87-85-4

Usage

Uses

Used in Pharmaceutical Industry:
Hexamethylbenzene is used as a pharmaceutical intermediate, playing a crucial role in the synthesis of various pharmaceutical compounds. Its unique structure allows for the development of new drugs and the improvement of existing ones.
Used in Organic Synthesis:
HMB serves as a key component in the organic synthesis of a wide range of compounds. Its ability to undergo various chemical reactions makes it a valuable building block for creating new organic molecules.
Used in He-NMR Spectroscopy:
As a solvent for He-NMR spectroscopy, hexamethylbenzene provides a suitable environment for the analysis of various chemical compounds. Its properties contribute to the accurate determination of molecular structures and the study of chemical reactions.
Used in Organometallic Chemistry:
Hexamethylbenzene acts as a ligand in organometallic chemistry, enabling the formation of metal complexes with unique properties and potential applications in various fields, such as catalysis and materials science.
Used in Chemical Reactions:
The reaction of hexamethylbenzene with dimethyldioxirane results in the formation of an unusual oxepane triepoxide, which can be further utilized in the synthesis of other compounds or for studying the reaction mechanisms.

Purification Methods

Sublime hexamethylbenzene, then crystallise it from abolute EtOH, *benzene, EtOH/*benzene or EtOH/cyclohexane. It has also been purified by zone melting. Dry it in a vacuum over P2O5. [Beilstein 5 H 450, 5 IV 1137.]

InChI:InChI=1/C12H18/c1-7-8(2)10(4)12(6)11(5)9(7)3/h1-6H3

Upstream product

• 67-56-1 methanol 
• 6334-11-8 2,4,6-trimethylaniline hydrochloric acid salt 
• 74-83-9 methyl bromide 
• 5153-40-2 2,3,4,5,6-pentamethylbromobenzene 
• 917-64-6 methyl magnesium iodide 
• 87-82-1 hexabromobenzene 
• 608-74-2 hexaiodobenzene 
• 503-17-3 dimethylacetylene 
• 100-99-2 triisobutylaluminum 
• 74-87-3 methylene chloride 
• 527-53-7 1,2,3,5-Tetramethylbenzene 
• 700-12-9 pentamethylbenzene, 
• 115-10-6 Dimethyl ether 
• 106-42-3 para-xylene 

Downstream Products

• 40205-81-0 hexakis-chloromethyl-benzene 
• 95-47-6 o-xylene 
• 21376-77-2 hexamethylbenzene tetrabromo-p-benzoquinone complex 
• 3962-98-9 chloro-[1,4]benzoquinone; compound with hexamethylbenzene 
• 1795-13-7 1,2,3,4,5,6-hexamethyl-cyclohexane 
• 106-42-3 para-xylene 
• 484-65-1 2,3,4,5,6-pentamethylbenzyl chloride 
• 18801-63-3 3,4,5,6-tetramethyl-1,2-dinitrobenzene 
• 517-60-2 benzenehexacarboxylic acid 
• 91497-58-4 tetramethyl-phthalic acid 
• 108-38-3 m-xylene 
• 3095-73-6 1,2,3,4,5,6-hexa(bromomethyl)benzene 
• 71-43-2 benzene 
• 850-23-7 tetrachloro-[1,4]benzoquinone; compound with hexamethylbenzene 

Relevant academic research and scientific papers

Surface Photochemistry: On the Mechanism of the Semiconductor Photoinduced Valence Isomerization of Hexamethyl-Dewar Benzene to Hexamethylbenzene

The CdS-, TiO2-, and ZnO-photoinduced valence isomerization of hexamethyl-Dewar benzene to hexamethylbenzene has been investigated in methylene dichloride solution and found to be very efficient.The reaction appears to follow modified Langmuir-Hinshelwood and Eley-Rideal mechanisms.A surface cation radical chain mechanism is proposed since the reaction can be efficiently quenched by electron donors, and quantum yields greater than unity were obtained in TiO2 and ZnO reactions.The quenching also followed modified Langmuir-Hinshelwood and Eley-Rideal pathways, in which the latter predominantly contributed to the owerall quenching rates.CdS of different origins with different surface areas, purities, and structures were used, and the rates varied by a factor of 2.3.None of these functions appear to play a dominant role in the rate of reaction.

