Binuclear Platinum(IV) Complexes with Bridging Amidoalkyl Groups

Jun 11, 2009 - Matthew S. McCreadyRichard J. Puddephatt. ACS Omega 2018 3 (10), ... Richard H. W. Au , Michael C. Jennings and Richard J. Puddephatt...
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Organometallics 2009, 28, 3734–3743 DOI: 10.1021/om9001878

Binuclear Platinum(IV) Complexes with Bridging Amidoalkyl Groups and Their Self-Assembly through Hydrogen Bonding Richard H. W. Au, Michael C. Jennings, and Richard J. Puddephatt* Department of Chemistry, University of Western Ontario, London, Canada N6A 5B7 Received March 11, 2009

Oxidative addition of the reagents {4-BrCH2C6H4-(CH2)x-C(dO)NH-(CH2)y}2Z to [PtMe2(bu2bipy)], bu2bipy = 4,40 -di-t-butyl-2,20 -bipyridine, gave the corresponding diplatinum(IV) complexes [{PtBrMe2(bu2bipy)-4-CH2C6H4-(CH2)x-C(dO)NH-(CH2)y}2Z], with Z = o-, m-, or p-C6H4 and x, y = 0 or 1; or Z = 1,2-C2H4 and x = y = 0. The complexes are formed selectively by trans oxidative addition to both platinum(II) centers and contain long bridging alkanediyl ligands containing two amide units in the backbone. Several iodide analogues were prepared by displacement of bromide from the bromoplatinum(IV) complexes by reaction with lithium iodide, and in one case, a chloride derivative was formed by the reaction of a bromoplatinum(IV) complex with solvent carbon tetrachloride. In the solid state, the compounds undergo self-assembly to form supramolecular polymers, ribbon polymers, or a sheet structure by forming intermolecular hydrogen bonds of the type NH 3 3 3 OdC, NH 3 3 3 BrPt or NH 3 3 3 ClPt. Introduction There is continuing interest in the self-assembly of polymers and networks using simple coordination complexes and organometallic complexes as building blocks to give functional molecular materials. In this broad field, the combination of inorganic and organometallic synthetic methods with selfassembly through hydrogen bonding has led to the formation of many unusual polymeric and network materials.1,2 In coordination chemistry, the use of bis(amidopyridine) *To whom correspondence should be addressed. E-mail: [email protected]. (1) (a) Aakeroy, C. B.; Beattie, A. M. Aust. J. Chem. 2001, 54, 409. (b) Robin, A. Y.; Fromm, K. M. Coord. Chem. Rev. 2006, 250, 2127. (c) Chen, C. L.; Kang, B. S.; Su, C. Y. Aust. J. Chem. 2006, 59, 3. (d) Uemura, K.; Kumamoto, Y.; Kitagawa, S. Chem.;Eur. J. 2008, 14, 9565. (e) Perez, J.; Riera, L. Chem. Soc. Rev. 2008, 37, 2658. (f) Brammer, L. Chem. Soc. Rev. 2004, 33, 476. (g) Tiekink, E. R. T.; Vittal, J. J. Frontiers of Crystal Engineering; J. Wiley: Chichester, U.K., 2006. (h) Beatty, A. M. Coord. Chem. Rev. 2003, 248, 131. (2) (a) Braga, D.; Grepioni, F. Coord. Chem. Rev. 1999, 183, 19. (b) Mareque Rivas, J. C.; Brammer, L. Coord. Chem. Rev. 1999, 183, 43. (c) Haiduc, I.; Edelmann, F. T. Supramolecular Organometallic Chemistry; Wiley-VCH: Weinheim, Germany, 1999. (d) Natale, D.; Mareque Rivas, J. C. Chem. Commun. 2008, 425. (e) Laguna, A., Ed. Modern Supramolecular Gold Chemistry; Wiley-VCH: Weinheim, Germany, 2008. (3) (a) Kaes, C.; Katz, A.; Hosseini, M. W. Chem. Rev. 2000, 100, 3553. (b) Muthu, S.; Yip, J. H. K.; Vittal, J. J. J. Chem. Soc., Dalton Trans. 2002, 4561. (c) Pansanel, J.; Jouati, A.; Ferlay, S.; Hosseini, M. W.; Planeix, J. M.; Kyritsakas, N. New J. Chem. 2006, 30, 683. (d) Zhang, P.; Niu, Y.-Y.; Wu, B.-L.; Zhang, H.-Y.; Niu, C.-Y.; Hou, H.-W. Inorg. Chim. Acta 2008, 361, 2609. (f) Yeh, C. W.; Chen, J. D.; Wang, J. C. Polyhedron 2008, 27, 3611. (g) Adarsh, N. N.; Kumar, D. K.; Dastidar, P. Inorg. Chem. Commun. 2008, 11, 636. (h) Yeh, C. W.; Chen, J. D.; Wang, J. C. Polyhedron 2008, 27, 3611. (e) Sarkar, M.; Biradha, K. Cryst. Growth Des. 2007, 17, 1318. (4) (a) Burchell, T. J.; Eisler, D. J.; Jennings, M. C.; Puddephatt, R. J. Chem. Commun. 2003, 2228. (b) Burchell, T. J.; Eisler, D. J.; Puddephatt, R. J. Chem. Commun. 2004, 944. (c) Qin, Z.; Jennings, M. C.; Puddephatt, R. J. Inorg. Chem. 2001, 40, 6220. (d) Qin, Z.; Jennings, M. C.; Puddephatt, R. J. Inorg. Chem. 2002, 41, 5174. (e) Qin, Z.; Jennings, M. C.; Puddephatt, R. J. Inorg. Chem. 2003, 42, 1965. (f) Qin, Z.; Jennings, M. C.; Puddephatt, R. J. Chem.;Eur. J. 2002, 8, 735. (g) Burchell, T. J.; Eisler, D. J.; Puddephatt, R. J. Cryst. Growth Des. 2006, 6, 974. pubs.acs.org/Organometallics

ligands such as A in Chart 1 has given many useful binuclear building block molecules of general type B (M = metal, L = ligand) by simple coordination of the pyridine groups.1-4 By analogy, it was considered that the bis(amido-bromomethyl) derivatives such as C in Chart 1 might give a route to binuclear organometallic building block molecules such as D by oxidative addition of the C-Br bonds to suitable transition metal complexes MLn. Self-assembly by hydrogen bonding of the amide groups of D would then be expected, in an analogous way to the known self-assembly of molecules of type B.3,4 Complexes of type D containing bridging alkanediyl groups, but without the amide functionalities, have been of interest as models for catalytic intermediates in the FischerTropsch synthesis and similar reactions.5 Organoplatinum(IV) complexes with bridging alkanediyl groups and with alkyl groups containing amide units, such as E, F, and G in Chart 2, have been prepared6 and used in self-assembly,7 but bridging alkanediyl groups containing amide units in the (5) (a) Overett, M. J.; Hill, R. O.; Moss, J. R. Coord. Chem. Rev. 2000, 206, 581. (b) Moss, J. R.; Scott, L. G. Coord. Chem. Rev. 1984, 60, 171. (c) Ceccon, A.; Santi, S.; Orian, L.; Bisello, A. Coord. Chem. Rev. 2004, 248, 683. (d) Beck, W.; Niemer, B.; Wieser, M. Angew. Chem., Int. Ed. 1993, 32, 923. (e) Casey, C. P.; Audett, J. D. Chem. Rev. 1986, 86, 339. (f) Wigginton, J. R.; Chokshi, A.; Graham, T. W.; McDonald, R.; Ferguson, M. J.; Cowie, M. Organometallics 2005, 24, 6398. (g) Brown, M. P.; Fisher, J. R.; Franklin, S. J.; Puddephatt, R. J.; Seddon, K. R. Chem. Commun. 1978, 749. (h) Hill, R. H.; Puddephatt, R. J.; Frew, A. A.; Manojlovic-Muir, Lj.; Muir, K. W. J. Chem. Soc. Chem. Comm. 1982, 198. (i) Brown, M. P.; Cooper, S. J.; Frew, A. A.; Manojlovic-Muir, Lj.; Muir, K. W.; Puddephatt, R. J.; Thomson, M. A. Dalton Trans. 1982, 299. (6) (a) Monaghan, P. K.; Puddephatt, R. J. Organometallics 1985, 4, 1406. (b) Monaghan, P. K.; Puddephatt, R. J. Dalton Trans. 1988, 595. (c) Scott, J. D.; Puddephatt, R. J. Organometallics 1986, 5, 1538. (d) Scott, J. D.; Crespo, M.; Anderson, C. M.; Puddephatt, R. J. Organometallics 1987, 6, 1772. (e) Byers, P. K.; Canty, A. J.; Skelton, B. W.; Traill, P. R.; Watson, A. A.; White, A. H. Organometallics 1990, 9, 3080. (7) (a) Au, R. H. W.; Jennings, M. C.; Puddephatt, R. J. Dalton Trans. 2009, 3519. (b) Au, R. H. W.; Fraser, C. S. A.; Eisler, D. J.; Jennings, M. C.Puddephatt, R. J. Organometallics 2009, 28, 1719. (c) Au, R. H. W.; Jennings, M. C.; Puddephatt, R. J. Eur. J. Inorg. Chem. 2009, 1526.

