Cyano-ambivalence: Spectroscopy and photophysics of [Ru(diimine)(CN-BR3)4]2− complexes

Ngo, Danh X.; Ciello, Sarah A. Del; McNicholas, Brendon J.; Sanders, Brian C.; Fajardo, Javier; Gray, Harry B.

doi:10.1016/j.poly.2020.114692

Cited by 5 publications

(19 citation statements)

References 14 publications

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“…As two of the boronated complexes have greatly separated potentials [ Ru-flpy-BCF (3.19 V); Ru-bpy-BCF (3.52 V)] and long excited-state lifetimes, they likely will be useful photooxidants and photoreductants (see Figure for excited-state potentials of Ru-flpy-BCF and Ru-bpy-BCF . The [Ru(bpz) 3 ] 2+ excited-state potential (1.07 V vs Fc +/0 ) is comparable to that of Ru-flpy-BCF ). ,, …”

Section: Electrochemistrymentioning

confidence: 75%

“…It is well-known that Fe and Ru diimine complexes exhibit two well-defined MLCT absorption maxima in the visible/near-UV region that are strongly solvatochromic . For example, the Ru-flpy MLCT absorptions red shift by 5500 cm –1 when the solvent is changed from water to acetonitrile . This shift is expected in view of the much larger Gutmann–Beckett acceptor number of H 2 O compared to MeCN .…”

Section: Infrared and Uv–visible Spectroscopymentioning

confidence: 93%

“…MLCT bands in BCF adducts are blueshifted more than those reported for Fe(bpy) 2 (CN-BPh 3 ) and Os(bpy) 2 (CN-BPh 3 ) 2 , , likely due to the greater ligand field stabilization of occupied d orbitals upon boronation of the tetracyano complexes . The flpy trifluoromethyl substituents inductively withdraw electron density, redshifting MLCT transitions, while boronation blue shifts them . Additionally, BCF steric hindrance attenuates the MLCT energy dependence on solvent.…”

Section: Infrared and Uv–visible Spectroscopymentioning

confidence: 97%

“…While excited-state lifetimes for BPh 3 adducts are virtually identical with those of the parents, both Fe-bpy-BCF (22.4 ± 2.3 ps) and Fe-phen-BCF (25.1 ± 2.3 ps) exhibit slight increases, presumably due to diminished solvent-based nonradiative decay pathways Table S1 lists all excited-state lifetimes; Figures S41–S55 provide additional time-dependent TA data and first-order exponential decay fits.…”

Section: Transient Absorption Spectroscopymentioning

confidence: 99%

“…24 For example, the Ru-flpy MLCT absorptions red shift by 5500 cm −1 when the solvent is changed from water to acetonitrile. 25 This shift is expected in view of the much larger Gutmann− Beckett acceptor number of H 2 O compared to MeCN. 26 In contrast to the dramatic shifts observed in MLCT transitions, the π−π* absorption shifts only slightly (550 cm −1 ), indicating that solvent interactions and, by extension MCN-B bonding, minimally perturb diimine orbital energies.…”

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confidence: 95%

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Electronic Structures, Spectroscopy, and Electrochemistry of [M(diimine)(CN-BR₃)₄]^2– (M = Fe, Ru; R = Ph, C₆F₅) Complexes

et al. 2020

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Table S2. Crystal data and structure refinement for (PPN)2[Fe(phen)(CN-BPh3)4]. ______________________________________________________________________________ Empirical formula C161 H130 B4 Cl2 Fe N8 P4 Formula weight 2470.59 Temperature 100(2) K Wavelength 1.54178 Å Crystal system Monoclinic Space group C2/c Unit cell dimensions a = 21.782(2) Å a= 90°. b = 17.4783(19) Å b= 94.841(7)°. c = 35.354(5) Å g = 90°. Volume 13412(3) Å 3 Z 4 Density (calculated) 1.224 Mg/m 3 Absorption coefficient 2.151 mm -1 F(000) 5168 Crystal size 0.300 x 0.200 x 0.050 mm 3 Theta range for data collection 3.246 to 74.772°. Index ranges -27 ≤ h ≤ 26, -21 ≤ k ≤ 21, -44 ≤ l ≤ 43 Reflections collected 112475 Independent reflections 13749 [R(int) = 0.0780] Completeness to theta = 67.679° 100.0 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 1.

