The crystal structure of the bis-tricarbonylchromium complex of dibenzo[a,e]cyclooctatetraene: Cr(CO)3 orientation controlled by short C–H⋯O hydrogen bonding

Brown, Martyn A.; Zubkowski, Jeffrey D.; Valente, E.; Yang, Gin-Zong; Henry, William P.

doi:10.1016/s0022-328x(00)00527-1

Cited by 11 publications

(4 citation statements)

References 90 publications

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“…In complex 8b , the close contacts measured between the two phenyl groups would suggest a diffuse multicenter interaction that involves the ortho hydrogen of the proximal aryl group and at least two other centers, i.e., the chromium and the carbon atoms of one CO ligand that syn-eclipses the Pd (Figure ). If the values of the interatomic distances are compared to the data collected for other reported cases of established intermolecular C−H···CO interaction, in 8b they fall far from what is actually expected for a strong interaction . The reason for the endo tilting of the aryl group toward the Cr(CO) 3 therefore does not seem to be a weak intramolecular interaction.…”

Section: Resultsmentioning

confidence: 71%

Chloride-Promoted Synthesis of Cis Bis-Chelated Palladium(II) Complexes from Ortho-Mercurated Tricarbonyl(η⁶-arene)chromium Complexes

Berger¹,

Djukic²,

Pfeffer³

et al. 2003

Organometallics

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A new method of synthesis of homo- and heteroleptic cis bis-chelated Pd(II) species by a transmetalation reaction of the ortho-mercurated 2-[tricarbonyl(η6-phenyl)chromium]pyridine with a series of bis(μ-chloro) palladacyclic aromatic compounds in the presence of a large excess of the chloride salt [NMe4]Cl is reported. These (CO)3Cr-bound bis-chelated Pd(II) species can be designed for the preparation of enantiopure planar chiral cyclopalladated (η6-arene)Cr(CO)3 complexes. The study of the mechanism of this transmetalation reaction reveals the key role of the excess of chloride salt, which is necessary for the isolation of persistent heteroleptic bis-chelated Pd(II) complexes. This method was further applied to the synthesis of highly enantioenriched (+) and (−) samples of the ortho-chloropalladated 2-[tricarbonyl(η6-phenyl)chromium]pyridine, whose enantiopurity was assessed with the aid of diamagnetic Λ and Δ TRISPHAT salts used as chiral shift 1H NMR agents. The absolute configurations of the two enantioenriched complexes were obtained from the corresponding absolute structures determined by X-ray diffraction analyses. The molecular structures of six new heteroleptic bis-chelated Pd(II) complexes are reported.

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Section: Resultsmentioning

confidence: 71%

Chloride-Promoted Synthesis of Cis Bis-Chelated Palladium(II) Complexes from Ortho-Mercurated Tricarbonyl(η⁶-arene)chromium Complexes

Berger¹,

Djukic²,

Pfeffer³

et al. 2003

Organometallics

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“…First coordination compounds with dbcot as ligand contained silver and palladium as metals, followed by reports on complexes with chromium or molybdenum . With chromium, coordination via the benzo groups was also observed , and the inertness of [MH 2 (dbcot)L 2 ] + (M = Rh, Ir; L = phosphane) is especially noteworthy; that is, no hydrogenation of the dbcot ligand is observed.…”

Section: Introductionmentioning

confidence: 99%

Chiral Olefins as Steering Ligands: Syntheses of C₁-Symmetric Dibenzo[a,e]cyclooctenes (^Rdbcot)

2005

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A simple three-step synthesis of chiral dibenzo[a,e]cyclooctenes (dbcot) starting from commercially available dibenzosuberenone was developed. These compounds give highly stable and robust rhodium(I) and iridium(I) diene complexes of the type [M(Rdbcot)(L1)(L2)] (M = Rh, Ir; L1, L2 = MeCN, Cl, diamine, chloride). The complex [Rh((R)-Phdbcot)((R)-(+)-1,1‘-binaphthyl-2,2‘-diamine)]+OTf- could be obtained in enantiomerically pure form and catalyzes the enantioselective 1,2-addition of PhB(OH)2 to α,β-unsaturated ketones with good activity and acceptable enantiomeric excess (62%). The iridium complex [Ir(Phdbcot)(MeCN)2]+OTf- catalyzes the hydrogenation of dimethylitaconate with good activity, while the rhodium complexes are almost inactive. Likewise, the complex [Ir(Phdbcot)(H2NCH2CH2NH2)]+OTf- serves as a rather efficient catalyst precursor with an activity 4 orders of magnitude higher than for the analogous rhodium complex. These experiments further establish the use of dienes as steering ligands in catalysis.