Published on Web 06/11/2009

r 2009 American Chemical Society

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Organometallics, Vol. 28, No. 13, 2009 Chart 1

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Chart 3

Chart 2

backbone, such as D, have not been exploited. This article describes a systematic study of the synthesis of complexes analogous to D in Chart 1, in which MLn = PtMe2(bu2bipy), with bu2bipy=4,40 -di-t-butyl-2,20 -bipyridine. It includes the synthesis of complexes with the longest bridging alkanediyl groups known to date.5

Results Bis(bromomethyl) Reagents. The bis(bromomethyl) reagents used in this work are shown in Chart 3. They were prepared by condensation reactions using the corresponding diamine with either a carboxylic acid or acid bromide. For example, the reagent 1,2-C6H4{NHC(dO)-4-C6H4CH2Br}2, 1, was prepared by the reaction of 1,2-phenylenediamine with 4-bromomethyl benzoyl bromide with the elimination of HBr. Reagents 3, 4, 7, and 9, which contain NHC(dO)-4C6H4CH2Br units, were prepared similarly from the corresponding diamine. The reagent 1,2-C6H4{NHC(O)CH2-4C6H4CH2Br}2, 2, was prepared by reaction of 1,2-phenylenediamine with 4-(bromomethyl)phenylacetic acid with elimination of water, using EDC = 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride as coupling reagent. Reagents 5, 6, and 8, which contain NHC(dO)CH2-4C6H4CH2Br units were prepared similarly from the corresponding diamine.8 The reagents were readily characterized (8) (a) Ulrich, H. Chemistry and Technology of Carbodiimides; Wiley: New York, 2007. (b) Yurteri, S.; Cianga, I.; Yagci, Y. Des. Monomers Polym. 2005, 8, 61.

by their NMR and mass spectra. Reagents 1, 3, and 7 differ by having 1,2-, 1,3-, or 1,4-phenylene groups at the center, and this obviously changes the orientation of the amide and bromomethyl substituents. Reagents 2, 4-6, and 8 contain one or, in the case of 6 only, two additional methylene groups adjacent to the amide groups. The methylene group breaks the conjugation of the amide unit with the adjacent phenylene group and therefore allows much greater flexibility. Reagent 9 does not contain a central phenylene group and is likely to adopt a conformation with an intramolecular NH 3 3 3 OdC hydrogen bond. The reaction of each of these reagents with the electron-rich platinum(II) complex [PtMe2(bu2bipy)] was then studied. Platinum(IV) Complexes with the o-Phenylene Spacer Group. The reaction in a 2:1 molecular ratio of [PtMe2(bu2bipy)], 10,9 with ligands 1 and 2 gave the diplatinum(IV) complexes 11a and 12, respectively (Scheme 1). Subsequent reaction of the bromo derivative 11a with lithium iodide gave the corresponding iodo derivative 11b. The platinum(IV) complexes have the stereochemistry expected for products of trans oxidative addition. For example, in the 1H NMR spectrum, complex 11a gave a single methylplatinum resonance at δ=1.42 with coupling constant 2J(PtH)=68 Hz and a single PtCH2 resonance at δ=2.88 with coupling constant 2 J(PtH)=97 Hz. The complexes 11a and 11b are isostructural, and the illustrative structure of 11a is shown in Figure 1. The complex has C2 symmetry, and therefore, it is in a chiral conformation with the amide groups twisted to opposite sides of the o-phenylene group. Each platinum center has octahedral stereochemistry with the benzyl group trans to bromide, as expected. The chiral binuclear molecules form complementary NH 3 3 3 OdC hydrogen bonds with conformers of opposite chirality as shown, for complex 11b, in Figure 2. The overall effect is to form a ribbon polymer. The hydrogen bond distances N(40) 3 3 3 O(39B) =3.069(9) and 3.108(9) A˚ in 11a and 11b, respectively, indicate relatively weak hydrogen bonding.10 (9) (a) Achar, S.; Scott, J. D.; Vittal, J. J.; Puddephatt, R. J. Organometallics 1993, 12, 4592. (b) Scott, J. D.; Puddephatt, R. J. Organometallics 1983, 2, 1643. (10) (a) Desiraju, G. R.; Steiner, T. The Weak Hydrogen Bond; Oxford Science: Oxford, U.K., 1999. (b) Jeffrey, G. A. An Introduction to Hydrogen Bonding; Oxford University Press: Oxford, U.K., 1997.

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Au et al. Scheme 1.a

a

N-N = bu2bipy.

Platinum(IV) Complexes with the m-Phenylene Spacer Group. The oxidative addition of reagents 3-6 with [PtMe2(bu2bipy)], 10, gave the corresponding complexes 13a, 14a, 15, and 16 whose structures are illustrated in Chart 4. Reaction of 13a and 14a with lithium iodide gave the corresponding iodide derivatives 13b and 14b. Crystals for structure determination were obtained only for complex 14a, which is derived from 1,3-xylenediamine. The structure of 14a is shown in Figure 3. The complex adopts a helical conformation. There is no crystallographically imposed symmetry, but the molecule has roughly C2 symmetry, and therefore, it is conformationally chiral. The molecule crystallizes as the solvate 14a 3 2Me2CO 3 MeOH, and there is a hydrogen bond between one of the carbonyl groups of 14a and the methanol molecule (Figure 3). The hydrogen bonding in 14a (Figure 4) is different from that in 11a and 11b (Figure 2). In 14a, the hydrogen bonding is through Pt-Br 3 3 3 H-N units in place of the CdO 3 3 3 HN units in 11a and 11b. The overall effect is again to form a supramolecular polymer with alternating P 3 3 3 M 3 3 3 P 3 3 3 M conformers of 14a along the polymer chain. Each molecule forms both a donor and acceptor hydrogen bond to the molecules on either side, as shown in Figure 4. The polymers themselves stack in such a way as to form channels with approximate dimensions of 7.5  15 A˚2, in which the acetone molecules are located. Platinum(IV) Complexes with the p-Phenylene Spacer. The oxidative addition of the reagents 7 and 8 with [PtMe2(bu2bipy)], 10, gave the corresponding complexes 17a and 18a, whose structures are illustrated in Chart 5. Subsequent reaction of 17a with lithium iodide gave the corresponding iodide derivative 17b, while attempted recrystallization of 18a from carbon tetrachloride led to chloro for bromo exchange with the formation of 18b (Chart 5). Crystals for structure determination were obtained for complexes 17a and 18b. The structure of complex 17a is shown in Figure 5. There are two independent molecules in the unit cell, each of which has C2 symmetry (Figure 5). The conformation of the amide groups is therefore anti with respect to the p-phenylene spacer group. The platinum centers have the expected octahedral stereochemistry resulting from trans oxidative addition. The hydrogen bonding in 17a is surprisingly weak. The only significant interaction occurs between the Pt-Br units of the Pt(1) molecule with an NH group of the Pt(2) molecule on either side, as illustrated in Figure 6. The hydrogen bond Pt(1)Br(1) 3 3 3 HN(70) is characterized by the distance N(70) 3 3 3 Br(1) = 3.671(6) A˚. The distance for the corresponding interaction