Accurate oxidation potentials of 40 benzene and biphenyl derivatives with heteroatom substituents

The redox equilibrium method was used to determine accurate oxidation potentials in acetonitrile for 40 heteroatom-substituted compounds. These include methoxy-substituted benzenes and biphenyls, aromatic amines, and substituted acetanilides. The redox equilibrium method allowed oxidation potentials to be determined with high precision (≥ ±6 mV). Whereas most of the relative oxidation potentials follow well-established chemical trends, interestingly, the oxidation potentials of substituted N-methylacetanilides were found to be higher than those of the corresponding acetanilides. Density functional theory calculations provided insight into the origin of these surprising results in terms of the preferred conformations of the amides versus their cation radicals.

Photo-activated Valence Isomerization of Hexamethyl(Dewar benzene) (HMDB) assisted by Arene - Iron(II) Complexes: Luminescence Properties of 5-C5R5)Fe+(η6-arene)>* Adducts

Hexamethyl(Dewar benzene) (HMDB) isomerizes to hexamethylbenzene (HMB) under visible light irradiation in the presence of stoicheiometric or catalytic amounts of the cationic complexes 5-C5R5)Fe(η6-arene)>+X-, (R = H, Me; X = BF4-, PF6-), (1a - e) and (2), in dichloromethane solutions at 273 K; mixtures of HMDB and (1b - e) or (2) in dichloromethane exhibit a luminescence band at 530 - 540 nm probably due to formation of the corresponding exciplex.

Photoisomerization of Charge-Transfer Complexes of Hexamethyl(Dewar benzene). Contrasting Paths for Rearrangement Involving Adiabatic Reaction and Ionic Photodissociation

The charge-transfer (CT) complexes of hexamethyl(Dewar benzene) (HMDB) with electron acceptors, fumaronitrile, diethyl 1,2-dicyanofumarate, and 1,2,4,5-tetracyanobenzene, have been characterized and compared to similar complexes of hexamethylbenzene (HMB).Irradiation of HMDB CT bands in the 313-435-nm region under a variety of conditions leads to HMDB->HMB isomerization.The quantum yield of rearrangement in a nonpolar solvent is low (e.g., 0.06), although the relative yield of adiabatic isomerization, monitored by emission from excited complexes of HMB, is high (0.72).Quantum efficiencies for isomerization of complexes in polar media generally exceed unity, consistent with a radical-ion chain mechanism for ring opening.The quantum chain reaction depends on the polarity of the solvent, the reduction potential of the acceptor, the extent of conversion, and the wavelength of irradiation.The wavelength effect is associated with excitation to upper vibrational levels of a CT band with enhancement of ionic photodissociation.Comparison of the quantum yield results for excited CT complexes with the findings for rearrangement of HMDB via exciplexes reveals generally different patterns of reactivity.

Generation of Trialkylcyclopropenyl Radicals by Pulse Radiolysis and Radical-Ion Complex Formation

Trimethylcyclopropenyl radical, generated by pulse radiolysis from the corresponding cation, complexes with the cation.

Isomerization of Hexamethyl(Dewar benzene) to Hexamethylbenzene Catalyzed by Electron Acceptors. Thermal Generation of an Exciplex

The reaction of hexamethyl(Dewar benzene) (HMD) with ground-state electron and with singlet and triplet excited electron acceptors reveals parallel behavior.The thermal acceptors catalyze the conversion of HMD to hexamethylbenzene (HMB) without formation of ions free in solution.The excited-state acceptors in some cases give ions, and in others only neutral ground-state products.The behavior of these electron acceptors is interpreted to indicate that formation of an exciplex in both the thermal and photochemical reactions initiates the process responsible for isomerization.In some cases electron transfer in the exciplex and dissociation lead to ionic products.

