Natural optical activity of tris(ethylendiamine)cobalt(3+) and tris(ethylenediamine)chromium(3+)ions. Interpretations with complete operator matrices

Evans, Robert S.; Schreiner, A. F.; Hauser, P. J.

doi:10.1021/ic50139a025

Cited by 34 publications

(18 citation statements)

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“…The CD spectrum of the cobalt(III) complex Λ-[Co(en) 3 ] 3+ has been extensively studied both experimentally and theoretically since the early work of Kobayashi and Mathieu. , The rotatory strengths for the low-energetic part of the spectrum were characterized with measurements performed on the crystal structure at 80 K and in aqueous solution at room temperature. , A first characteristic of the spectrum is the two CD bands around 21000 cm –1 that exhibit R with opposite sign ( R ≈ ±55 × 10 –40 cgs). These bands were assigned to transitions into the excited singlet states spanning the E and A 2 irreducible representations (“irreps”) of the D 3 point group. − In order to rationalize the magnitude and the sign of these R , several models based on CF or ligand-field (LF) theory were developed during the 1960s and 1970s. − Despite the large amount of analysis, none of these models were able to fully reproduce the experimental data as they were designed to describe only metal-centered 3 d transitions. The importance of the metal–ligand interactions on the CD spectrum was then demonstrated by using restricted Hartree–Fock theory in the early 1990s and fully rationalized by the use of TDDFT calculations. − , Another important feature in the CD spectrum is the presence of weak CD bands corresponding to formally spin-forbidden transitions into the lowest excited triplet states .…”

Section: Resultsmentioning

confidence: 99%

“…The electronic structure of Λ-[Co(en) 3 ] 3+ has been already described using CF theory − and different flavors of DFT and TDDFT calculations. − , Its principal features are summarized in Figure with a state energy diagram obtained from the CAS(10,12)SCF-SR/SO calculations and plots of the isosurfaces of the natural orbitals generated in this active space. At the SR level, the GS corresponds to the nondegenerate singlet 1 A 1 in the D 3 symmetry point group.…”

Section: Resultsmentioning

confidence: 99%

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Ab Initio Study of Circular Dichroism and Circularly Polarized Luminescence of Spin-Allowed and Spin-Forbidden Transitions: From Organic Ketones to Lanthanide Complexes

Gendron

Moore

Cador

et al. 2019

J. Chem. Theory Comput.

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Complete and restricted active space self-consistent field (CAS-/ RAS-SCF) wavefunction methods are applied for the calculation of circular dichroism (CD) and circularly polarized luminescence (CPL) of a series of molecules comprising four organic ketones, the chiral Cobalt(III) complex Λ-[Co(en) 3 ] 3+ and the Europium(III) complex [Eu(DPA) 3 ] 3 -. The abinitio results are in good agreement with the experimental data and previous results obtained with Kohn-Sham density functional theory in the case of the spin-allowed transitions. CD and CPL properties are calculated ab-initio for the first time for the spin-forbidden transitions of both a transition metal and a lanthanide complex. on a large set of organic compounds and on the spin-allowed transitions of some transition metal complexes. For instance, the experimental CD and CPL spectra of -camphorquinone and ( , )trans--hydrindanone were nicely reproduced when using TDDFT calculations with inclusion of the vibronic effects. 36 The results revealed that in both cases, the chiroptical properties arise from transitions between the and * orbitals of the carbonyl groups. Subsequently, Pecul and Ruud 37 applied TDDFT to a set of bicyclic ketones 38 and showed that the differences in sign and magnitude between abs and lum are essentially related to the structural differences between the ground and excited states. Based on a similar set of compounds, it was shown that equation-of-motion CCSD (EOM-CCSD) and TDDFT with the CAM-B3LYP functional provided similar accuracy for abs and lum , 39 while the popular B3LYP functional led to incorrect results in some of the emission properties.There is also a substantial body of research on the calculation of spin-allowed electronic CD spectra of transition metal complexes, where TDDFT remains the main computational tool. See, e.g., References 33, 40 and 41 for reviews and References 19, 42-50 for selected original studies. CPL calculations for transition metal complexes are scarce in comparison. A first attempt was made in 2008 by Coughlin et al. 21 with the use of TDDFT in combination with an approximate formulation of lum , in order to determine the chiroptical properties associated to the 0 ← 1 emission in a series of Iridium(III) complexes. Another attempt was made in 2013 with the use of multi-reference perturbative methods (CASSCF and CASPT2) on a cycloplatinated-[6]helicene compound. 19 Despite the ability of lanthanide complexes to exhibit the largest dissymmetry factors, no ab-initio calculations of CD or CPL properties have been performed yet. Theoretical work on lanthanide complexes has so far relied on CF models 51,52 in combination with the semiempirical Judd-Ofelt theory. 53,54 Recently, such CF based models were used to simulate the CD spectrum 55 and the Raman optical activity 56 of Ln-based compounds. TDDFT has been also used to calculate the CD spectrum of some Eu(III) and Yb(III) complexes, [57][58][59] but these studies focused on the UV-Vis part of the energy spectrum which corresponds mostly to intra-ligand ...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Ab Initio Study of Circular Dichroism and Circularly Polarized Luminescence of Spin-Allowed and Spin-Forbidden Transitions: From Organic Ketones to Lanthanide Complexes

