC)}4] (9)a

a

Clusters without boron atoms.

In the reaction of the Ag4Sn6 cluster 4 with monodentate ligands such as pyridine and tert-butylisonitrile we have found formation of tetranuclear complexes with tetrahedral cluster cores. The geometry of the clusters 8 and 9 can be compared with the trimethylphosphine reaction product [{Ag(SnB11H11)(PMe3)}4]4- (Chart 1 type 3), which was isolated from the reaction of AgCl, PMe3, and nucleophilic tin ligand [SnB11H11]2-. In complexes 8 and 9 a tetrahedron of silver atoms is surrounded by four tin ligands coordinating

Figure 3. Diamond plot of the anion of [Et4N]2[{Ag(SnB11H11)py}4] (8). The cations, the hydrogen atoms, and the boron atoms have been omitted for clarity; ellipsoids are at 50% probability. Interatomic distances [A˚]: Ag1-Ag20 2.8092(4), Ag1-Ag10 2.8178(5), Ag1-Ag2 2.8277(4), Ag10 -Ag2 2.8092(4), Ag2Ag20 2.8686(6), Ag1-Sn1 2.8194(4), Ag1-Sn10 2.8774(4), Ag1-Sn2 3.0749(4), Ag2-Sn2 2.7856(4), Ag20 -Sn2 2.8928(4), Ag10 -Sn1 2.8773(4), Ag2-Sn1 3.0742(4), Ag2-Sn20 2.8928(4), Ag1-N1 2.229(3), Ag2-N2 2.212(3).

at the triangles of the tetrahedron and four co-ligands ligating the silver electrophile. The silver complexes were characterized by elemental analysis and single-crystal structure analysis. In Figure 3 only the tetraanion of the pyridine adduct is presented and important distances are listed. The Ag-Ag distances of the pyridine adduct and the tert-butylisonitrile adduct (see the Supporting Information for details) are closely related and in the range of the published trimethylphosphine derivative [{Ag(SnB11H11)PMe3}4]4-.21 The size of the silver cluster depends on the sterical demand of the co-ligand, and obvoiusly in the case of the pyridine and tert-butylisonitrile molecules the ligands are small enough to realize a tetrameric cluster. The Ag-Ag interatomic distances in both silver cores of 8 and 9 are in the range 2.7917(8)-2.8540(8) A˚ and belong in the class of comparable silver tetrahedra to the

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Scheme 4. Formation of the Polymer {[Et4N]14[Ag10(SnB11H11)12(DIB)3]}n (10)a

a

L = 1, 4-diisocyanobenzene (DIB); clusters without boron atoms.

group of short Ag-Ag contacts.35-40 The Ag-Sn distances are longer than the respective interatomic distances in the Ag2Sn2 dimer (Chart 1 type 1) and are comparable with the bond lengths in the published tertramer [{Ag(SnB11H11)PMe3}4]4-.21 Generally the Ag-Sn distances in stannacloso-dodecaborate coordination chemistry increase on an average from Ag-Sn single bond (2.65 A˚) to bridging modes μ2-Sn-Ag2 (2.70-2.83 A˚) to μ3-Sn-Ag3 (2.77-3.11 A˚).21 Stimulated by these results we reacted the starting material 4 with a trans bridging ligand in order to synthesize aggregated structures. The diisonitrile 1,4-diisocyanobenzene (DIB), which is known to form polymers in coordination chemistry, was reacted in acetonitrile at room temperature with the silver-tin complex 4.41-48 From this mixture we isolated green crystals consisting of a polymeric anion with a tin-silver cluster building unit (Scheme 4). These units are connected to give a polymer on one side via two and on the other via one bridging diisonitrile ligand. (35) Henkel, G.; Betz, P.; Krebs, B. Angew. Chem. 1987, 26, 145. (36) Fenske, D.; Langetepe, T. Angew. Chem. 2002, 41, 300. (37) Canales, S.; Crespo, O.; Gimeno, M. C.; Jones, P. G.; Laguna, A.; Silvestru, A. Inorg. Chim. Acta 2003, 347, 16. (38) Kanatzidis, M. G.; Huang, S.-P. Angew. Chem. 1989, 28, 1513. (39) Zhao, J.; Adcock, D.; Pennington, W. T.; Kolis, J. W. Inorg. Chem. 1990, 29, 4358. (40) Schuerman, J. A.; Fronczek, F. R.; Selbin, J. Inorg. Chim. Acta 1989, 160, 43. (41) Guitard, A.; Mari, A.; Beauchamp, A. L.; Dartiguenave, Y.; Dartiguenave, M. Inorg. Chem. 1983, 22, 1603. (42) Fortin, D.; Drouin, M.; Harvey, P. D. Inorg. Chem. 2000, 39, 2758. (43) Irvin, M. J.; Rendina, L. M.; Vittal, J. J.; Puddephatt, R. J. Chem. Commun. 1996, 1281. (44) Irvin, M. J.; Vittal, J. J.; Puddephatt, R. J. Organometallics 1997, 16, 3541. (45) Irvin, M. J.; Jia, G.; Payne, N. C.; Puddephatt, R. J. Organometallics 1996, 15, 51. (46) Berube, J.-F.; Gagnon, K.; Fortin, D.; Decken, A.; Harvey, P. D. Inorg. Chem. 2006, 45, 2812.  (47) Coco, S.; Cordovilla, C.; Espinet, P.; Martin-Alvarez, J.; Mu~ noz, P. Inorg. Chem. 2006, 45, 10180. (48) Ito, H.; Saito, T.; Oshima, N.; Kitamura, N.; Ishizaka, S.; Hinatsu, Y.; Wakeshima, M.; Kato, M.; Tsuge, K.; Sawamura, M. J. Am. Chem. Soc. 2008, 130, 10044.

