Stevens, Charlotte J., Dallanegra, Romaeo, Chaplin, Adrian B., Weller, Andrew S., Macgregor, Stuart A., Ward, B. (Bryan), McKay, D. (David), Alcaraz, Gilles and Sabo-Etienne, Sylviane. (2011) [Ir(PCy(3))(2)(H)(2)(H(2)B-NMe(2))](+) as a latent source of aminoborane : probing the role of metal in the dehydrocoupling of H(3)B center dot NMe(2)H and retrodimerisation of [H(2)BNMe(2)](2). Chemistry: A European Journal, Vol.17 (No.10). pp. 3011-3020. ISSN 0947-6539

Full text not available from this repository.

Abstract

The Ir(III) fragment {Ir(PCy(3))(2)(H)(2)}(+) has been used to probe the role of the metal centre in the catalytic dehydrocoupling of H(3)B center dot NMe(2)H (A) to ultimately give dimeric aminoborane [H(2)BNMe(2)](2) (D). Addition of A to [Ir(PCy(3))(2)(H)(2)(H(2))(2)][BAr(4)(F)] (1; Ar(F) =(C(6)H(3)(CF(3))(2)), gives the amineborane complex [Ir(PCy(3))(2)(H)(2)(H(3)B center dot NMe(2)H)][BAr(4)(F)] (2a), which slowly dehydrogenates to afford the aminoborane complex [Ir(PCy(3))(2)(H)(2)(H(2)B-NMe(2))][BAr(4)(F)] (3). DFT calculations have been used to probe the mechanism of dehydrogenation and show a pathway featuring sequential BH activation/H(2) loss/NH activation. Addition of D to 1 results in retrodimerisation of D to afford 3. DFT calculations indicate that this involves metal trapping of the monomer-dimer equilibrium, 2H(2)BNMe(2) reversible arrow [H(2)BNMe(2)](2). Ruthenium and rhodium analogues also promote this reaction. Addition of MeCN to 3 affords [Ir(PCy(3))(2)(H)(2)(NCMe)(2)][BAr(4)(F)] (6) liberating H(2)B-NMe(2) (B), which then dimerises to give D. This is shown to be a second-order process. It also allows on-and off-metal coupling processes to be probed. Addition of MeCN to 3 followed by A gives D with no amine-borane intermediates observed. Addition of A to 3 results in the formation of significant amounts of oligomeric H(3)B center dot NMe(2)BH(2)center dot NMe(2)H (C), which ultimately was converted to D. These results indicate that the metal is involved in both the dehydrogenation of A, to give B, and the oligomerisation reaction to afford C. A mechanism is suggested for this latter process. The reactivity of oligomer C with the Ir complexes is also reported. Addition of excess C to 1 promotes its transformation into D, with 3 observed as the final organometallic product, suggesting a B-N bond cleavage mechanism. Complex 6 does not react with C, but in combination with B oligomer C is consumed to eventually give D, suggesting an additional role for free aminoborane in the formation of D from C.

