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Inorg. Chem. 1991.30,3 115-3 1 16 Acknowledgment. We thank the CICYT for financial support (Grant PB86-0290). Suppknentary Material A n l h b k For complex (Bun4N)(Z),tabla of crystallographic data, complete atomic wadinates and anisotropic and isotropic thermal parameters, bond lengths, and bond angles (4 pages); a table of structure factors (9 pages). Ordering information is given on any current masthead page. Department of Organic Chemistry Universitat de Valhcia Dr. Moliner. 50 46100 Burjassot. Spain
ICMaB Campus Universidad Authoma de
Viemte S a m Teresa Pieher Pedro Palanu
Pedro Gmez-Romero
Barcelona 08193 Bellaterra (Barcelona), Spain Department of Inorganic Chemistry Universitat de VaDncia Dr. Moliner. 50 46100 Burjassot, Spain
Eli Llopis J& A. Ramirez Daniel BeltrHn Antonio Cervilla'
Cluster of Clusters. Structure of a New 25-Metal-Atom Cluster [@-Tnl,P)l~ul~glzCl,](SbF,)z Containing a Nearly Staggered-Eclipsed-Staggered Metal Configuration and Five Doubly Bridging Ligands Clusters of increasing nuclearity can often be obtained by fusing together smaller cluster units.I-ll Recently we reported the synthesis and structural characterization of a 25-metal-atom cluster [ @ - T O I ~ P ) ~ ~ U ~(1):'~ A which ~ ~ ~ can B ~be ~ described ]+ as two centered icosahedra sharing a common vertex. The metal
(2)
(3) (4)
(5)
A
a
S
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P
S
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A S
B
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y B
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B
Received January 8. 1991
(1)
framework is characterized by the staggered-staggeredstaggered (sss) configuration of the four metal pentagons, giving rise to an idealized symmetry of DJdfor the metal core. We now wish to report the structure of a novel 25-metal-atom cluster [@To13P)loAul,AglzC1,]z~ (2), which has a nearly staggered-xlipsed-staggered (ses) metal configuration with an idealized symmetry of D5 for the metal core.
P
S
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A 2
The title compound 2 was isolated as the SbF; salt from the reduction of a mixture of p-TollP, HAuC14, and AgSbF6 with NaBH4 in ethanol.'z Other structurally characterized clusters of this series include the 37-metal-atom cluster [@T O ~ ~ P ) , ~ A ~ ~ (3): ~ A the ~ ~ 38-metal-atom , B ~ ~ ~ ] ~cluster + [@(4): and the 46-metal-atom cluster [ ( P ~ ~ P ) ~ z A ~ z z A ~(9.9 z~C~IZI
The title cluster 2 conforms to the crystallographic site symmetry Cz-2. Figure l a depicts the metal core which can be described as two 13-atom-Au-centeredicosahedra sharing a vertex (Au13). As shown in Figure Ih, there are IO phosphine ligands, coordinated to the IO peripheral Au atoms. Five doubly bridging chloride ligands connect the two Ag, pentagons and two terminal chloride ligands (CII 1 and CII 1') coordinate to the two apical Ag atoms ( A g l l and Agll'). Several novel features of the structure of 2 are noteworthy. First, the most significant structural characteristic of 2 is the observed (nearly) staggered-xlipsedstaggered (ses) configuration (a)Adamc.R.D.:Dawmdi.Z.:Farest.D.F.:Segmulla.B.E.J.Am. for the metal core" (cf. Figure la&), which is to be contrasted Chrm.Sor. 1983.105, 831. (b) Williams. P. D.:Cunis. M. D.: Duffry. with the staggeredstaggeredstaggered (sss) metal configuration D. N.: B u l k . W. M . Ormmnurollicr 1983. 2. 