585-48-8

Basic information

• Product Name: 2,6-DI-TERT-BUTYLPYRIDINE
• Synonyms: Pyridine, 2,6-bis(1,1-dimethylethyl)-;Pyridine, 2,6-di-tert-butyl-;2,6-DI-T-BUTYLPYRIDINE;2,6-DI-TERT-BUTYLPYRIDINE;2,6-DI-TERT-BUTYLPYRIDINE, >=97%;2,6-DI-TERT-BUTYLPYRIDINE 97%;2,6-Bis(1,1-dimethylethyl)pyridine;2,6-Bis(tert-butyl)pyridine
• CAS NO: 585-48-8
• Molecular Formula: C₁₃H₂₁N
• Molecular Weight: 191.31
• EINECS: 209-557-6
• Product Categories: Pyridines, Pyrimidines, Purines and Pteredines;Heterocyclic Compounds;C9 to C46;Heterocyclic Building Blocks;Pyridines
• Mol File: 585-48-8.mol
• Article Data: 4

Chemical Properties

• Melting Point: 2°C(lit.)
• Boiling Point: 100-101 °C (23 mmHg)
• Flash Point: 72 °C
• Appearance: Clear yellow/Liquid
• Density: 0.852
• Vapor Pressure: 0.307mmHg at 25°C
• Refractive Index: 1.472-1.474
• Storage Temp.: 2-8°C
• Solubility: Chloroform (Slightly), Methanol (Slightly)
• PKA: 3.58(at 25℃)
• Water Solubility: Miscible with alcohol, acetone, and hexane. Immiscible with water.
• Stability: Stable. Combustible. Incompatible with strong acids, strong oxidizing agents.
• Merck: 14,3036
• BRN: 125886
• CAS DataBase Reference: 2,6-DI-TERT-BUTYLPYRIDINE(CAS DataBase Reference)
• NIST Chemistry Reference: 2,6-DI-TERT-BUTYLPYRIDINE(585-48-8)
• EPA Substance Registry System: 2,6-DI-TERT-BUTYLPYRIDINE(585-48-8)

Safety Data

• Hazard Codes: Xn,Xi
• Statements: 36/37/38-22
• Safety Statements: 37/39-26-36/37/39-36
• RIDADR: 3267
• WGK Germany: 3
• Hazardous Substances Data: 585-48-8(Hazardous Substances Data)

Usage

Description

2,6-Di-tert-butylpyridine (DTBP) is a weak base with the chemical formula C15H25N. It is a dark brown liquid and is known for its unusually low basicity due to steric hindrance to hydration of its protonated form, DTBPH+. This characteristic has attracted the interest of researchers for various applications in the field of chemistry.

Uses

Used in Chemical Synthesis:
2,6-Di-tert-butylpyridine is used as a proton scavenger to check the progress of the living polymerization of isobutylene. It is also involved in the preparation of vinyl triflate using polymer-bound 2,6-di-tert-butylpyridine.
Used in Organic Chemistry:
DTBP is associated with ceric ammonium nitrate (CAN) and used in the α-enolation of aldehydes, leading to the formation of 1,4-dicarbonyl systems. This reaction is important in the synthesis of various organic compounds.
Used in the Preparation of 2,6-di-tert-butylpyridine hydrotriflate:
2,6-Di-tert-butylpyridine is used in the preparation of its hydrotriflate derivative, which is a valuable intermediate in the synthesis of various chemical compounds.

Reference

H. C. BROWN and B. KANNERJ. Am. Chem. Soc. 75, 3865 (1953). E. M. ARNETT and B. CHAWLAJ. Am. Chem. Soc. 101, 7141 (1979). H.P.HOPKINSD,.V.JAHAGIRDAP.RS,.MOULIKD,.H.AUE, H. M. WEBB,W. R. DAVIDSON and M. D. PEDLEY. J.. Am. Chem. Soc. 106,4341 (1984). M. MEOT-NEaRnd L. W. SIECK J. Am. Chem. Soc. 105, 2956 (1983)

Purification Methods

Redistil it from KOH pellets. [Beilstein 20 III/IV 2868.]