Item Type:	Journal Article
Subjects:	Q Science > QD Chemistry
Divisions:	Faculty of Science > Chemistry
Library of Congress Subject Headings (LCSH):	Amines, Boranes, Catalysis, Density functionals, Iridium, Reaction mechanisms (Chemistry)
Journal or Publication Title:	Chemistry: A European Journal
Publisher:	Wiley - V C H Verlag GmbH & Co. KGaA
ISSN:	0947-6539
Date:	March 2011
Volume:	Vol.17
Number:	No.10
Page Range:	pp. 3011-3020
Identification Number:	10.1002/chem.201002517
Status:	Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Restricted or Subscription Access
Funder:	University of Oxford, Centre national de la recherche scientifique (France) (CNRS), France. Agence nationale de la recherche (ANR), Université de Toulouse, Engineering and Physical Sciences Research Council (EPSRC), Heriot-Watt University
Grant number:	ANR-09-BLAN-0184-01 HyBoCat (ANR), EP/E02971X/1 (EPSRC)
References:	[1] T. J. Clark, K. Lee, I. Manners, Chem. Eur. J. 2006, 12, 8634 –8648. [2] A. Staubitz, A. P. M. Robertson, M. E. Sloan, I. Manners, Chem. Rev. 2010, 110, 4023 –4078. [3] a) C. W. Hamilton, R. T. Baker, A. Staubitz, I. Manners, Chem. Soc. Rev. 2009, 38, 279 –293; b) A. Staubitz, A. P. M. Robertson, I. Manners, Chem. Rev. 2010, 110, 4079 –4124. [4] A. Staubitz, A. P. Soto, I. Manners, Angew. Chem. 2008, 120, 6308 – 6311; Angew. Chem. Int. Ed. 2008, 47, 6212 –6215. [5] a) J. Spielmann, M. Bolte, S. Harder, Chem. Commun. 2009, 6934 – 6936; b) D. J. Liptrot, M. S. Hill, M. F. Mahon, D. J. MacDougall, Chem. Eur. J. 2010, 16, 8508 – 8515. [6] C. A. Jaska, K. Temple, A. J. Lough, I. Manners, J. Am. Chem. Soc. 2003, 125, 9424 –9434. [7] a) M. C. Denney, V. Pons, T. J. Hebden, D. M. Heinekey, K. I. Goldberg, J. Am. Chem. Soc. 2006, 128, 12048 –12049; b) N. Blaquiere, S. Diallo-Garcia, S. I. Gorelsky, D. A. Black, K. Fagnou, J. Am. Chem. Soc. 2008, 130, 14034 –14035; c) M. K�ß, A. Friedrich, M. Drees, S. Schneider, Angew. Chem. 2009, 121, 922 –924; Angew. Chem. Int. Ed. 2009, 48, 905 – 907; d) S.-K. Kim, W.-S. Han, T.-J. Kim, T.-Y. Kim, S. W. Nam, M. Mitoraj, �. Piekos , A. Michalak, S.-J. Hwang, S. O. Kang, J. Am. Chem. Soc. 2010, 132, 9954 –9955; e) M. Zahmakiran, S. zkar, Inorg. Chem. 2009, 48, 8955 –8964. [8] a) D. Pun, E. Lobkovsky, P. J. Chirik, Chem. Commun. 2007, 3297 – 3299; b) R. J. Keaton, J. M. Blacquiere, R. T. Baker, J. Am. Chem. Soc. 2007, 129, 1844 –1845. [9] G. Alcaraz, S. Sabo-Etienne, Angew. Chem. 2010, 122, 7326 –7335; Angew. Chem. Int. Ed. 2010, 49, 7170 –7179. [10] V. Pons, R. T. Baker, N. K. Szymczak, D. J. Heldebrant, J. C. Linehan, M. H. Matus, D. J. Grant, D. A. Dixon, Chem. Commun. 2008, 6597 – 6599. [11] R. Dallanegra, A. B. Chaplin, J. Tsim, A. S. Weller, Chem. Commun. 2010, 46, 3092 –3094. [12] A. B. Chaplin and A. S. Weller, Angew. Chem. 2010, 122, 591 – 594; Angew. Chem. Int. Ed. 2010, 49, 581 –584. [13] A. B. Chaplin, A. S. Weller, Inorg. Chem. 2010, 49, 1111 –1121. [14] T. M. Douglas, A. B. Chaplin, A. S. Weller, J. Am. Chem. Soc. 2008, 130, 14432 – 14433. [15] T. M. Douglas, A. B. Chaplin, A. S. Weller, X. Z. Yang, M. B. Hall, J. Am. Chem. Soc. 2009, 131, 15440 –15456. [16] R. Dallanegra, A. B. Chaplin, A. S. Weller, Angew. Chem. 2009, 121, 7007 – 7010; Angew. Chem. Int. Ed. 2009, 48, 6875 –6878. [17] G. Alcaraz, L. Vendier, E. Clot, S. Sabo-Etienne, Angew. Chem. 2010, 122, 930 –932; Angew. Chem. Int. Ed. 2010, 49, 918 –920. [18] C. Y. Tang, A. L. Thompson, S. Aldridge, Angew. Chem. 2010, 122, 933 – 937; Angew. Chem. Int. Ed. 2010, 49, 921 –925. [19] A. Rossin, M. Caporali, L. Gonsalvi, A. Guerri, A. Lledos, M. Peruzzini, F. Zanobini, Eur. J. Inorg. Chem. 2009, 3055 – 3059. [20] A. Friedrich, M. Drees, S. Schneider, Chem. Eur. J. 