Theoretical Prediction of the Electronic Properties of Bidentate Ligands (HEP2) and Synthesis of Bis( N -heterocyclic carbene) Silver and Palladium Complexes
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide A theoretical approach based on density functional theory (DFT) was developed to determine the electronic Huynh parameter for bidentate ligands (HEP2). The 13 C chemical shift of the carbene carbon atom in the 1,3-diisopropylbenzimidazolin-2-ylidene ligand ( i Pr 2 -bimy) was calculated within the model complexes [PdBr(L 2 )( i Pr 2 -bimy)] +, where L 2 represents a bidentate ligand. Strong correlations were observed between the calculated and experimental chemical shifts for both N -donor and C -donor L 2 ligands, with R 2 values of 0.9699 and 0.9926, respectively. This DFT approach demonstrates the potential for estimating the HEP2 parameter of bidentate ligands of these types. This method was applied to estimate the HEP2 values for three bis( N -heterocyclic carbene) ligands containing carboxylate groups, (diNHC R ) 2–, which are explored as ligands in this study. These NHC ligands were derived from three precursor compounds: 1-(carboxymethyl)-3-((3-(carboxymethyl)-1 H -imidazol-3-ium-1-yl)methyl)-1 H -imidazol-3-ium bromide ( 1a ), 1-(1-carboxyethyl)-3-((3-(1-carboxyethyl)-1 H -imidazol-3-ium-1-yl) methyl)-1 H -imidazol-3-ium bromide ( 1b ), and 2-(1-(2-(1-(carboxymethyl)-1 H -imidazol-3-ium-3-yl)ethyl)-1 H -imidazol-3-ium-3-yl)acetate bromide ( 1c ). They were synthesized and characterized using IR, NMR, and single-crystal X-ray crystallography (for 1a and 1c ). The interaction of 1a and 1c with Ag 2 O in the presence of aqueous sodium hydroxide produced the complexes [Na 2 (H 2 O) 8 ][Ag 2 (di CH2 NHC H ) 2 ] ( 2a ) and [Na 2 (H 2 O) 8 ][Ag 2 (di C2H4 NHC H ) 2 ] ( 2c ), respectively. Complex 2a was structurally characterized, revealing a binuclear structure in which the bis-carbene ligand adopts a bridging μ-κ 1 (C),κ 1 (C′) coordination. Furthermore, 2a exhibited reactivity in transmetalation, allowing the synthesis of complex [Na 2 (H 2 O) 10 ][Pd(di CH2 NHC H ) 2 ] ( 3a ) through a reaction with palladium acetate. Complex 3a, which was also structurally characterized, consists of a mononuclear tetracarbene species where each bis-carbene ligand coordinates in a bidentate κ 2 (C,C′) fashion.
Source: Inorganic Chemistry
Institutions: Universidad de Sevilla, Instituto de Investigaciones Químicas
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Award: G2357960155
OpenAlex ID: W4412464219