Fuertes Sara, Chueca Andrés J, Sicilia Violeta
Departamento de Química Inorgánica, Facultad de Ciencias, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza , Pedro Cerbuna 12, 50009 Zaragoza, Spain.
Departamento de Química Inorgánica, Escuela de Ingeniería y Arquitectura de Zaragoza, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), CSIC-Universidad de Zaragoza , Campus Río Ebro, Edificio Torres Quevedo, 50018 Zaragoza, Spain.
Inorg Chem. 2015 Oct 19;54(20):9885-95. doi: 10.1021/acs.inorgchem.5b01655. Epub 2015 Oct 8.
The synthesis of 1-(4-cyanophenyl)-1H-imidazol (1) has been carried out by an improved method. Then its corresponding imidazolium iodide salt, 2, has been used to prepare the N-heterocyclic carbene (NHC) cycloplatinated compound [{Pt(μ-Cl)(C^C*)}2] (4) (HC^C*-κC* = 1-(4-cyanophenyl)-3-methyl-1H-imidazol-2-ylidene) following a step-by-step protocol. The intermediate complex [PtCl(η(3)-2-Me-C3H4) (HC^C*-κC*)] (3) has also been isolated and characterized. Using 4 as precursor, several heteroleptic complexes of stoicheometry [PtCl(C^C*)L] (L = PPh3 (5), pyridine (py, 6), 2,6-dimethylphenyl isocyanide (CNXyl, 7), and 2-mercapto-1-methylimidazole (MMI, 8)) and [Pt(C^C*)LL']PF6 (L = PPh3, L' = py (9), CNXyl (10), and MMI (11)) have been synthesized. Complexes 6-8 were obtained as a mixture of cis- and trans-(C*,L) isomers, while trans-(C*,L) isomer was the only one observed for complexes 5 and 9-11. Their geometries have been discussed in terms of the degree of transphobia (T) of pairs of trans ligands and supported by theoretical calculations. The trans influence of the two σ Pt-C bonds present in these molecules, Pt-C(Ar) and Pt-C*(NHC), has been compared from the J(Pt-P) values observed in the new complex [Pt(C^C*)(dppe)]PF6 (dppe = 1, 2-bis(diphenylphosphino)ethane, 12).
