2388-04-7Relevant academic research and scientific papers
The effect of solubility on the stability of titanium(IV) arene complexes derived from hexasubstituted arenes and TiCl4
Kiprof, Paul,Li, Jun,Renish, Catherine L.,Kalombo, Eddie K.,Young Jr., Victor G.
, p. 113 - 118 (2007/10/03)
The investigation of new titaniuni(IV) hexaalkylarene complexes gave new insight into the stability of high-valent metal arene complexes. In contrast to low-valent transition metal arene complexes these complexes are in equilibrium with the free arenes. The stability of the complexes was shown to depend strongly on both the donor ability of the arene and on their solubility. This is unprecedented in transition metal arene chemistry.
"IPSO" AROMATIC ALKYLATION IN THE GAS PHASE. INTERMEDIACY AND STRUCTURE GASEOUS HEPTAALKYLBENZENIUM IONS
Attina, Marina,Cacace, Fulvio,Petris, Giulia de,Fornarini, Simonetta,Giacomello, Pierluigi
, p. 2297 - 2302 (2007/10/02)
The structure of heptaalkylbenzenium ions has been investigated in the gas phase with complementary techniques, i. e., chemical ionization mass spectrometry, alkylation of hexaalkylbenzenes by radiolytically generated cations, and collisianally induced dissociation mass spectrometry.The results allow us to assign the ?-complex ( Wheland intermedisate ) structure to the free, gaseous heptaalkylbenzenium ions, in agreement with the established structure of their salts in solution and in the solid state.The heptaalkylbenzenium ions represent the charged intermediates of the gas-phase "ipso"-substitution reactions, whose occurence has been demonstrated and whose mechanism is briefly discussed.
On the Mechanism of the Singulet Excited Photo-Isomerization of the Homofulvene System
Brune, Hans-Albert,Lach, Peter,Schmidtberg, Guenter
, p. 1781 - 1789 (2007/10/02)
Syntheses of the four at the cyclopropane part alkyl-substituted homofulvenes 6-endo-Ethyl-1,2,3,5-tetramethyl-4-methylenebicyclohex-2-ene (endo-1a), 6-exo-Ethyl-1,2,3,5-tetramethyl-4-methylenebicyclohex-2-ene (exo-1a), 6-endo-Isopropyl-1,2,3,5-tetramethyl-4-methylenebicyclohex-2-ene (endo-1b) and 6-exo-Isopropyl-1,2,3,5-tetramethyl-4-methylenebicyclohex-2-ene (exo-1b) are reported.Following singulet excitation endo-1a, endo-1b and exo-1b underwent photo-isomerization to 6-Ethyl-1,2,3,4-tetramethyl-5-methylenecyclohexa-1,3-diene (2a) and 6-Isopropyl-1,2,3,4-tetramethyl-5-methylenecyclohexa-1,3-diene (2b) resp.It is demonstrated, that C-6 - the top of the cyclopropane ring in 1 - is transferred to C-6 - adjacent to the exo-methylene substituent - in the 5-methylenecyclohexa-1,3-diene system 2.A mechanism is suggested. - Keywords: Homofulvene System, Photo-Isomerization, Mechanism
