Properties of metal-metal single bonds. Vibrational and electronic spectra of binuclear rhodium(II) and iridium(II) isocyanide complexes with comparisons to decacarbonyldimanganese [Mn2(CO)10]

Miskowski, Vincent M.; Smith, Terrance P.; Loehr, Thomas M.; Gray, Harry B.

doi:10.1021/ja00312a021

Cited by 57 publications

(43 citation statements)

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“…We assign this line to the totally symmetric Rh-Rh stretching vibration (ν s (Rh-RH)). A very similar ν s (Rh-Rh) has been observed for binuclear Rh II isocyanide complexes [39].…”

Section: Electrochemical Propertiessupporting

confidence: 76%

Dinuclear Rh^II-Phthalocyaninates with a Rh-Rh Single Bond: X-ray Crystal Structure of Di(pyridinephthalocyaninato(2-)rhodium(II))

Hückstädt

Bruhn

Homborg

1997

J. Porphyrins Phthalocyanines

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Red, diamagnetic di(phthalocyaninato(2-)rhodium(II)), [( Rhpc 2−)2] is prepared by thermal decomposition of acidophthalocyaninatorhodium(III) or di(acido)phthalocyaninatorhodates(III) in inert, high boiling solvents or under reduced pressure at T < 350° C . It is insoluble in most common solvents except pyridine ( py ), yielding red, diamagnetic di(pyridinephthalocyaninato(2-)rhodium(II)), [{ Rh ( py ) pc 2−}2]. This crystallizes as benzene solvate in the cubic space group Ia-3 (no. 206) (a = 35.960(7) Å) with Z = 24. The Rh - Rh distance (d( Rh - Rh ) = 2.741(2) Å) indicates a strong unsupported Rh - Rh single bond. Due to the axial coordination of py the Rh atoms are virtually bonded in the centre ( ct ) of the pc 2− core (d( Rh - ct ) = 0.08(1) Å). The pc 2− ligands are staggered with the skew angle φ( N iso - Rh - Rh '- N iso ') = 42(1)°. Asymmetrical doming of the pc 2− ligands is caused by a short interplanar distance (d( ct - ct ) = 2.89(1) Å) and axial coordination of pyridine. Due to the labilizing trans influence of the Rh - Rh bond the d( Rh - N py ) = 2.309(8) Å is rather long. Two quasi-reversible anodic and four cathodic electron transfer processes are observed in the differential pulse voltammogram of [{ Rh ( py ) pc 2−}2] at 0.81, 0.55, −0.33, −0.50, −0.75 and −1.33 V. The UV/vis NIR spectrum of [{ Rh ( py ) pc 2−}2] shows the typical π-π* transitions of the pc 2− ligand. The B region is split into two bands at 15 440 ( B −) and 16 890 cm−1( B +) of equal intensity due to strong excitonic coupling. The totally symmetric Rh - Rh stretching vibration is selectively enhanced in the Fourier Transform–Raman spectrum at 176 cm−1.

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“…We assign this line to the totally symmetric Rh-Rh stretching vibration (ν s (Rh-RH)). A very similar ν s (Rh-Rh) has been observed for binuclear Rh II isocyanide complexes [39].…”

Section: Electrochemical Propertiessupporting

confidence: 76%

Dinuclear Rh^II-Phthalocyaninates with a Rh-Rh Single Bond: X-ray Crystal Structure of Di(pyridinephthalocyaninato(2-)rhodium(II))

Hückstädt

Bruhn

Homborg

1997

J. Porphyrins Phthalocyanines

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“…The influence of charge redistribution on vibrations of a molecule is known for more than half a century. Prime examples are partial electronic charge transfer between ligand and metal centers in metal carbonyls, − metal cyanides, − and metal isocyanides that changes the corresponding vibrational frequencies of the ligands. This influence is routinely used by inorganic chemists to assess the degree of charge redistribution in organometallic complexes.…”

Section: Hammett Parameters Interfacial Fields and Their Vibrational ...mentioning

confidence: 99%

Electrodes as Polarizing Functional Groups: Correlation between Hammett Parameters and Electrochemical Polarization

et al. 2019

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Bridging the concepts of homogeneous and heterogeneous reactions is an important challenge in modern chemistry. Toward that end, here, we connect the homogeneous chemistry concept of the Hammett parameter, used by organic and organometallic chemists to quantify the electron-withdrawing capability of a functional group, to the electrochemical concept of polarization induced by a biased electrode. Because these two effects share similar origins, a theoretically motivated and experimentally verifiable link between them can be established. A convenient experiment that links the two is measuring the shift of vibrational frequency that is induced by these factors. To achieve this, first, we have measured the vibrational frequency of the nitrile stretch of 4-R-benzonitrile for a series of functional groups R spanning the Hammett parameter range −0.83 ≤ σp ≤ +1.11. Because the nitrile stretch is sensitive to molecular polarization, its frequency depends on the Hammett parameter of the polarizing functional groups. Second, we have measured the nitrile vibrational frequency of 4-mercaptobenzonitrile tethered on a gold electrode and polarized in an electrochemical cell as a function of potential from −1.4 to +0.6 V versus Ag/AgCl. Comparison of the nitrile-stretch frequency between the two experiments allows us to correlate the polarization caused by a functional group to that induced by the electrode. The data suggest equivalence between the Hammett parameter σp and the local electric field at the electrode interface, therefore allowing a polarizing electrode to be treated as a functional group. Computational work supports the experimental results and allows for a quantitative relation between the interfacial electric field and σp. We anticipate the benefits of this correlation, in particular, in linking concepts between homogeneous and heterogeneous reactions.