Figure 4. Diamond plot of the tin-silver cluster unit of the polymer {[Et4N]14[Ag10(SnB11H11)12(DIB)3]}n (10). The cations, the hydrogen atoms, the boron atoms, and the connecting phenyl rings have been omitted for clarity; ellipsoids are at 50% probability. Interatomic distances [A˚]: Ag1-Ag2 2.7778(8), Ag1-Ag3 2.8510(8), Ag2-Ag3 2.8983(7), Ag2-Ag4 2.9165(8), Ag2-Ag5 2.9276(8), Ag3-Ag4 2.8959(8), Ag3-Ag5 2.9331(9), Ag4-Ag5 2.8659(11), Sn1-Ag1 3.2628(8), Sn1-Ag2 2.6793(7), Sn2-Ag1 3.5377(8), Sn2-Ag3 2.6513(7), Sn3-Ag1 2.8976(7), Sn3- Ag2 2.9553(7), Sn3-Ag3 2.9537(7), Sn3-Ag4 3.0852(9), Sn4-Ag1 2.9070(8), Sn4-Ag2 2.9274(7), Sn4-Ag3 2.8898(7), Sn4-Ag5 3.0332(8), Sn5-Ag2 2.7135(7), Sn5-Ag4 3.0928(10), Sn5-Ag5 3.1681(9), Sn6-Ag3 2.7276(7), Sn6-Ag4 3.0679(10), Sn6-Ag5 3.0269(9), Ag1-C1 2.151(7), Ag4-C2 2.160(7), Ag5-C3 2.158(7), C1-N1 1.149(8), C2-N2 1.140(9), C3-N3 1.154(9).

Figure 5. Diamond plot of the tin-silver cluster unit of the polymer {[Et4N]14[Ag10(SnB11H11)12(DIB)3]}n (10). The cations and the connecting phenyl rings have been omitted for clarity. Two boron clusters with hydrogen atoms are presented. Ellipsoids are at 50% probability. Interatomic distances [A˚]: Ag4-B3 2.92(1), Ag4-B4 2.92(1), Ag5-B1 2.88(1), Ag5-B1 2.94(1).

The polymer was characterized by elemental analysis and single-crystal structure determination. In Figures 4 and 5 the tin-silver cluster unit of the polyanionic coordination polymer is shown. Important interatomic distances and angles are listed. In the polymer the silver-tin units are bridged by two or one 1,4-diisocyanobenzene ligand. The geometry of the monomeric unit can be compared with a pentagonal bipyramid (Ag5Sn2) capped by two μ3- and two μ2-tin ligands (Figure 4). In the solid-state structure the boron cluster at Sn6 shows a disorder. In the Sn-Ag cluster core of the polymer 10 the Ag-Ag distances vary between 2.7778(8) and 2.9331(9) A˚ and the Ag-Sn distances between 2.6793(7) and 3.5377(8) A˚. The Ag-Ag distances can be compared with the value in metallic

