Organometallics
Communication
(PiPr3)2, which exhibits stabilizing CH−π interactions between
the closest methyl groups of the phosphines and the vacant pz
(π*) atomic orbital of the boron atoms.16 For complex 2, the
SOPT of the NBO method locates similar stabilizing
delocalizations (σ-C−H → pz-B, one interaction per
phosphine; see the Supporting Information) with a computed
ΔE(2) energy of −1.9 kcal/mol (CH···B bond distance of 2.568
Å). Moreover, the lone pairs of sulfur and nitrogen atoms
produce an additional stabilization of the [HB(S)(NH2)]−
ligand, as they can delocalize into the atomic pz boron orbital
as well (associated SOPT energy ΔE(2) = −57.6 and −65.1
kcal/mol, respectively). As a consequence of these electronic
delocalizations, the atomic pz-B orbital presents a significant
electronic occupation (0.58e).
In conclusion, our results demonstrate that unsaturated
complexes containing an electrophilic metal center coordinated
to a soft base with free electron pairs not only promote the
release of molecular hydrogen from amine−boranes but also
capture the amino−borane dehydrogenation products, before
their coupling to form polymers or oligomers.
Weller, A. S.; Yang, X.; Hall, M. B. J. Am. Chem. Soc. 2009, 131, 15440.
(e) Friedrich, A.; Drees, M.; Schneider, S. Chem. Eur. J. 2009, 13,
10339. (f) Tang, C. Y.; Thompson, A. L.; Aldridge, S. J. Am. Chem. Soc.
2010, 132, 10578. (g) Stevens, C. J.; Dallanegra, R.; Chaplin, A. B.;
Weller, A. S.; Macgregor, S. A.; Ward, B.; Mckay, D.; Alcaraz, G.; Sabo-
Etienne, S. Chem. Eur. J. 2011, 17, 3011. (h) Ledger, A. E. W.; Ellul, C.
E.; Mahon, M. F.; Williams, J. M. J.; Whittlesey, M. K. Chem. Eur. J.
2011, 17, 8704. (i) Sewell, L. J.; Lloyd-Jones, G. C.; Weller, A. S. J. Am.
Chem. Soc. 2012, 134, 3598. (j) Schreiber, D. F.; O’Connor, C.; Grave,
C.; Ortin, Y.; Muller-Bunz, H.; Phillips, A. D. ACS Catal. 2012, 2,
̈
́ ́
2505. (k) Rosello-Merino, M.; Lopez-Serrano, J.; Conejero, S. J. Am.
Chem. Soc. 2013, 135, 10910. (l) St. John, A.; Goldberg, K. I.;
Heinekey, D. M. Top Organomet. Chem. 2013, 40, 271. (m) Waterman,
R. Chem. Soc. Rev. 2013, 42, 5629.
(5) (a) Davis, B. L.; Dixon, D. A.; Garner, E. B.; Gordon, J. C.;
Matus, M. H.; Scott, B.; Stephens, F. H. Angew. Chem., Int. Ed. 2009,
48, 6812. (b) Smythe, N. C.; Gordon, J. C. Eur. J. Inorg. Chem. 2010,
509. (c) Sutton, A. D.; Burrell, A. K.; Dixon, D. A.; Garner, E. B., III;
Gordon, J. C.; Nakagawa, T.; Ott, K. C.; Robinson, J. P.; Vasiliu, M.
Science 2011, 331, 1426. (d) Whittell, G. R.; Manners, I. Angew. Chem.,
Int. Ed. 2011, 50, 10288.
(6) Buil, M. L.; Elipe, S.; Esteruelas, M. A.; Onate, E.; Peinado, E.;
̃
Ruiz, N. Organometallics 1997, 16, 5748.
(7) Esteruelas, M. A.; Lop
Commun. 2013, 49, 7543.
́
ez, A. M.; Mora, M.; Onate, E. Chem.
̃
ASSOCIATED CONTENT
* Supporting Information
Text, figures, a table, and a CIF file giving experimental details
and characterization data, X-ray data, and computational details.
This material is available free of charge via the Internet at
■
S
(8) Grutzmacher, H. Angew. Chem., Int. Ed. 2008, 47, 1814.
̈
(9) (a) Shaw, W. J.; Linehan, J. C.; Szymczak, N. K.; Heldebrant, D.
J.; Yonker, C.; Camaioni, D. M.; Baker, R. T.; Autrey, T. Angew. Chem.,
Int. Ed. 2008, 47, 7493. (b) Yang, X.; Zhao, L.; Fox, T.; Wang, Z.-X.;
Berke, H. Angew. Chem., Int. Ed. 2010, 49, 2058.
(10) Malakar, T.; Roy, L.; Paul, A. Chem. Eur. J. 2013, 19, 5812.
