Π-Cyclopentadienyl-Π-Cycloheptatrienyl VANADIUM

King, R. B.; Stone, F. G. A.

doi:10.1021/ja01528a063

Cited by 84 publications

(33 citation statements)

References 3 publications

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“…This structure ( Fig. 4) can be derived from Ib-s ( Table 2 Chromium-carbon(cycloheptatrienyl) distances (in Å) for the (C 7 H 7 ) 2 Cr 2 (CO) 6 structures Table 4 Chromium-carbon(cycloheptatrienyl) distances (in Å) for the (C 7 H 7 ) 2 Cr 2 (CO) 5 structures 4 Four starting structures of (C 7 H 7 ) 2 Cr 2 (CO) 4 , namely doubly CObridged cis and trans structures as well as unbridged cis and trans structures, were optimized using the B3LYP and BP86 methods. The global minimum of (C 7 H 7 ) 2 Cr 2 (CO) 4 was found to be the doubly semibridged singlet structure (g 5 -C 7 H 7 ) 2 Cr 2 (CO) 4 (IIIa-s), which has two pentahapto C 7 H 7 rings and two semibridging carbonyl groups (Fig.…”

Section: (C 7 H 7 ) 2 Cr 2 (Co)mentioning

confidence: 99%

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Formal chromium–chromium triple bonds and bent rings in the binuclear cycloheptatrienylchromium carbonyls (C7H7)2Cr2(CO)n (n=6,5,4,3,2,1,0): A density functional theory study

Wang

Xie

King

et al. 2008

Journal of Organometallic Chemistry

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Section: (C 7 H 7 ) 2 Cr 2 (Co)mentioning

confidence: 99%

“…1), such as (g 7 -C 7 H 7 )V(g 5 -C 5 H 5 ) (Refs. [5,6]) and (g 7 -C 7 H 7 )V(CO) 3 (Ref. [7]), were also heptahapto derivatives, in which all seven carbon atoms of the C 7 H 7 ring are within bonding distance of the metal atom.…”

Section: Introductionmentioning

confidence: 99%

Formal chromium–chromium triple bonds and bent rings in the binuclear cycloheptatrienylchromium carbonyls (C7H7)2Cr2(CO)n (n=6,5,4,3,2,1,0): A density functional theory study

Wang

Xie

King

et al. 2008

Journal of Organometallic Chemistry

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“…Magnetic susceptibilities were studied with a superconducting quantum interference device susceptometer (Quantum Design) in the temperature range from 1.8 to 300 K. The data were corrected for magnetization of the sample holder (KLF), and diamagnetic corrections were applied to the magnetic susceptibility data on the basis of Pascal's constants. Trovacene 1 [27], phenyl- [5]trovacene 2 [20], 1,3-di( [5]trovacenyl)benzene 3 [18], Pd(dppf)Cl 2 [28], and 1,3,5-triiodobenzene [29] were prepared as described in the literature. 2,4,6-Triiodoanisole was purchased from Sigma.…”

Section: Methodsmentioning

confidence: 99%

Trovacenyl-based organometallic triradicals: Spin frustration, competing interactions and redox splitting

et al. 2004

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Two new triradicals based on trovacene [(q7-tropylium)vanadium(qS-cyclopentadienyl)], 1,3,5-tri ([5]trovacenyl)benzene 4 and 1,3,5-tri([5]trovacenyl)-6-methoxybenzene 5 were prepared and their magnetic properties were studied by continuous-wave X-band electron paramagnetic resonance (EPR) spectroscopy and by temperature-dependent magnetic susceptometry. The EPR spectra of 4 and 5 in liquid toluene solution demonstrate that the three unpaired electrons localized on the vanadium atoms interact with each other in both complexes. The data from magnetic susceptometry revealed that the electron spins in both triradicals ate antiferromagnetically coupled despite the meta-phenylene bridge. The exchange coupling constants ate equal in the C3-symmetrical triradical 4 (J = J' = -0.68 cm-~), which leads to a twofold degenerate spin ground state (spin frustration). The symmetry lowering by methoxy substitution of the benzene spacer in 5 results in the effect of competing interactions ( 3 " = -1 . 8 3 cm -~ and J ' = -2 . 3 8 cm-~). In addition to magnetocommunication, the effect of ring substitution on electrocommunication is also discernable. It manifests itself in disparate redox splittings 8E1/2 (0/-, -/ 2 -) and 5EI/2 ( -/ 2 -, 2 -/ 3 -) for 5, while these parameters are equal for the C3-symmetrical trinuclear complex 4.