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Figure 6. Space-filling model of the polymer 10 (cations are omitted, boron atoms green, tin atoms pale blue, silver atoms red, nitrogen atoms blue, carbon atoms gray). The octahedral surrounding of the silver cluster by the heteroboranes is evident. Scheme 5. Formation of the Network Structure {[Me4N]4[Ag4(SnB11H11)4(DIB)6/2]}n (12)a

Figure 7. Diamond plot of the building unit of the network structure {[Me4N]4[Ag4(SnB11H11)4(DIB)6/2]}n (12). The cations, the hydrogen atoms, the boron atoms, and the connecting phenyl rings have been omitted for clarity; ellipsoids are at 50% probability. Interatomic distances [A˚]: Ag1-Ag2 3.0549(9), Ag1-Ag3 3.2512(12), Ag2-Ag20 2.8388(11), Ag2-Ag3 2.7408(9), Sn1-Ag2 2.7776(8), Sn1-Ag3 2.9093(6), Sn2-Ag2 2.8257(9), Sn3-Ag2 2.9483(9), Sn3-Ag3 2.8922(11), Ag1-C1 2.194(11), Ag1-C2 2.198(8), Ag2-C3 2.152(8), Ag3-C4 2.140(10).

a Clusters without boron atoms. Only half of the bridging diisonitrile molecules are drawn.

silver, 2.89 A˚. In the case of the Ag-Sn distances the very long interatomic distances belong to the tin ligands Sn1 and Sn2, which show a short bond to Ag3 [Sn2-Ag3 2.6513(7) A˚] and Ag2 [Sn1-Ag2 2.6793(7) A˚] and a relatively long value to Ag1. Both clusters Sn1 and Sn2 can be interpreted as single bonded to the silver cluster. The μ3-coordinated heteroborates with Sn5 and Sn6 show bond lengths that are typical for this type of stannaborate bridging coordination mode. In the case of the clusters of Sn3 and Sn4 four silver atoms are coordinated at each tin and two BH units of each stannaborate skeleton are coordinated at silver atoms (Figure 5). The six heteroborate units nearly form an octahedral arrangement around the silver cluster core. In Figure 6 the spacefilling model exhibits the heteroborate packing in the coordination polymer. Since we are aware of the influence of the countercation on the structures of the polyanionic clusters we have varied the tetraalkylammonium cations in the synthesis of the starting material 4. With the tetramethylammonium cation another starting material was isolated from the mixture of silver nitrate and the tetramethylammonium stanna-closododecaborate salt: [Me4N]2[SnB11H11]. Crystals of this reaction product were not of the quality to result in a satisfying structural solution, but the elemental analysis of the crystals reveals the composition [Me4N][Ag(SnB11H11)] (11).

The reaction between the coordinating 1,4-diisocyanobenzene and this silver tetramethylammonium salt was carried out in a mixture of benzonitrile and acetonitrile (Scheme 5). After two days yellow crystals were isolated and characterized by elemental analysis and crystal structure determination, exhibiting a polyanionic network structure. In the coordination network structure of 12 the silver atoms form a tetrahedron (Figure 7) that is surrounded by three μ2- and one μ3-coordinated stanna-closo-dodecaborate ligand. As expected, the Ag-Ag distances in the tetrahedron bridged by a tin ligand (Ag2-Ag20 , Ag2-Ag3, Ag20 -Ag3) are shorter than the unbridged Ag-Ag bonds. Furthermore the μ2-coordinated tin ligands show shorter contacts to silver than the μ3-coordinated ligand. The Ag-Ag and Ag-Sn contacts exhibit distances in the range of compounds known for SnB11H11 silver coordination chemistry. In Figures 8 and 9 a view along the c axis without the cations and the incorporated solvent molecules is presented. In these figures the hexagonal channels with six clusters pointing toward the center are visible. Especially in Figure 9 a channel along the c axis is evident. In these channels we find the position of the solvent molecules acetonitrile and benzonitrile. Projections of the other planes, a-c and b-c, are presented in the Supporting Information. By layering the insoluble crystals of 12 with dichloromethane we were able to exchange the acetonitrile and benzonitrile molecules with dichloromethane molecules. After 24 h in dichloromethane the crystals were still of the quality to give a satisfying single-crystal structure analysis and the dichloromethane molecules were found inside the channels. A reversible single crystal to single crystal exchange of guest molecules ethanol and cyclohexane

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Figure 8. View along plane a-b, without incorporated acetonitrile, benzonitrile, and countercations.

was reported for a zinc porphyrin network structure.49 The search for porous materials and their construction with organometallic reagents is currently of great interest.49-53 However the reported silver-tin network structure 12 is not stable without solvent, and a repeated solvent exchange is not possible.