InChI:InChI=1/C13H21N/c1-12(2,3)10-8-7-9-11(14-10)13(4,5)6/h7-9H,1-6H3

Synthetic route

2-tert-butylpyridine (5944-41-2) → 2,6-di-tert-butyl-pyridine (585-48-8)

Conditions	Yield
With diethyl ether; tert.-butyl lithium; Petroleum ether

1,2,6-trimethylpyridinium iodide (2525-19-1) + methyl iodide (74-88-4) → 2,6-di(isopropyl)pyridine (6832-21-9) + 2-isopropyl-6-t-butylpyridine (5402-34-6) + 2,6-di-tert-butyl-pyridine (585-48-8) + 2-ethyl-6-isopropyl pyridine (74701-47-6)

Conditions	Yield
With sodium hydride 1.) Dioxan, 80 deg C, 1 h, then 100 deg C, 3 h, then heating, 2 h, 2.) 250-270 deg C; Multistep reaction;
With sodium hydride 1.) Dioxan, 80 deg C, 1 h, then 100 deg C, then 3 h, heating, 2 h, 2.) 250-270 deg C; Multistep reaction;

2,6-di-tert-butylpiperidine (85237-75-8) → 2,6-di-tert-butyl-pyridine (585-48-8)

Conditions	Yield
at 170℃; for 1h;	40 %Spectr.

C39H49Cl2N3Ru + 2,6-di-tert-butylpyridinium tetrafluoroborate → 2,6-di-tert-butyl-pyridine (585-48-8) + C68H88Cl4N4Ru2 + pyridinium tetrafluoroborate

Conditions	Yield
In dichloromethane-d2 at 25℃; Equilibrium constant; Inert atmosphere; Sealed tube;

dichloro(N,N'-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene)(pyridine)ruthenium(II) + 2,6-di-tert-butylpyridinium tetrafluoroborate → 2,6-di-tert-butyl-pyridine (585-48-8) + C56H64Cl4N4Ru2 + pyridinium tetrafluoroborate

Conditions	Yield
In dichloromethane-d2 at -10℃; Equilibrium constant; Inert atmosphere; Sealed tube;

2,6-di-tert-butyl-pyridine (585-48-8) + 2C4H10O*C24BF20*H(1+) → 2,6-di-tert-butylpyridininum tetrakis(pentafluorophenyl)borate (1309604-77-0)

Conditions	Yield
In dichloromethane for 2h; Inert atmosphere;	95%

2,6-di-tert-butyl-pyridine (585-48-8) + sodium hexacarbonylvanadate (15602-41-2) → 2,6-di-t-butylpyridinium hexacarbonylvanadate (104437-79-8)

Conditions	Yield
In water N2-atmosphere; pH=4-5; filtration, drying (over P4O10, reduced pressure); elem. anal.;	93%

2,6-di-tert-butyl-pyridine (585-48-8) + (pentafluorophenyl)xenon(II) hexafluoroarsenate → [C6F5Xe(C5H3(C(CH3)3)2N)](1+)*[AsF6](1-)=[C6F5Xe(C5H3(C(CH3)3)2N)][AsF6] (175907-31-0)

Conditions	Yield
In dichloromethane; acetonitrile Ar atm.; 10% excess of base, stirring (-78°C), pptn.; decantation, washing (CH2Cl2, -78°C), drying (8 h, -40°C, 0.1 mbar);	92%
In water Ar atm.; equimolar ratio, stirring (0°C), pptn.; decantation, washing (CH2Cl2, 0°C), drying (8 h, -20°C, 0.1 mbar);	70%
In dichloromethane Ar atm.; 10% excess of base, stirring (-78°C, 3 h); decantation, washing (CH2Cl2, -40°C), drying (vac., 8 h, -40°C, 0.1 mbar);	61%