Gendron

Moore

Cador

et al. 2019

J. Chem. Theory Comput.

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“…All CPL and total luminescence (TL) data were obtained on an instrument constructed in this laboratory, whose operation has been recently described. 14 The Tb(III) complexes were excited at 295 nm (16-nm band-pass), and analyzed by a 0.5-m grating monochromator whose band-pass equaled 10 Á. Further increases in resolution of the analyzing monochromator did not yield any improvement of the spectral features, which is not unexpected since all measurements were made in fluid solution at room temperature.…”

Section: Methodsmentioning

confidence: 93%

Optical activity induced in terbium(III) tris(pyridine-2,6-dicarboxylate) through association with certain chiral amino acids

Brittain¹

1981

Inorg. Chem.

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“…MCD is used for the three PdP(4)/B-DNA systems, since (1) its probe region is the "drug" itself, PdP(4), and (2) its selection rules 28 -31 differ significantly from those [32][33][34] of CD and optical absorption methods, so that MCD allows new and complementing structural conclusions to be drawn. The three techniques do have in common the need for a nonvanishing electric dipole transition moment (edtm), ͌D aj , for electronic excitation ͉a͘3͉j͘, where ͌D aj ϭ ͗a//j͘.…”

Section: Introductionmentioning

confidence: 99%

5,10,15,20-Tetrakis(4-N-methylpyridyl)porphyrinatopalladium(II) as a differentiation probe for sensing binding modes with B-DNA duplexes: Electronic MCD and CD spectra

Barnes¹,

Stroud²,

Robinson³

et al. 1999

Biospectroscopy

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We report our detailed electronic MCD, CD, and optical spectroscopic measurements and analysis of the porphyrin Soret (B0) region of four‐coordinate 5,10,15,20‐tetrakis(4‐N‐methylpyridyl)porphyrinatopalladium(II), PdP(4), and its bound states with B‐DNA duplexes poly(A‐T)2, poly(G‐C)2, and calf thymus DNA (CT DNA). For system PdP(4)/poly(A‐T)2 it was possible to conclude that the porphyrin is bound edge‐on in the major groove, specifically at the 5′AT3′ site. For this orientation the porphyrin's electric dipole transition moments (edtm), μx (most perturbed direction) and μy (least perturbed direction), have tilt angles α ∼ 90° and ∼ 45°, respectively, relative to the helix axis. It was further concluded from the small shifts of B0 optical and MCD band intensities and wavelengths and from the net MCD (+) A‐term sign retention upon binding that the porphyrin's frontier pπ MOs (1a1u 3a2u 4eg) are only weakly perturbed by the heterocyclic bases of poly(A‐T)2, and therefore that the LUMO (4eg) splitting is less than the |1a1u−3a2u| energy separation, ΔHOMO, that is, ΔLUMO < ΔHOMO for the bound state in PdP(4)/poly(A‐T)2. For intercalation systems PdP(4)/poly(G‐C)2 and /CT DNA, with PdP(4) centered in the intercalation “pocket” and having two of its 4‐N‐methylpyridyls extending into each of the major and minor grooves, the edtms μx and μy were determined to be oriented perpendicular (γ ∼ 0°) and parallel (γ ∼ 90°) to the hydrogen bonds of the base pairs, respectively. Intercalation is characterized by a much stronger binding interaction, viz., the B0 optical band and net MCD extrema wavelength shifts are relatively large, and the net MCD (+) A‐term of PdP(4) is substantially quenched as it becomes the (−) pseudo‐A‐term of intercalated PdP(4)/poly(G‐C)2. This A‐term sign reversal informs that the porphyrin MOs are so strongly perturbed by the GC base pairs that ΔLUMO > ΔHOMO, which gives rise to a (−) pseudo‐A‐term. Also, the findings demonstrate (1) the potential of PdP(4) as a sensitive, discriminating analytical probe of DNA sequences and (2) the diagnostic capability of the composite of five spectra [net MCD, CD, and optical of free and bound PdP(4)] in differentiating the site and sequence selectivity and preferred binding mode of this porphyrin. © 1999 John Wiley & Sons, Inc. Biospectroscopy 5: 179–188, 1999

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Natural optical activity of tris(ethylendiamine)cobalt(3+) and tris(ethylenediamine)chromium(3+)ions. Interpretations with complete operator matrices

Cited by 34 publications

References 1 publication

Ab Initio Study of Circular Dichroism and Circularly Polarized Luminescence of Spin-Allowed and Spin-Forbidden Transitions: From Organic Ketones to Lanthanide Complexes

Ab Initio Study of Circular Dichroism and Circularly Polarized Luminescence of Spin-Allowed and Spin-Forbidden Transitions: From Organic Ketones to Lanthanide Complexes

Optical activity induced in terbium(III) tris(pyridine-2,6-dicarboxylate) through association with certain chiral amino acids

5,10,15,20-Tetrakis(4-N-methylpyridyl)porphyrinatopalladium(II) as a differentiation probe for sensing binding modes with B-DNA duplexes: Electronic MCD and CD spectra

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