Conclusion With the dianionic stannylene stanna-closo-dodecaborate [SnB11H11]2- silver tin aggregation with co-ligands such as pyridines and isonitriles results in the formation of dimers, tetramers, polymers, and network structured materials. The tin-bridged silver-silver contacts show very short interatomic Ag-Ag distances.

Experimental Section General Comments. All manipulations were carried out under argon atmosphere in Schlenk glassware. Solvents were dried and purified by standard methods and were stored under argon. NMR spectra were recorded on a Bruker DRX-250 NMR spectrometer equipped with a 5 mm ATM probe head and operating at 250.13 MHz (1H) and 80.25 MHz (11B). Chemical shifts are reported in δ values in ppm relative to external TMS (49) Deiters, E.; Bulach, V.; Hosseini, M. W. Chem. Commun. 2005, 3906. (50) Chui, S. S.-Y.; Lo, S. M.-F.; Charmant, J. P. H.; Orpen, A. G.; Williams, I. D. Science 1999, 283, 1148. (51) Lefebvre, J.; Batchelor, R. J.; Leznoff, D. B. J. Am. Chem. Soc. 2004, 126, 16117. (52) Ohmori, O.; Kawano, M.; Fujita, M. CrystEngComm 2005, 7, 255. (53) Braga, D. Chem. Commun. 2003, 2751.

(1H) or BF3 3 Et2O (11B) using the chemical shift of the solvent 2H resonance frequency. Elemental analyses were carried out with an Vario EL elemental analyzer from Elementar Co. operating in CHNS modus. Starting materials stanna-closododecaborate,54 2,20 -bipyridine, 1,100 -phenanthroline, 1,4-diisocyanobenzene (DIB), and tert-butylisonitrile were purchased commercially; 5,50 -dimethyl-2,20 -dipyridine (mbipy) and [Et4N]8[Ag4(SnB11H11)6] were prepared according to literature methods or modifications thereof. Crystallography. X-ray data for compounds 5-10 and 12 were collected on a Stoe IPDS 2T diffractometer and were corrected for Lorentz and polarization effects and absorption by air. Probably due to partial loss of solvent, the crystals of 12 were not of the highest quality. Furthermore one of the included benzonitrile molecules shows a severe disorder; therefore one hydrogen atom was not calculated. The hydrogen atoms of the included and severe disordered acetonitrile molecules were also not calculated, giving the respected empirical formula in Table 1. The programs used in this work are Stoe’s X-Area55 and the WinGX suite56 of programs including SHELXS and SHELXL57,58 for structure solution and refinement. Numerical absorption correction based on crystal-shape optimization was applied for 4 with Stoe’s X-Red and X-Shape.59 (54) Chapman, R. W.; Chester, J. G.; Folting, K.; Streib, W. E.; Todd, L. J. Inorg. Chem. 1992, 31, 979. (55) X-AREA 1.26; Stoe & Cie GmbH: Darmstadt, 2004. (56) Farrugia, L. F. J. Appl. Crystallogr. 1999, 32, 837. (57) Sheldrick, G. M. SHELXS 97, Program for the Solution of Crystal Structures; G€ottingen, 1997. (58) Sheldrick, G. M. SHELXS 97, Program of the Crystal Structure Refinement; G€ottingen, 1997. (59) (a) X-RED 1.26, Data Reduction for STAD4 and IPDS; Stoe & Cie: Darmstadt, 1996. (b) X-SHAPE 2.05, Crystal Optimization for Absorption Correction; Stoe & Cie: Darmstadt, 1996.

