Reaction of the quintuply-bonded dichromium Cr2[μ-η2-HC(N-2,6- iPr2C6H3)2]2 and BH3NH3 afforded Cr[η2-HC(N-2,6-iPr2C6H3)2(BH2NH2)] [η2-HC(N-2,6-iPr2C6H3)2(BH3)] (1). When more sterically hindered amine-boranes BH3NH2R (R = iPr, 2,6-iPr2C6H3) were used, a bis(σ-B-H) complex Cr[η2-HC(N-2,6-iPr2C6H3)2(BH3)]2 (2) was isolated. Moreover, reactions of the less sterically hindered quintuply-bonded dichromium Cr2[μ-η2-HC(N-2,6-Et2C6H3)2]2 with BH3NH3 and BH3NMe2H engendered the formation of a σ-borane complex Cr[η2-HC(N-2,6- Et2C6H3)2(BH3)]2 (3). Besides, reactions of Cr2[μ-η2-HC(N-2,6- iPr2C6H3)2]2 with nBu3SnH and H2 gave rise to the formation of a hydride- bridged complex, {Cr(μ-H)[μ-η2-HC(N-2,6-iPr2C6H3)2](THF)}2 (5), which gradually transformed to Cr2[μ-η2-HC(N-2,6-iPr2C6H3)2]2 through an unstable intermediate Cr2(μ-H)(THF)[μ-η2-HC(N-2,6-iPr2C6H3)2][μ-η2- HC(N-2,6-iPr2C6H3)(N-2-(η1-CH2)CH3CH-6-iPrC6H3)] (4).
Exposure of a solution of Ru(Nacnac)Dipp(η6-p-cymene) (6a) ((Nacnac)Dipp = HC[C(Me)N-2,6-iPr2C6H3]2) to 1 equivalent of nitric oxide, three products were isolated: a dehydrogenatively dearomatized complex Ru(Nacnac)Dipp[η5-Me(C6H4)CMe2] (6h), a NO-bridged as well as thermally stable dinuclear complex [(μ-NO)Ru(Nacnac)Dipp]2 (7) with both ruthenium possessing 14-electron configuration, and a trinuclear complex Ru[(μ-NO)2Ru(Nacnac)Dipp]2 (8). When Ru(Nacnac)Dipp(η6- benzene) (10) was used to react with NO, 7 and Ru(Nacnac)Dipp{η5- [HC(C6H6)(C(Me)N-2,6-iPr2C6H3)2]}(11) were generated. KC8 reduction of Ru(Nacnac)Dipp(NO)2(OTf) (6c) also resulted in the isolation of complex 7. Moreover, exposure of solution 6a, 7, and 10 to excess nitric oxide, all led to the isolation of Ru(Nacnac)Dipp(NO)3 (6d) and (μ-κ1:κ1-O-N=N-O)[Ru(Nacnac)Dipp(NO)2]2 (6e). Reaction of 6e with a catalytic amount of 2,6-dimethylpyridine hydrochloride afforded 6d. 7 reacted with terminal alkynes RCCH (R = C3H7, Me3Si, Ph) to furnish the 3-legged piano-stool complexes [Ru(RCNN)](μ-NO)2[Ru(Nacnac)Dipp]
(R = C3H7, 12a; Me3Si, 12b) and [Ru(PhCNN)](μ-NO)]2 (13) (CNN = HC(RCCH)[(2,6-iPr2C6H3)N=C(Me)]2).
Addtionally, treatment of [(μ-Cl)Ru(η6-cymene)]2 with CH3COOK at 90 ℃ gave (μ-Cl)(μ-CH3COO)[Ru(η6-cymene)]2 (14). Reaction of
Cr2[μ-η2-HC(N-2,6-iPr2C6H3)2]2 and excess nitric oxide produced an
organic product HC(N-2,6-iPr2C6H3)[(NO)N-2,6-iPr2C6H3] (15).

(1) (a) Kubas, G. J. Chem. Rev. 2007, 107, 4152(b) Perutz, R. N.; Sabo-Etienne, S. Angew. Chem. Int. Ed. 2007, 46, 2578(c) Marder, T. B.; Lin, Z. Contemporary Metal Boron Chemistry I : Borylenes, Boryls, Borane σ-Complexes, and Borohydrides Structure and Bonding, vol. 130; Springer Berlin, 2008.
