Tetraalkylalkene vertical ionization potentials revisited

Abstract

The vertical ionization potentials for three tetra-a-branched-alkyl-substituted alkenes (13-15) are reported, compared with literature data for other tetralkylalkenes, and the values discussed with reference to AM1 semiempirical and B3LYP density functional calculations.

A new versatile binuclear seven-coordinate complex of molybdenum(II), [(μ-Cl)2{Mo(μ-Cl)(SnCl3)(CO)3}2]2−

“…The coupling of two norbornylidene ligands leads to the formation of bi-nbe. This compound is formed as a mixture of four stereoisomers identified by NMR spectroscopy due to four proton signals at d 2.79, 2.76, 2.58, and 2.54 ppm, characteristic of the methine protons HC-1 [4,6,27], and was observed here in all experiments, even at a 1:1 molar ratio of nbe:H 2 O (Fig. 3).…”

Photochemical reaction of W(CO)6 with GeCl4 as a source of germyl and germylene compounds acting as initiators for ring-opening metathesis polymerization of norbornene

“…For the first time the carbene-carbene coupling reaction was applied in synthesis of bi-(NBE) from NBE in reaction catalyzed by a WASn compound [30]. Previously, the McMurry and Fleming procedure for reductive dimerization of ketones had been applied for the synthesis of compounds of that type [31,39]. As shown here, compound 1 can also be used as a catalyst in synthesis of bi-(NBE), which is formed as a mixture of four stereoisomers.…”

“…It should be noted that poly-(NBE) is poorly soluble in benzene and for that reason its characteristic olefinic proton signals at d = 5.53 for trans and d = 5.39 for cis (ACH@CHA) units are of low intensity [28]. The most intense signals in the spectrum are due to protons of exo-2-phenyl- [30,31]. During the conversion of NBE in the presence of 1 monitored by 1 H NMR spectroscopy in chloroform-d 1 solution, the decay of NBE and the appearance of poly-(NBE) as well as bi-(NBE) are nicely detected (Fig.…”

“…0.15 g, 50%). The GC-MS analysis of the residue obtained after separation of polymer revealed the formation of 2-phenylnorbornane (M r = 172.27) [42] and 2,2 0 -binorbornylidene (M r = 188.32) [30,31] in a molar ratio of ca. 6:1.…”

Computational and experimental studies into NMR characterization of [2+2] cycloaddition products of norbornene

“…]hept-2-ylidenebicyclo[2.2.1]heptane (2,2-binorbornylidene, bi-nbe) (Scheme 2), characterized by 1 H and 13 C NMR spectroscopy and GC-MS analysis [15,16]. This dimerization reaction is concurrent to ring-opening metathesis polymerization (ROMP) and can be regarded as a coupling of two norbornylidene ligands [16][17][18][19].…”