Cyclopentadienyl chromium complexes with halide, methyl, isothiocyanate and isoselenocyanate ligands: Structures of [η5-(C5H4-COOCH3)]Cr(NO)2(Br) and [η5-(C5H4-COOCH3)]Cr(NO)2(NCS)

Wang, Yu-Pin; Leu, Hsien-Li; Yu, Wei; Cheng, Hsiu‐Yao; Lin, Tso-Shen

doi:10.1016/j.jorganchem.2007.03.043

Cited by 10 publications

(5 citation statements)

References 22 publications

(29 reference statements)

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“…Pseudohalides of the general formula {NCE} − (E = O, S, Se) are ubiquitous and largely employed in coordination chemistry, and they may behave as ligands through either the nitrogen or chalcogen atom according to the nature of the metal center [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. Metal binding of {NCO} − through the nitrogen atom (isocyanate) is predominant over the O -coordination (cyanate), and activation of the isocyanate ligand by nucleophilic addition to the unsaturated carbon atom may be subsequently viable [ 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

Diiron Aminocarbyne Complexes with NCE− Ligands (E = O, S, Se)

et al. 2023

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Diiron μ-aminocarbyne complexes [Fe2Cp2(NCMe)(CO)(μ-CO){μ-CN(Me)(R)}]CF3SO3 (R = Xyl, [1aNCMe]CF3SO3; R = Me, [1bNCMe]CF3SO3; R = Cy, [1cNCMe]CF3SO3; R = CH2Ph, [1dNCMe]CF3SO3), freshly prepared from tricarbonyl precursors [1a–d]CF3SO3, reacted with NaOCN (in acetone) and NBu4SCN (in dichloromethane) to give [Fe2Cp2(kN-NCO)(CO)(μ-CO){μ-CN(Me)(R)}] (R = Xyl, 2a; Me, 2b; Cy, 2c) and [Fe2Cp2(kN-NCS)(CO)(μ-CO){μ-CN(Me)(CH2Ph)}], 3 in 67–81% yields via substitution of the acetonitrile ligand. The reaction of [1aNCMe–1cNCMe]CF3SO3 with KSeCN in THF at reflux temperature led to the cyanide complexes [Fe2Cp2(CN)(CO)(μ-CO){μ-CNMe(R)}], 6a–c (45–67%). When the reaction of [1aNCMe]CF3SO3 with KSeCN was performed in acetone at room temperature, subsequent careful chromatography allowed the separation of moderate amounts of [Fe2Cp2(kSe-SeCN)(CO)(μ-CO){μ-CN(Me)(Xyl)}], 4a, and [Fe2Cp2(kN-NCSe)(CO)(μ-CO){μ-CN(Me)(Xyl)}], 5a. All products were fully characterized by elemental analysis, IR, and multinuclear NMR spectroscopy; moreover, the molecular structure of trans-6b was ascertained by single crystal X-ray diffraction. DFT calculations were carried out to shed light on the coordination mode and stability of the {NCSe-} fragment.

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Section: Introductionmentioning

confidence: 99%

Diiron Aminocarbyne Complexes with NCE− Ligands (E = O, S, Se)

et al. 2023

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“…Importantly, the 13 C NMR chemical shift of quaternary carbon atoms of the Cp* ligand can be considered as an empirical parameter to estimate the electron density at the metal center. , These values nicely correlate with the σ-Hammett parameter of the various substituents on the pic ligand (Figure ): the more positive the σ-Hammett parameter (i.e., the more electron withdrawing is the substituent), the more the 13 C NMR chemical shift of the quaternary carbon atom is high-frequency-shifted. This correlation therefore allows establishing a reliable trend in electron-donating ability of the pic ligands to compare with that in the catalytic activity, as further discussed in the next sections.…”

Section: Resultsmentioning

confidence: 95%

Substituent Effects on the Activity of Cp*Ir(pyridine-carboxylate) Water Oxidation Catalysts: Which Ligand Fragments Remain Coordinated to the Active Ir Centers?

et al. 2021

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Identifying structure–property correlations for molecular water oxidation catalysts (WOCs) is strongly hampered by the complexity of the water oxidation (WO) reaction mechanism and catalyst in situ modifications. Here, the substitution effects for [Cp*Ir(X-pic)NO3] WOCs (pic = κ2-pyridine-2-carboxylate complexes) have been systematically explored by synthesizing several complexes differing for the nature of the X substituent on the pyridine-carboxylate ligand and testing them in WO driven by NaIO4. The activity data were correlated with the σ-Hammett parameter of the various substituents, which was proven to effectively reproduce the trends in electron donor properties of the ligands. The measured TOFmax values were found to roughly increase with the σ-Hammett parameter (i.e., with decreasing electron density at the metal center), reaching plateaux at activity values comparable to that of the simpler [Cp*Ir(H2O)3](NO3)2 catalyst. This trend has been typically observed for WOCs following a water nucleophilic attack mechanism. However, nuclear magnetic resonance studies on the reaction between [Cp*Ir(X-pic)NO3] and NaIO4 suggest that the activity is actually determined by the ease of pyridine-carboxylate ligand loss, likely being a necessary step toward precatalyst activation. This indicates that the same active species is generated from all [Cp*Ir(X-pic)NO3] starting complexes, albeit at different rates and/or in different amounts. A somewhat clear picture therefore appears to emerge, partially in contradiction with some of the hypotheses previously proposed: the active species should contain some degradation fragments of the Cp* (based on previous literature studies) and no X-pic derived ligands (based on the results reported in this work).

