992-04-1

Usage

Uses

Used in Fluorescent Nanorods:
Hexaphenylbenzene is used as a starting material to prepare fluorescent nanorods for the detection of trinitrotoluene (TNT). The fluorescent properties of these nanorods make them suitable for sensitive and selective detection of explosives.
Used in Chemical Synthesis:
Hexaphenylbenzene can be used as a starting material to synthesize various compounds and materials, such as:
1. 1,2,3,4,5,6-Hexacyclohexylcyclohexane by Pd/C catalyzed hydrogenation reaction, which can be used in the production of polymers and other organic compounds.
2. Stable hexatrityl cations and porous organic polymers for applications in catalysis and gas storage, which can improve the efficiency of chemical reactions and provide efficient gas storage solutions.
3. Hexa-peri-hexabenzocoronene via one-pot substitution and oxidative cyclodehydrogenation reaction in the presence of t-BuCl/FeCl3, which can be used as a structural unit for the synthesis of polymers of intrinsic microporosity, offering potential applications in gas separation and storage.
Overall, hexaphenylbenzene is a valuable chemical intermediate with a wide range of applications in various industries, including the development of fluorescent nanorods for explosive detection, synthesis of stable cations and porous organic polymers for catalysis and gas storage, and the production of polymers with intrinsic microporosity for gas separation and storage.

Synthesis

Hexaphenylbenzene has been prepared by heating tetraphenylcyclopentadienone and diphenylacetylene without solvent and by trimerization of diphenylacetylene with bis-(benzonitrile)-palladium chloride and other catalysts. The reaction proceeds via a Diels-Alder reaction to give the hexaphenyldienone, which then eliminates carbon monoxide.Multi-Step Synthesis of hexaphenylbenzene from benzilProcedure: Add 0.8 g of tetraphenylcyclopentadienone, 0.8 g of diphenylacetylene (synthesized by you in CH 2270 lab last semester), and 4 g of benzophenone to a 25 mL round-bottom flask. Place a magnetic stir bar in the flask. Make sure no material lodges on the neck or walls of the flask. Attach the condenser to the round-bottom flask. Do not attach the hoses. The condenser will be used as an “air condenser” for this experiment. Heat the reaction mixture VERY HIGH with the sand bath on the hot plate/stirrer. Benzophenone is your solvent and its boiling point is over 300 °C! Heat the reaction mixture to reflux. Carbon monoxide is evolved, the purple color begins to fade in 15-20 minutes, and the color changes to a reddish brown in 25-30 minutes. When no further lightening in color is observed (after about 45 minutes), the heat is removed and 1 mL of diphenyl ether is added to prevent subsequent solidification of the benzophenone. The crystals that separate are brought into solution by reheating and the solution is let stand for crystallization at room temperature. The product is collected and washed free of brown solvent with toluene to give colorless plates.

InChI:InChI=1/C42H30/c1-7-19-31(20-8-1)37-38(32-21-9-2-10-22-32)40(34-25-13-4-14-26-34)42(36-29-17-6-18-30-36)41(35-27-15-5-16-28-35)39(37)33-23-11-3-12-24-33/h1-30H

Upstream product

• 56-23-5 tetrachloromethane 
• 4997-62-0 hexaphenyl-[3,3']bicycloprop-1-enyl 
• 501-65-5 diphenyl acetylene 
• 479-33-4 2,3,4,5-tetraphenylcyclopenta-2,4-dienone 
• 103-30-0 (E)-1,2-diphenyl-ethene 
• 19931-08-9 Bis-(1,2,3-triphenyl-cycloprop-2-enyl)-methanethione 
• 544-25-2 Cyclohepta-1,3,5-triene 
• 21289-08-7 (E,E)-(1,2,3,4-tetramethyl-1,3-butadien-1,4-ylidene)-dilithium 
• 201230-82-2 carbon monoxide 
• 59647-77-7 bis(3-methoxyphenyl)acetylene 
• 18169-72-7 trimethylsilyl isocyanide 
• 170651-17-9 6-phenylhex-5-yn-1-yl acetate 
• 16510-49-9 1,2,3-triphenylcyclopropene 
• 98-07-7 Benzotrichlorid 

