Synthesis, characterization, crystal structures and photophysical properties of copper(I) complexes containing 1,1′-bis(diphenylphosphino)ferrocene (B-dppf) in doubly-bridged mode

• Published in: Inorganica Chimica Acta 2011-10, Vol.376 (1), p.549-556
• Main Authors: Trivedi, Manoj, Nagarajan, R., Kumar, Abhinav, Rath, Nigam P., Valerga, Pedro
• Format: Article
• Language: English
• Subjects: Bis(diphenylphosphino)ferrocene (B-dppf); Copper(I) complexes; Luminescence; TD-DFT; X-ray crystal structures
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2011.07.024

The syntheses and full characterization of five copper(I) complexes of the general composition [Cu2(μ-X)2(κ2-P,P-B-dppf)2] (X= Cl(1), Br(2), I(3), CN(4), and SCN(5)) are reported. The structure of the complexes [Cu2(μ-Cl)2(κ2-P,P-B-dppf)2] (1), [Cu2(μ-Br)2(κ2-P,P-B-dppf)2] (2) and [Cu2(μ-CN)2(κ2-P,P-B-dppf)2] (4) have been determined by single crystal X-ray analysis. All the complexes exhibited moderately strong luminescence properties in the solution state at ambient temperature. [Display omitted] ► CuX:B-dppf (1:1). ► X-ray crystal structure of [Cu2(μ-Br)2(κ2-P,P-B-dppf)2] and[Cu2(μ-η1-CN)2(κ2-P,P-B-dppf)2]. ► 3c–2e system in [Cu2(μ-η1-CN)2(κ2-P,P-B-dppf)2]. ► Photophysical properties of copper(I) complexes. Five copper(I) complexes having general formula [Cu2(μ-X)2(κ2-P,P-B-dppf)2] (X=Cl(1), Br(2), I(3), CN(4), and SCN(5)) were prepared starting with CuX and B-dppf in 1:1 molar ratio in DCM-MeOH (50:50V/V) at room temperature. The complexes have been characterized by elemental analyses, IR, 1H NMR, 31P NMR and electronic spectral studies. Molecular structures for 1, 2 and 4 were determined crystallographically. Complexes 1, 2 and 4 exist as centrosymmetric dimers in which the two copper atoms are bonded to two bridging B-dppf ligands and two bridging (pseudo-)halide groups in a μ-η1 bonding mode to generate nearly planar Cu2(μ-η1-X)2 framework. Both bridging B-dppf ligands are arranged in antiperiplanar staggered conformation in 1 and 2 (mean value 56.40–56.76°), and twisted from the eclipsed conformation (mean value 78.19°) in 4. The Φ angle value in 4 is relatively larger as compared to 1 and 2. This seems to indicate that the molecular core [Cu2(μ-η1-X)2] in 4 is a sterically demanding system that forces the B-dppf ligand to adopt a relatively strained conformation in comparison to less strained system in 1 and 2. All the complexes exhibit moderately strong luminescence properties in the solution state at ambient temperature.