A Quantitative Description of the σ‐Donor and π‐Acceptor Properties of Substituted Phenanthrolines

Abstract

The bond between molybdenum and substituted 1,10-phenanthroline ligands in a series of [Mo(CO)4(phen*)]\ud complexes has been studied by combining experimental data (νCO) with DFT calculations. First, natural orbitals for chemical valence (NOCV) were calculated: The resulting charge-transfer magnitudes (Δqi) associated with the deformation density channels (Δρi) were related to σ-donation and π-back-donation.\ud Then, energy decomposition analysis was performed by applying the extended transition state (ETS) scheme. The outcomes of the ETS-NOCV approach has allowed us to quantify the energetic contribution of both ligand-to-metal (Eσ) and metal-to ligand (Eπ) interactions. A new parameter (Tphen) has been introduced comprising both Eσ and Eπ and thus providing a descriptor for the overall electronic contribution given by phenanthrolines\ud to the metal–ligand bond. This was corroborated by the linear correlation found between Tphen and the νCO vibration\ud modes of [Mo(CO)4(phen*)] complexes, at least for those containing a 2,9-unsubstituted phenanthroline. The case of\ud [Mo(CO)4(phen*)] derivatives with a 2,9-substituted phen* is also discussed

Transition Metal Catalyzed Reductive Cyclization Reactions of Nitroarenes and Nitroalkenes

“…These ligands share the ability to stabilize both high and low oxidation state metal complexes and to act as non‐innocent ligands …”

“…These ligands share the ability to stabilize both high and low oxidation state metal complexes and to act as non-innocent ligands. [42][43][44][45] Concerning phenanthrolines, the introduction of donating groups usually improves performance. Among the most useful ligands, 3,4,7,8-tetramethyl-phenanthroline has been employed in nitroarene cyclization reactions for many years.…”

Tuning the Fluorescence Emission and HOMO‐LUMO Band Gap in Homoleptic Zinc(II) Complexes with N,O‐Bidentate (Imidazo[1,5‐a]pyrid‐3‐yl)phenols

“…[27] Among nitrogen-based ligands, imidazo-pyridines are known for their interesting photochemical properties, both as free molecules [28][29][30][31][32] and when coordinated to transition metals. [33][34][35][36][37][38] In our ongoing study on complexes with nitrogen-containing ligands, [39][40][41][42][43][44][45][46][47][48] we also investigated zinc(II) [49,50] and silver(I) [51] complexes bearing N,N-coordinated imidazo-pyridines. Herein, we report on the luminescence properties of a series of homoleptic zinc(II) complexes (Zn(L R ) 2 ) with (imidazo[1,5-a]pyrid-3yl)phenols, which in this case act as N,O-bidentate ligands.…”

Electrochemically Driven Reduction of Carbon Dioxide Mediated by Mono‐Reduced Mo‐Diimine Tetracarbonyl Complexes: Electrochemical, Spectroelectrochemical and Theoretical Studies

“…Complexes 1 , 2 and 3 were synthesized according to reported procedures [14a,e,33] . The detailed synthesis and spectroscopic characterization of the complexes are given in the electronic supplementary information part.…”