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“…The vanadium structure (η 7 -C 7 H 7 )V(η 5 -C 7 H 7 ) (V-1D) has a 17-electron metal configuration and is closely related to the compound (η 7 -C 7 H 7 ) 2 V(η 5 -C 5 H 5 ), known since 1959. [9] The lowest energy quartet structure found for (C 7 H 7 ) 2 V is (η 7 -C 7 H 7 )V(η 4 -C 7 H 7 ) (V-2F) with one heptahapto and one tetrahapto C 7 H 7 ring analogous to the lowest energy triplet structure (η 7 -C 7 H 7 )Ti(η 4 -C 7 H 7 ) (Ti-3T) found for (C 7 H 7 ) 2 Ti. This quartet structure lies 13.7 kcal/mol (B3LYP) or 13.5 kcal/mol (BP86) above the V-1D global minimum.…”

Section: V(c 7 H 7 )mentioning

confidence: 99%

“…[6] The first such η 7 -C 7 H 7 M complex was the cation (η 7 -C 7 H 7 )-Mo(CO) 3 + (Figure 2), prepared in 1958 [7,8] by the hydride abstraction from the triene complex (η 6 -C 7 H 8 )Mo(CO) 3 . Shortly thereafter, the neutral sandwich compound [9,10] (η 5 -C 5 H 5 )V(η 7 -C 7 H 7 ) was obtained from the thermal reaction of cycloheptatriene with (η 5 -C 5 H 5 )V(CO) 4 . Another feature of the cycloheptatrienyl ligand is its ability to form metal complexes involving only partial bonding of the seven-membered ring to the metal atom.…”

Section: Introductionmentioning

confidence: 99%

Bis(cycloheptatrienyl) Derivatives of the First‐Row Transition Metals: Variable Hapticity of the Cycloheptatrienyl Ring

et al. 2008

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Extrapolation from ferrocene and dibenzenechromium suggests the currently unknown 18‐electron sandwich compound (η7‐C7H7)2Ti as a possible stable molecule. However, density functional theory (DFT) methods using the B3LYP and BP86 functionals predict (η7‐C7H7)2Ti to distort by ring slippage to give a singlet 16‐electron complex (η7‐C7H7)Ti(η5‐C7H7) having an uncomplexed C=C double bond in one of the C7H7 rings but otherwise closely related to the known (η7‐C7H7)Ti(η5‐C5H5). The situation is similar with (C7H7)2V except that the corresponding structures have doublet spin multiplicity. However, an analogous (η7‐C7H7)Cr(η5‐C7H7) structure is not found for chromium. Instead the most stable (C7H7)2Cr structure is a singlet d0 six‐coordinate formally CrVI complex with two tridentate cyclopropyldivinyl C7H7 ligands. The latter rearrangement of the C7H7 rings bonded to chromium can involve initially a (η6‐C7H7)2Cr diradical sandwich compound followed by a bis(η5‐norcaradienyl)Cr intermediate. For the later first‐row transition metals the lowest energy (C7H7)2M structures are predicted to be doublet (η7‐C7H7)Mn(η3‐C7H7) rather than (η5‐C7H7)2Mn for manganese, singlet cis and trans structures (η5‐C7H7)2Fe for iron, doublet (η3‐C7H7)2Co for cobalt, and two singlet (η3‐C7H7)2Ni stereoisomers for nickel.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

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Π-Cyclopentadienyl-Π-Cycloheptatrienyl VANADIUM

Cited by 84 publications

References 3 publications

Formal chromium–chromium triple bonds and bent rings in the binuclear cycloheptatrienylchromium carbonyls (C7H7)2Cr2(CO)n (n=6,5,4,3,2,1,0): A density functional theory study

Formal chromium–chromium triple bonds and bent rings in the binuclear cycloheptatrienylchromium carbonyls (C7H7)2Cr2(CO)n (n=6,5,4,3,2,1,0): A density functional theory study

Trovacenyl-based organometallic triradicals: Spin frustration, competing interactions and redox splitting

Bis(cycloheptatrienyl) Derivatives of the First‐Row Transition Metals: Variable Hapticity of the Cycloheptatrienyl Ring

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