2009, 15, 10339 – 10342, and references therein. [21] M. E. Sloan, A. Staubitz, T. J. Clark, C. A. Russell, G. C. Lloyd- Jones, I. Manners, J. Am. Chem. Soc. 2010, 132, 3831 –3841. [22] a) X. Yang, M. B. Hall, J. Am. Chem. Soc. 2008, 130, 1798 – 1799; b) Y. Luo, K. Ohno, Organometallics 2007, 26, 3597 –3600. [23] A. Paul, C. B. Musgrave, Angew. Chem. 2007, 119, 8301 –8304; Angew. Chem. Int. Ed. 2007, 46, 8153 –8156. [24] P. M. Zimmerman, A. Paul, Z. Y. Zhang, C. B. Musgrave, Inorg. Chem. 2009, 48, 1069 –1081. [25] Aminoboranes can be represented as H2B=NMe2, recognising that there is a significant dative B�N p interaction, or H2B�NMe2, indicating the availabilty of the empty boron p orbital and the lone pair on nitrogen. In this contribution we use the H2B�NMe2 form. See: B. L. Kormos, C. J. Cramer, Inorg. Chem. 2003, 42, 6691 –6700; D. J. Grant, D. A. Dixon, J. Phys. Chem. A 2006, 110, 12955 – 12962. [26] Y. Chen, J. L. Fulton, J. C. Linehan, T. Autrey, J. Am. Chem. Soc. 2005, 127, 3254 –3255. [27] C. Y. Tang, A. L. Thompson, S. Aldridge, J. Am. Chem. Soc. 2010, 132, 10578 – 10591. [28] H. Nçth, H. Vahrenkamp, Chem. Ber. 1967, 100, 3353 – 3357. [29] A. B. Burg, C. L. Randolph, J. Am. Chem. Soc. 1951, 73, 953 –957. [30] A. Staubitz, M. Besora, J. N. Harvey, I. Manners, Inorg. Chem. 2008, 47, 5910 –5918. [31] a) B. L. Davis, D. A. Dixon, E. B. Garner, J. C. Gordon, M. H. Matus, B. Scott, F. H. Stephens, Angew. Chem. 2009, 121, 6944 – 6948; Angew. Chem. Int. Ed. 2009, 48, 6812 – 6816; b) N. C. Smythe, J. C. Gordon, Eur. J. Inorg. Chem. 2010, 509 –521; c) P. G. Campbell, L. N. Zakharov, D. J. Grant, D. A. Dixon, S.-Y. Liu, J. Am. Chem. Soc. 2010, 132, 3289 –3291. [32] R. H. Crabtree, M. Lavin, L. Bonneviot, J. Am. Chem. Soc. 1986, 108, 4032 –4037. [33] G. Alcaraz, A. B. Chaplin, C. J. Stevens, E. Clot, L. Vendier, A. S. Weller, S. Sabo-Etienne, Organometallics 2010, 29, 5591 – 5595. [34] G. J. Kubas, Metal Dihydrogen and s-Bond Complexes, Kluwer Academic/ Plenum Publishers, New York, 2001. [35] Y. Kawano, M. Hashiva, M. Shimoi, Organometallics 2006, 25, 4420 – 4426. [36] C. A. Tolman, Chem. Rev. 1977, 77, 313 –348. [37] G. Alcaraz, S. Sabo-Etienne, Coord. Chem. Rev. 2008, 252, 2395 – 2409. [38] a) N. Merle, G. Koicok-Kçhn, M. F. Mahon, C. G. Frost, G. D. Ruggerio, A. S. Weller, M. C. Willis, Dalton Trans. 2004, 3883 –3892; b) Y. Kawano, T. Kakizawa, K. Yamaguchi and M. Shimoi, Chem. Lett. 2006, 35, 568 –569. [39] H. Nçth, H. Vahrenkamp, Chem. Ber. 1966, 99, 1049 – 1067. [40] M. E. Sloan, T. J. Clark, I. Manners, Inorg. Chem. 2009, 48, 2429 – 2435. [41] a) R. H. Crabtree, H. Felkin, G. E. Morris, J. Organomet. Chem. 1977, 141, 205 –215; b) G. L. Moxham, T. M. Douglas, S. K. Brayshaw, G. Kociok-Kçhn, J. P. Lowe, A. S. Weller, Dalton Trans. 2006, 5492 – 5505. [42] Y. Kawano, M. Uruichi, M. Shimoi, S. Taki, T. Kawaguchi, T. Kakizawa, H. Ogino, J. Am. Chem. Soc. 2009, 131, 14946 –14957. [43] The difficulty in forming 1·D reflects the size of the PCy3 ligands. Calculations using PMe3 ligands showed Ir·D’ to be more accessible (G=�4.6 kJmol�1) and gave an overall barrier to retrodimerisation of 100.0 kJmol�1. [44] M. J. Ingleson, S. K. Brayshaw, M. F. Mahon, G. D. Ruggiero, A. S. Weller, Inorg. Chem. 2005, 44, 3162 –3171. [45] M. A. Esteruelas, F. J. Fern ndez-Alvarez, A. M. L�pez, M. Mora, E. OÇate, J. Am. Chem. Soc. 2010, 132, 5600 – 5601. [46] In our hands addition of alternate ligands to 3 such as bipy lead to decomposition. [47] O. W. Howarth, C. H. McAteer, P. Moore, G. E. Morris, J. Chem. Soc. Dalton Trans. 