38575-32-5

Upstream product

• 627-20-3 (Z)-pent-2-ene 
• 61080-14-6 dimesityl diazomethane 
• 87871-33-8 bis(mesityl)ketene 
• 85236-86-8 di(2,4,6-trimethylphenyl)carbene 
• 49633-78-5 2,4,6,2',4',6'-hexamethylbenzophenoneimine 
• 5740-42-1 2,2-bis(2,4,6-trimethylphenyl)acetic acid 
• 108-67-8 1,3,5-trimethyl-benzene 
• 96873-14-2 dimesityldiazomethane 

Relevant academic research and scientific papers

Hindered Tetraphenylethylene Helicates: Chiral Fluorophores with Deep-Blue Emission, Multiple-Color CPL, and Chiral Recognition Ability

New hindered tetraphenylethylene (TPE) helicates with substitution at 2,6-position of phenyl rings were designed and synthesized. Due to the increased hindrance, the TPE helicates emit strong deep-blue to violet fluorescence both in the solid state and in

Spectroscopic and product studies of the effect of para substituents on the reactivity of triplet bis(2,6-dimethylphenyl)carbenes

A series of diazobis(2,6-dimethylphenyl)methanes (1) bearing eight symmetrical para di-substituents have been prepared and photolyzed to generate the corresponding carbenes (2). Product analysis studies showed that carbenes (2) decay mainly either by dimerization to form tetra(aryl)ethylene (3) or by attack at an o-methyl group to afford 1,2-dihydrobenzocyclobutenes (4) by way of o-quinodimethanes (6) in solution. The zero-field splitting parameters, D and E, were measured in matrices of different viscosities and are analyzed in terms of a sigma-dot (σ.) scale of spin-delocalization substituent constants. Fairly good correlation with σ. was found for the D values of 32 in its minimum energy geometry. Stabilities of 32 were estimated either by measuring the temperature at which the triplet carbene signals disappeared upon thawing the matrix or by analyzing the decay kinetics of 32 in a degassed solution at room temperature. They are examined in terms of the D values in matrix at low temperature and in terms of product distributions in solution at room temperature.

Polymethylated and poly(tert)butylated diphenylcarbenes. Generation, reactions, kinetics, and deuterium isotope effects of sterically congested triplet carbenes

Dimesitylcarbene (2a) was shown to decay by undergoing dimerization and to have a half-life of 160 ms, some 5 orders of magnitude longer-lived than diphenylcarbene. Didurylcarbene (2b) was twice as long-lived as 2a, while decamethyldiphenylcarbene (2c) de

Resolution and Enantiomerization Barrier of Tetramesitylethylene

The 1H NMR spectrum of tetramesitylethylene (2) was analyzed, and the signals were assigned by means of a 2D NOESY spectrum.Attempts to observe anisochrony of the enantiotopic groups of a racemic mixture of 2 in a chiral solvent by 1H NMR were unsuccesful.Molecular mechanics and MNDO calculations satisfactorily reproduce the ground-state conformation.The calculated barrier for the enantiomerization process is 21.8 (MM2) and 28.2 (MNDO) kcal mol-1. 2 was chromatographically resolved on a (+)-poly(triphenylmethyl)methacrylate (PTrMA) column.Its specific rotation is 25 = -12100 deg at 365 nm and -2300 deg at 589 nm (D line).The activation parameters for the enantiomerization of 2 in perhydrofluorene are ΔG = ΔH = 39.6 kcal mol-1 and ΔS = 0 cal mol-1 K-1.The barrier for 2 is the highest determined experimentally for a correlated rotation.

Singlet and Triplet Dimesitylcarbene

The triplet states of essentially all diarylcarbenes react with substrates such as methanol or their parent diazo compounds both of which are thought to be specific quenchers for the singlet state.To rationalize these results, investigators have proposed that the singlet and triplet states of these carbenes are linked by efficient equilibria.In this kinetic study we have found that the singlet and triplet states of dimesitylcarbene exhibit quite distinct chemistries.The singlet state alone reacts with methanol, 1-propanol, and 1,3-cyclohexadiene, while the triplet carbene dimerizes to give olefin or, for example, reacts with oxygen.No evidence was found for reaction of the triplet carbene via the singlet manifold.Arguments are presented to explain the enhanced free energy difference between the spin states of this carbene and the relative persistence if its triplet.

Dimesitylcarbene: The Distinct Chemistries of its Singlet and Triplet States

Dimesitylcarbene is unique amongst the diarylcarbenes thus far investigated since its triplet state cannot readily convert into the singlet state.