Downstream Products

• 190-24-9 hexabenzocoronene 
• 103692-62-2 9,18-diohenyltetrabenzanthracene 
• 19057-50-2 4,4''-dibromo-3',4',5',6'-tetrakis(4-bromophenyl)-1,1':2',1''-terphenyl 
• 116172-84-0 tricarbonyl(hexaphenylbenzene)chromium⁽⁰⁾ 
• 1027097-67-1 1,3-diaxial-2,4,5,6-tetraequatorial-hexaphenylcyclohexane 
• 1027097-66-0 all-cis-1,2,3,4,5,6-hexaphenylcyclohexane 
• 124-38-9 carbon dioxide 
• 701915-34-6 phenyl(3',4',5',6'-tetraphenyl-[1,1':2',1''-terphenyl]-4-yl)methanone 

Relevant academic research and scientific papers

Synthesis and fluorescence of 3,4,6,7,8,9-hexaphenyl-1H-benzo[g]isochromen-1-one

Highly step- and atom-economic synthetic route to 3,4,6,7,8,9-hexaphenyl-1H-benzo[g]isochromen-1-one (1) based on the rhodium catalyzed reaction of terephthalic acid with diphenylacetylene was developed. The best catalytic system for this reaction is [CpRhI2]n/Cu(OAc)2. Compound 1 shows fluorescent properties with a strong Stokes shift.

Stabilization of a two-coordinate mononuclear cobalt(0) compound

Compound (Me2-cAAC:)2Co0 (2; Me 2-cAAC:=cyclic (alkyl) amino carbene;:C(CH2)(CMe 2)2N-2,6-iPr2C6H3) was synthesized by the reduction of the precursor (Me2-cAAC:) 2CoICl (1) with KC8 in THF. The cyclic voltammogram of 1 exhibited one-electron reduction, which suggests that synthesis of a bent 2-metallaallene (2) from 1 should be possible. Compound 2 contains one cobalt atom in the formal oxidation state zero, which is stabilized by two Me2-cAAC: ligands. Bond lengths from X-ray diffraction are 1.871(2) and 1.877(2)? with a C-Co-C bond angle of 170.12(8)?. The EPR spectrum of 2 exhibited a broad resonance attributed to the unique quasi-linear structure, which favors near degeneracy and gives rise to very rapid relaxation conditions. The cAAC-Co bond in 2 can be considered as a typical Dewar-Chatt-Duncanson type of bonding, which in turn retains 2.5electron pairs on the Co atom as nonbonding electrons.

Quasilinear 3d-metal(i) complexes [KM(N(Dipp)SiR3)2] (M = Cr-Co) - structural diversity, solution state behaviour and reactivity

The synthesis and characterization of neutral quasilinear 3d-metal(i) complexes of chromium to cobalt of the type [KM(N(Dipp)SiMe3)2] (Dipp = 2,6-di-iso-propylphenyl) are reported. In solid state these metal(i) complexes either occur as isolated molecules (Co) or are part of a potassium ion linked 1D-coordination polymer (Cr-Fe). In solution the potassium cation is either ligated within the ligand sphere of the metal silylamide or is separated from the complex depending on the solvent. For iron, we showcase that it is possible to use sodium or lithium metal for the reduction of the metal(ii) precursor. However, in these cases the resulting iron(i) complexes can only be isolated upon cation separation using an appropriate crown-ether. Further, the neutral metal(i) complexes are used to introduce NBu4+as an organic cation in the case of cobalt and iron. The impact of the intramolecular cation complexation was further demonstrated upon reaction with diphenyl acetylene which leads to bond formation processes and redox disproportionation instead of η2-alkyne complex formation.

Deactivation of the cobalt catalyst for the cyclotrimerization of acetylenes in ionic liquids: Solvent effects on the mechanism and thermal and pressure activation parameters

The deactivation reaction of the [CoCp(1,4-σ-C4[Ph] 4)PPh3] catalyst for the cyclotrimerization of acetylenes has been kinetico-mechanistically studied under different temperature, pressure, and solvent conditions. The results indicate a dramatic change in mechanism from conventional to ionic liquid solvents due to the polarity of the medium.

Formation of a Naphthalene Framework by Rhodium(III)-Catalyzed Double C-H Functionalization of Arenes with Alkynes: Impact of a Supporting Ligand and an Acid Additive

An efficient protocol has been developed for the synthesis of larger condensed arenes from aromatic hydrocarbons and internal alkynes. This protocol uses readily available [CpRhI2]nas a catalyst and Cu(OAc)2as an oxidant and proceeds smoothly through undirected double C-H activation. The addition of trifluoroacetic acid has a crucial positive impact on the reaction selectivity and the yields of the target products. In contrast to the previously reported catalytic systems, the new conditions allow the use of both dialkyl- and diarylacetylenes with the same high efficiency.

