EPR of copper(II) complexes with tripodal ligands: dynamical properties

Polypyridyl‐Based Copper Phenanthrene Complexes: A New Type of Stabilized Artificial Chemical Nuclease

“…Deconvolution analysis then revealed that these signals can be simulated assuming two types of spectra, an almost axial signal with g ∥ > g ⊥ and a rhombic signal with g x > g y > g z (Supporting Information, section S‐3, Figure S‐7). The first is typical for elongated tetragonal‐octahedral or square‐planar geometry with a ground state, whereas the second occurs for complexes with a ground state and TBP stereochemistry . For all complexes except for Cu‐TPMA‐Bipy, both the hexa‐ and pentacoordinated structures contributed to the EPR spectra in organic solvents (Supporting Information, section S‐3).…”

“…The cw‐EPR spectra of both samples are shown in Figure C along with the simulated spectra (generated using the parameters given in Figure A). The magnetic parameters of the two compounds are identical and resemble reported values for other Cu II ‐TPMA derivatives and complexes with nitrogen‐donor ligands characterized by a TBP geometry . Both complexes are best described by a dominating ground state, but the non‐axial character of the g tensor implies also a possible contribution of the orbital, indicative of a penta‐coordination halfway between TBP and square‐based pyramidal…”

“…The first is typical for elongated tetragonal-octahedralo rs quare-planar geometry with ad x 2 Ày 2 ground state, whereas the second occursf or complexesw ith ad z 2 ground state and TBP stereochemistry. [39][40][41] For all complexes except for Cu-TPMA-Bipy, both the hexa-and pentacoordinated structures contributed to the EPR spectra in organic solvents (Supporting Information, section S-3). In the Bipy complex, dissolution in DMF or DMSO yielded almosti dentical spectra from whichaclear TBP geometry was evident ( Figure 2B).…”

“…The magnetic parameters of the two compounds are identicala nd resemble reportedv alues for other Cu II -TPMA derivatives and complexes with nitrogen-donor ligands characterizedb yaT BP geometry. [39][40][41][42][43][44] Both complexes are best described by ad ominating d z 2 ground state, butt he non-axial character of the g tensor implies also ap ossible contribution of the d x 2 Ày 2 orbital, indicative of ap enta-coordination halfway between TBP and square-based pyramidal. [41] Due to the limited excitation profile of microwavep ulses and large anisotropy of EPR spectra, only molecules with aspecific range of orientations with respectt ot he direction of the static magnetic field may contributet ot he corresponding ENDOR spectrum.…”

Molecular structure, bioavailability and bioactivity of [Cu(o-phen)2(cnge)](NO3)2·2H2O and [Cu(o-phen)(cnge)(H2O)(NO3)2] complexes

“…However, it is to note that the axial appearance of many of the EPR spectra of TBP Cu(II) complexes may be not due to a small but important d x 2 Ày 2 contribution that remains in the ground state, but to the metal d z 2 orbital contribution to vibronic effects that average the in-plane g and A values [34,35]. As in the usual Jahn-Teller effect, it appears that appropriate vibrational modes may be admitted to allow deviation from the d z 2 ground state that has been forced upon Cu(II) by constraining bidentate (o-phenanthroline) ligands.…”