2,6-di-tert-butyl-pyridine (585-48-8) + trifluoromethylsulfonic anhydride (358-23-6) + 2-(4-(N-methyl-N-tert-butoxycarbonylamino)phenyl)benzo[d]thiazol-6-ol (1301256-39-2) → 2-(4-(N-methyl-N-tert-butoxycarbonylamino)phenyl)-6-trifluoromethanesulfonyloxybenzo[d]thiazole

Conditions	Yield
In dichloromethane at 20℃; for 0.5h; Inert atmosphere;	92%

2,6-di-tert-butyl-pyridine (585-48-8) + trifluorormethanesulfonic acid (1493-13-6) → 2,6-di-tert-butylpyridin-1-ium trifluoromethanesulfonate (134967-72-9)

Conditions	Yield
In dichloromethane at 20℃;	91%
In dichloromethane at 0℃; for 0.0833333h;	90%
In dichloromethane at 22 - 26℃; for 0.75h; Inert atmosphere;	90%

2,6-di-tert-butyl-pyridine (585-48-8) + trimethoxonium tetrafluoroborate (420-37-1) + (6-but-3-enyl-2-hydroxypyridin-3-yl)carbamic acid benzyl ester (343566-71-2) → (6-but-3-enyl-2-methoxypyridin-3-yl)carbamic acid benzyl ester (343566-72-3)

Conditions	Yield
In dichloromethane; ethyl acetate	91%

2,6-di-tert-butyl-pyridine (585-48-8) + 1,1,1,2,2,2-hexamethyldisilane (1450-14-2) → C16H29NSi

Conditions	Yield
With potassium tert-butylate In tetrahydrofuran at 65℃; Inert atmosphere;	90%

tetrafluoroboric acid diethyl ether (67969-82-8) + 2,6-di-tert-butyl-pyridine (585-48-8) → 2,6-di-tert-butylpyridinium tetrafluoroborate

Conditions	Yield
In diethyl ether at 0℃; for 0.166667h; Inert atmosphere;	89%

2,6-di-tert-butyl-pyridine (585-48-8) + bis(pinacol)diborane (73183-34-3) → 2,6-di-tert-butyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (1392146-23-4)

Conditions	Yield
With (1,5-cyclooctadiene)(methoxy)iridium(I) dimer; 4,4'-di-tert-butyl-2,2'-bipyridine In tert-butyl methyl ether at 80℃; for 0.5h; Microwave irradiation;	88%
Stage #1: bis(pinacol)diborane With (1,5-cyclooctadiene)(methoxy)iridium(I) dimer; 4,4'-di-tert-butyl-2,2'-bipyridine In hexane at 55℃; for 0.5h; Inert atmosphere; Stage #2: 2,6-di-tert-butyl-pyridine In hexane at 55℃; for 72h; Inert atmosphere;	82%
Stage #1: bis(pinacol)diborane With 4,4'-di-tert-butyl-2,2'-bipyridine; (1,5-cyclooctadiene)(methoxy)iridium(I) dimer In methyl t-butylether Inert atmosphere; Sealed vial; Stage #2: 2,6-di-tert-butyl-pyridine In methyl t-butylether at 80℃; for 2h;	60%

2,6-di-tert-butyl-pyridine (585-48-8) + (4-nitrophenyl) formate (1865-01-6) + (5S)-N-((3-(4-amino-3-fluorophenyl)-2-oxo-1,3-oxazolidin-5-yl)methyl)acetamide (181997-31-9) → 5-(S)-Acetamidomethyl-3-[4'-formamido-3'-fluorophenyl]oxazolidine-2-one (324788-61-6)

Conditions	Yield
In tetrahydrofuran; 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran; acetone	85%