Pt(2)Br 3 3 3 HN(30) is N(30) 3 3 3 Br(2) = 3.914(6), which is considered too long to be a hydrogen bond. The normal range for N-H 3 3 3 Br hydrogen bonding interactions is N 3 3 3 Br = 3.12 - 3.69 A˚,11 and the value for complex 17a indicates that the hydrogen bond Pt(1)Br(1) 3 3 3 HN(70) is relatively weak.10,11 The overall result is that the complexes form a supramolecular polymer with alternating Pt(1) and Pt(2) molecules, as illustrated in Figure 6. There are channels in the structure that contain acetone molecules of solvation, but the acetone molecules are not involved in hydrogen bonding. The structure of complex 18b is shown in Figure 7. It contains a 20-memberered alkanediyl bridging group, which appears to be the longest that has been characterized crystallographically.5 The molecule contains a center of inversion; therfore, like 17a, it has the anti conformation of amide groups about the p-phenylene spacer group. The molecules of 18b pack to form a sheet structure as shown in Figure 8. The hydrogen bonding occurs in the sense PtCl 3 3 3 HN with distance Cl 3 3 3 N(41B) = 3.35(2) A˚, in the typical range of 3.1 - 3.4 for Cl 3 3 3 HN hydrogen bonds.12 Each molecule forms two donor hydrogen bonds and two acceptor hydrogen bonds, and therefore, it interacts with four neighbors as shown in Figure 8. The sheets are oriented so as to form channels that contain CCl4 molecules of crystallization. Platinum(IV) Complex with an Ethylenediamine Spacer. In order to study the effect of having a flexible alkane spacer group in place of the rigid arene spacer groups in reagents 1, 3, and 7 (Chart 3), reagent 9 based on the ethylenediamine spacer group was used. Reaction of 9 with [PtMe2(bu2bipy)], 10, gave the corresponding platinum(IV) complex 19 according to Scheme 2. The conformation with an intramolecular hydrogen bond is unsymmetrical, but the 1H NMR spectrum indicates that the complex has effective 2-fold symmetry in solution. Thus, there was a single methylplatinum resonance at δ=1.43, 2J(PtH)=69 Hz, a single PtCH2 (11) For examples of NH 3 3 3 Br hydrogen bonding distances see (a) Dobrza nska, L. Acta Crystallogr., Sect. E 2005, 61, m1625. (b) Kavallieratos, K.; Bertao, C. M.; Crabtree, R. H. J. Org. Chem. 1999, 64, 1675. (c) Ion, L.; Morales, D.; Nieto, S.; Perez, J.; Riera, L.; Riera, V.; Miguel, D.; Kowenicki, R. A.; McPartlin, M. Inorg. Chem. 2007, 46, 2846. (d) Jones, P. G.; Gray, L. Acta Crystallogr., Sect. C 2002, 58, o282. (e) Budzianowski, A.; Katrusiak, A. J. Phys. Chem. B 2006, 110, 9755. (f) Varga, R. A.; Silvestru, C. Acta Crystallogr., Sect. E 2007, 63, o3381. (g) Chan, C. W.; Mingos, D. M. P.; White, A. J. P.; Williams, D. J. Chem. Commun. 1996, 81. (12) (a) Telfer, S. G.; Bernardinelli, G.; Williams, A. F. Dalton Trans. 2003, 435. (b) Song, D.; Morris, R. H. Organometallics 2004, 23, 4406. (c) Fraser, C. S. A.; Jenkins, H. A.; Jennings, M. C.; Puddephatt, R. J. Organometallics 2000, 19, 1635.

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Chart 4. a

Figure 1. Structure of complex 11a. Selected bond distances: Pt-C(1), 2.043(9); Pt-C(2), 2.053(10); Pt-C(31), 2.075(10); Pt-Br, 2.573(1) A˚. Corresponding distances for 11b: Pt-C(1), 2.074(8); Pt-C(2), 2.066(9); Pt-C(31), 2.105(9); Pt-I, 2.7667(7) A˚. Transformation for symmetry equivalent: -x, y, 5/2 - z.

a

Figure 2. (a) Hydrogen bonding in complex 11b. Only the NCCN atoms of the bu2bipy ligands are shown for clarity. The stacking of chiral conformers occurs as P 3 3 3 M 3 3 3 P 3 3 3 M, with P and M forms shown in red and blue. Hydrogen bond distance: N(40) 3 3 3 O(39B), 3.108(9) A˚. In 11a, N(40) 3 3 3 O(39B), 3.069(9) A˚. (b) View down the polymer chain direction, with t-butyl groups omitted for clarity. Symmetry transformations for neighboring molecules: x, -y, -1/2 + z; x, -y, 1/2 + z.

resonance at δ=2.84, 2J(PtH) = 98 Hz, and a single CH2N resonance at δ=3.46. Evidently, the intramolecular hydrogen bond is easily and reversibly cleaved in solution. The structure of complex 19 is shown in Figure 9. This confirms that 19 is formed by trans oxidative addition. The flexible C2H4 spacer group allows the formation of an intramolecular NH 3 3 3 OdC hydrogen bond with distance N(40) 3 3 3 O(45) = 2.88(3) A˚; therefore, the molecule has no internal symmetry. There is then only one NH group to take part in intermolecular hydrogen bonding, and it forms a hydrogen bond to a PtBr group of a neighboring molecule with N(43) 3 3 3 Br(1A) = 3.54(2) A˚. The intermolecular hydrogen bonding leads to the formation of a supramolecular polymer (Figure 9).

Discussion The new platinum(IV) complexes described above may be considered to have the general structural form XPt-Y-

N-N = bu2bipy.

C(dO)NH-Z-NHC(dO)-Y-Pt-X, where X=halogen, and Y and Z = organic spacer groups. They possess two NH groups, which can act as hydrogen donors and four potential hydrogen bond acceptor groups (two carbonyl groups and two halide ligands). Most of the solid state structures observed can be considered as supramolecular polymers, but there are several different forms. The simple supramolecular polymer is one-dimensional and has one hydrogen bond to each neighboring molecule.1-7,12-16 This structure is observed for complexes 17a and 19 (Figures 6 and 9, respectively), both of which propagate through NH 3 3 3 BrPt hydrogen bonds, though in different ways, as shown schematically in Chart 6. In 19, there is an intramolecular NH 3 3 3 OdC hydrogen bond [graph set description S(7)];17 (13) (a) Rendina, L. M.; Puddephatt, R. J. Chem. Rev. 1997, 97, 1735. (b) Hill, R. H.; Puddephatt, R. J. J. Am. Chem. Soc. 1985, 107, 1218. (c) Canty, A. J.; Watson, R. P.; Karpiniec, S. S.; Rodemann, T.; Gardiner, M. G.; Jones, R. C. Organometallics 2008, 27, 3203. (14) (a) Fraser, C. S. A.; Jennings, M. C.; Puddephatt, R. J. J. Chem. Soc., Chem. Commun. 2001, 1310. (b) Fraser, C. S. A.; Jennings, M. C.; Puddephatt, R. J. J. Chem. Soc., Chem. Commun. 2002, 1224. (c) Fraser, C. S. A.; Eisler, D. J.; Puddephatt, R. J. Polyhedron 2005, 25, 266. (15) (a) Gianneschi, N. C.; Tiekink, E. R. T.; Rendina, L. M. J. Am. Chem. Soc. 2000, 122, 8474. (b) Zhang, F.; Jennings, M. C.; Puddephatt, R. J. J. Chem. Soc., Chem. Commun. 2007, 1498. (c) Kocher, S.; Lutz, M.; Spek, A. L.; Walfort, B.; Ruffer, T.; van Klink, G. P. M.; van Koten, G.; Lang, H. J. Organomet. Chem. 2008, 693, 2244. (d) Libri, S.; Jasim, N. A.; Perutz, R. N.; Brammer, L. J. Am. Chem. Soc. 2008, 130, 7842. (e) Braga, D.; Giaffreda, S. L.; Rubini, K.; Grepioni, F.; Chierotti, M. R.; Gobetto, R. CrystEngComm. 2007, 9, 39. (f) Davies, P. J.; Veldman, N.; Grove, D. M.; Spek, A. L.; Lutz, B. T. G.; van Koten, G. Angew. Chem., Int. Ed. 1996, 35, 1959. (g) Rashidi, M.; Jennings, M. C.; Puddephatt, R. J. CrystEngComm 2003, 5, 65. (h) James, S. L.; Verspui, G.; Spek, A. L.; van Koten, G. Chem. Commun. 1996, 1309. (16) (a) Khripum, A. V.; Kukushkin, V. Y.; Koldobskii, G. I.; Haukka, M. Inorg. Chim. Acta 2006, 359, 320. (b) Khripum, A. V.; Selivanov, S. I.; Kukushkin, V. Y.; Haukka, M. Inorg. Chem. Commun. 2006, 10, 250. (c) Hafizovic, J.; Krivokapic, A.; Szeto, K. C.; Jakobsen, S.; Lillerud, K. P.; Olsbye, U.; Tilset, M. Cryst. Growth Des. 2007, 7, 2302. (17) Bernstein, J.; Davis, R. E.; Shimoni, L.; Chang, N.-L. Angew. Chem., Int. Ed. 1995, 34, 1555.

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Au et al. Chart 5. a

a

Figure 3. View of the structure of complex 14a, including a hydrogen bond to methanol solvate CdO 3 3 3 HOMe. Selected bond distances: Pt(1)-C(1), 2.05(2); Pt(1)-C(2), 2.06(2); Pt(1)-C(51), 2.09(2); Pt(1)-Br(1), 2.588(2); Pt(2)-C(3), 2.06(2); Pt(2)-C(4), 2.04(2); Pt(2)-C(78), 2.09(2); Pt(2)-Br(2), 2.584(2) A˚. Hydrogen bond distance O(71) 3 3 3 O(302), 2.74(3) A˚.