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Section: Electrochemistrymentioning

confidence: 75%

Section: Infrared and Uv–visible Spectroscopymentioning

confidence: 93%

Section: Infrared and Uv–visible Spectroscopymentioning

confidence: 97%

Section: Transient Absorption Spectroscopymentioning

confidence: 99%

mentioning

confidence: 95%

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Electronic Structures, Spectroscopy, and Electrochemistry of [M(diimine)(CN-BR₃)₄]^2– (M = Fe, Ru; R = Ph, C₆F₅) Complexes

et al. 2020

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Borylation in the Second Coordination Sphere of Fe^II Cyanido Complexes and Its Impact on Their Electronic Structures and Excited-State Dynamics

et al. 2022

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Second coordination sphere interactions of cyanido complexes with hydrogen-bonding solvents and Lewis acids are known to influence their electronic structures, whereby the non-labile attachment of B(C6F5)3 resulted in several particularly interesting new compounds lately. Here, we investigate the effects of borylation on the properties of two FeII cyanido complexes in a systematic manner by comparing five different compounds and using a range of experimental techniques. Electrochemical measurements indicate that borylation entails a stabilization of the FeII-based t2g-like orbitals by up to 1.65 eV, and this finding was confirmed by Mössbauer spectroscopy. This change in the electronic structure has a profound impact on the UV–vis absorption properties of the borylated complexes compared to the non-borylated ones, shifting their metal-to-ligand charge transfer (MLCT) absorption bands over a wide range. Ultrafast UV–vis transient absorption spectroscopy provides insight into how borylation affects the excited-state dynamics. The lowest metal-centered (MC) excited states become shorter-lived in the borylated complexes compared to their cyanido analogues by a factor of ∼10, possibly due to changes in outer-sphere reorganization energies associated with their decay to the electronic ground state as a result of B(C6F5)3 attachment at the cyanido N lone pair.

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Boronated Cyanometallates

et al. 2022

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Thirteen boronated cyanometallates [M(CN-BR 3 ) 6 ] 3/4/5− [M = Cr, Mn, Fe, Ru, Os; BR 3 = BPh 3 , B(2,4,6,-F 3 C 6 H 2 ) 3 , B(C 6 F 5 ) 3 ] and one metalloboratonitrile [Cr(NC-BPh 3 ) 6 ] 3− have been characterized by X-ray crystallography and spectroscopy [UV−vis−near-IR, NMR, IR, spectroelectrochemistry, and magnetic circular dichroism (MCD)]; CASSCF+NEVPT2 methods were employed in calculations of electronic structures. For (t 2g ) 5 electronic configurations, the lowest-energy ligand-tometal charge-transfer (LMCT) absorptions and MCD C-terms in the spectra of boronated species have been assigned to transitions from cyanide π + B−C borane σ orbitals. CASSCF+NEVPT2 calculations including t 1u and t 2u orbitals reproduced t 1u /t 2u → t 2g excitation energies. Many [M(CN-BR 3 ) 6 ] 3/4− complexes exhibited highly electrochemically reversible redox couples. Notably, the reduction formal potentials of all five [M(CN-B(C 6 F 5 ) 3 ) 6 ] 3− anions scale with the LMCT energies, and Mn(I) and Cr(II) compounds, [K(18-crown-6)] 5 [Mn(CN-B(C 6 F 5 ) 3 ) 6 ] and [K(18-crown-6)] 4 [Cr(CN-B(C 6 F 5 ) 3 ) 6 ], are surprisingly stable. Continuous-wave and pulsed electron paramagnetic resonance (EPR; hyperfine sublevel correlation) spectra were collected for all Cr(III) complexes; as expected, 14 N hyperfine splittings are greater for (Ph 4 As) 3 [Cr(NC-BPh 3 ) 6 ] than for (Ph 4 As) 3 [Cr(CN-BPh 3 ) 6 ].

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Cyano-ambivalence: Spectroscopy and photophysics of [Ru(diimine)(CN-BR3)4]2− complexes

Cited by 5 publications

References 14 publications

Electronic Structures, Spectroscopy, and Electrochemistry of [M(diimine)(CN-BR₃)₄]^2– (M = Fe, Ru; R = Ph, C₆F₅) Complexes

Electronic Structures, Spectroscopy, and Electrochemistry of [M(diimine)(CN-BR₃)₄]^2– (M = Fe, Ru; R = Ph, C₆F₅) Complexes

Borylation in the Second Coordination Sphere of Fe^II Cyanido Complexes and Its Impact on Their Electronic Structures and Excited-State Dynamics

Boronated Cyanometallates

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Cyano-ambivalence: Spectroscopy and photophysics of [Ru(diimine)(CN-BR3)4]2− complexes

Cited by 5 publications

References 14 publications

Electronic Structures, Spectroscopy, and Electrochemistry of [M(diimine)(CN-BR3)4]2– (M = Fe, Ru; R = Ph, C6F5) Complexes

Electronic Structures, Spectroscopy, and Electrochemistry of [M(diimine)(CN-BR3)4]2– (M = Fe, Ru; R = Ph, C6F5) Complexes

Borylation in the Second Coordination Sphere of FeII Cyanido Complexes and Its Impact on Their Electronic Structures and Excited-State Dynamics

Boronated Cyanometallates

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Product

Resources

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Electronic Structures, Spectroscopy, and Electrochemistry of [M(diimine)(CN-BR₃)₄]^2– (M = Fe, Ru; R = Ph, C₆F₅) Complexes

Electronic Structures, Spectroscopy, and Electrochemistry of [M(diimine)(CN-BR₃)₄]^2– (M = Fe, Ru; R = Ph, C₆F₅) Complexes

Borylation in the Second Coordination Sphere of Fe^II Cyanido Complexes and Its Impact on Their Electronic Structures and Excited-State Dynamics