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“…They were also restrained to have the same U ij components, with a standard uncertainty of 0.01 Å 2 . Besides, 1-Y, 2-La, 4-Tb, 5-Dy, and 6-Er were refined as inversion twins with BASF values refined to 0.445(3), 0.466 (25), 0.348 (10), 0.403 (11), and 0.485 (7), respectively. These five structures were examined by PLATON, 50 and no additional symmetry was found.…”

Section: Y(dbcot)(thf) 4 ][Y(dbcot) 2 ] (1-y)mentioning

confidence: 99%

“…Specifically, sym -dibenzo[ a , e ]cyclooctatetraene (DBCOT; Scheme b), a π-expanded derivative of COT, was shown to function as an enhanced π-donor for transition-metal catalysis, − as well as a redox-active subunit for organic electrode materials . In our recent work, we reported the chemical reduction behavior of DBCOT with all Group 1 metals and showed that it can readily accept two electrons to form a planarized π-expanded dianion .…”

Section: Introductionmentioning

confidence: 99%

Homoleptic Rare-Earth-Metal Sandwiches with Dibenzo[a,e]cyclooctatetraene Dianions

Zhu,

Mahoney,

Babson

et al. 2024

Inorg. Chem.

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A family of rare-earth complexes [RE(III) = Y, La, Gd, Tb, Dy, and Er] with doubly reduced dibenzo[a,e]cyclooctatetraene (DBCOT) has been synthesized and structurally characterized. X-ray diffraction analysis confirms that all products of the [RE(DBCOT)(THF) 4 ][RE(DBCOT) 2 ] composition consist of the anionic sandwich [RE(DBCOT) 2 ] − and the cationic counterpart [RE(DBCOT)(THF) 4 ] + . Within the sandwich, two elongated π decks are slightly bent toward the metal center (avg. 7.3°) with a rotation angle of 35.9−37.6°. The RE(III) ion is entrapped between the central eight-membered rings of DBCOT 2− in a η 8 fashion.The trends in the RE−COT bond lengths are consistent with the variations of the ionic radii of RE(III) centers. The 1 H NMR spectra of the diamagnetic Y(III) and La(III) analogues illustrate the distinct solution behavior for the cationic and anionic parts in this series. Magnetic measurements for the Dy analogue reveal single-molecule magnetism, which was rationalized by considering the effect of crystal-field splitting for both building units analyzed by electronic structure calculations.

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The crystal structure of the bis-tricarbonylchromium complex of dibenzo[a,e]cyclooctatetraene: Cr(CO)3 orientation controlled by short C–H⋯O hydrogen bonding

Cited by 11 publications

References 90 publications

Chloride-Promoted Synthesis of Cis Bis-Chelated Palladium(II) Complexes from Ortho-Mercurated Tricarbonyl(η⁶-arene)chromium Complexes

Chloride-Promoted Synthesis of Cis Bis-Chelated Palladium(II) Complexes from Ortho-Mercurated Tricarbonyl(η⁶-arene)chromium Complexes

Chiral Olefins as Steering Ligands: Syntheses of C₁-Symmetric Dibenzo[a,e]cyclooctenes (^Rdbcot)

Homoleptic Rare-Earth-Metal Sandwiches with Dibenzo[a,e]cyclooctatetraene Dianions

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The crystal structure of the bis-tricarbonylchromium complex of dibenzo[a,e]cyclooctatetraene: Cr(CO)3 orientation controlled by short C–H⋯O hydrogen bonding

Cited by 11 publications

References 90 publications

Chloride-Promoted Synthesis of Cis Bis-Chelated Palladium(II) Complexes from Ortho-Mercurated Tricarbonyl(η6-arene)chromium Complexes

Chloride-Promoted Synthesis of Cis Bis-Chelated Palladium(II) Complexes from Ortho-Mercurated Tricarbonyl(η6-arene)chromium Complexes

Chiral Olefins as Steering Ligands: Syntheses of C1-Symmetric Dibenzo[a,e]cyclooctenes (Rdbcot)

Homoleptic Rare-Earth-Metal Sandwiches with Dibenzo[a,e]cyclooctatetraene Dianions

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Chloride-Promoted Synthesis of Cis Bis-Chelated Palladium(II) Complexes from Ortho-Mercurated Tricarbonyl(η⁶-arene)chromium Complexes

Chloride-Promoted Synthesis of Cis Bis-Chelated Palladium(II) Complexes from Ortho-Mercurated Tricarbonyl(η⁶-arene)chromium Complexes

Chiral Olefins as Steering Ligands: Syntheses of C₁-Symmetric Dibenzo[a,e]cyclooctenes (^Rdbcot)