(S)-N-[3-[3-fluoro-4-N-methylaminophenyl]-2-oxo-5-oxazolidinylmethyl]acetamide (324788-63-8) + 2,6-di-tert-butyl-pyridine (585-48-8) + (4-nitrophenyl) formate (1865-01-6) → 5-(S)-acetamidomethyl-3-[4'-(N-methylformamido)-3'-fluorophenyl]oxazolidine-2-one (324788-66-1)

Conditions	Yield
In tetrahydrofuran	85%

2,6-di-tert-butyl-pyridine (585-48-8) + phenacyl 3-hydroxy-2-n-tetradecyl-11-icosenoate + t-butyldimethylsiyl triflate (69739-34-0) → phenacyl 3-(t-butyldimethylsilyloxy)2-n-tetradecyl-11-icosenoate

Conditions	Yield
In dichloromethane; water	82.6%

N-bromosaccharin (35812-01-2) + 2,6-di-tert-butyl-pyridine (585-48-8) → C20H24N2O3S

Conditions	Yield
In dichloromethane at 20℃; for 24h; Inert atmosphere; Irradiation; chemoselective reaction;	79%

2,6-di-tert-butyl-pyridine (585-48-8) + [ReOCl3(OPPh3)(SMe2)] (108695-90-5, 178232-84-3, 186843-76-5) + 2-(2′-hydroxyphenyl)-2-thiazoline (101821-30-1) → C9H8Cl3NO2ReS(1-)*C13H22N(1+)

Conditions	Yield
In ethanol at 78℃; for 0.25h;	78%

2,6-di-tert-butyl-pyridine (585-48-8) + 2-(2'-Hydroxyphenyl)-2-oxazolin (20237-92-7) + [ReOCl3(OPPh3)(SMe2)] (108695-90-5, 178232-84-3, 186843-76-5) → C9H8Cl3NO3Re(1-)*C13H22N(1+)

Conditions	Yield
In ethanol at 78℃; for 0.25h;	76%

(4R)-2-phenyl-1,3-thiazolidine-4-carboxylic acid (196930-46-8) + trifluoro-[1,3,5]triazine (675-14-9) + 2,6-di-tert-butyl-pyridine (585-48-8) + 1-Naphthoxyacetic acid (2976-75-2) → (2RS,4R)-3-((1-naphthyloxy)acetyl)-2-phenylthiazolidine-4-carboxylic acid

Conditions	Yield
With pyridine In C2Cl2; dichloromethane	75%

2,6-di-tert-butyl-pyridine (585-48-8) + potassium (3-hydroxy-3-methylbut-1-yl)trifluoroborate → C18H31NO

Conditions	Yield
With manganese(III) triacetate dihydrate; acetic acid; trifluoroacetic acid In 2,2,2-trifluoroethanol at 60℃; for 4h; Minisci Aromatic Substitution; Schlenk technique; Inert atmosphere;	74%

2,6-di-tert-butyl-pyridine (585-48-8) + 2-methyl-1-butanethiol (20089-07-0, 110549-12-7, 1878-18-8) → 2,6-di-tert-butyl-4-pyridyl 2-methyl-1-butyl sulfide

Conditions	Yield
Stage #1: 2,6-di-tert-butyl-pyridine With (1,5-cyclooctadiene)(methoxy)iridium(I) dimer; bis(pinacol)diborane; 4,4'-di-tert-butyl-2,2'-bipyridine In tetrahydrofuran at 80℃; for 24h; Schlenk technique; Inert atmosphere; Stage #2: 2-methyl-1-butanethiol With pyridine; copper diacetate In N,N-dimethyl-formamide at 120℃; for 24h; Schlenk technique; Inert atmosphere; regioselective reaction;	72%

methanol (67-56-1) + 2,6-di-tert-butyl-pyridine (585-48-8) → 2,6-di-tert-butyl-4-methylpyridine (38222-83-2)