Case Study of N-iPr versus N-Mes Substituted NHC Ligands in Nickel Chemistry: The Coordination and Cyclotrimerization of Alkynes at [Ni(NHC)2]

A case study on the effect of the employment of two different NHC ligands in complexes [Ni(NHC)2] (NHC=iPr2ImMe 1Me, Mes2Im 2) and their behavior towards alkynes is reported. The reaction of a mixture of [Ni2(iPr2ImMe)4(μ-(η2 : η2)-COD)] B/ [Ni(iPr2ImMe)2(η4-COD)] B’ or [Ni(Mes2Im)2] 2, respectively, with alkynes afforded complexes [Ni(NHC)2(η2-alkyne)] (NHC=iPr2ImMe: alkyne=MeC≡CMe 3, H7C3C≡CC3H7 4, PhC≡CPh 5, MeOOCC≡CCOOMe 6, Me3SiC≡CSiMe3 7, PhC≡CMe 8, HC≡CC3H7 9, HC≡CPh 10, HC≡C(p-Tol) 11, HC≡C(4-tBu-C6H4) 12, HC≡CCOOMe 13; NHC=Mes2Im: alkyne=MeC≡CMe 14, MeOOCC≡CCOOMe 15, PhC≡CMe 16, HC≡C(4-tBu-C6H4) 17, HC≡CCOOMe 18). Unusual rearrangement products 11 a and 12 a were identified for the complexes of the terminal alkynes HC≡C(p-Tol) and HC≡C(4-tBu-C6H4), 11 and 12, which were formed by addition of a C?H bond of one of the NHC N-iPr methyl groups to the C≡C triple bond of the coordinated alkyne. Complex 2 catalyzes the cyclotrimerization of 2-butyne, 4-octyne, diphenylacetylene, dimethyl acetylendicarboxylate, 1-pentyne, phenylacetylene and methyl propiolate at ambient conditions, whereas 1Me is not a good catalyst. The reaction of 2 with 2-butyne was monitored in some detail, which led to a mechanistic proposal for the cyclotrimerization at [Ni(NHC)2]. DFT calculations reveal that the differences between 1Me and 2 for alkyne cyclotrimerization lie in the energy profile of the initiation steps, which is very shallow for 2, and each step is associated with only a moderate energy change. The higher stability of 3 compared to 14 is attributed to a better electron transfer from the NHC to the metal to the alkyne ligand for the N-alkyl substituted NHC, to enhanced Ni-alkyne backbonding due to a smaller CNHC?Ni?CNHC bite angle, and to less steric repulsion of the smaller NHC iPr2ImMe.

Three-coordinate Bis(N-heterocyclic carbene)iron(0) complexes with alkene and alkyne ligation: Synthesis and characterization

The synthesis and characterization of the three-coordinate iron(0) complex [(IMesMe)2Fe(η2-CH2CHSiMe3)] (1, IMesMe = 1-(2′4′6′-trimethylphenyl)-3-methyl-2-ylidene) as well as its reactions with alkynes have been investigated. Complex 1 was prepared in 76% yield from the reaction of FeCl2 with two equiv. of IMesMe, one equiv. of CH2[dbnd]CHSiMe3, and two equiv. of KC8. The characterization data obtained from solution magnetic susceptibility measurement, single-crystal X-ray diffraction study, and 57Fe M?ssbauer spectroscopy, in combination with theoretical calculations suggest an S = 1 ground spin-state for 1 that has enhanced iron-to-alkene π-backdonation as compared to that in the bis(alkene) complex [(IPr)Fe(η2-CH2CHSiMe3)2] (IPr = 1,3-di-(2′6′-diisopropylphenyl)-2-ylidene). The equimolar reactions of 1 with the internal alkynes PhC[tbnd]CPh, EtC[tbnd]CEt, and PhC[tbnd]CMe yield the iron(0) alkyne complexes [(IMesMe)2Fe(η2-RCCR′)] (R = R′ = Ph, 2; R = R′ = Et, 3; R = Ph, R′ = Me, 4). In addition, the reaction of 1 with five equiv. of PhC[tbnd]CMe is found to give a paramagnetic cyclobutadiene iron complex [(IMesMe)2Fe(η4-C(Ph)C(CH3)C(Ph)C(CH3))] (5). The molecular structure and 57Fe M?ssbauer spectroscopy data indicate an S = 1 ground spin-state for 2–5. Complex 1 is an effective catalyst for cyclotrimerization reactions of internal alkynes R1C[tbnd]CR2 (R1 = R2 = Ph; R1 = R2 = Et; R1 = Me, R2 = Ph).

