Cyclometalated platinum(ii) complexes of 2,2′-bipyridine N-oxide containing a 1,1′-bis(diphenylphosphino)ferrocene ligand: structural, computational and electrochemical studies

Abstract

The preparation and characterization of new heteronuclear-platinum(ii) complexes containing a 1,1'-bis(diphenylphosphino)ferrocene (dppf) ligand are described. The reaction of the known starting complex [PtMe(κN,C-bipyO-H)(SMe)], A, in which bipyO-H is a cyclometalated rollover 2,2'-bipyridine N-oxide, with the dppf ligand in a 2 : 1 ratio or an equimolar ratio led to the formation of the corresponding binuclear complex [PtMe(κN,C-bipyO-H)(μ-dppf)], 1, or the mononuclear complex [PtMe(κC-bipyO-H)(dppf)], 2, respectively. According to the reaction conditions, the dppf ligand in 1 and 2 behaves as either a bridging or chelating ligand. All complexes were characterized by NMR spectroscopy. The solid-state structure of 2 was determined by the single-crystal X-ray diffraction method and it was shown that the chelating dppf ligand in this complex was arranged in a "synclinal-staggered" conformation. Also, the occurrence of intermolecular C-HO interactions in the solid-state gave rise to an extended 1-D network. The electronic absorption spectra and the electrochemical behavior of these complexes are discussed. Density functional theory (DFT) was used for geometry optimization of the singlet states in solution and for electronic structure calculations. The analysis of the molecular orbital (MO) compositions in terms of occupied and unoccupied fragment orbitals in 2 was performed.

A Convenient Approach to Luminescent Cyclometalated Platinum(II) Complexes with Organometallic π‐Bonded Benzenedithiolate

“…To this end various cyclometalated platinum complexes were described with β‐diketonate ligands, 8‐hydroxyquinolinate, carbenes, phosphinine coligand, and more recently with a phosphinoferrocene ligand . However cyclometalated platinum(II) complexes containing benzenedithiolate (bdt) as coligands are not very common, only two square planar anionic cyclometalated Pt II complexes [(C ^ N)Pt(S ^ S)][NBu 4 ] {(C ^ N = ppy = 2‐phenylpyridine; tbpiq = 4‐ tert ‐butylphenyl)isoquinoline; (S ^ S) = benzenedithiolate (bdt) } were described .…”

Rollover Cyclometalation as a Valuable Tool for Regioselective C–H Bond Activation and Functionalization

“…Some mono- and dinuclear complexes with diphosphines have been reported earlier in this review. Other series of mono, and dinuclear complexes with diphosphines, 45 – 48 (see Figure 32 ), have been reported by us [ 76 ] and other researchers [ 77 , 78 ], comprising the bipyridine N -Oxide complex [Pt(N^C)(dppm)(p-tolyl)], 49 , analogous to 48 , with p-tolyl in place on methyl.…”

Stable trans isomer as the kinetic and theromodynamic product for the oxidative addition of MeI to cycloplatinated(II) complexes comprising isocyanide ligands

“…Another discrete signal assignable to the H 3 proton of O‐bpy appears as a sharp doublet signal. This signal is considerably deshielded to near 10 ppm due to being directly in contact through space with oxygen atom of the O‐bpy …”