Bulky Cyclohexyl Groups Research Articles

High-Performance Anion Exchange Membrane Water Electrolyzers Enabled by Highly Gas Permeable and Dimensionally Stable Anion Exchange Ionomers.

Designing suitable anion exchange ionomers is critical to improving the performance and in situ durability of anion exchange membrane water electrolyzers (AEMWEs) as one of the promising devices for producing green hydrogen. Herein, highly gas-permeable and dimensionally stable anion exchange ionomers (QC6xBA and QC6xPA) are developed, in which bulky cyclohexyl (C6) groups are introduced into the polymer backbones. QC650BA-2.1 containing 50mol% C6 composition shows 16.6 times higher H2 permeability and 22.3 times higher O2 permeability than that of QC60BA-2.1 without C6 groups. Through-plane swelling of QC650BA-2.1 decreases to 12.5% from 31.1% (QC60BA-2.1)while OH- conductivity slightly decreases (64.9 and 56.2mScm-1 for QC60BA-2.1 and QC650BA-2.1, respectively, at 30 °C). The water electrolysis cell using the highly gas permeable QC650BA-2.1 ionomer and Ni0.8Co0.2O in the anode catalyst layer achieves two times higher performance (2.0Acm-2 at 1.69V, IR-included) than those of the previous cell using in-house ionomer (QPAF-4-2.0) (1.0Acm-2 at 1.69V, IR-included). During 1000h operation at 1.0Acm-2, the QC650BA-2.1 cell exhibits nearly constant cell voltage with a decay rate of 1.1µVh-1 after the initial increase of the cell voltage, proving the effectiveness of the highly gas permeable and dimensionally stable ionomer in AEMWEs.

Preparation of biphenyl-containing polybenzoxazines with low dielectric constants and high thermal stability

In this work, two biphenyl-containing benzoxazine monomers (C-tfmb and C-dmb) have been synthesized using 2,2′-bis(trifluoromethyl)benzidine/2,2′-dimethylbenzidine, 4-cyclohexylphenol and paraformaldehyde as raw materials. The thermal curing behaviors of the benzoxazine monomers were investigated by Fourier transform infrared spectroscopy and non-isothermal differential scanning calorimetry. After curing, the biphenyl-containing polybenzoxazines (PC-tfmb and PC-dmb) exhibited high thermal stability with the 5% weight loss temperatures at 335 °C and 367 °C, respectively. Moreover, both polybenzoxazine films showed high hydrophobicity and low dielectric properties. Due to the presence of low-polarity and bulky cyclohexyl and trifluoromethyl groups, PC-tfmb had a dielectric constant of 2.78 and a dielectric loss of 0.0035 at 1 MHz.

Methane Borylation Catalyzed by Ru, Rh, and Ir Complexes in Comparison with Cyclohexane Borylation: Theoretical Understanding and Prediction.

Methane borylation catalyzed by Cp*M(Bpin)n (M = Ru or Rh; HBpin = pinacolborane; n = 2 or 3) and (TMPhen)Ir(Bpin)3 (TMPhen = 3,4,7,8-tetramethyl-1,10-phenanthroline) was investigated by DFT in comparison with cyclohexane borylation. Because Ru-catalyzed borylation has not been theoretically investigated yet, its reaction mechanism was first elucidated; Cp*Ru(Bpin)3 1-Ru is an active species, and Cp*Ru(Bpin)3(H)(CH3) 4-Ru is a key intermediate. In 4-Ru, the Ru is understood to have an ambiguous oxidation state between +IV and +VI because it has a H··Bpin bonding interaction with a bond order of about 0.5. Methane borylation occurs through oxidative addition of methane C-H bond followed by reductive elimination of borylmethane in all of these catalysts. The catalytic activity for methane borylation increases following the order Cp*Ru(Bpin)3 < (TMPhen)Ir(Bpin)3 < Cp*Rh(Bpin)2. Cyclohexane borylation occurs in the same mechanism except for the presence of isomerization of a key intermediate. Chemoselectivity of methane over cyclohexane increases following the order Ir < Ru < Rh. In all of these catalysts, the rate-determining step (RDS) of cyclohexane borylation needs a larger ΔG°‡ than the RDS of methane borylation because the more bulky cyclohexyl group induces larger steric repulsion with the ligand than methyl. One reason for the worse chemoselectivity of the Ir catalyst is its less congested transition state of the reductive elimination of borylcyclohexane. Herein, use of a strongly electron-donating ligand consisting of pyridine and N-heterocyclic carbene with bulky substituents is computationally proposed as a good ligand for the Ir catalyst; actually, the Ir complex of this ligand is calculated to be more active and more chemoselective than Cp*Rh(Bpin)2 for methane borylation.