Three-Coordinate Iron(0) Complexes with N-Heterocyclic Carbene and Vinyltrimethylsilane Ligation: Synthesis, Characterization, and Ligand Substitution Reactions

Low-coordinate iron(0) species are implicated as intermediates in a range of iron-catalyzed organic transformations. Isolable iron(0) complexes with coordination numbers of less than four, however, are rarely known. In continuing with our interests in three-coordinate iron(0) complexes with N-heterocyclic carbene (NHC) and alkene ligation, we report herein the synthesis and ligand substitution reactivity of three-coordinate iron(0) complexes featuring monodentate alkene ligands, [(NHC)Fe(η2-vtms)2] (vtms = vinyltrimethylsilane, NHC = 1,3-bis(2′,6′-diisopropylphenyl)-imidazol-2-ylidene (IPr), 1; 1,3-bis(2′,6′-diisopropylphenyl)-4,5-tetramethylene-imidazol-2-ylidene (cyIPr), 2; 1,3-bis(2′,6′-diisopropylphenyl)-4,5,6,7-tetrahydro-1,3-diazepin-2-ylidene (7-IPr), 3). Complexes 1-3 were synthesized from the one-pot reactions of ferrous dihalides with the N-(2,6-diisopropylphenyl)-substituted NHC ligands, vtms, and KC8. Reactivity study of 1 revealed its facile ligand substitution reactions with terminal aryl alkynes, ketones, isocyanides, and CO, by which iron(0) complexes [(IPr)Fe(η2-HCCAr)] (Ar = Ph, 5; p-CH3C6H4, 6; 3,5-(CF3)2C6H3, 7), [(IPr)Fe(η2-OCPh2)2] (8), [(IPr)Fe(CNR)4] (R = 2,6-Me2C6H3, 9; But, 10), and (IPr)Fe(CO)4 (11) were prepared in good yields. These iron(0) complexes have been characterized by 1H NMR, solution magnetic susceptibility measurement, single-crystal X-ray diffraction study, 57Fe M?ssbauer spectroscopy, and elemental analysis. Characterization data and computational studies suggest S = 1 ground-spin states for three-coordinate iron(0) complexes 1-3 and 5-8 and S = 0 ground states for 9-11. Theoretical studies on the three-coordinate complexes 1, 6, and 8 indicated pronounced metal-to-ligand backdonation from occupied Fe 3d orbitals to the π* orbitals of the C= C, C=C, and C= O moieties of the πligands. In addition, 1 proved an effective precatalyst for the cyclotrimerization reaction of alkynes.

Exploration of [2 + 2 + 2] cyclotrimerisation methodology to prepare tetrahydroisoquinoline-based compounds with potential aldo-keto reductase 1C3 target affinity

Tetrahydroisoquinoline (THIQ) is a key structural component in many biologically active molecules including natural products and synthetic pharmaceuticals. Here, we report on the use of transition-metal mediated [2 + 2 + 2] cyclotrimerisation of alkynes to generate tricyclic THIQs with potential to selectively inhibit AKR1C3.

Group 4 Diarylmetallocenes as Bespoke Aryne Precursors for Titanium-Catalyzed [2 + 2 + 2] Cycloaddition of Arynes and Alkynes

Despite the ubiquity of reports describing titanium (Ti)-catalyzed [2 + 2 + 2] cyclotrimerization of alkynes, the incorporation of arynes into this potent manifold has never been reported. The in situ generation of arynes often requires fluoride, which instead will react with the highly fluorophilic Ti center, suppressing productive catalysis. Herein, we describe the use of group 4 diarylmetallocenes, CpR2MAr2 (CpR = C5H5, C5Me5; M = Ti, Zr), as aryne precursors for the Ti-catalyzed synthesis of substituted naphthalenes via coupling with 2 equiv of an alkyne. Fair-to-good yields of the desired naphthalene products could be obtained with 1% catalyst loadings, which is roughly an order of magnitude lower than similar reactions catalyzed by palladium or nickel. Additionally, naphthalenes find broad applications in the electronics, photovoltaics, and pharmaceutical industries, urging the discovery of more economic syntheses. These results indicate that aryne transfer from a CpR2M(?2-aryne) complex to another metal is a viable route for the introduction of aryne fragments into organometallic catalytic processes.