Electronic spectra of dinuclear cobalt carbonyl complexes

Abrahamson, Harmon B.; Frazier, C. C.; Ginley, David S.; Gray, Harry B.; LILIENTHAL, J.; Tyler, David R.; Wrighton, Mark S.

doi:10.1021/ic50172a062

Cited by 65 publications

(27 citation statements)

References 2 publications

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“…This is corroborated by the increase in intensity of this band upon lowering the temperature, an effect which has been observed before for σ-σ* transitions of metalmetal bonds. [62,63] …”

Section: Electronic Absorption Spectra Of Complexes 6 Andmentioning

confidence: 99%

Preparation and Properties of Carbonyliron Complexes of 1-Aza-4-oxa-1,3-butadiene (α-Imino Ketone) – X-ray Crystal Structures of Fe(CO)3[MeNC(Ph)C(Ph)=O] and Fe2(CO)4[tBuNC(H)(Me)C(O)(O)C(Me)C(H)=NtBu]

Siebenlist¹,

Frühauf²,

Vrieze³

et al. 2000

Eur. J. Inorg. Chem.

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The reaction of Fe2(CO)9 at room temperature in THF or toluene with the α‐imino ketones R1N=C(R2)–C(R3)=O (L) (R1 = alkyl, R2 = H, Me, Ph, R3 = Me, Ph) (a–k), initially results in the formation of the mononuclear chelate Fe(CO)3(α‐imino ketone) complexes 6 which can be isolated in moderate (6h) to high (6e–g) yield. Under these reaction conditions, complexes 6 subsequently react with [Fe(CO)4] fragments or dimerise, to form the dinuclear complexes Fe2(CO)6(α‐imino ketone) (7a–j) or Fe2(CO)4(L–L) (8a,b,k), respectively. The complexes 8 contain two α‐imino ketone ligands C–C coupled at the ketone carbon atoms. Complexes 8a,b react with CO at elevated temperatures to quantitatively yield Fe(CO)3(α‐imino ketone) (6a,b). This reaction can be reversed photochemically. Irradiation of a solution of 6a,b in the low‐energy band results in the reformation of 8a,b in almost quantitative yield. The extremely air‐sensitive complexes 6 and the dinuclear complexes 7 and 8 have been characterised spectroscopically (IR, UV/Vis, 1H and 13C NMR) and by elemental analysis. The solid state structures of complexes 6g and 8a have been determined by single‐crystal X‐ray diffraction. The molecular structure of 6g confirms the flat σ‐O,σ‐N chelate coordination of the α‐imino ketone. The structure of 8a consists of two metal–metal‐bonded Fe(CO)2 units, bridged by a formally 10e‐donating dianionic C–C coupled (tBu‐ADO) ligand. A mechanism for the formation of complexes 8 is discussed.

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“…This is corroborated by the increase in intensity of this band upon lowering the temperature, an effect which has been observed before for σ-σ* transitions of metalmetal bonds. [62,63] …”

Section: Electronic Absorption Spectra Of Complexes 6 Andmentioning

confidence: 99%

Preparation and Properties of Carbonyliron Complexes of 1-Aza-4-oxa-1,3-butadiene (α-Imino Ketone) – X-ray Crystal Structures of Fe(CO)3[MeNC(Ph)C(Ph)=O] and Fe2(CO)4[tBuNC(H)(Me)C(O)(O)C(Me)C(H)=NtBu]

Siebenlist¹,

Frühauf²,

Vrieze³

et al. 2000

Eur. J. Inorg. Chem.

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“…The widely used assignments of transitions in dinuclear complexes [34][35][36][37][38][39][40] follow the designation suggested by Levenson et al [35] for [Mn 2 (CO) 10 ] which exists in the non-bridged form. The intense, near-UV band (around 340 nm) was ascribed to sAEs * transition (where s denotes metal-metal bond) based on the intensity, polarization and energy criteria.…”

Section: Calculated Spectramentioning

confidence: 99%

“…The first low energy band of [Re 2 (CO) 10 ] was suggested to overlap with the intense near-UV band [37]. For [Co 2 (CO) 8 ] two low energy bands at about 430 and 410 nm were ascribed to dAEs * transitions in the non-bridged and bridged isomers, respectively, and two higher energy bands at about 350 and 280 nm were ascribed to sAEs * transitions in non-bridged and bridged isomers, respectively [39].…”

Section: Calculated Spectramentioning

confidence: 99%

Structure, Spectroscopy and Photochemistry of the [M(η5-C5H5)(CO)2]2 Complexes (M=Fe, Ru)

Jaworska

Macyk

Stasicka

2004

Structure and Bonding

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The structures of all possible isomeric forms of the [M(h 5 -C 5 H 5 )(CO) 2 ] 2 complexes (M=Fe, Ru) are calculated with the use of the DFT method. The results indicate that both dimers can occur in three stable forms: bridged trans and cis and non-bridged trans. Contrary to the previous reports, the cis non-bridged form turns out to be an unstable transition state. Instead, an additional stable structure, a gauche non-bridged one, is found but only in the case of the Ru compound. Without any outer-sphere interaction the trans-bridged form is of the lowest energy for both dimers. The results are compared with the experimental data. Strong impact of the medium on the stability of the individual structures in solution is emphasized. The electronic spectra of all stable forms, calculated using TDDFT method, reproduce well spectral properties of both complexes. Moreover, they are useful in interpreting the medium effect and photochemical behaviour. The photoreactivity is briefly reviewed pointing at analogies and differences between the Fe and Ru complexes.

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“…This classic method is the one frequently used for generating metal cnrbonyl radicals (18,19): Co(CO), (32,33); CpNi(C0) (33)(34)(35)(36) The method has been extended recently to include M,(CNR); (M = Pd, Pt)-type dimers (37,38):…”

Section: A Homolysis Of Metal-metal Bondsmentioning

confidence: 99%