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Figure 9. Perspective view along axis c, without incorporated acetonitrile, benzonitrile molecules, and countercations. The dinuclear silver(I) complexes 5-7 were prepared according to the following general procedure: To a solution of 80 mg of [Et4N]8[Ag4(SnB11H11)6] (0.027 mmol) in 10 mL of acetonitrile was added the NN ligand (0.16 mmol). After stirring this mixture for 30 min and filtration through Celite, colorless crystals were obtained by slow diffusion of diethyl ether into the acetonitrile phase. [Et4N]2[Ag2(SnB11H11)2(bipy)2] (5). Yield: 43 mg (62%). 1H NMR (CH3CN): δ 8.82 (br, 4H, bipy), 8.35 (br, 4H, bipy), 8.0 (br, 4H, bipy), 7.52 (br, 4H, bipy), 3.16 (q, 16H, N-CH2-CH3), 1.21 (t,24H, CH2-CH3). 11B{1H} NMR (CH3CN): δ -13.2 (s, 10B, B2-B11), -4.8 (s, 1B, B12). Anal. Calcd for C36H78B22Ag2N6Sn2 (1286.05): C, 33.62; H, 6.11; N, 6.58. Found: C, 33.64; H, 7.18; N, 6.71. [Et4N]2[Ag2(SnB11H11)2(mbipy)2] (6). Yield: 52 mg (72%). 1H NMR (CH3CN): δ 8.67 (br, 4H, mbipy), 8.16 (br, 4H, mbipy), 7.8 (br, 4H, mbipy), 3.16 (q, 16H, N-CH2-CH3), 2.38 (br, 12H, mbipy), 1.21 (t, 24H, CH2-CH3). 11B{1H} NMR (CH3CN): δ -13.1(s, 10B, B2-B11), -4.7 (s, 1B, B12). Anal. Calcd for C40H86B22Ag2N6Sn2 3 CH3CN (1383.21): C, 36.47; H, 6.49; N, 7.09. Found: C, 36.10; H, 6.84; N, 6.99. [Et4N]2[Ag2(SnB11H11)2(phen)2] (7). Yield: 56 mg (78%). 1H NMR (CH3CN): δ 9.27 (br, 4H, phen), 8.59 (br, 4H, phen), 8.0 (br, 4H, phen), 7.94 (br, 4H, phen), 3.16 (q, 16H, N-CH2-CH3), 1.21 (t, 24H, CH2-CH3). 11B{1H} NMR (CH3CN): δ -13.3 (s, 10B, B2-B11), -5.5 (s, 1B, B12). For analytical purposes crystals were dried under vacuum overnight. Anal. Calcd for C40H78B22Ag2N6Sn2 (1334.09): C, 36.01; H, 5.89; N, 6.30. Found: C, 35.89; H, 5.85; N, 6.38. [Et3NMe]4[Ag4(SnB11H11)4(pyridine)4] (8). To a solution of 80 mg of [Et3NMe]8[Ag4(SnB11H11)6] (0.027 mmol) in acetonitrile

(5 mL) was added 17 μL of pyridine (0.2 mmol). After stirring this mixture for 30 min and filtration through Celite colorless crystals were obtained by slow diffusion of diethyl ether into the acetonitrile phase. Yield of 8: 32 mg (55%). Anal. Calcd for C48H136B44Ag4N8Sn4 (2207.65): C, 26.11; H, 6.21; N, 5.08. Found: C, 26.21; H, 5.82; N, 5.17. [Et4N]4[Ag4(SnB11H11)4(t-BuNC)4] (9). To a solution of 80 mg of [Et4N]8[Ag4(SnB11H11)6] (0.027 mmol) in acetonitrile (10 mL) was added 13.2 μL of tert-butyl isonitrile (0.21 mmol). After stirring this mixture for 30 min and filtration through Celite colorless crystals were obtained by slow diffusion of diethyl ether into the acetonitrile phase. Yield of 9: 41 mg (67%). Anal. Calcd for C52H160B44Ag4N8Sn4 (2279.89): C, 27.39; H, 7.07; N, 4.91. Found: C, 27.42; H, 7.16; N, 4.84. {[Et4N]14[Ag10(SnB11H11)12(DIB)3]}n (10). To a solution of 60 mg of [Et4N]8[Ag4(SnB11H11)6] (0.02 mmol) in acetonitrile (10 mL) was added 1,4-diisocyanobenzene (DIB) (10 mg, 0.8 mmol). After stirring this mixture for 30 min and filtration through Celite, green crystals were obtained by slow diffusion of diethyl ether into the acetonitrile phase. For analytical purposes crystals were dried under vacuum overnight, resulting in the loss of acetonitrile. Yield of 10: 20 mg (32%). Anal. Calcd for C136H424Ag10B132N20Sn12 3 4CH3CN (6435.46): C, 26.88; H, 6.83; N, 5.22. Found: C, 26.9; H, 6.78; N, 5.34. [Me4N][Ag(SnB11H11)] (11). From a solution of 20 mg of AgNO3 (0.12 mmol) and 46 mg of [Me4N]2[SnB11H11] (0.12 mmol) in 10 mL of CH3CN green crystals were isolated after filtration and slow diffusion of diethyl ether. Yield of 11: 26 mg (51%). Anal. Calcd for {[Me4N][Ag(SnB11H11)]}4 3 3(CH3CN)C22H101Ag4B44N7Sn4 (1846.09): C, 14.31; H, 5.51; N, 5.31. Found: C, 14.17; H, 5.20; N, 5.40.