Conditions	Yield
With hydrogenchloride; 2,4-diphenylquinoline In water for 24h; Inert atmosphere; UV-irradiation;	71%

2,6-di-tert-butyl-pyridine (585-48-8) + 4,4'-dichlorodiphenyl disulfide (1142-19-4) → 2,6-di-tert-butyl-4-pyridyl 4-chlorophenyl sulfide (1393715-67-7)

Conditions	Yield
Stage #1: 2,6-di-tert-butyl-pyridine With (1,5-cyclooctadiene)(methoxy)iridium(I) dimer; bis(pinacol)diborane; 4,4'-di-tert-butyl-2,2'-bipyridine In tetrahydrofuran at 80℃; for 24h; Inert atmosphere; Stage #2: 4,4'-dichlorodiphenyl disulfide With [2,2]bipyridinyl; copper(l) chloride In water; dimethyl sulfoxide at 80℃; for 24h; Inert atmosphere; regioselective reaction;	68%

2,6-di-tert-butyl-pyridine (585-48-8) + diphenyl diselenide (1666-13-3) → 2,6-di-tert-butyl-4-pyridyl phenyl selenide

Conditions	Yield
Stage #1: 2,6-di-tert-butyl-pyridine With (1,5-cyclooctadiene)(methoxy)iridium(I) dimer; bis(pinacol)diborane; 4,4'-di-tert-butyl-2,2'-bipyridine In tetrahydrofuran at 80℃; for 24h; Schlenk technique; Inert atmosphere; Stage #2: diphenyl diselenide With pyridine; copper diacetate In N,N-dimethyl-formamide at 120℃; for 24h; Schlenk technique; Inert atmosphere; regioselective reaction;	66%

2,6-di-tert-butyl-pyridine (585-48-8) + tert-butylisonitrile (119072-55-8, 7188-38-7) → N,2,6-tri-tert-butylisonicotinamide

Conditions	Yield
With sodium persulfate In acetonitrile at 120℃; for 24h; Sealed tube;	66%

2,6-di-tert-butyl-pyridine (585-48-8) + Cyclohexanecarboxylic acid (98-89-5) → 2,6-di-tert-butyl-4-cyclohexylpyridine

Conditions	Yield
With hydrogenchloride; cerium(III) chloride heptahydrate; tetrabutyl-ammonium chloride In 2,2,2-trifluoroethanol; water for 17h; Schlenk technique; Inert atmosphere; Electrochemical reaction; Irradiation;	63%

2,6-di-tert-butyl-pyridine (585-48-8) + anthranilic acid nitrile (1885-29-6) → Dimethyl N-[2-(cyano)phenyl]-(S)-aspartate

Conditions	Yield
In CH3 Cl; hexane	62%
In CH3Cl; CH3Cl-hexane; hexane	62%

2,6-di-tert-butyl-pyridine (585-48-8) + (1-diazo-2-ethoxy-2-oxoethyl)(2-(2-ethoxy-2-oxoethoxy)carbonylphenyl)iodonium trifluoromethanesulfonate → C17H25N3O2

Conditions	Yield
With tris(2,2-bipyridine)ruthenium(II) hexafluorophosphate; sodium hydrogencarbonate In acetonitrile at 20℃; for 2h; Irradiation;	56%

2,6-di-tert-butyl-pyridine (585-48-8) + 1-dodecylthiol (112-55-0) → 2,6-di-tert-butyl-4-pyridyl dodecyl sulfide