1981, 1481 –1485. [48] R. B. Jordan, Reaction Mechanisms of Inorganic and Organometallic System, Oxford University Press, New York, 2007. [49] The computed barrier to retrodimerisation is very functional dependent and, for the functionals tested, ranges from +78.8 kJmol�1 (BLYP) to +94.2 kJmol�1 (M06). Moreover, in many cases the free energy change of retrodimerisation was computed to be exoergic, contrary to expectation (BP86: �7.1 kJmol�1; BLYP: �43.8 kJmol�1; B3LYP: �26.6 kJmol�1; BPW91: �15.2 kJmol�1). A similar result has been previously reported with the B3LYP approach.[ 22b] Other functionals do give a positive free energy change (TPSS: +1.8 kJmol�1; B97-D: +6.3 kJmol�1; M06: +16.8 kJmol�1), although these methods also tend to give the higher computed activation enthalpies. See the Supporting Information for full details. [50] A. J. M. Miller, J. E. Bercaw, Chem. Commun. 2010, 46, 1709 – 1711. [51] K. Gruet, E. Clot, O. Eisenstein, D. H. Lee, B. Patel, A. Macchioni, R. H. Crabtree, New J. Chem. 2003, 27, 80– 87. [52] [IrACHTUNGTRENUNG(PCy3)2H5] is relatively insoluble in C6H5F meaning that a reliable comparison of relative rates is difficult; 1 mol% was chosen arbitrarily. [53] A. Staubitz, M. E. Sloan, A. P. M. Robertson, A. Friedrich, S. Schneider, P. J. Gates, J. S. auf der G�nne, I. Manners, J. Am. Chem. Soc. 2010, 132, 13332 –13345. [54] Such interactions could be facilitated by a h2–h1 change in coordination mode of the borane with the opening up of a vacant coordination site: see ref. [38a]. [55] F. J. Hartwig, Organotransition Metal Chemistry: From Bonding to Catalysis, University Sciencee Books, Sausalito, 2010. [56] X. Chen, J.-C. Zhao. S. G. Shore, J. Am. Chem. Soc. 2010, 132, 10658 – 10659. [57] J. Spielmann, D. J. Piesik. S. Harder, Chem. Eur. J. 2010, 16, 8307 – 8318. [58] A. F. Borowski, S. Sabo-Etienne, M. L. Christ, B. Donnadieu. B. Chaudret, Organometallics 1996, 15, 1427 –1434. [59] Gaussian 03, Revision D.01, M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgomery, Jr., T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J. Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D. Daniels, M. C. Strain, O. Farkas, D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S. Clifford, J. Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson, W. Chen, M. W. Wong, C. Gonzalez, J. A. Pople, Gaussian, Inc., Wallingford CT, 2004. [60] D. Andrae, U. Haussermann, M. Dolg, H. Stoll and H. Preuss, Theor. Chim. Acta 1990, 77, 123 – 141. [61] A. Hçllwarth, M. Bçhme, S. Dapprich, A.W. Ehlers, A. Gobbi, V. Jonas, K. F. Kçhler, R. Stegmann, A. Veldkamp, G. Frenking, Chem. Phys. Lett. 1993, 208, 237 –240. [62] W. J. Hehre, R. Ditchfied, J. A. Pople, J. Chem. Phys. 1972, 56, 2257 – 2258; P. Hariharan, J. A. Pople, Theor. Chim. Acta 1973, 28, 213 – 222. [63] Gaussian 09, Revision A.02, M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G. A. Petersson, H. Nakatsuji, M. Caricato, X. Li, H. P. Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng, J. L. Sonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, J. A. Montgomery, Jr., J. E. Peralta, F. Ogliaro, M. Bearpark, J. J. Heyd, E. Brothers, K. N. Kudin, V. N. Staroverov, R. Kobayashi, J. Normand, K. Raghavachari, A. Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J. M. Millam, M. Klene, J. E. Knox, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, R. L. Martin, K. Morokuma, V. G. Zakrzewski, G. A. Voth, P. Salvador, J. J. Dannenberg, S. Dapprich, A. D. Daniels, . Farkas, J. B. Foresman, J. V. Ortiz, J. Cioslowski, D. J. Fox, Gaussian, Inc., Wallingford CT, 2009.
URI:	http://wrap.warwick.ac.uk/id/eprint/40510

Data sourced from Thomson Reuters' Web of Knowledge

Request changes to a record

Actions (login required)

View Item