Figure 4. Hydrogen bonding in complex 14a, with solvent molecules and t-butyl groups omitted for clarity. The stacking of chiral conformers occurs as P 3 3 3 M 3 3 3 P 3 3 3 M, with P and M forms shown in red and blue. Hydrogen bond distances: Br(1) 3 3 3 N69A, 3.38(1); Br(2) 3 3 3 N(60B), 3.41(1) A˚. Symmetry transformations for neighboring molecules: -x, 3 - y, -z; -1 - x, 3 - y, 1 - z.

therefore, only one NH group is available for self-assembly of the polymer, and each molecule provides one donor NH group and one acceptor BrPt group for forming the supramolecular polymer through hydrogen bonding [graph set description for the Chain: C(13)].17 In 17a, there are two

N-N = bu2bipy.

nonequivalent molecules; one of these molecules provides two NH donor groups, and the other provides two PtBr acceptor groups for hydrogen bonding, while its NH groups are not involved in hydrogen bonding (Chart 6) [graph set description: C22(30)].17 In a one-dimensional ribbon polymer, each molecule forms two hydrogen bonds with each neighbor, and examples are found in complexes 11a, 11b, and 14a (Figures 2 and 4). In these structures, all NH groups are involved in the self-assembly process. In complexes 11a and 11b, the self-assembly occurs through NH 3 3 3 OdC hydrogen bonding, and these are the only cases in which this classic form of self-assembly of amide groups, which has been observed in coordination complexes of type B (Chart 1), is observed (Chart 6).1-4 In these complexes, 11, the supramolecular structure (Figure 2), contains both chains and rings {graph set description: C(4)[R22(14)]}.17 In contrast, complex 14a self-assembles through NH 3 3 3 BrPt hydrogen bonding to form a different kind of ribbon polymer (Figure 4) with longer repeat units in the chains and larger rings {graph set description C(10)[R22(32)]}.17 Several iodoplatinum derivatives, such as 14b, have been prepared with the idea that the hard hydrogen bond might favor NH 3 3 3 OdC bonding over the NH 3 3 3 IPt hydrogen bond and therefore allow engineering of the self-assembly. However, in all cases in which NH 3 3 3 BrPt was preferred over NH 3 3 3 OdC hydrogen bonding, the corresponding iodide derivative failed to form good single crystals; therefore, it has not been possible to prove that structure switching can be achieved in this way. The serendipitously prepared complex 18b (Figure 8) was the only one which formed a two-dimensional sheet structure, shown schematically in Chart 7. In this complex, all hydrogen bonding interactions are of the type NH 3 3 3 ClPt, and each molecule interacts with four neighbors by providing two NH hydrogen bond donors and two ClPt hydrogen bond acceptors. The complex is formed from the bromoplatinum complex 18a by reaction with solvent carbon tetrachloride over a period of several weeks. It is likely that 18a forms much weaker intermolecular NH 3 3 3 BrPt hydrogen bonds and therefore does not crystallize easily, whereas 18b forms stronger NH 3 3 3 ClPt hydrogen bonds to give the less soluble network complex. The network again contains both chain and ring components, with the new features that the rings contain four hydrogen bond donors and four acceptors and that the chain repeat size and ring size are the largest achieved in this study {graph set description C22(32)[R44(64)]}.17 This work significantly extends the use of organoplatinum(IV) complexes in supramolecular chemistry and the use of

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Figure 5. Structures of the two independent molecules of complex 17a. Selected bond distances: Pt(1)-C(34), 2.045(8); Pt(1)C(35), 2.049(7); Pt(1)-C(21), 2.071(7); Pt(1)-N(1), 2.181(6); Pt(1)-N(12), 2.156(5); Pt(1)-Br(1), 2.5820(8); Pt(2)-C(74), 2.049(7); Pt(2)-C(75), 2.068(7); Pt(2)-C(61), 2.088(7); Pt(2)N(41), 2.176(6); Pt(2)-N(52), 2.152(5); Pt(2)-Br(2), 2.6147(8) A˚. Symmetry transformations: Pt(1) molecule; 2 - x, 1 - y, z; Pt(2) molecule; 1 - x, 2 - y, 1 + z.

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Figure 7. Structure of complex 18b. Pt-C(1), 2.12(1); Pt-C(2), 2.20(2); Pt-C(31), 2.05(1); Pt-N(11), 2.15(1); Pt-N(22), 2.19(1); Pt-Cl, 2.470(3) A˚.

Figure 8. Part of the sheet structure formed by the self-assembly of complex 18b, showing a central molecule surrounded by its four H-bonded neighbors. Hydrogen bond distance: Cl 3 3 3 N(41B) = 3.35(2) A˚. Scheme 2. a Figure 6. Part of the polymeric chain formed by hydrogen bonding between molecules of complex 17a. Hydrogen bond distance: N(70) 3 3 3 Br(1) = 3.671(6) A˚.

oxidative addition as a route to functional organoplatinum(IV) complexes.7,13-16 The stability of the alkylplatinum(IV) bond toward protic reagents and the very high yields obtained in oxidative addition are key factors in making this chemistry possible.13 These alkylplatinum(IV) complexes have particularly long bridging alkanediyl groups,5,6 yet they can be prepared in high yield and with few complications from isomerization or reductive elimination.13 The crystal engineering of the products remains challenging. This work suggests that the hydrogen bond strength follows the sequence NH 3 3 3 ClPt > NH 3 3 3 BrPt, NH 3 3 3 OdC > NH 3 3 3 IPt, and this may be a useful rule of thumb in designing future supramolecular structures.

a

(N-N = bu2bipy).

Experimental Section 1 H NMR spectra were recorded using a Varian Mercury 400 NMR or a Varian Inova 400 NMR spectrometer. The nomenclature used in NMR listings is Ar1 for the central and

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Au et al. Chart 7

Figure 9. Structure of complex 19, including hydrogen bonding to a neighboring molecule. Selected bond distances: Pt(1)-C(1), 2.09(2); Pt(1)-C(2), 1.99(2); Pt(1)-C(31), 1.95(2); Pt(1)-N(11), 2.10(1); Pt(1)-N(22), 2.14(1); Pt(1)-Br(1), 2.589(2); Pt(2)C(3), 2.13(2); Pt(2)-C(4), 2.16(2); Pt(2)-C(52), 2.10(2); Pt(2)-N(61), 2.17(1); Pt(2)-N(72), 2.10(1); Pt(2)-Br(2), 2.571(2) A˚. Hydrogen bonding distances: N(40) 3 3 3 O(45) = 2.89(2); N(43) 3 3 3 Br(1A) = 3.54(2) A˚. Symmetry transformation for the neighboring molecule: 1/2 + x, y, 1/2 + z. Chart 6

Ar2 for the outer C6H4 groups. FTIR spectra were recorded with NaCl discs in Nujol Mull using a Perkin-Elmer FT-IR 2000 spectrometer. Mass spectra were recorded using Electrospray PE-Sciex API 365 with NaI as the ionizing reagent. The complexes [Pt2Me4(μ-SMe2)2] and [PtMe2(bu2bipy)] were prepared using the literature method.9