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Table 1. Crystal Data and Structure Refinement Parameters for 7, 8, 10, and 12

empirical formula Mr [g mol-1] wavelength [A˚] temperature [K] cryst syst space group Z a [A˚] b [A˚] c [A˚] R [deg] β [deg] γ [deg] volume [A˚3] density Fcalc [g/cm3] absorp coeff μ [mm-1] F(000) cryst size [mm3] θ range [deg] limiting indices reflns collected indep reflns completeness absorp corr max. and min. transmn restraints/params final R indices [I > 2σ(I)] R indices, all data goodness-of-fit on F2 largest diff peak and hole [e 3 A-3]

7 3 3CH3CN

8

10 3 5CH3CN

12 3 3C7H5N 3 2CH3CN

C46H87Ag2B22N9Sn2 1457.23 0.71073 173(2) triclinic P1 2 11.5380(3) 16.6084(5) 18.6275(5) 80.130(2) 76.476(2) 71.289(2) 3269.09(16) 1.480 1.385 1460 0.1  0.1  0.1 3.22 to 29.29 -15 e h e 15, -22 e k e 22, -25 e l e 25 55 293 17 548 [Rint = 0.0706] 98.2% none

C48H136Ag4B44N8Sn4 2207.61 0.71073 173(2) monoclinic C2/c 4 26.4490(17) 16.1365(8) 24.1068(14)

C78H221Ag5B66N15Sn6 3334.78 0.71073 173(2) triclinic P1 2 16.0544(10) 16.0191(10) 30.6972(18) 87.648(5) 83.507(5) 72.780(5) 7492.1(8) 1.478 1.661 3318 0.22  0.18  0.15 5.67 to 26.37 -18 e h e 20, -19 e k e 19, -38 e l e 38 50 221 26 842 [Rint = 0.0509] 87.6% numerical 0.8430, 0.6646 307/1308 R1 = 0.0606, wR2 = 0.1144 R1 = 0.0860, wR2 = 0.1254 1.103 2.639, -2.059

C65H118Ag4B44N15Sn4 2491.70 0.71073 173(2) monoclinic C2/m 4 36.4616(17) 19.2841(11) 16.0675(9)

0/660 R1 = 0.0489, wR2 = 0.0980 R1 = 0.0674, wR2 = 0.1048 1.088 1.741, -0.852

114.725(4) 9345.4(9) 1.569 1.907 4352 0.23  0.18  0.15 2.97 to 28.60 -35 e h e 35, -21 e k e 17, -30 e l e 31 40 652 11 255 [Rint = 0.0534] 94.1% numerical 0.7953, 0.7009 0/487 R1 = 0.0387, wR2 = 0.0679 R1 = 0.0571, wR2 = 0.0737 1.139 0.930, -1.209

{[Me4N]4[Ag4(SnB11H11)4(DIB)6/2]}n (12). A solution of 26 mg of 1,4-diisocyanobenzene (0.2 mmol) in benzonitrile (5 mL) was layered with a solution of 43 mg of compound 11 (0.1 mmol) in acetonitrile (5 mL). Within two days yellow crystals formed and were collected by filtration. For analytical purposes crystals were dried under vacuum overnight, resulting in the loss of the solvent. Yield of 12: 28 mg (53%). Anal. Calcd

95.679(4) 11242.1(10) 1.472 1.597 4884 0.26  0.16  0.13 5.68 to 26.37 -45 e h e 45, -24 e k e 24, -20 e l e 20 70 333 11 708 [Rint = 0.1173] 98.7% numerical 0.8609, 0.6389 21/504 R1 = 0.0713, wR2 = 0.1257 R1 = 0.1007, wR2 = 0.1356 1.171 1.497, -0.751

for C40H104Ag4B44N10Sn4 (2107.33): C, 22.8; H, 4.97; N, 6.65. Found: C, 22.47; H, 5.61; N, 6.48. Supporting Information Available: Results of crystal structure analysis of compounds 5, 6, and 9 and cif files of all published structures. This material is available free of charge via the Internet at http://pubs.acs.org.