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“…This behavior should be investigated more thoroughly, as it could have far reaching implications for assisting photoinduced electron and energy flows. [18,20,40,60,129]. [130].…”

Section: Relaxation Of Higher Excited Statesmentioning

confidence: 99%

“…Oxidized species are coordinatively saturated d 7 -d 7 complexes with a full metal-metal single bond. Each complex exhibits a very intense dσ→dσ* transition in the near UV spectral region whose energy depends on the extent of mixing between dσ and axial-ligand σ orbitals [40,104,129]. A weaker absorption band, attributed to dπ→dσ* transitions, occurs at slightly lower energies, usually in the visible range [40,129].…”

Section: Relaxation Of Higher Excited Statesmentioning

confidence: 99%

Electronic structures and photophysics of d8-d8 complexes

Gray

Záliš

Vlček

2017

Coordination Chemistry Reviews

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108

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Harry B. Gray), zalis@jh-inst.cas.cz (Stanislav Záliš), a.vlcek@qmul.ac.uk (Antonín Vlček) Dedicated to Barry Lever, consummate scholar and treasured friend, in recognition of his deep and lasting contributions to coordination chemistry. Abstract Research on d 8 -d 8 complexes is being actively pursued, owing, in part, to newly developed timeresolved optical, IR, and X-ray methods that directly interrogate bonding changes upon excitation. Our review covers work on the ground-and electronic excited states, as well as the oxidized and reduced forms, of these complexes. Recent experimental and theoretical results add a new chapter to the rich history of d 8 -d 8 spectroscopic and chemical behavior.2 4.2. 3 dσ*pσ decay mechanism ……………………………………………………………………………………….. 4.3. Singlet and triplet excited-state properties and reactivity ………………………………………… 4.4. Excited-state spectroscopy ………………………………………………………………………………………. 4.5. Vibrational coherence ……………………………………………………………………………………………… 4.6. Relaxation of higher excited states …………………………………………………………………………… 4.7. Metal-metal to ligand charge transfer and ligand-centered excited states ………………. 5. Conclusions …………………………………………………………………………………………………………………………….. Acknowledgments ……………………………………………………………………………………………………………………… Appendix: computational details ………………………………………………………………………………………………… References ………………………………………………………………………………………………………………………………….

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Properties of metal-metal single bonds. Vibrational and electronic spectra of binuclear rhodium(II) and iridium(II) isocyanide complexes with comparisons to decacarbonyldimanganese [Mn2(CO)10]

Cited by 57 publications

References 1 publication

Dinuclear Rh^II-Phthalocyaninates with a Rh-Rh Single Bond: X-ray Crystal Structure of Di(pyridinephthalocyaninato(2-)rhodium(II))

Dinuclear Rh^II-Phthalocyaninates with a Rh-Rh Single Bond: X-ray Crystal Structure of Di(pyridinephthalocyaninato(2-)rhodium(II))

Electrodes as Polarizing Functional Groups: Correlation between Hammett Parameters and Electrochemical Polarization

Electronic structures and photophysics of d8-d8 complexes

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Properties of metal-metal single bonds. Vibrational and electronic spectra of binuclear rhodium(II) and iridium(II) isocyanide complexes with comparisons to decacarbonyldimanganese [Mn2(CO)10]

Cited by 57 publications

References 1 publication

Dinuclear RhII-Phthalocyaninates with a Rh-Rh Single Bond: X-ray Crystal Structure of Di(pyridinephthalocyaninato(2-)rhodium(II))

Dinuclear RhII-Phthalocyaninates with a Rh-Rh Single Bond: X-ray Crystal Structure of Di(pyridinephthalocyaninato(2-)rhodium(II))

Electrodes as Polarizing Functional Groups: Correlation between Hammett Parameters and Electrochemical Polarization

Electronic structures and photophysics of d8-d8 complexes

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Product

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Dinuclear Rh^II-Phthalocyaninates with a Rh-Rh Single Bond: X-ray Crystal Structure of Di(pyridinephthalocyaninato(2-)rhodium(II))

Dinuclear Rh^II-Phthalocyaninates with a Rh-Rh Single Bond: X-ray Crystal Structure of Di(pyridinephthalocyaninato(2-)rhodium(II))