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“…In view of the shortness of the Cr1-NO distances in (I) and (II) (ca 1.71 Å ) compared with the Cr-NCS distance of 1.983 (3) Å in compound (7) (Wang et al, 2007), appreciable d back-donation from the Cr atom to the * orbitals of the nitrosyl group is demonstrated. It appears that canonical form iv rather than iii makes a greater contribution to the chromium-nitrosyl bonding.…”

Section: Figurementioning

confidence: 94%

“…The solid was recovered through frit filtration and washed several times with distilled water. Compound (I) (yield 2.24 g, 74%) was obtained after vacuum drying (Wang et al, 2007). An X-ray sample (granular black-brown crystals) was prepared by recrystallization using the solvent expansion method from hexane-tetrahydrofuran (5:2) at 273 K for 48 h. The same procedure was followed for the preparation of (II) (in 90% yield), starting from ( 5 -benzoylcyclopentadienyl)dicarbonylnitrosylchromium (benzoylcynichrodene), (6) (1.23 g, 4.00 mmol).…”

Section: Methodsmentioning

confidence: 99%

“…The analogous bromide compounds, viz. ( 5 -C 5 H 4 COOH)Cr(NO) 2 Br, (I), and ( 5 -C 5 H 4 COC 6 H 5 )Cr-(NO) 2 Br, (II), were prepared using hydrogen bromide/ isoamyl nitrite from (5) and (6), respectively (Wang et al, 2007). Wang et al (1995Wang et al ( , 1999 reported the qualitative relationship of the nonplanarity of the Cp-exocyclic carbon system to the substituent -donor and -acceptor interactions.…”

Section: Commentmentioning

confidence: 99%

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Bromido(η⁵-carboxycyclopentadienyl)dinitrosylchromium(0) and (η⁵-benzoylcyclopentadienyl)bromidodinitrosylchromium(0)

Wang

Leu²,

Lin³

et al. 2009

Acta Crystallogr C

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In the structures of each of the title compounds, [CrBr(C(6)H(5)O(2))(NO)(2)], (I), and [CrBr(C(12)H(9)O)(NO)(2)], (II), one of the nitrosyl groups is located at a site away from the exocyclic carbonyl C atom of the cyclopentadienyl (Cp) ring, with twist angles of 174.5 (3) and 172.5 (1) degrees. The observed orientation is surprising, since the NO group is expected to be situated trans to an electron-rich C atom in the ring. The organic carbonyl plane is turned away from the Cp ring plane by 5.6 (8) and 15.2 (3) degrees in (I) and (II), respectively. The exocyclic C-C bond in (I) is bent out of the Cp ring plane towards the Cr atom by 2.8 (3) degrees , but is coplanar with the Cp ring in (II); the angle is 0.1 (1) degrees .

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Cyclopentadienyl chromium complexes with halide, methyl, isothiocyanate and isoselenocyanate ligands: Structures of [η5-(C5H4-COOCH3)]Cr(NO)2(Br) and [η5-(C5H4-COOCH3)]Cr(NO)2(NCS)

Cited by 10 publications

References 22 publications

Diiron Aminocarbyne Complexes with NCE− Ligands (E = O, S, Se)

Diiron Aminocarbyne Complexes with NCE− Ligands (E = O, S, Se)

Substituent Effects on the Activity of Cp*Ir(pyridine-carboxylate) Water Oxidation Catalysts: Which Ligand Fragments Remain Coordinated to the Active Ir Centers?

Bromido(η⁵-carboxycyclopentadienyl)dinitrosylchromium(0) and (η⁵-benzoylcyclopentadienyl)bromidodinitrosylchromium(0)

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Cyclopentadienyl chromium complexes with halide, methyl, isothiocyanate and isoselenocyanate ligands: Structures of [η5-(C5H4-COOCH3)]Cr(NO)2(Br) and [η5-(C5H4-COOCH3)]Cr(NO)2(NCS)

Cited by 10 publications

References 22 publications

Diiron Aminocarbyne Complexes with NCE− Ligands (E = O, S, Se)

Diiron Aminocarbyne Complexes with NCE− Ligands (E = O, S, Se)

Substituent Effects on the Activity of Cp*Ir(pyridine-carboxylate) Water Oxidation Catalysts: Which Ligand Fragments Remain Coordinated to the Active Ir Centers?

Bromido(η5-carboxycyclopentadienyl)dinitrosylchromium(0) and (η5-benzoylcyclopentadienyl)bromidodinitrosylchromium(0)

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Bromido(η⁵-carboxycyclopentadienyl)dinitrosylchromium(0) and (η⁵-benzoylcyclopentadienyl)bromidodinitrosylchromium(0)