165, (d Johnson. B of 1." Second, there areflue bridging chloride ligands in 2 instead (a) Hayward, C. M. T.: Shapley. J. R.: Churchill. M. R.: Bucna. C.; of six as in 1. As shown in Figure IC, all five bridging chloride Rheingold. A. L. J. Am. Chem. Soe. 1982,104,7347. (b) Maninengo. ligands are symmetrical with an average Ag-CI distance of 2.44 S.: Fumagalli, A.: Bonfichi. R.: C h i . G.: Sironi, A. 1. Chcm. Sm.. A. Third, cluster 2 is a dication instead of a monocation (as in Chcm. Commun.1982.825. (E) Albano. V. 0.:Bellon. P. L.3. Orpanomer. Chem. 1969. 19, 405,'id) Pcnoia. R.0.:Demartin. F.; Gir1). The last two observations a r e related in that removal of one lawhclli. L , Uanarseo. M ; Maninengo. S.; Sansoni. M. Inorg. Chm. halide ligand in 1 causes the increase of the overall charge of the 1987. 26, 3487 le) Fumagalli. A ; Maninengo. S ; C h i . G . ;Sironi. cluster from + I to +2 (as in 2). As a result, the number of A J Chrm Sor.. Chrm Commvn 1983.451. electrons remains the same (25 (metals) - 7 (Cl) - 2 (charges) Drake. S.R.: Henrick. K.; Johnson. B. F.6.:Lewis. I.: McPanlin. M.: Morris. J J Chrm Sor.. Chem Commun. 1986. 928 = 16). la) Wcdnikw. E 0 , Ercmcnko. h' K I. Orgonome!. Chm 1986. The intraicosahedral metal-metal distances (Au 1I-centered CJJ-CI7. 301. lbl Mednikor. E. C : Ercmenko. Y . K.:Slovokholov. icosahedra) are significantly shorter than intericosahedral distances (Aul3-centered bicapped pentagonal prism), suggesting that inref la. ( c ) Mcdnikov, E. G.; Ercmcnko, N. K.: Slovakhaiov; Yu. L.: Struchkov. Yu. T.: Gubin, S. P. 3. Orfanomel. Chrm. 1983,258, 247. traicosahedral bondings are substantially stronger than interim For reviews on metal clusters. sse. far example: (a) Kharas, K.; Dahl, sahedral bonding (cf. Figure 1 caption). This observation is L. Ado. Chcm. Phvs. 1988. 7012). 1. lb) Chini. P. Gam. Chim. Irni. consistent with the clusrer of clusters conceptlo," wherein the 1979. IW.225. (i)Chini. P. ~.'O;R~&I&.Chem 1980. 200, 37. (d) individual icosahedra serve as the basic building blocks. Chin,. P.; Longoni. G ; Albano. Y - G Adr Orgonomer. Chem. 1976. 14. 285 (e) Johnson, B F. G.. Ed. Tmnrirton Mdol C'lurrrrr. WI. Ie).lnterscience: Chichertcr. E n d a n d . 1980 John-". B. F. G.:
(n
thtmrrq:Gwffroy.(i'., Ed.; W,k; New York.7981 (gl Fcnrkc. D.; Ohmrr. J ; Hachgcnci. J ; Ucrzucilcr. K A n g n . Chem, In! Ed Engl 1988. 27. 1277 lh) Schmid.G, Srrurr. Bonding(8erlin) 1985.62. SI 16) l a , Tco. B K ; Zhana. H ; Shi. X lnorp. Chrm. 1990.29.2081. lbl .. T&. B. K.: K 4 n g . k . 3. Am: Chrm. h e . 1984, 106. 2224. Tco. B. K.: Hang. M.C.: Zhang. H.: Huang, D. 8. Angnv. Chem.. IN. Ed. Engl. 1987. 26, 897. (a) Tw. B. K.: Zhang. H.: Shi. X. 1.Am. Chrm. Sm. 1990.112.8552. (b) Tm. 8. K.: Hong. M.: Zhang. H.; Huang, D.: Shi. X. 1.Chcm. Sm.. Chrm. Commun. 1988, 204. Tw, B. K.: Shi. X.: Zhang. H. Quoted in Chrm. Eng. News 1989.67 (Jan 9). 6. (IO) (a) Tw. 8. K.: Zhang. H. lnorg. Chim. A d a 1988.144. 173. (b) Teo, B. K.: Zhang. H. Inorg. Chsm. 1988.27,414. ( I I ) For reviews on Au-Ag cluster of EIUS~C~S. see: (a) Tw, E. K. Polyhedron 1988. 7, 2317. (b) Tw.E. K.; Zhsng. H. 1.Ciusrcr Sci. 1990. 1.223. (e) Tm, E.K.:Zhsng. H. 1.Clusrer Sei. 1990.1. 155. (d) Tw. E. K.: Zhang. H. Polyhedron 1990.9, 1985
