title: Crystal structures and DFT calculations of new chlorido-dimethylsulfoxide-M(III) (M = Ir, Ru, Rh) complexes with the N-pyrazolyl pyrimidine donor ligand: kinetic vs. thermodynamic isomers.
abstract: New chlorido-dimethylsulfoxide-iridium(III), ruthenium(III) and rhodium(III) complexes with the 2-(1H-pyrazol-1-yl)-pyrimidine (pyrapyr) ligand (OC-6-N1)-[Rh(III)Cl3(DMSO-κS)(pyrapyr)] (1a, N = 3 and 1b, N = 4); (OC-6-N1)-[Ru(III)Cl3(DMSO-κS)(pyrapyr)] (2a, N = 3 and 2b, N = 4) and (OC-6-N1)-[Ir(III)Cl3(DMSO-κS)(pyrapyr)] (3a, N = 3 and 3b, N = 4) have been synthesized and characterized by spectroscopic techniques and by single crystal X-ray diffraction studies (1a, 1b, 2a, 2b, a disordered crystal 3a/3b and a cocrystal 3a·3b). In all cases, the metal centers show octahedral geometry coordinated to three chloride ligands and one S coordinated dimethylsulfoxide (DMSO-κS). The coordination sphere of the metal is completed by the pyrapyr molecule. Two different coordination modes are observed: (i) the DMSO-κS is opposite to the pyrimidinic N atom (IUPAC nomenclature is OC-6-31 denoted herein as trans); (ii) DMSO-κS is opposite to the pyrazolic N atom (IUPAC nomenclature is OC-6-41 denoted as cis). For Rh(III) the kinetic product (cis) yields the thermodynamic (trans) upon heating a solution of the kinetic product and both isomers have been X-ray characterized. Conversely for Ru(III), both kinetic and thermodynamic complexes have been obtained by using different procedures. Both isomers have been characterized by X-ray crystallography and the kinetic product does not yield the thermodynamic upon heating a solution of the former. Furthermore, the Ir(III) behaves differently, since both isomers are energetically equivalent and both isomers co-crystallize in the solid state. The kinetic/thermodynamic mechanism that yields the different isomers has been studied by using theoretical DFT calculations for each metal. Finally, two Ru(II) complexes (OC-6-N1)-[Ru(II)Cl2(DMSO-κS)2(pyrapyr)] (1a, N = 3 and 4b, N = 4) are also described and X-ray characterized. They were obtained as minor products during the synthesis of 2a.
authors.affiliation: Departament de Química, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122 Palma de Mallorca (Balears), Spain. toni.frontera@uib.es.
authors.forename: María M
authors.initials: MM
authors.lastname: Cánaves
authors.forename: María I
authors.initials: MI
authors.lastname: Cabra
authors.forename: Antonio
authors.initials: A
authors.lastname: Bauzá
authors.forename: Pablo
authors.initials: P
authors.lastname: Cañellas
authors.forename: Kika
authors.initials: K
authors.lastname: Sánchez
authors.forename: Francisca
authors.initials: F
authors.lastname: Orvay
authors.forename: Angel
authors.initials: A
authors.lastname: García-Raso
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Fiol
authors.forename: Angel
authors.initials: A
authors.lastname: Terrón
authors.forename: Miquel
authors.initials: M
authors.lastname: Barceló-Oliver
authors.forename: Pablo
authors.initials: P
authors.lastname: Ballester
authors.forename: Ignasi
authors.initials: I
authors.lastname: Mata
authors.forename: Elies
authors.initials: E
authors.lastname: Molins
authors.forename: Firasat
authors.initials: F
authors.lastname: Hussain
authors.forename: Antonio
authors.initials: A
authors.lastname: Frontera
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D007495:Iridium / Q000737:chemistry*; D007536:Isomerism; D007700:Kinetics; D008024:Ligands; D008968:Molecular Conformation; D011720:Pyrazoles / Q000737:chemistry; D011743:Pyrimidines / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D056831:Coordination Complexes; D008024:Ligands; D011720:Pyrazoles; D011743:Pyrimidines; C031280:pyrazole; D007495:Iridium; D012428:Ruthenium; D012238:Rhodium; C030986:pyrimidine; D004121:Dimethyl Sulfoxide