Experimental and theoretical studies of new rhenium carbonyls containing 4,5-bis(chalcogenodiphenylphosphinoyl)-1,2,3-triazolates Karla P. Salas-Martin a , Ingrid A. Espinosa-L  opez a , Marisol Reyes-Lezama a , Elizabeth Huerta-Salazar a , David Ramírez-Palma a , Fernando Cort  es-Guzm  an a , Ver  onica García-Montalvo a , Herbert H € opfl b , No  e Zú ~ niga-Villarreal a, * a Instituto de Química, Universidad Nacional Aut onoma de M exico, Ciudad Universitaria, Circuito Exterior, 04510, Ciudad de M exico, Mexico b Centro de Investigaciones Químicas, Universidad Aut onoma del Estado de Morelos, Avenida Universidad 1001, C.P. 62210, Cuernavaca Morelos, Mexico article info Article history: Received 27 July 2016 Received in revised form 5 September 2016 Accepted 8 September 2016 Available online 9 September 2016 Keywords: Rhenium carbonyls 4,5-bis(chalcogenodiphenylphosphinoyl)- 1,2,3-triazolates Carbonyl substitution reactions abstract The novel binuclear complexes [Re(CO) 3 -m-{k 3 -N,N 0 ,E-L T-E2 } 2 ] 2 E ¼ S and Se were prepared upon reaction of the corresponding potassium bis(chalcogenodiphenylphosphinoyl)triazolate, K[L TE2 ], and [ReBr(CO) 5 ]. 31 P{ 1 H}-NMR monitoring studies showed that formation of the binuclear complexes was preceded by the corresponding mononuclear complex [Re(CO) 4 {k 2 -N,E-L T-E2 ] (E ¼ S, Se). Theoretical calculations indicated that a faster reaction time for the formation of the sulfur binuclear complex in comparison with its selenium analog stems from thermodynamic considerations. The new complexes herein reported were characterized by standard spectroscopic techniques and single crystal X-ray analysis. © 2016 Elsevier B.V. All rights reserved. 1. Introduction Rhenium carbonyl species have attracted widespread attention due to their numerous applications in bioorganometallic chemistry as luminophores in fluorescence cell imaging [1,2], as catalysts for the isomerization of propargylic alcohols [3], as electrocatalysts for CO 2 reduction [4], and CO-releasing molecules (CORMs) [5], to mention but a few. In all the areas where rhenium carbonyl cores play a part, the ligands to which they are bound are determinant for their specific application. Thus, coordination studies of unexplored ligands pose a challenge and a necessity for suitable complex formation. The 4,5-bis(chalcogenodiphenylphosphinoyl)-1,2,3-triazoles, [L TE2 ]H, E ¼ O, S, and Se, comprise a set of compounds that has attracted great attention since they are thermally, oxidatively, and hydrolytically stable. The first congener of the series, the 4,5- bis(diphenylphosphinoyl)-1,2,3-triazole, was reported several years ago by Trofimenko et al. [6] and its molecular structure is shown in Chart 1 . Since the 4,5-bis(chalcogenodiphenylphosphinoyl)-1,2,3- triazoles were first discovered several efforts have been made to explore their coordination chemistry: The 4,5- bis(diphenylphosphinoyl)-1,2,3-triazolate, [L TO2 ], ligates to cobalt(II) and rhodium(I) ions in a k 2 -N,O chelation mode in the complexes [Co(L TO2 ) 2 (py) 2 ]$2py, py ¼ pyridine and [Rh(L TO2 )(cod)], cod ¼ cyclooctadiene achieving five-membered metallarings; whereas coordination to uranium(VI) and lanthanu- m(III) metal centers, being both more oxophilic, exhibited a k 2 -O,O chelation mode, despite the sterically disfavored seven-membered rings formed in the complexes [UO 2 (L TO2 ) 2 (dmf)]) and [La(L TO2 ) 3 (dmf) 2 ], dmf ¼ dimethylformamide [6]. Interestingly it was reported that the 4,5-bis(diphenylphosphinoyl)-1,2,3- triazolate presents both k 2 -O,O and k 2 -N,O chelation modes, in the same coordination sphere, in the complexes [Ln(k 2 -O,O-L T- O2 ) 2 (k 2 -O,N-L T-O2 )(dmso) 2 ], Ln ¼ La, Ce, dmso ¼ dimethylsulfoxide [7]. Synthesis and reactivity of the sulfur analogue of 4,5- bis(diphenylphosphinoyl)-1,2,3-triazole showed the k 2 -N,S chela- tion mode to Pd(II) in the complexes [Pd(L TS2 ) 2 ] and [Pd(L TS2 )(methallyl)] [8]. Although the selenium analogue ([L TSe2 ]H) was reported in 2003 [9], its coordination chemistry to some transition metals was not reported until 2014: Coordination of [L TSe2 ] in the complexes [Cu(L TSe2 ) 2 (thf) 2 ] and [Zn 2 (L TSe2 ) 4 ] was achieved through nitrogen and selenium atoms (k 2 -N,Se) and through both nitrogen and selenium atoms (k 3 -N,N 0 ,Se) resp. * Corresponding author. Contents lists available at ScienceDirect Journal of Organometallic Chemistry journal homepage: www.elsevier.com/locate/jorganchem http://dx.doi.org/10.1016/j.jorganchem.2016.09.007 0022-328X/© 2016 Elsevier B.V. All rights reserved. Journal of Organometallic Chemistry 822 (2016) 250e258