Synthesis and Structural Characterization of High Spin M/Cu (M = Mn, Fe) Heterobimetallic and Fe/Cu₂ Trimetallic Phosphinoamides

Abstract

The heterobimetallic complexes [Mn((i)PrNPPh(2))(3)Cu((i)PrNHPPh(2))] (1) and [Fe((i)PrNPPh(2))(3)Cu((i)PrNHPPh(2))] (2) have been synthesized by the one pot reaction of LiN(i)PrPPh(2), MCl(2) (M = Mn, Fe), and CuI in high yield. Addition of excess CuI into 2 or directly to the reaction mixture led to the formation of a heterotrimetallic [Fe((i)PrNPPh(2))(3)Cu(2)((i)PrNPPh(2))] (3) in good yield. Complexes 1-3 have been characterized by means of elemental analysis, paramagnetic (1)H NMR, UV-vis spectroscopy, cyclic voltammetry, and single crystal X-ray analysis. In all three complexes, Mn or Fe are in the +2 oxidation state and have a high spin electron configuration, as evidenced by solution Evans' method. In addition, the oxidation state of Fe in complex 3 is confirmed by zero-field (57)Fe Mössbauer spectroscopy. X-ray crystallography reveals that the three coordinate Mn/Fe centers in the zwitterionic complexes 1-3 adopt an unusual trigonal planar geometry.

A series of C3-symmetric heterobimetallic Cr–M (M = Fe, Co and Cu) complexes

“…Basis sets and functionals were chosen based on methods that had previously proven successful with other heterobimetallic complexes and were optimized for computational time and accuracy. 17,18,47 Starting with crystallographically determined geometries as a starting point, when available, the geometries were optimized to a minimum, followed by analytical frequency calculations to conrm that no imaginary frequencies were present. Mayer bond order analysis was performed with the routines included in the Gaussian09 package.…”

Vanadium–iron complexes featuring metal–metal multiple bonds

“…[ i PrNKPPh 2 ] and VCl 3 (THF) 3 were prepared using literature procedures. 22,23 Anhydrous FeBr 2 and FeI 2 were purchased from Strem Chemicals and used aer 12 h drying at 100 C/1 Torr. NMR spectra were recorded at ambient temperature on a Varian Inova 400 MHz instrument.…”

“…Basis sets and functionals were chosen based on methods that had previously proven successful with other heterobimetallic complexes and were optimized for computational time and accuracy. 10,12,22 Starting with crystallographically determined geometries as a starting point, when available, the geometries were optimized to a minimum, followed by analytical frequency calculations to conrm that no imaginary frequencies were present. Mayer bond order analysis was performed with the routines included in the Gaussian09 package.…”

Homo- and heteroleptic group 4 2-(diphenylphosphino)pyrrolide complexes: Synthesis, coordination chemistry and solution state dynamics

“…Unlike traditional tetragonal bimetallics, trigonal systems with weaker ligand fields should promote more favorable metal-metal bonding interactions. Systematic analysis of different metal pairs and ligand donor sets has allowed Lu and Thomas example, metal-metal bonding with the first row transition metals is typically best when metals and coordination environments are similar, and becomes weaker (ultimately leading to the inability to form d-and p-bonds) as the metals and/or their coordination environments become more disparate [47][48][49][50][51][52][53][54][55][56]. In the case of first row late transition metals paired with heavier second and third row early metals, multiple bonding is possible, although highly polarized [21].…”