Conditions	Yield
Stage #1: 2,6-di-tert-butyl-pyridine With (1,5-cyclooctadiene)(methoxy)iridium(I) dimer; bis(pinacol)diborane; 4,4'-di-tert-butyl-2,2'-bipyridine In tetrahydrofuran at 80℃; for 24h; Schlenk technique; Inert atmosphere; Stage #2: 1-dodecylthiol With pyridine; copper diacetate In N,N-dimethyl-formamide at 120℃; for 24h; Schlenk technique; Inert atmosphere; regioselective reaction;	53%
Stage #1: 2,6-di-tert-butyl-pyridine With (1,5-cyclooctadiene)(methoxy)iridium(I) dimer; bis(pinacol)diborane; 4,4'-di-tert-butyl-2,2'-bipyridine In tert-butyl methyl ether at 80℃; for 1h; Inert atmosphere; Glovebox; Microwave irradiation; Stage #2: 1-dodecylthiol With pyridine; copper diacetate In N,N-dimethyl-formamide at 120℃; for 1.5h; Inert atmosphere; Microwave irradiation; regioselective reaction;	46%

2,6-di-tert-butyl-pyridine (585-48-8) + dimethyl diselenide (7101-31-7) → 2,6-di-tert-butyl-4-pyridyl methyl selenide

Conditions	Yield
Stage #1: 2,6-di-tert-butyl-pyridine With (1,5-cyclooctadiene)(methoxy)iridium(I) dimer; bis(pinacol)diborane; 4,4'-di-tert-butyl-2,2'-bipyridine In tetrahydrofuran at 80℃; for 24h; Schlenk technique; Inert atmosphere; Stage #2: dimethyl diselenide With pyridine; copper diacetate In N,N-dimethyl-formamide at 120℃; for 24h; Schlenk technique; Inert atmosphere; regioselective reaction;	53%

phthalimide (136918-14-4) + 2,6-di-tert-butyl-pyridine (585-48-8) → 2-(2,6-di-tert-butylpyridin-3-yl)isoindoline-1,3-dione (1620204-80-9)

Conditions	Yield
With [bis(acetoxy)iodo]benzene; iodine In dichloromethane at 20℃; for 12h; Irradiation;	53%

2,6-di-tert-butyl-pyridine (585-48-8) + tri-n-butylstannylmethanol (27490-33-1) + methyl trifluoromethanesulfonate (333-27-7) + tert-Butyl-((3aR,6R,7S,7aR)-6-ethylsulfanyl-2,2-dimethyl-tetrahydro-[1,3]dioxolo[4,5-c]pyran-7-yloxy)-dimethyl-silane (207741-57-9) → (C4H9)3SnCH2OC8H12O3OH + (C4H9)3SnCH2OC8H12O3OH

Conditions	Yield
In diethyl ether; dichloromethane Ar atmosphere; addn. of Sn-compd., butylpyridine, molecular seives and MeOTf to soln. of thioglycoside (stirring, 0°C, 12 h); concn. (vac.), chromy. (hexanes/EtOAc = 98:2), dissolving in THF, addn.of TBAF, stirring (2 h, room temp.), solvent removal (reduced pressure), chromy. (hexanes/EtOAc = 80:20);	A 45% B n/a

2,6-di-tert-butyl-pyridine (585-48-8) + tetrakis(acetonitrile)palladium(II) tetrafluoroborate (21797-13-7) + nitromethane (75-52-5) → Pd(2,6-t-Bu2C5H2N)2(MeNO2)2(BF4)2

Conditions

Yield

With styrene In nitromethane byproducts: polystyrene; dropwise addn. of 2,6-di-tert-butylpyridine to stirred soln. of Pd complex in CH3NO2, under anaerobic conditions; addn. of styrene after 1 d; stirring for 1 d;; filtration; addn. of (C2H5)2O/pentane; isolation of bottom layer; dissolving in small amt. of CH3NO2; pptn. by addn. of benzene/(C2H5)2O/pentane; pptn. in about 20 min; washing with pentane; drying under vac.; elem. anal.; detn. by gas chromy.;;

44%

Upstream product

• 5944-41-2 2-tert-butylpyridine 
• 85237-75-8 2,6-di-tert-butylpiperidine 
• 2525-19-1 1,2,6-trimethylpyridinium iodide 
• 74-88-4 methyl iodide 