(2) (a) Lata, C. J.; Crudden, C. M. J. Am. Chem. Soc. 2009, 132, 131(b) Burgess, K.; Ohlmeyer, M. J. Chem. Rev. 1991, 91, 1179(c) Beletskaya, I.; Pelter, A. Tetrahedron 1997, 53, 4957.
(3) (a) Hartwig, J. F.; Cook, K. S.; Hapke, M.; Incarvito, C. D.; Fan, Y.; Webster, C. E.; Hall, M. B. J. Am. Chem. Soc. 2005, 127, 2538(b) Chen, H.; Schlecht, S.; Semple, T. C.; Hartwig, J. F. Science 2000, 287, 1995(c) Mkhalid, I. A. I.; Barnard, J. H.; Marder, T. B.; Murphy, J. M.; Hartwig, J. F. Chem. Rev. 2009, 110, 890(d) Miyaura, N. Catalytic Heterofunctionalization (Eds. : A. Togni, H. Grutzmacher); Wiley-VCH Weinheim, 2001.
(4) (a) Marder, T. B. Angew. Chem. Int. Ed. 2007, 46, 8116(b) Stephens, F. H.; Pons, V.; Tom Baker, R. Dalton. Trans. 2007, 2613(c) Hamilton, C. W.; Baker, R. T.; Staubitz, A.; Manners, I. Chem. Soc. Rev. 2009, 38, 279.
(5) Alcaraz, G.; Sabo-Etienne, S. Angew. Chem. Int. Ed. 2010, 49, 7170.
(6) Hartwig, J. F.; Muhoro, C. N.; He, X.; Eisenstein, O.; Bosque, R.; Maseras, F. J. Am. Chem. Soc. 1996, 118, 10936.
(7) Alcaraz, G.; Clot, E.; Helmstedt, U.; Vendier, L.; Sabo-Etienne, S. J. Am. Chem. Soc. 2007, 129, 8704.
(8) Shimoi, M.; Nagai, S.-i.; Ichikawa, M.; Kawano, Y.; Katoh, K.; Uruichi, M.; Ogino, H. J. Am. Chem. Soc. 1999, 121, 11704.
(9) (a) Heinekey, D. M.; Oldham, W. J. Chem. Rev. 1993, 93, 913(b) Schubert, U. In Adv. Organometa Chem.; Stone, F. G. A., Robert, W., Eds.; Academic Press, 1990; Vol. Volume 30(c) Crabtree, R. H. Angew. Chem. Int. Ed. 1993, 32, 789.
(10) Kakizawa, T.; Kawano, Y.; Shimoi, M. Organometallics 2001, 20, 3211.
(11) (a) Jaska, C. A.; Manners, I. J. Am. Chem. Soc. 2004, 126, 2698(b) Jaska, C. A.; Temple, K.; Lough, A. J.; Manners, I. J. Am. Chem. Soc. 2003, 125, 9424(c) Jaska, C. A.; Temple, K.; Lough, A. J.; Manners, I. Chem. Commun. 2001, 962.
(12) Chaplin, A. B.; Weller, A. S. Angew. Chem. Int. Ed. 2010, 49, 581.
(13) Alcaraz, G.; Vendier, L.; Clot, E.; Sabo-Etienne, S. Angew. Chem. Int. Ed. 2010, 49, 918.
(14) Koshland, D. E. Science 1992, 258, 1861.
(15) Wong, M. W.; Nobes, R. H.; Bouma., W. J.; Radom, L. Chem. Phys. 1989, 91, 2971.
(16) McCleverty, J. A. Chem. Rev. 2004, 104, 403.
(17) (a) Ye, R. W.; Averill, B. A.; Tiedje, J. M. Appl. Environ. Microbiol 1994, 60, 1053(b) Berk, B. C.; Ferguson, S. J.; Moir, J. W. B.; Richardson, D. J. Biochim. Biophys. Acta 1995, 1232, 97.
(18) Averill, B. A. Chem. Rev. 1996, 96, 2951.
(19) Wasser, I. M.; Vries, S. d.; Moenne-Loccoz, P.; Schroder, I.; Karlin, K. D. Chem. Rev. 2002, 102, 1201.
