Synthesis and structure of free and complexed cyclopentadienyl selanes

Thaler, Georg; Fimml, Walter; Wurst, Klaus; Sladky, F.

doi:10.1016/s0020-1693(03)00041-0

Cited by 9 publications

(6 citation statements)

References 26 publications

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“…The average carbon-selenium bond length of 1.98 A ˚is greater than the sum of the covalent radii (1.93 A ˚), and slightly shorter than that seen in Cp* 2 Se (2.00 A ˚). 10 The value of the C(10)-Se-C( 11) angle (99.7(1) • ) is considerably smaller than its equivalent in Cp* 2 Se (109.6(2) • ), 10 and resembles that in (C 5 Bu t 2 H 3 )SePh (100.3(3) • ) 4 and Cp*SeFc (101.8(4) • ), 3 where the two allylic methyl groups are also absent.…”

Section: Resultsmentioning

confidence: 96%

“…The single peak at 60.3 ppm is in the expected region for a deshielded sp 3 carbon atom and is assigned to C 5 . The final four peaks are in the expected region for C=C double bonds and are assigned to the carbon atoms C [1][2][3][4] . The 1 H and 13 C NMR spectra show that the four methyl groups on each cyclopentadienyl ring are non-equivalent, and that the molecule has two-fold symmetry.…”

Section: Resultsmentioning

confidence: 99%

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Tetramethylcyclopentadienylselenium derivatives

et al. 2005

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Bis(1,2,3,4-tetramethylcyclopentadienyl)selane (1) has been prepared by the reaction of tetramethylcyclopentadienyllithium (Cp(t)Li) with selenium bis(diethyldithiocarbamate). Treatment of Cp(t)Li with elemental selenium, followed by air oxidation, led to loss of the allylic hydrogen atom, and formation of the novel tricyclic compound 1,4,5,6,7,10,11,12-octamethyltricyclo[7.3.0.0]-2,8-diselenadodeca-3,5,9,11-tetraene (2). The sulfur analogue of 2 has been obtained by a similar procedure. The X-ray crystal structures of compounds 1 and 2 have been determined, and the molecular geometry observed for has been probed using DFT calculations.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Tetramethylcyclopentadienylselenium derivatives

et al. 2005

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“…The optimised gas-phase geometries for the noncyclic diselanes 1a-e and 4 are represented by the typical skew conformation which has been found by electron diffraction e.g., for Me 2 Se 2 1c [19], and also in the solid state for other diorganodiselanes [20,21]. The dihedral angles including the Se-Se bond axis range from 83 • to 90.5 • .…”

Section: Structuresmentioning

confidence: 99%

Indirect Nuclear 77Se?77Se Spin?Spin Coupling Constants. Application of Density Functional Theory (DFT) Calculations

Wrackmeyer

2005

Struct Chem

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Calculations of the isotropic indirect nuclear spin-spin coupling constants n J( 77 Se, 77 Se) (n = 1,2,3) have been carried out at the B3LYP/6-311+G(d,p) level of theory. The compounds considered were non-cyclic and cyclic diselanes 1, boryl-substituted diselanes 2, dichlorodiselane 4, selenium Se 8 , Se 6 , Se 5 and various mixed selenium sulfides 3, and the bis(ethylene)tetraselenafulvalene (TSeF) 5. In comparison with experiment, both magnitude and sign, if available, were reproduced. The Coupled Perturbed DFT method gave the total coupling constant and the contributions arising from the Fermi contact term (FC), the spin-dipole (SD) and the spin.orbital terms (PSO and DSO). FC contributions play a minor role in most cases when compared with the non-contact terms.SD and PSO.

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“…The Se-C(10) distance is considerably shorter (1.868(10) Å ), as would be expected for a bond to an sp 2 hybridised carbon atom, and indeed appears to be one of the shortest carbon-selenium single bonds [15]). The C(10)-Se-C(11) angle of 101.8(4)°is considerably smaller than its equivalent in 1 (109.6(2)° [12]), where the steric requirements of the two allylic methyl groups appear to be dominant in determining the observed geometry, and resembles that in SeðC 5 Bu t 2 H 3 ÞPh (100.3(3)° [14]) and Se (C 5 Me 4 H) 2 (99.7(1)° [10]), where these methyl groups are absent.…”

Section: Resultsmentioning

confidence: 89%