Reactions of 2-(arylazo)aniline with ruthenium substrates: Isolation, characterizations and reactivities of delocalized diazoketiminato and orthometallated Ru(II) chelates Jahar Lal Pratihar, Shantanu Bhaduri, Poulami Pattanayak, Debprasad Patra, Surajit Chattopadhyay * Department of Chemistry, University of Kalyani, Kalyani 741 235, India article info Article history: Received 30 April 2009 Received in revised form 22 June 2009 Accepted 26 June 2009 Available online 1 July 2009 Keywords: 2-(Arylazo)aniline Ruthenium Cycloruthenation Redox Hydrogen transfer reaction abstract Reactions of 2-(arylazo)aniline, HL-NH 2 [H represents the dissociable protons upon complexation and HL-NH 2 is p-RC 6 H 4 N@NC 6 H 4 -NH 2 ; R = H for HL 1 -NH 2 ; CH 3 for HL 2 -NH 2 and Cl for HL 3 -NH 2 ] with Ru(H) (CO)(PPh 3 ) 3 Cl and Ru(CO) 3 (PPh 3 ) 2 afforded products of compositions [(HL-NH)Ru(CO)Cl(PPh 3 ) 2 ] and [(L-NH)Ru(PPh 3 ) 2 (CO)], respectively. All the complexes were characterized unequivocally. The X-ray structures of the complexes 4c and 5c have been determined. The cyclic volatammograms exhibited one reversible oxidative response in the range of 0.56–0.16 V versus SCE for [(L-NH)Ru(PPh 3 ) 2 (CO)] and a quasi reversible oxidative response within 0.56–0.70 V versus SCE for [(HL-NH)Ru(CO)Cl(PPh 3 ) 2 ]. The conversion of ketones to corresponding alcohols has been studied in presence of newly synthesized ruthenium complexes. Ó 2009 Elsevier B.V. All rights reserved. 1. Introduction Research in the area of coordination chemistry of ruthenium incorporating various kinds of ligands has upsurged in recent years due to the fascinating reactivities exhibited by the resultant com- plexes [1–4]. Studies on the chemistry of ruthenium complexes with azo ligands have been ongoing and several interesting results, related to electron transfer reaction [5–26], metal–carbon bond formation [14,22,23,25,26], aromatic ring amination [16–18], isomerism [7,8,24], cytotoxicity toward cancer cells [5–11] and application in catalytic transformations [25,26], were reported. The p-acidic nature of azo (–N@N–) function was indicated to be one of the reasons for fascinating properties of such ruthenium complexes [5–26]. As a consequence we expected that the appro- priately designed azo ligands can dictate the properties of ruthe- nium complexes to originate new and more attractive results. In general, the azo ligand systems may be divided into two cat- egories: (i) arylazo heterocycles, 1 and (ii) associates of azobenzene moiety, 2. Among these ligands most widely studied system is 2- arylazo pyridine (AAP), 1a. AAP ligands bind to the ruthenium cen- ter in bidentate fashion (N,N) affording different types of isomeric complexes [7,8]. It was also reported that the metal mediated aryl ring amination of AAP ligand lead to the formation of tridentate (N,N,N) ligands [16–18], Aryl ring thiolation was studied in ruthe- nium complexes of AAP to obtain new complexes where the ligands bind with tridentate (N,N,S) mode [20], Several studies N N Hy X N N N R N N R NH Hy = R = Alkyl ; X= R N N X Y X Y H H OH H OH OH SR' H R & R' = Alkyl 2 1 or or or H 2a 2b 2c 2d 1a 1b 1c N Hy = , 0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.jorganchem.2009.06.038 * Corresponding author. Tel.: +91 33 24149725; fax: +91 33 25828282. E-mail address: scha8@rediffmail.com (S. Chattopadhyay). Journal of Organometallic Chemistry 694 (2009) 3401–3408 Contents lists available at ScienceDirect Journal of Organometallic Chemistry journal homepage: www.elsevier.com/locate/jorganchem