Bond length ethylene

Fig. 2. Time-evolution of the methyl/ethyl C-C distances for both the zirconocene and the corresponding titanocene catalyst. The two curves starting at around 3.2 A represent the distance between the methyl carbon atom and the nearest-by ethylene carbon atom in the zirconocene-ethylene and the titanocene-ethylene complex, respectively. The two curves starting at around 1.35 A reflect the ethylene internal C-C bond lengths in the two complexes.

Structure. Ethylene is a planar molecule with a carbon—carbon bond distance of 0.134 nm, which is shorter than the C—C bond length of 0.153 nm found in ethane. The C—H bond distance is 0.110 nm, and the bond angles are [Pg.432]

The stmctural parameters of ethylene oxide have been determined by microwave spectroscopy (34). Bond distances iu nm determined are as follows C—C, 0.1466 C—H, 0.1085 and C—O, 0.1431. The HCH bond angle is 116.6°, and the COC angle 61.64°. Recent ah initio studies usiug SCF, MP2, and CISD have predicted bond lengths that are very close to the experimental values (35,36). 

Ethylene, bond angles in, 16 bond lengths in, 16 bond strengths in, 16 electrostatic potential map of, 74, 147... 

Table 3 Bond lengths of C5-X and C5-CHj at the tamsition states in Diels-Alder reactions between 5-methyl-5-X-cyclopentadienes and ethylene (AMI)...

Table I. Bond lengths (in A) and bond angles (in degrees) for the ethylene molecule...

The reaction between [PdCl2(MeCN)2] and ethylene diamine-A, 3-ethylguanine yields the analogous C8-cyclometalated compound [PdCl(en-Et-A-C< )]+ 28 (Pd-C bond length 1.974 A) (56) (Fig. 29). Again, proton transfer to the adjacent N7 accompanies C8-metalation and this is observed downfield in the NMR spectrum... 

The ir-bond between two silicon atoms (>Si=Si<) was formerly thought to be non-existent and then was found to be extremely weak. This has been explained in the past by the extended bond length, with respect to ethylene, which was thought to be the origin of a seemingly low 3p-3p(ir) atomic overlap S(tt) [1]. However, the overlap actually has never been calculated before. Calculations indicate quite similar p-p(ir) overlap integrals in disilene and ethylene so that the different bond lengths for C=C and Si=Si must be explained by the different orbital radii (Fig. 1). 

The units by which crystallographers describe interatomic distances are Angstrom units (A = 10 8 cm.). Normal values for carbon-carbon interatomic distances are 1.34 A for a double bond (as in ethylene) and 1.54 A (as for-diamond) for a single bond. In a truly aromatic compound (such as benzene) the C-C bond length, as mentioned above, is 1.39 A. C-C-C angles are 109.5° for a tetrahedral carbon atom (sp3) and 120.0° for a trigonal carbon atom (sp2). 

Additionally, and interestingly, the DFT calculations suggest that the Zr-N bonds that lie on the same plane as the polymerization sites expand and contract according to the reaction coordinate of the ethylene insertion (2.23-2.34 A), while the Zr-O bond length remains virtually unchanged (Fig. 13). From studying these results, we... 

Substituted ethylenes, with hydrogen atoms replaced by various alkyl groups, have a common feature in their electronic spectra, i.e. an absorption band at ca. 164 — 180 nm. This band is interpreted to show that the delocalization of the electron pair is largely confined to the vicinity of the unsaturated centre, commonly referred to as the C=C double bond. If the de-localization is assumed not to exceed a linear distance of one bond length on either side of the double bond, the electron pair remains in a linear potential box of width 3d, with allowed energy levels of... 

The first isolable alkenetitanium complex, the bis(pentamethylcyclopentadienyl)-titanium—ethylene complex 5, was prepared by Bercaw et al. by reduction of bis(penta-methylcyclopentadienyl)titanium dichloride in toluene with sodium amalgam under an atmosphere of ethylene (ca. 700 Torr) or from ( (n-C5Mc5)2Ti 2(fJ-N2)2 by treatment with ethylene [42], X-ray crystal structure analyses of 5 and of the ethylenebis(aryloxy)trimethyl-phosphanyltitanium complex 6 [53] revealed that the coordination of ethylene causes a substantial increase in the carbon—carbon double bond length from 1.337(2) A in free ethylene to 1.438(5) A and 1.425(3) A, respectively. Considerable bending of the hydrogen atoms out of the plane of the ethylene molecule is also observed. By comparison with structural data for other ethylene complexes and three-membered heterocyclic compounds, the structures of 5 and 6 would appear to be intermediate along the continuum between a Ti(11)-ethylene (4A) and a Ti(IV)-metallacyclopropane (4B) (Scheme 11.1) as... 

Favini et al. (189) also report calculations on 1,1 -diphenyl-2,2-di-rm-butyl-ethylene (130b), which has been shown by X-ray crystallography to be twisted by 24° and has R(C=C) 136 pm (191). The calculated twist and bond length, 19.8° and 135.7 pm, as well as most other structural details, agree well with the experimental data. 

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