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(12) The cluster [@-Tol,P),~u,,,Ag,~Cl,](SbF~)~.nEtOH forms dark rcd prismatic crystals. It crystallize8 in the tetragonal spa qraup P4,2,2, with (1 = 20.510 (6) A, e = 61.78 ( I ) A. V = 25988.1 A ,and Z = 4. Single-crystal X-ray diffraction data were collected by using an Enref-Nonius diffractomctcr (Mo Ka radiation). The tolyl groups and the SbF; anion were refined as rigid badics with C(mcthyl)-C(rin ) C (ring)-C(ring). and S b F distances of 1.47. 1.395, and 1.86 spectivcly (see ref 8a for details). Anisotropic refinement gave R, = 9.6% for 581 I indcpendent reflections (28 5 46O) with I > 30. Crystalloarmhie (Tabla I-VI and VIII) and " m t i v e (Table VII) details can h n d in the supplemcntar) m a & & (13) One can envision the successive buildup of a one-dimensionalSfNCtUrC of nuclearitier addim one atom and One ~ .I. . 7. ~13. , 19. 25. 31. 37. ... bv ~,~ oentaaon at a time. The infinite chain analoaue is observed in the ;olid&lc compounds Ta,S (Franzen, H FYSmeggtl. J G Acto ( r ) $ l O / / O R r IW9. 825. 1736) and Ta,S (Franzcn. H F , Smcggll. J (i Acto (iysrallop 1970. 826. 125) The structural rclauonohip of the h m h IIUCICB~IIV cluslers and Ihe solid-statecomwundr Ihocforc provid& a link between clusters and tho bulk."'
.f:ri
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0 1991 American Chemical Society
Inorg. Chem. 1991,30, 31 16-31 18 The relative orientation of the four metal pentagons can be described as ABAB (sss) for 1 and ABBA (ses) for 2, respectively. The corresponding orientation of the two icosahedra may be described as ~$9). and a(y)/3,respectively. The former has an ‘additional” icosahedron (whase orientation is in parentheses) in the middle due to the staggered arrangement of the two middle rings in the sss configuration. The latter produces a bicapped pentagonal prism whose orientation is designated as y (in parentheses). The propagation of icosahedra via vertex, edge, or face sharing through space is critically dependent upon the relative orientation of the icosahedral units (the building blocks) and is of current interest in terms of the structures of quasi crystal^'^ and amorphous material^.'^ Finally, we note that the ses metal configuration (as observed for 2) allows stereochemically a ‘polyicosahedral” growth pathway via vertex sharing to give bi-, tri-, and tetraicosahedral supraclusters as exemplified by the structurally characterized 25- (2), 37- (3)’ or 38- (4),8 and 46- (5)9 metal-atom Au-Ag clusters, respectively. In all these structures, the icosahedral units are linked by (interpenetrating) bicapped pentagonal prisms (y), instead of the (interpenetrating) icosahedra (8) as observed in the 25metal-atom cluster P with an sss metal configuration. Acknowledgment is made to the National Science Foundation (Grant CHE-8722339) for financial support of this research. We would also like to express our sincere gratitude to Professor C. Strouse of UCLA for helpful discussions concerning modification of the crystallographic programs. Supplementary Material AVPU.Me: Full listings of complete structural data (Table I), positional parameters (Table 11), anisotropic thermal parameters (Table 111), positional and orientational parameters of 15 tolyl group (Table IV), interatomic distances (Table V), interatomic angles (Table VI), and details of the preparation and crystallization (Table VII) for the title compound (20 pages); a listing of observed and calculated structure factors (Table VIII) (61 pages). Ordering information is given on any current masthead page. (14) (a) Schechtman,D.; Blech, I.; Gratis, D.; Cahn, J. W.Phys. Rev.f e r r . 1984,53,1951. (b) Levine, D.; Steinhardt, P. J. Phys. Reu. fert. 1984, 53, 2477. (c) Bagley, B. Nature 1965, 208, 674. (d) Smith, D. J.; Mark, L. D. J . Cryst. Growrh 1981, 54, 433. (15) (a) Briant, C. L.; Burton, J. J . Phys. Status Solidi 1978,85, 393 and references cited therein. (b) Machizaud, F.; Kuhnast, F. A.; Flechon, J. Ann. Chim. (Paris) 1978, 3, 177.