Downstream Products

• 109-06-8 α-picoline 
• 62907-61-3 2,6-di-tert-butylpyridinium ion 
• 644-98-4 2-isopropylpyridine 
• 108-48-5 2,6-dimethylpyridine 
• 87-85-4 hexamethylbenzene radical cation 
• 935-28-4 2,6-diethylpyridine 
• 66922-18-7 cis-2,6-di-tert-butylpiperidine 
• 343566-72-3 (6-but-3-enyl-2-methoxypyridin-3-yl)carbamic acid benzyl ester 
• 329901-37-3 (R)-N-(4-[Anilinosulphonyl]-2,5-dimethoxyphenyl)-3,3,3-trifluoro-2-hydroxy-2-methylpropanamide 
• 329901-38-4 (R)-N-(2,5-Dimethoxy-4-[dimethylaminosulphonyl]phenyl)-3,3,3-trifluoro-2-hydroxy-2-methylpropanamide 
• 242139-87-3 (R)-N-[2-chloro-4-iodophenyl]-2-hydroxy-2-methyl-3,3,3-trifluoropropanamide 
• 324788-61-6 5-(S)-Acetamidomethyl-3-[4'-formamido-3'-fluorophenyl]oxazolidine-2-one 
• 324788-66-1 5-(S)-acetamidomethyl-3-[4'-(N-methylformamido)-3'-fluorophenyl]oxazolidine-2-one 
• 869954-98-3 [N-(2,6-diisopropylphenyl)-2-(2,6-diisopropylphenylimino)propanamidato-κ2N,N](η3-benzyl)nickel 

Relevant articles and documents

Examining the Effects of Monomer and Catalyst Structure on the Mechanism of Ruthenium-Catalyzed Ring-Opening Metathesis Polymerization

The mechanism of Ru-catalyzed ring-opening metathesis polymerization (ROMP) is studied in detail using a pair of third generation ruthenium catalysts with varying sterics of the N-heterocyclic carbene (NHC) ligand. Experimental evidence for polymer chelation to the Ru center is presented in support of a monomer-dependent mechanism for polymerization of norbornene monomers using these fast-initiating catalysts. A series of kinetic experiments, including rate measurements for ROMP, rate measurements for initiation, monomer-dependent kinetic isotope effects, and activation parameters were useful for distinguishing chelating and nonchelating monomers and determining the effect of chelation on the polymerization mechanism. The formation of a chelated metallacycle is enforced by both the steric bulk of the NHC and by the geometry of the monomer, leading to a ground-state stabilization that slows the rate of polymerization and also alters the reactivity of the propagating Ru center toward different monomers in copolymerizations. The results presented here add to the body of mechanistic work for olefin metathesis and may inform the continued design of catalysts for ROMP to access new polymer architectures and materials.

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Efficient hydrogen storage is one of the critical requirements for the use of hydrogen fuel cells in light-duty vehicles. Our investigation of reversible chemical hydrogen storage systems has led to the development of a mixed endothermic-exothermic carrier system. Herein we further investigate the factors affecting the dehydrogenation rate of these carriers. A range of heterogeneous catalysts was synthesized via sol-gel methodology and their activity for indoline dehydrogenation was assessed. Metals used included Fe, Co, Ni, Cu, Ru, Rh, Pd, Ir and Pt. SiO2, Al2O3, TiO2 and ZrO2 were used as supports and Pd/SiO2 gave the highest conversion over a fixed time. A marked increase in the rate of indoline dehydrogenation was observed when the temperature was increased between 100 and 180 °C, with measured first order rate constants of 1.8 × 10 -4 s-1 at 100 °C and 5.9 × 10-4 at 120 °C. Although piperidines dehydrogenate more slowly than indolines, steric hindrance around the nitrogen atom in piperidine increases its dehydrogenation rate significantly.