(20) Hayton, T. W.; Legzdins, P.; Sharp, W. B. chem. Rev. 2002, 102, 935.
(21) (a) Crease, A. E.; Legzdins, P. J. Chem. Soc, Dalton Trans. 1973, 1501(b) Crease, A. E.; Legzdins, P. J.Chem.Soc.,Chem.Commun. 1972, 268.
(22) (a) Gibson, C. P.; Bem, D. S.; Falloon, S. B.; Hitchens, T. K.; Cortopassi, J. E. Organometallics 1992, 11, 1742(b) Odom, A. L.; Cummins, C. C.; Protasiewicz, J. D. J. Am. Chem. Soc. 1995, 117, 6613(c) Legzdins, P.; Rettig, S. J.; Sayers, S. F. J. Am. Chem. Soc. 1994, 116, 12105.
(23) (a) Weiner, W. P.; White, M. A.; Bergman, R. G. J. Am. Chem. Soc. 1981, 103, 3612(b) Weiner, W. P.; Bergman, R. G. J. Am. Chem. Soc. 1983, 105, 3922(c) Lin, S.-H.; Peng, S.-M.; Liu, R.-S. J.Chem.Soc.,Chem.Commun. 1992, 615(d) Lin, S. H.; Lee, G. H.; Peng, S. M.; Liu, R. S. Organometallics 1993, 12, 2591.
(24) (a) Franz, K. J.; Lippard, S. J. J. Am. Chem. Soc. 1998, 120, 9034(b) Franz, K. J.; Lippard, S. J. J. Am. Chem. Soc. 1999, 121, 10504(c) Ruggiero, C. E.; Carrier, S. M.; Tolman, W. B. Angew. Chem. Int. Ed. 1994, 33, 895(d) Schneider, J. L.; Carrier, S. M.; Ruggiero, C. E.; Young, V. G.; Tolman, W. B. J. Am. Chem. Soc. 1998, 120, 11408(e) Ruggiero, C. E.; Carrier, S. M.; Antholine, W. E.; Whittaker, J. W.; Cramer, C. J.; Tolman, W. B. J. Am. Chem. Soc. 1993, 115, 11285(f) Tolman, W. B. Adv.Chem.Ser. 1995, 246, 195.
(25) (a) Littlejohn, D.; Chang, S. G. Ind.Eng.Chem.Res. 1990, 29, 10(b) Sun, K. S.; Kong, K. C.; Cheng, C. H. Inorg. Chem. 1991, 30, 1998.
(26) (a) Alnaji, O.; Dartiguenave, M.; Dartiguenave, Y.; Simard, M.; Beauchamp, A. L. Inorg. Chim. Acta. 1991, 187, 31(b) Field, C. N.; Green, J. C.; Mayer, M.; Nasluzov, V. A.; Rösch, N.; Siggel, M. R. F. Inorg. Chem. 1996, 35, 2504.
(27) (a) Rahman, A. F. M. M.; Salem, G.; Stephens, F. S.; Wild, S. B. Inorg. Chem. 1990, 29, 5225(b) Del Zotto, A.; Mezzetti, A.; Novelli, V.; Rigo, P.; Lanfranchi, M.; Tiripicchio, A. J.Chem.Soc.,DaltonTrans. 1990, 1035.
(28) Muhoro, C. N.; He, X.; Hartwig, J. F. J. Am. Chem. Soc. 1999, 121, 5033.
(29) Hebden, T. J.; Denney, M. C.; Pons, V.; Piccoli, P. M. B.; Koetzle, T. F.; Schultz, A. J.; Kaminsky, W.; Goldberg, K. I.; Heinekey, D. M. J. Am. Chem. Soc. 2008, 130, 10812.
(30) (a) Baya, M.; Crochet, P.; Esteruelas, M. A.; Gutiérrez-Puebla, E.; Ruiz, N. Organometallics 1999, 18, 5034(b) Nguyen, D. H.; Laurenczy, G.; Urrutigoïty, M.; Kalck, P. Eur. J. Inorg. Chem. 2005, 2005, 4215.