Mechanistic studies of olefin and alkyne trimerization with chromium catalysts: Deuterium labeling and studies of regiochemistry using a model chromacyclopentane complex

A system for catalytic trimerization of ethylene utilizing chromium(III) precursors supported by diphosphine ligand PNPO4 = (o-MeO-C 6H4)2PN(Me)P(o-MeO-C6H 4)2 has been investigated. The mechanism of the olefin trimerization reaction was examined using deuterium labeling and studies of reactions with α-olefins and internal olefins. A well-defined chromium precursor utilized in this studies is Cr(PNPO4)-(o,o′- biphenyldiyl)Br. A cationic species, obtained by halide abstraction with NaB[C6H3(CF3)2]4, is required for catalytic turnover to generate 1-hexene from ethylene. The initiation byproduct is vinylbiphenyl; this is formed even without activation by halide abstraction. Trimerization of 2-butyne is accomplished by the same cationic system but not by the neutral species. Catalytic trimerization, with various (PNPO4)Cr precursors, of a 1:1 mixture of C2D 4 and C2H4 gives isotopologs of 1-hexene without H/D scrambling (C6D12, C6D 8H4, C6D4H6, and C 6H12 in a 1:3:3:1 ratio). The lack of crossover supports a mechanism involving metallacyclic intermediates. Using a SHOP catalyst to perform the oligomerization of a 1:1 mixture of C2D4 and C2H4 leads to the generation of a broader distribution of 1-hexene isotopologs, consistent with a Cossee-type mechanism for 1-hexene formation. The ethylene trimerization reaction was further studied by the reaction of trans-, cis-, and gem-ethylene-d2 upon activation of Cr(PNPO4)(o,o′-biphenyldiyl)Br with NaB-[C6H 3(CF3)2]4. The trimerization of cis- and trans-ethylene-d2 generates 1-hexene isotopomers having terminal CDH groups, with an isotope effect of 3.1(1) and 4.1(1), respectively. These results are consistent with reductive elimination of 1-hexene from a putative Cr(H)[(CH2)4CH=CH2] occurring much faster than a hydride 2,1-insertion or with concerted 1-hexene formation from a chromacycloheptane via a 3,7-H shift. The trimerization of gem-ethylene-d 2 has an isotope effect of 1.3(1), consistent with irreversible formation of a chromacycloheptane intermediate on route to 1-hexene formation. Reactions of olefins with a model of a chromacyclopentane were investigated starting from Cr(PNPO4)(o,o′-biphenyldiyl)Br. α-Olefins react with cationic biphenyldiyl chromium species to generate products from 1,2-insertion. A study of the reaction of 2-butenes indicated that β-H elimination occurs preferentially from the ring CH rather than exo-CH bond in the metallacycloheptane intermediates. A study of cotrimerization of ethylene with propylene correlates with these findings of regioselectivity. Competition experiments with mixtures of two olefins indicate that the relative insertion rates generally decrease with increasing size of the olefins.

Mechanism of Hemin-Catalyzed Epoxidations: Electron Transfer from Alkenes

Two rearrangements of alkenes, known to proceed through the intermediacy of the alkene cation radical, have been observed to accompany the hemin-catalyzed epoxidations of these alkenes.Hexamethyl(Dewar benzene) partially rearranged to hexamethylbenzene during its epoxidation using (tetraphenylporphyrinato)iron(III) chloride and m-chloroperbenzoic acid, but not with either of the reagents separately.In a similar manner the diene, 1,4,4a,5,8,8a-hexahydro-1,4,5,8-endo,endo-dimethanonaphthalene, closed to the known "birdcage hydrocarbon" under these conditions.This diene also brought about some N-alkylation of the catalyst during the reaction.These observations are interpreted in terms of an electron transfer from alkene to the high-valent iron intermediate, leading to both rearrangement and epoxidation.

SYNTHESES OF METAL CARBONYLS. XVII. FORMATION OF A HETERONUCLEAR ORGANOMETALLIC CLUSTER CONTAINING RUTHENIUM AND RHODIUM; CRYSTAL AND MOLECULAR STRUCTURE OF (3(μ3-CO)2)

Ru(C6Me6)(C2H4)2 reacts with Rh(C5Me5)(CO)2 to give the known dinuclear complex 2 and the new heteronuclear cluster complex (3(μ3-CO)2) which has been fully characterized by a single crystal X-ray diffraction study.

Photosensitized Isomerization of Hexamethyl (Dewar benzene) by Interactions with 1,4-Dicyanonaphthalene-Arene Exciplexes. An Adiabatic Triplex Pathway

The isomerization of Hexamethyl (Dewar benzene) to hexamethylbenzene is photosensitized by 1,4-dicyanonaphthalene-arene exciplexes.Spectroscopic and quantum-yield studies suggest that the isomerization proceeds mostly through an adiabatic pathway from hypothetical termolecular excited complexes (triplexes).