1,2-C6H4(NHC(O)-4-C6H4CH2Br)2 (1). A mixture of triethylamine (1.2 mL) and 1,2-phenylenediamine (0.27 g, 2.50 mmol) in dry THF (8 mL) was added dropwise to a solution 4-bromomethyl benzoyl bromide (1.40 g, 5.0 mmol) in dry THF (2 mL) at 0 °C. The reaction mixture was warmed to ambient temperature and stirred for 2 h. The product precipitated from the solution as a light yellow solid. It was filtered, washed with THF and cold water, and dried in vacuo. Yield 94% (1.18 g). NMR in DMSO-d6: δ(1H)=4.72 [s, 4H, CH2Br], 7.30 [dd, 2H, 3J(HH)=6 Hz, 4J(HH)=3 Hz, Ar1(H3, H4)], 7.61 [d, 4H, 3J(HH)=8 Hz, Ar2(H3, H5)], 7.76 [dd, 2H, 3J(HH) = 6 Hz, 4J(HH) = 3 Hz, Ar1(H2, H5)], 8.06 [d, 4H, 3J(HH) = 8 Hz, Ar2(H2, H6)], 9.90 [s, broad, 2H, NH]. MS: m/z calcd, 499.9735; found, 499.9727. 1,2-C6H4[NHC(O)CH2-4-C6H4(CH2Br)]2 (2). 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC, 137 mg, 0.72 mmol) was added to a solution of 4-(bromomethyl)phenylacetic acid (164 mg, 0.72 mmol) in 1:1 DMF/dry CH2Cl2 (6 mL) at 0 °C. The reaction mixture was stirred for 15 min, then a solution of 1,2-phenylenediamine (19.3 mg, 0.18 mmol) in dry CH2Cl2 (6 mL) was added dropwise. The reaction mixture was warmed to ambient temperature, stirred for 2 h, and then diluted with EtOAc (25 mL) and washed with 1 M HCl (25 mL), saturated aqueous NaHCO3 (25 mL), and NaBr (25 mL). The organic layer was dried with anhydrous MgSO4, filtered, and concentrated in vacuo. Recrystallization from EtOAc/heptane gave a light pink solid in 63% yield (60.0 mg). NMR in DMSO-d6: δ(1H) = 3.65 [s, 4H, OdCCH2]; 4.71 [s, 4H, CH2Br]; 7.14 [dd, 2H, 3J(HH) = 6 Hz, 4J(HH) = 4 Hz, Ar1(H4, H5)]; 7.37 [m, 4H, Ar2(H2, H6)]; 7.44 [m, 4H, Ar2(H3, H5)]; 7.52 [dd, 2H, 3J(HH) = 6 Hz, 4J(HH) = 4 Hz, Ar1(H3, H6)]; 9.11 [s, broad, 2H, NH]. MS: m/z calcd, 528.0048; found, 528.0031. 1,3-C6H4(NHC(O)-4-C6H4CH2Br)2 (3). This was prepared by the same method as that used for compound 1 from 4bromomethyl benzoyl bromide (1.40 g, 5.0 mmol), triethylamine (1.2 mL), and 1,3-phenylenediamine (0.27 g, 2.50 mmol). Yield: 93% (1.17 g). NMR in DMSO-d6: δ(1H) = 4.77 [s, 4H, CH2Br]; 7.30 [t, 2H, 3J(HH) = 8 Hz, Ar1(H5)]; 7.48 [dd, 2H, 3J(HH) = 8 Hz, 4J(HH) = 2 Hz, Ar1(H4, H6)]; 7.58 [d, 2H, 3J(HH) = 8 Hz, Ar2(H3, H5)]; 7.93 [d, 2H, 3J(HH) = 8 Hz, Ar2(H2, H6)]; 8.30 [t, 1H, 4J(HH) = 2 Hz, Ar1(H2)]; 10.33 [s, 2H, NH]. MS: m/z calcd, 499.9735; found, 499.9747. 1,3-C6H4(CH2NHC(O)-4-C6H4CH2Br)2 (4). This was prepared by the same method as that used for compound 1 from 4-bromomethyl benzoyl bromide (1.40 g, 5.0 mmol), triethylamine (1.2 mL), and m-xylylenediamine (0.34 g, 2.50 mmol). A white solid was produced. Yield: 88% (1.17 g). NMR in DMSO-d6: δ(1H) = 4.46 [d, 4H, 3J(HH) = 6 Hz, CH2N]; 4.77 [s, 4H, CH2Br]; 7.19 [d, 2H, 3J(HH) = 8 Hz, Ar1(H4, H6)]; 7.28 [m, 2H, Ar1(H2, H5)]; 7.51 [d, 2H, 3J(HH)= 8 Hz, Ar2(H3, H5)];

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Table 1. Crystal Data and Structure Refinement

formula fw T (K) λ (A˚) cryst. syst. sp. gp.

11a 3 CH2Cl2

11b 3 Me2CO

C63H80Br2Cl2N6O2Pt2 1574.23 150(2) 0.71073 monoclinic C2/c

C65H78I2N6O3Pt2 1635.31 150(2) 0.71073 monoclinic C2/c

14a 3 2Me2CO 3 MeOH C71H98Br2N6O5Pt2 1665.55 150(2) 0.71073 triclinic P-1

17a 3 3Me2CO

18b

19

C71H96Br2N6O5Pt2 1663.54 150(2) 0.71073 triclinic P-1

C64H82Cl2N6O2Pt2 1428.44 150(2) 0.71073 monoclinic C2/c

C58H78Br2N6O2Pt2 1441.26 150(2) 0.71073 orthorhombic Fdd2

12.1246(4) 12.9238(3) 22.7407(7) 83.547(2) 88.3780(10) 78.375(2) 3468.11(18) 2 1.593 5.234 0.0431

27.917(6) 18.462(4) 20.296(4) 90 130.06(3) 90 8007(3) 4 1.338 3.593 0.0728

24.7532(12) 94.361(5) 11.0667(5) 90 90 90 25849(2) 16 1.481 5.602 0.0669

Cell Dimensions a (A˚) b (A˚) c (A˚) R (deg) β (deg) γ (deg) V (A˚3) Z dcalc (Mg m-3) μ (mm-1) R1[I > 2σ(I)]

42.5634(15) 14.3713(5) 10.2918(3) 90 96.689(2) 90 6252.6(4) 4 1.672 5.880 0.0522

42.325(2) 14.9464(7) 10.2716(5) 90 95.601(3) 90 6466.9(5) 4 1.680 5.324 0.0524

15.1472(8) 15.5000(11) 17.7434(12) 65.439(3) 68.972(3) 83.967(4) 3531.8(4) 2 1.566 5.139 0.0799

7.83 [d, 2H, 3J(HH) = 8 Hz, Ar2(H2, H6)]; 9.08 [t, 2H, 3J(HH) = 12 Hz, NH]. MS: m/z calcd, 528.0048; found, 528.0068. 1,3-C6H4[NHC(O)CH2-4-C6H4(CH2Br)]2 (5). This was prepared using the same method as that used for compound 2 from 4-(bromomethyl)phenylacetic acid (164 mg, 0.72 mmol) in 1:1 DMF/dry CH2Cl2 (6 mL), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC, 137 mg, 0.72 mmol), and 1,3-phenylenediamine (19.3 mg, 0.18 mmol) in 1:1 DMF/dry CH2Cl2 (12 mL). A light brown solid was produced. Yield: 50% (47.4 mg). NMR in DMSO-d6: δ(1H) = 3.63 [s, 4H, OdCCH2]; 4.69 [s, 4H, CH2Br]; 7.18 [m, 4H, Ar1(H5)]; 7.26 [m, 2H, Ar1(H4, H6)]; 7.32 [m, 4H, Ar2(H2, H6)]; 7.39 [m, 4H, Ar2(H3, H5)]; 7.48 [m, 4H, Ar1(H2)]; 7.92 [s, 2H, NH]. MS: m/z calcd, 528.0048; found, 528.0034. 1,3-C6H4(CH2NHC(O)CH2-4-C6H4CH2Br)2 (6). This was prepared by the same method as that used for compound 2 from 4-(bromomethyl)phenylacetic acid (164 mg, 0.72 mmol) in 1:1 DMF/dry CH2Cl2 (6 mL), 1-(3-dimethylaminpropyl)-3ethylcarbodiimide hydrochloride (EDC, 137 mg, 0.72 mmol), and m-xylylenediamine (19.3 mg, 0.18 mmol) in 1:1 DMF/dry CH2Cl2 (12 mL). Yield: 26% (26 mg). NMR in DMSO-d6: δ(1H) = 3.47 [s, 4H, OdCCH2]; 4.22 [d, 4H, 3J(HH) = 5 Hz, CH2N]; 4.68 [s, 4H, CH2Br]; 7.08 [m, 3H, Ar1(H2, H4, H6)]; 7.23 [m, 1H, Ar1(H5)]; 7.28 [d, 4H, 3J(HH) = 8 Hz, Ar2(H2, H6)]; 7.83 [m, 4H, Ar2(H3, H5)]; 8.57 [t, 2H, 3J(HH) = 10 Hz, NH]. MS: m/z calcd, 556.0361; found, 556.0318. 1,4-C6H4[NHC(O)-4-C6H4(CH2Br)]2 (7). This was prepared by the same method as that used for compound 1 from 4bromomethyl benzoyl bromide (1.40 g, 5.0 mmol), triethylamine (1.2 mL), and 1,4-phenylenediamine (0.27 g, 2.50 mmol). Yield: 96% (1.20 g). NMR in DMSO-d6: δ(1H) = 4.78 [s, 4H, CH2Br]; 7.60 [d, 4H, 3J(HH)=8 Hz, Ar2(H3, H5)]; 7.74 [s, 4H, Ar1(H2, H3, H5, H6)]; 7.94 [d, 4H, 3J(HH)=8 Hz, Ar2(H2, H6)]; 10.29 [s, 2H, NH]. MS: m/z calcd, 499.9735; found, 499.9732. 1,4-C6H4[NHC(O)CH2-4-C6H4(CH2Br)]2 (8). This was prepared by the same method as that used for compound 2 from 4(bromomethyl)phenylacetic acid (164 mg, 0.72 mmol) in 1:1 DMF/dry CH2Cl2 (6 mL), 1-(3-dimethylaminpropyl)-3-ethylcarbodiimide hydrochloride (EDC, 137 mg, 0.72 mmol), and 1,4-phenylenediamine (19.3 mg, 0.18 mmol) in 1:1 DMF/dry CH2Cl2 (6 mL). A light pink solid was produced. Yield: 98% (93.5 mg). NMR in DMSO-d6: δ(1H) = 3.62 [s, 4H, OdCCH2]; 4.74 [s, 4H, CH2Br]; 7.32 [d, 4H, 3J(HH)=8 Hz, Ar2(H2, H6)]; 7.38 [d, 4H, 3J(HH) = 8 Hz, Ar2(H3, H5)]; 7.50 [s, 4H, Ar1(H2, H3, H5, H6)]; 10.17 [s, 2H, NH]. MS: m/z calcd, 528.0048; found, 528.0044. 1,2-C2H4(NHC(O)-4-C6H4CH2Br)2 (9). This was prepared by the same method as that used for compound 1 from