(31) (a) Ding, K.; Brennessel, W. W.; Holland, P. L. J. Am. Chem. Soc. 2009, 131, 10804(b) Monillas, W. H.; Yap, G. P. A.; Theopold, K. H. Angew. Chem. Int. Ed. 2007, 46, 6692(c) Bonyhady, S. J.; Collis, D.; Frenking, G.; Holzmann, N.; Jones, C.; Stasch, A. Nature Chemistry 2010, 2, 865.
(32) Hsu, C.-W., Nation Tsing Hua University, 2008.
(33) (a) Evans, D. F.; Fazakerley, G. V.; Phillips, R. F. J. Chem. Soc. A 1971, 1931(b) Evans, D. F. J. Chem. Soc. 1959, 2003.
(34) Lin, K.-M., Nation Tsing Hua University, 2008.
(35) Man, W.-L.; Tang, T.-M.; Wong, T.-W.; Lau, T.-C.; Peng, S.-M.; Wong, W.-T. J. Am. Chem. Soc. 2003, 126, 478.
(36) Xu, G.; Ren, T. Inorg. Chem. 2001, 40, 2925.
(37) (a) Chang, J.; Bergman, R. G. J. Am. Chem. Soc. 1987, 109, 4298(b) Kuwata, S.; Kura, S.; Ikariya, T. Polyhedron 2007, 26, 4659.
(38) Crimmin, M. R.; Bergman, R. G.; Toste, F. D. Angew. Chem. Int. Ed. 2011, 50, 4484.
(39) Bourget-Merle, L.; Lappert, M. F.; Severn, J. R. Chemical Reviews 2002, 102, 3031.
(40) Averill, B. A. Chem. Rev. 1996, 96, 2951.
(41) (a) Bhaduri, S.; Johnson, B. F. G.; Pickard, A.; Raithby, P. R.; Sheldrick, G. M.; Zuccaro, C. I. J. Chem. Soc. Chem. Commun. 1977, 354(b) Arulsamy, N.; Bohle, D. S.; Imonigie, J. A.; Moore, R. C. Polyhedron 2007, 26, 4737(c) Arikawa, Y.; Asayama, T.; Moriguchi, Y.; Agari, S.; Onishi, M. J. Am. Chem. Soc. 2007, 129, 14160(d) Arikawa, Y.; Matsumoto, N.; Asayama, T.; Umakoshi, K.; Onishi, M. Dalton Trans. 2011, 40, 2148(e) Xu, N.; Campbell, A. L. O.; Powell, D. R.; Khandogin, J.; Richter-Addo, G. B. J. Am. Chem. Soc. 2009, 131, 2460.
(42) Phillips, A. D.; Laurenczy, G.; Scopelliti, R.; Dyson, P. J. Organometallics 2007, 26, 1120.
(43) Cotton, F. A.; Wilkinson, G. Advanced Inorganic Chemistry; 5th ed.; Wiley-Interscience: New York, 1980.
(44) Legzdins, P.; Rettig, S. J.; Sanchez, L.; Bursten, B. E.; Gatter, M. G. J. Am. Chem. Soc. 1985, 107, 1411.
(45) Legzdins, P.; Rettig, S. J.; Sanchez, L. Organometallics 1985, 4, 1470.
(46) Legzdins, P.; Sanchez, L. J. Am. Chem. Soc. 1985, 107, 5525.
(47) (a) Cokoja, M.; Gemel, C.; Steinke, T.; Schroder, F.; Fischer, R. A. Dalton. Trans. 2005, 44(b) Walstrom, A. G.; Pink, M.; Yang, X.; Caulton, K. G. Dalton. Trans. 2009, 6001.
(48) Wu, P.-F., National Tsing Hua University, 2010.
(49) (a) Hodson, E.; Simpson, S. J. Polyhedron 2004, 23, 2695(b) Roberts, R. M. J. Org. Chem. 1949, 14, 277(c) Spielmann, J.; Harder, S. J. Am. Chem. Soc. 2009, 131, 5064(d) Podall, H.; Foster, W. E.; Giraitis, A. P. J. Org. Chem. 1958, 23, 82(e) Stender, M.; Wright, R. J.; Eichler, B. E.; Prust, J.; Olmstead, M. M.; Roesky, H. W.; Power, P. P. J. Chem. Soc, Dalton Trans. 2001, 3465.