(11) Manners has reported the synthesis of aminothioboranes,
related to the ligands described here: Robertson, A. P. M.; Haddow,
M. F.; Manners, I. Inorg. Chem. 2012, 51, 8254.
AUTHOR INFORMATION
Corresponding Author
Notes
■
(12) Esteruelas, M. A.; Fernan
́ ́
dez-Alvarez, F. J.; Lopez, A. M.; Mora,
M.; Onate, E. J. Am. Chem. Soc. 2010, 132, 5600.
̃
(13) Braunschweig, H.; Dewhurst, R. D.; Herbst, T.; Radacki, K.
The authors declare no competing financial interest.
Angew. Chem., Int. Ed. 2008, 47, 5978.
(14) Buil, M. L.; Esteruelas, M. A.; Fernan
́
dez, I.; Izquierdo, S.;
ACKNOWLEDGMENTS
■
Onate, E. Organometallics 2013, 32, 2744.
̃
Financial support from the Spanish MINECO (Projects
CTQ2011-23459 and Consolider Ingenio 2010 (CSD2007-
00006)), the DGA (E35), and the European Social Fund (FSE)
is acknowledged. M.M. thanks the Spanish MEC for her FPU
grant.
(15) (a) Weiss, J.; Stetzkamp, D.; Nuber, B.; Fischer, R. A.; Boehme,
C.; Frenking, G. Angew. Chem., Int. Ed. Engl. 1997, 36, 70. (b) Fischer,
R. A.; Schulte, M. M.; Weiss, J.; Zsolnai, L.; Jacobi, A.; Huttner, G.;
Frenking, G.; Boehme, C.; Vyboishchikov, S. F. J. Am. Chem. Soc.
́
1998, 120, 1237. (c) Braunschweig, H.; Fernandez, I.; Frenking, G.;
Radacki, K.; Seeler, F. Angew. Chem., Int. Ed. 2007, 46, 5215.
(d) Braunschweig, H.; Herbst, T.; Rais, D.; Ghosh, S.; Kupfer, T.;
REFERENCES
■
Radacki, K.; Crawford, A. G.; Ward, R. M.; Marder, T. B.; Fernan
I.; Frenking, G. J. Am. Chem. Soc. 2010, 131, 8989.
(16) Esteruelas, M. A.; Fernandez, I.; Lopez, A. M.; Mora, M.; Onate,
E. Organometallics 2012, 31, 4646.
́
dez,
(1) Lewis, N. S.; Nocera, D. G. Proc. Natl. Acad. Sci. U.S.A. 2006, 103,
15729.
(2) The Hydrogen Economy: Opportunities, Costs, Barriers and R & D
́
́
̃
Needs; National Academic Press: Washington, DC, 2004.
(3) See for example: (a) Pons, V.; Baker, R. T.; Szymczak, N. K.;
Heldebrant, D. J.; Linehan, J. C.; Matus, M. H.; Grant, D. J.; Dixon, D.
A. Chem. Commun. 2008, 6597. (b) Blaquiere, N.; Diallo-Garcia, S.;
Gorelsky, S. I.; Black, D. A.; Fagnou, K. J. Am. Chem. Soc. 2008, 130,
14034. (c) Alcaraz, G.; Vendier, L.; Clot, E.; Sabo-Etienne, S. Angew.
Chem., Int. Ed. 2010, 49, 918. (d) Lu, Z.; Conley, B. L.; Williams, T. J.
Organometallics 2012, 31, 6705. (e) Baker, R. T.; Gordon, J. C.;
Hamilton, C. W.; Henson, N. J.; Lin, P.-H.; Maguire, S.; Murugesu,
M.; Scott, B. L.; Smythe, N. C. J. Am. Chem. Soc. 2012, 134, 5598.
(f) Marziale, A. N.; Friedrich, A.; Klopsch, I.; Drees, M.; Celinski, V.
R.; Schmedt auf der Gunne, J.; Schneider, S. J. Am. Chem. Soc. 2013,
̈
135, 13342. (g) Nelson, D. J.; Truscott, B. J.; Egbert, J. D.; Nolan, S. P.
Organometallics 2013, 32, 3769.
(4) See for example: (a) Sloan, M. E.; Clark, T. J.; Manners, I. Inorg.
Chem. 2009, 48, 2429. (b) Kawano, Y.; Uruichi, M.; Shimoi, M.; Taki,
S.; Kawaguchi, T.; Kakizawa, T.; Ogino, H. J. Am. Chem. Soc. 2009,
131, 14946. (c) Hamilton, C. W.; Baker, R. T.; Staubitz, A.; Manners,
I. Chem. Soc. Rev. 2009, 38, 279. (d) Douglas, T. M.; Chaplin, A. B.;
1107
dx.doi.org/10.1021/om500027p | Organometallics 2014, 33, 1104−1107