4-bromomethyl benzoyl bromide (1.40 g, 5.0 mmol), triethylamine (1.2 mL), and 1,2-ethylenediamine (0.34 g, 2.50 mmol). Yield: 84% (0.95 g). NMR in DMSO-d6: δ(1H) = 3.41 [m, 4H, NCH2]; 4.72 [s, 4H, CH2Br]; 7.51 [d, 4H, 3J(HH) = 8 Hz, Ar(H3, H5)]; 7.80 [d, 4H, 3J(HH) = 8 Hz, Ar(H2, H6)]; 8.62 [s, 2H, NH]. MS: m/z calcd, 451.9735; found, 451.9721. [{1,2-C6H4(NHC(O)-4-C6H4CH2PtBrMe2(bu2bipy)}2] (11a). A mixture of [PtMe2(bu2bipy)], 10 (100.0 mg, 0.20 mmol), and compound 1 (50.0 mg, 0.10 mmol) in 1:10 MeOH/acetone (22 mL) was stirred for 7 h at room temperature. The color of the solution changed from orange to yellow as the reaction proceeded. The solvent was evaporated under vacuum, and the resulting yellow solid was washed with water and pentane and dried in vacuo. It was recrystallized from CH2Cl2. Yield: 90% (134 mg). NMR in CD2Cl2: δ(1H)=1.35 [s, 36H, bipy-bu]; 1.43 [s, 12H, 2J(PtH)=70 Hz, PtMe]; 2.84 [s, 4H, 2J(PtH) = 98 Hz, PtCH2]; 6.42 [d, 4H, 3J(HH)=8 Hz, 4J(PtH)=19 Hz, Ar2(H3, H5)]; 7.17 [d, 4H, 3J(HH) = 8 Hz, Ar2(H2, H6)]; 7.20 [d, 2H, 3 J(HH)=6 Hz, Ar1(H3, H4)]; 7.43 [d, 4H, 3J(HH)=6 Hz, bipy 5 50 (H , H )]; 7.45 [d, 2H, 3J(HH)=6 Hz, Ar1(H2, H5)]; 7.97 [s, 4H, 0 bipy(H30, H3 )]; 8.49 [d, 4H, 3J(HH)=6 Hz, 4J(PtH)=19 Hz, bipy (H6, H6 )]. Anal. Calcd. for C62H78Br2N6O2Pt2: C, 50.00; H, 5.28; N, 5.64. Found: C, 50.03; H, 5.36; N, 5.45%. [{1,2-C6H4(NHC(O)-4-C6H4CH2PtIMe2(bu2bipy)}2] (11b). A mixture of complex 11a (30.0 mg, 0.020 mmol) and lithium iodide (16.2 mg, 0.120 mmol) in acetone (20 mL) was stirred for 24 h at room temperature. The solvent was evaporated under vacuum, and the resulting yellow solid was washed with water and pentane and dried in vacuo. It was recrystallized from acetone/pentane. Yield: 95% (30.1 mg). NMR in CD2Cl2: δ(1H) = 1.36 [s, 36H, bipy-bu]; 1.57 [s, 12H, 2J(PtH) = 70 Hz, PtMe]; 2.88 [s, 4H, 2J(PtH) = 95 Hz, PtCH2]; 6.41 [d, 4H, 3J(HH)=8 Hz, 4J(PtH)=19 Hz, Ar2(H3, H5)]; 7.16 [d, 4H, 3 J(HH) = 8 Hz, Ar2(H2, H6)]; 7.26 [d, 2H, 3J(HH) = 6 Hz, Ar1(H3,0 H4)]; 7.42 [dd, 4H, 3J(HH)=6 Hz, 4J(HH)=2 Hz, bipy (H5, H5 )]; 7.47 [dd, 2H, 3J(HH)=6 Hz, 4J(HH)=3 Hz, Ar1(H2, 0 H5)]; 7.96 [d, 4H, 4J(HH) = 2 Hz, bipy(H3, H0 3 )]; 8.54 [d, 4H, 3 J(HH)=6 Hz, 4J(PtH)=19 Hz, bipy(H6, H6 )]; 8.60 [s, broad, 2H, NH]. Anal. Calcd. for C62H78I2N6O2Pt2: C, 47.03; H, 4.97; N, 5.31. Found: C, 46.75; H, 4.76; N, 5.11%. [1,2-C6H4{NHC(O)CH2-4-C6H4CH2PtBrMe2(bu2bipy)}2] (12). A mixture of [PtMe2(bu2bipy)], 10 (25.0 mg, 0.050 mmol), and ligand 2 (13.3 mg, 0.025 mmol) in acetone (25 mL) was stirred for 2 days at room temperature. The solvent was evaporated under vacuum, and the resulting yellow solid was washed with (i) water and (ii) pentane, and dried in vacuo. Yield: 95% (36.0 mg). NMR in CD2Cl2: δ(1H) = 1.43 [s, 12H, 2J(PtH) = 69 Hz, PtMe]; 1.40 [s, 36H, bipy-bu]; 2.79 [s, 4H, 2J(PtH) = 94 Hz,