Boon K.Teo* Hong Zhang
Department of Chemistry
University of Illinois at Chicago Chicago, Illinois 60680 Received December 26, 1990
Short Spin-Lattice Relaxation Times of Hydride Ligands. Proton-Metal DipoleDipole Interactions Figure 1. Molecular architecture of the 25-metal-atom cluster [@T O ~ ~ P ) ~ ~ U ~ ,(2) A as ~ ~the ~ C (SbFJ I ~ ) salt: ~ + (a) the metal core, Au13Agi2;(b) the metal-ligand framework, Pl,,Aui3Ag12CI,~ (c) projytion of the two silver pentagons and the five doubly bridging chloride ligands along the idealized 5-fold axis (which passes through Agl 1, Aull, Au13. Aul l’, and Agll’). Atoms related by the crystallographic 2-fold (C2-2)symmetry are designated as primes. All radial bonds (12 each) from Aul 1 and Aul 1’ have been omitted for clarity. All molecular parameters are normal. The importance distances are as follows ( n = 1-5): Aull-Au(n) = 2.749 (av) A, Aull-Ag(n) = 2.816 (av) A, Aull-AgII = 2.743 (9) A, Aull-Aul3 = 2.813 ( 5 ) A, Aul3-Ag(n) = 2.881 (av) A; intrapentagonal, Au(n)-Au(n + 1) = 2.914 (av) A, Ag(n)-Ag(n + 1) = 2.912 (av) A; interpentagonal, Au(n)-Ag(n or n 1) = 2.885 (av) A, A 1 Ag5‘ = 3.04 (1) A, Ag2-Ag4‘ = 2.94 ( I ) A, Ag3-Ag3‘ = 2.92 (1) W.Au-P = 2.35 (av) A, A g l l C l l 1 = 2.43(3) A, Ag(n)Cl(n) 2.44 (av) A. The five doubly bridging chloride ligands form a distorted pentagon with nonbondin (crystallographically independent) distances of CII...CII’ = 5.34 CII--.Cl2 = 4.69 A, and CIZ..*CI~ = 5.53 A.
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TI measurements have recently been used for obtaining structural information about metal hydride c o m p l e x e ~ . ~ - ~ Crabtree and Luo4 have recently tested the basis of the Ti method, assuming that only proton-proton dipole-dipole interactions (HHDDI) dominates the relaxation. They have found that, for a series of mononuclear polyhydrides for which both structural and relaxation data are available, there was good agreement between the calculated and observed TI values. This agreement is rather surprising in the case of rhenium hydrides, where significant metal-H dipole-dipole interactions (MHDDI) can be expected. Indeed, with rteH = 1.7 A and T~ = 0.62/2uus at 250 MHz, the well-known eq 1 (where C = (1) Hamilton, D. G.; Crabtree, R. H . J . Am. Chem. Soc. 1988,110.4126. ( 2 ) Crabtree. H. Acc. Res. 23. 95. - - ...., R. .. . .. ... Chcm. . . ... 1990. . --. ( j j Bautista, M. T.; Earl, K. A.; Maltby, P.A,; Morris, R. H.;Schweitzer, C. T.; Sella, A. J. Am. Chem. Soc. 1988, 110,7031. (4) Luo, X. L.; Crabtree, R. H . Itwrg. Chem. 1990, 29, 2788.
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0 1991 American Chemical Society