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PtCH2]; 3.17 [s, 4H, OdCCH2]; 6.33 [d, 4H, 3J(HH) = 8 Hz, 4 J(PtH) = 18 Hz, Ar2(H3, H5)]; 6.46 [d, 4H, 3J(HH) = 8 Hz, Ar2(H2, H6)]; 7.11 [d, 2H, 3J(HH)= 6 Hz, Ar1(H3, H4)]; 7.26 [d, 7.40 [s, broad, 2H, NH]; 7.47 [d, 2H, 3J(HH)=6 Hz, Ar1(H2, H5)]; 0 0 4H, 3J(HH)=6 Hz, bipy(H5, H5 )]; 8.00 [s, 4H, bipy(H3, H0 3 )]; 8.54 [d, 4H, 3J(HH) = 6 Hz, 4J(PtH) = 16 Hz, bipy(H6, H6 )]. Anal. Calcd. for C64H82Br2N6O2Pt2: C, 50.66; H, 5.45; N, 5.54. Found: C, 50.71; H, 5.14; N, 5.96%. [1,3-C6H4{NHC(O)-4-C6H4CH2PtBrMe2(bu2bipy)}2] (13a). This was prepared as a yellow solid using the same method as that used for complex 11a from a mixture of [PtMe2(bu2bipy)] (12.5 mg, 0.025 mmol) and compound 3 (25.0 mg, 0.050 mmol) in acetone (20 mL) stirred for 18 h at room temperature. Yield: 88% (32.8 mg). NMR in CD2Cl2: δ(1H)=1.42 [s, 36H, bipy-bu]; 1.46 [s, 12H, 2J(PtH)=68 Hz, PtMe]; 2.88 [s, 4H, 2J(PtH)=97 Hz, PtCH2]; 6.42 [d, 4H, 3J(HH)=8 Hz, 4J(PtH) = 18 Hz, Ar2(H3, 3H, H5)]; 7.14 [d, 4H, 3J(HH) = 8 Hz, Ar2(H2, H6)]; 7.31 [m, 5 50 , H )]; 7.65 Ar1(H4, H6)]; 7.50 [d, 4H, 3J(HH) = 6 Hz, bipy(H 0 [m, 2H, Ar1(H2, H5)]; 8.01 [s, 4H, bipy(H3, 0 H3 )]; 8.54 [d, 4H, 3 4 6 6 J(HH)=6 Hz, J(PtH)=19 Hz, bipy(H , H )]. Anal. Calcd. for C62H78Br2N6O2Pt2.Me2CO: C, 50.45; H, 5.55; N, 5.43. Found: C, 50.60; H, 5.52; N, 5.07%. [1,3-C6H4{NHC(O)-4-C6H4CH2PtIMe2(bu2bipy)}2] (13b). This was prepared as a yellow solid using the same method as that used for complex 11b from complex 13a (30.0 mg, 0.020 mmol) and excess lithium iodide (16.2 mg, 0.120 mmol). Yield: 70% (22.2 mg). NMR in CD2Cl2: δ(1H) = 1.42 [s, 36H, bipy-bu]; 1.59 [s, 12H, 2 J(PtH)=70 Hz, PtMe]; 2.90 [s, 4H, 2J(PtH) = 94 Hz, PtCH2]; 6.42 [d, 4H, 3J(HH)=8 Hz, 4J(PtH) = 18 Hz, Ar2(H3, H5)]; 7.15 [d, 4H, 3 J(HH)=8 Hz, Ar2(H2, H6)]; 7.310 [m, 2H, Ar1(H4, H6)]; 7.49 [d, 5 , H5 )]; 7.73 [m, 2H, Ar1(H2, H5)]; 4H, 3J(HH) = 6 Hz, bipy(H 3 30 8.00 [s, 4H, bipy(H 0 , H )]; 8.58 [d, 4H, 3J(HH) = 6 Hz, 4J(PtH) = 19 Hz, bipy(H6, H6 )]. Anal. Calcd. for C62H78I2N6O2Pt2: C, 47.03; H, 4.97; N, 5.31. Found: C, 47.33; H, 4.47; N, 4.92%. [1,3-C6H4{CH2NHC(O)-4-C6H4CH2PtBrMe2(bu2bipy)}2] (14a). This was prepared using the same method as that used for complex 11a from a mixture of [PtMe2(bu2bipy)] (25.0 mg, 0.050 mmol) and reagent 4 (13.3 mg, 0.025 mmol) in acetone (15 mL) stirred for 12 h at room temperature. A yellowish white solid was produced. Yield: 90% (34.1 mg). 1H NMR (400 MHz, CD2Cl2) δ 1.39 [s, 36H, bipybu]; 1.43 [s, 12H, 2J(PtH)=69 Hz, PtMe]; 2.83 [s, 4H, 2J(PtH)= 97 Hz, PtCH2]; 4.48 [d, 4H, 3J(HH)=6 Hz, NCH2]; 6.22 [d, 2H, 3 J(HH) = 6 Hz, NH]; 6.37 [d, 4H, 3J(HH) = 8 Hz, 4J(PtH) = 19 Hz, Ar2(H3, H5)]; 7.02 [d, 4H, 3J(HH) = 8 Hz, Ar2(H2, H6)]; 7.21 6 )]; 7.29 [m, 1H, Ar1(H5)]; 7.46 [d, 4H, 3J(HH) = [m, 3H, Ar1(H2, H4, H 5 50 3 30 6 Hz, bipy(H , H )]; 7.97 [s, 4H, bipy(H , 0H )]; 8.50 [d, 4H, 3 J(HH)=6 Hz, 4J(PtH)=20 Hz, bipy(H6, H6 )]. Anal. Calcd. for C64H82Br2N6O2Pt2: C, 50.66; H, 5.45; N, 5.54. Found: C, 50.90; H, 5.45; N, 5.13%. [1,3-C 6 H 4 {CH 2 NHC(O)-4-C 6 H 4 CH 2 PtIMe 2 (bu 2 bipy)} 2 ] (14b). This was prepared using the same method as that used for complex 11b from complex 14a (20.0 mg, 0.013 mmol) and excess lithium iodide (10.6 mg, 0.079 mmol). A yellowish white solid was produced. It was recrystallized from acetone/MeOH/ pentane. Yield: 56% (11.8 mg). NMR in CD2Cl2: δ(1H)=1.39 [s, 36H, bipy-bu]; 1.56 [s, 12H, 2J(PtH)=72 Hz, PtMe]; 2.86 [s, 4H, 2 J(PtH)=94 Hz, PtCH2]; 4.48 [s, 4H, NCH2]; 6.21 [m, 2H, NH]; 6.34 [d, 4H, 3J(HH)=8 Hz, 4J(PtH) = 19 Hz, Ar2(H3, H5)]; 7.01 [d, 4H, 3J(HH)=8 Hz, Ar2(H2, H6)]; 7.21 [m, 3H, Ar1(H2, H4, H6)]; 7.29 [m, 1H, Ar1(H50)]; 7.44 [dd, 4H, 3J(HH) =0 6 Hz, 4J(HH)=2 Hz, bipy(H5, H5 )]; 7.96 [s, 4H, bipy(H3, H3 )]; 8.54 [d, 0 4H, 3J(HH) = 6 Hz, 4J(PtH) = 19 Hz, bipy(H6, H6 )]. Anal. Calcd. for C64H82I2N6O2Pt2: C, 47.71; H, 5.13; N, 5.22. Found: C, 47.75; H, 5.44; N, 4.94%. [1,3-C6H4{NHC(O)CH2-4-C6H4CH2PtBrMe2(bu2bipy)}2] (15). This was prepared as a yellow solid by the same method as that used for complex 11a from [PtMe2(bu2bipy)] (25.0 mg, 0.050 mmol) and compound 5 (13.3 mg, 0.025 mmol). Yield: 92% (34.8 mg). NMR in CD2Cl2: δ(1H)= 1.42 [s, 12H, 2J(PtH) = 69 Hz, PtMe]; 1.43 [s, 36H, bipy-bu]; 2.79 [s, 4H, 2J(PtH) = 95 Hz, PtCH2]; 3.29 [s, 4H,

Au et al. OdCCH2]; 6.32 [d, 4H, 3J(HH)=8 Hz, 4J(PtH)=17 Hz, Ar2(H3, H5)]; 6.51 [d, 4H, 3J(HH) = 8 Hz, Ar2(H2, H6)];0 7.00 [m, 2H, Ar1(H5)]; 7.47 [d, 4H, 3J(HH)=6 Hz, bipy(H5, H5 )]; 7.60 [m, 2H, Ar1(H4, H6)]; 7.940 [s, broad, 2H, NH]; 7.97 [m, 1H, Ar1(H2)]; 8.01 [s, 4H, bipy(H30, H3 )]; 8.54 [d, 4H, 3J(HH)=6 Hz, 4J(PtH)=18 Hz, bipy(H6, H6 )]. Anal. Calcd. for C64H82Br2N6O2Pt2: C, 50.66; H, 5.45; N, 5.54. Found: C, 51.04; H, 5.51; N, 5.93%. [1,3-C6H4{CH2NHC(O)CH2-4-C6H4CH2PtBrMe2(bu2bipy)}2] (16). This was prepared as a yellow solid by the same method as that used for complex 11a from [PtMe2(bu2bipy)] (25.0 mg, 0.050 mmol) and compound 6 (14.0 mg, 0.025 mmol). Yield: 98% (37.8 mg). NMR in CD2Cl2: δ(1H) = 1.39 [s, 12H, 2J(PtH) = 70 Hz, PtMe]; 1.41 [s, 36H, bipy-bu]; 2.76 [s, 4H, 2J(PtH)=95 Hz, PtCH2]; 3.29 [s, 4H, OdCCH2]; 4.23 [s, 4H, NCH2]; 6.27 [d, 4H, 3 J(HH) = 7 Hz, 4J(PtH) = 16 Hz, Ar2(H3, H5)]; 6.47 [d, 4H, 3 J(HH)=8 Hz, Ar2(H2, H6)]; 6.39 [s, 1H, Ar1(H2)]; 6.99 [d, 2H, 3 J(HH) = 8 Hz, 4J(HH) = 3 Hz, Ar1(H4, H6)]; 7.19 [d, 2H, 3 J(HH)=8 Hz, Ar1(H5)]; 7.44 0[d, 4H, 3J(HH)=6 Hz, bipy(H5, 0 H5 )]; 8.00 [s, 4H, bipy(H3, H0 3 )]; 8.50 [d, 4H, 3J(HH) = 6 Hz, 4 J(PtH)=16 Hz, bipy(H6, H6 )]. Anal. Calcd. for C66H86Br2N6O2Pt2: C, 51.30; H, 5.61; N, 5.44. Found: C, 51.78; H, 5.35; N, 5.62%. [1,4-C6H4{NHC(O)-4-C6H4CH2PtBrMe2(bu2bipy)}2] (17a). This was prepared as a yellow solid using the same method as that used for complex 11a from a mixture of [PtMe2(bu2bipy)] (50.0 mg, 0.10 mmol) and compound 7 (25.0 mg, 0.05 mmol) in acetone (15 mL) stirred for 2 days at room temperature. Yield: 67% (50.0 mg). NMR in CD2Cl2: δ(1H)=1.42 [s, 36H, bipy-bu]; 1.46 [s, 12H, 2J(PtH)=70 Hz, PtMe]; 2.88 [s, 4H, 2J(PtH)=97 Hz, PtCH2]; 6.45 [d, 4H, 3J(HH) = 8 Hz, 4J(PtH) = 18 Hz, Ar2(H3, H5)]; 7.15 [d, 4H, 3J(HH)=8 Hz, Ar2(H2, H6)]; 7.19 [d, 3 5 50 4H, J(HH)=6 Hz, bipy(H , H )]; 7.53 [s, 4H, Ar1(H0 2, H3, H5, H6)]; 7.60 [s, broad, 2H, NH]; 8.00 [s, 4H, bipy(H3, H3 )]; 8.54 [d, 0 4H, 3J(HH) = 6 Hz, 4J(PtH) = 19 Hz, bipy(H6, H6 )]. Anal. Calcd. for C62H78Br2N6O2Pt2: C, 50.00; H, 5.28; N, 5.64. Found: C, 50.38; H, 5.65; N, 5.98%. [1,4-C6H4{NHC(O)-4-C6H4CH2PtIMe2(bu2bipy)}2] (17b). This was prepared as a yellow solid using the same method as that used for complex 11b from complex 17a (30.0 mg, 0.020 mmol) and excess lithium iodide (16.2 mg, 0.120 mmol). Yield: 74% (23.3 mg). NMR in CD2Cl2: δ(1H) = 1.42 [s, 36H, bipy-bu]; 1.59 [s, 12H, 2 J(PtH)=70 Hz, PtMe]; 2.90 [s, 4H, 2J(PtH) = 94 Hz, PtCH2]; 6.41 [d, 4H, 3J(HH)=8 Hz, 4J(PtH)=20 Hz, Ar2(H3, H5)]; 7.12 [d, 4H, 3 J(HH) = 8 Hz, Ar2(H2, H6)]; 7.48 [d, 4H, 3J(HH)=6 Hz, bipy(H5, 0 H5 )]; 7.53 [s, 4H, Ar1(H2, H0 3, H5, H6)]; 7.59 [s, broad, 2H, NH]; [d, 4H, 3J(HH) = 6 Hz, 7.99 [s, 4H, bipy(H3, H3 )]; 8.58 0 4 J(PtH) = 19 Hz, bipy(H6, H6 )]. Anal. Calcd. for C62H78I2N6O2Pt2: C, 47.03; H, 5.31; N, 5.31. Found: C, 46.76; H, 5.39; N, 5.08%. [1,4-C6H4{NHC(O)CH2-4-C6H4CH2PtBrMe2(bu2bipy)}2] (18a). This was prepared as a yellow solid using the same method as that used for complex 11a from a mixture of [PtMe2(bu2bipy)] (25.0 mg, 0.050 mmol) and reagent 8 (13.3 mg, 0.025 mmol). Yield: 92% (34.8 mg). NMR in CD2Cl2: δ(1H)=1.41 [s, 12H, 2J(PtH)=69 Hz, PtMe]; 1.42 [s, 36H, bipy-bu]; 2.79 [s, 4H, 2J(PtH)=95 Hz, PtCH2]; 3.29 [s, 4H, OdCCH2]; 6.31 [d, 4H, 3J(HH) = 8 Hz, 4J(PtH) = 18 Hz, Ar2(H3, H5)]; 6.50 [d, 4H, 3J(HH)=8 Hz, Ar2(H2, H6)]; 6.94 7.50 [d, 4H, 3J(HH)= [s, 2H, NH]; 7.29 [s, 4H, Ar1(H2, H3, H5, H6)]; 0 0 6 Hz, bipy(H5, H5 )]; 7.99 [s, 4H, bipy(H03, H3 )]; 8.55 [d, 4H, 3J(HH)= 6 Hz, 4J(PtH) = 16 Hz, bipy(H6, H6 )]. Anal. Calcd. for C64H82Br2N6O2Pt2: C, 50.66; H, 5.45; N, 5.54. Found: C, 50.25; H, 5.10; N, 5.54%. [1,4-C6H4{NHC(O)CH2-4-C6H4CH2PtClMe2(bu2bipy)}2] (18b). This was prepared in low yield by reaction of 18a with solvent during recrystallization from CCl4/MeOH/ether. NMR in CD2Cl2: δ(1H)=1.39 [s, 12H, 2J(PtH)=69 Hz, PtMe]; 1.39 [s, 36H, bipy-bu]; 2.75 [s, 4H, 2J(PtH) = 95 Hz, PtCH2]; 3.29 [s, 4H, OdCCH2]; 6.29 [d, 4H, 3J(HH)=8 Hz, 4J(PtH) = 18 Hz, Ar2(H3, H5)]; 6.48 [d, 4H, 3 J(HH) = 8 Hz, Ar2(H2, H6)]; 6.94 [s, 2H, NH]; 7.29 [s, 4H, Ar1(H2, 3 5 6 3 5 50 H , H , H )]; 7.47 [d, 4H, J(HH)=6 Hz, bipy(H , H )]; 7.98 [s, 4H,

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Organometallics, Vol. 28, No. 13, 2009 0

bipy(H30, H3 )]; 8.52 [d, 4H, 3J(HH)=6 Hz, 4J(PtH)=16 Hz, bipy (H6, H6 )]. [1,2-C2H4{NHC(O)-4-C6H4CH2PtBrMe2(bu2bipy)}2] (19). This was prepared as a yellow solid using the same method as that used for complex 11a from a mixture of [PtMe2(bu2bipy)] (25.0 mg, 0.050 mmol) and compound 9 (11.4 mg, 0.025 mmol) in acetone (15 mL) stirred for 2 days at room temperature. It was recrystallized from CH2Cl2/hexane. Yield: 86% (31.0 mg). NMR in CD2Cl2: δ(1H)=1.36 [s, 36H, bipy-bu]; 1.43 [s, 12H, 2 J(PtH)=69 Hz, PtMe]; 2.84 [s, 4H, 2J(PtH)=98 Hz, PtCH2]; 3.46 [m, 4H, NCH2]; 6.39 [d, 4H, 3J(HH) = 8 Hz, 4J(PtH) = 19 Hz, Ar2(H3, H5)]; 7.05 [d, 4H, 3J(HH)=8 Hz, Ar2(H2, H6)]; 3 5 50 7.43 [d, 4H, J(HH)=6 Hz, bipy(H , H )]; 7.96 [s, 4H, bipy(H3, 0 H30 )]; 8.49 [d, 4H, 3J(HH) = 6 Hz, 4J(PtH) = 19 Hz, bipy(H6, H6 )]. Anal. Calcd. for C58H78Br2N6O2Pt2: C, 48.34; H, 5.45; N, 5.83. Found: C, 48.77; H, 5.79; N, 5.47%. X-ray Structure Determinations. A crystal was mounted on a glass fiber. Data were collected using a Nonius-Kappa CCD diffractometer using COLLECT (Nonius, B.V. 1997-2002) software. The unit cell parameters were calculated and refined from the full data set. Crystal cell refinement and data reduction was carried out using the HKL2000 DENZO-SMN (Otwinowski & Minor, 1997). The absorption correction was applied using HKL2000 DENZO-SMN (SCALEPACK). The SHELXTL/PC V6.14 for Windows NT (Sheldrick, G. M., 2001) program package was used to solve the structure by direct methods. Subsequent difference Fourier syntheses allowed the remaining atoms to be located. All non-hydrogen atoms were refined with anisotropic thermal parameters, unless otherwise specified. The hydrogen atom positions were calculated geometrically and were included as riding on their respective carbon atoms. Details of the data collection and refinement are given in Table 1. Some of the compounds diffracted weakly, but the structures are clearly defined. Brief comments on unusual features are given below. [1,2-C6H4{CH2NHC(O)-4-C6H4CH2PtBrMe2(bu2bipy)}2] (11a 3 CH2Cl2). The solvent molecule was located on a symmetry element and was disordered. It was modeled isotropically. [1,2-C6H4{CH2NHC(O)-4-C6H4CH2PtIMe2(bu2bipy)}2] (11b 3 Me2CO). The acetone molecule was located on a symmetry

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element and was disordered. It was modeled isotropically without hydrogen atoms. [1,3-C6H4{CH2NHC(O)-4-C6H4CH2PtBrMe2(bu2bipy)}2] (14a 3 2Me2CO 3 MeOH). The crystal was twinned, and a single possible Twin Law was suggested by ROTAX. This caused an improvement in R1, GOOF, K, standard uncertainties and the top Q-peak, thus confirming the correctly chosen Twin Law. All non-hydrogen atoms, except C21 and C41, were refined with anisotropic thermal parameters. [1,4-C6H4{NHC(O)-4-C6H4CH2PtBrMe2(bu2bipy)}2] (17a 3 3Me2CO). There was indication of minor disorder of acetone solvates leading to high thermal parameters, but no suitable model was found. [1,4-C6H4{NHC(O)CH2-4-C6H4CH2PtClMe2(bu2bipy)}2] (18b). Crystals were grown by slow diffusion of ether into a solution of 18a in CCl4/MeOH. There was 0.5 molecules in the asymmetric unit, with an inversion center relating the symmetry equivalent half. The crystal diffracted weakly, and some weak high angle data was discarded. Two independent molecules of CCl4 were identified at partial occupancy, but they were poorly defined, and there was void space that contained unresolved electron density; therefore, SQUEEZE was used to remove electron density due to disordered solvent. The void space was large (32% of total volume), and the electron count removed was 911 e, corresponding to ca. 12 molecules/cell of CCl4. [1,2-C2H4{NHC(O)-4-C6H4CH2PtBrMe2(bu2bipy)}2] (19). The crystal diffracted weakly. A hexane molecule was located at partial occupancy, but it was poorly defined; therefore, it was removed by using SQUEEZE. This showed void space of 16.5%, and an associated total electron density of 1088 e/cell, corresponding to ca. 1.5 molecules of hexane/asymmetric unit.

Acknowledgment. We thank the NSERC (Canada) for financial support. Supporting Information Available: Tables of X-ray data in CIF format. This material is available free of charge via the Internet at http://pubs.acs.org.