How To Perform Suzuki–Miyaura Reactions of Nitroarene or Nitrations of Bromoarene Using a Pd0 Phosphine Complex: Theoretical Insight and Prediction

Pd0(BrettPhos) (1) was experimentally applied to Suzuki–Miyaura reactions of nitroarenes which occur through oxidative addition of nitroarene (ArNO2) to Pd0. On the other hand, Pd0(tBu-BrettPhos) (2) was experimentally applied to nitrations of bromoarenes which occur through reductive elimination of nitroarene. DFT calculations disclosed that oxidative addition of 4-nitroanisole to 1 was exergonic but that to 2 was endergonic, indicating that 1 is useful for oxidative addition of an Ar–NO2 bond but 2 is useful for reductive elimination of an Ar–NO2 bond. This difference in reactivity between 1 and 2 is explained in that bulky tBu groups on tBu-BrettPhos destabilize the PdII complex PdII(Ar)(NO2)(tBu-BrettPhos) due to large steric repulsion between Ar and tBu-BrettPhos but less bulky cyclohexyl groups on BrettPhos do not. It is theoretically predicted here that NMe2-substituted BrettPhos is better for Ar–NO2 bond cleavage than BrettPhos but xyl-BrettPhos is good for Ar–NO2 formation, as is tBu-BrettPhos, w...

Mechanism of Ligand-Controlled Regioselectivity-Switchable Copper-Catalyzed Alkylboration of Alkenes.

Cu-catalyzed alkylboration of alkenes with bis(pinacolato)diboron ((Bpin)2 ) and alkyl halides provides a ligand-controlled regioselectivity-switchable method for the construction of complex boron-containing compounds. Here, we employed DFT methods to elucidate the mechanistic details of this reaction and the origin of the different regioselectivity induced by Xantphos and Cy-Xantphos. The calculation results reveal that the catalytic cycle mainly proceeds through the migratory insertion of alkenes on Cu-Bpin complex, the oxidative addition of alkyl halides, and the reductive elimination of a C-C bond. Meanwhile, the rate- determining step is the oxidative addition of alkyl halides and the regioselectivity-determining step is the migratory insertion of alkenes. The bulky cyclohexyl group of Cy-Xantphos facilitates the approach of the substituents of alkenes to Bpin in the migratory insertion step and thus leads to the Markovnikov products. The less bulky phenyl group on Xantphos prefers keeping the substituents of alkenes away from the Bpin moiety in the migratory insertion step and thus results in anti-Markovnikov products.

Exploration of benzamidochromenone derivatives with conformational restrictor as interleukin-5 inhibitors

Novel amidochromen-4-one analogs 8a–k and 9a–f were prepared and studied for their IL-5 inhibitory activity. Among the synthesized compounds, (6-benzamido-2-cyclohexyl-4-oxo-4H-chromen-3-yl)methyl acetate (8a, 95% inhibition at 30μM, IC50=6.1μM) exhibited potent IL-5 inhibitory activity. The conformational restrictor at position 2 like bulky cyclohexyl group is favorable for the formation of effective conformer of side chain small ester like acetoxymethyl at position 3 of these chromenone analogs 8. In addition the hydrophobic planarity of benzamido group at position 6 should be important for the potent IL-5 inhibitory activity. Since replacing acetoxymethyl moiety with hydroxymethyl group at position 3 of chromenone decreases the activity, which indicates that the location of hydrogen bonding group should be near 4 atom distances away from chromenone ring is more optimum for the activity. Therefore, these benzamidochromen-4-one analogs 8 are novel scaffold for finding potent interleukin-5 inhibitors.

Unusual stability of reaction intermediates in ortho-metalation reactions of dicyclohexylphenylphosphane with dirhodium(II) tetraacetate

Reaction of dirhodium(II) tetraacetate with 1 molar equivalent of dicyclohexylphenylphosphane afforded the complex [Rh2(μ-O2CCH3)3{μ-(C6H4)PCy2}(CH3COOH)2] (1) in which the phosphane ligand is coordinated to the rhodium atoms in a bridging ortho-metalated mode. As a second product, [Rh2(μ-O2CCH3)3{μ-(C6H4)PCy2}(CH3COOH)(PhPCy2)] (2) was isolated from the same reaction. 2 proved to be unusually stable toward further reaction to a doubly ortho-metalated complex which has been accessible in the reaction of dirhodium(II) tetraacetate with other phosphane ligands. However, doubly ortho-metalated [Rh2(μ-O2CCH3)2{μ-(C6H4)PCy2}2(CH3COOH)2] (4) was isolated in low yield after a prolonged thermal reaction between dirhodium(II) tetraacetate and 2 equivalents of PhPCy2. Exchange of the bridging acetate ligands in 1 and 4 by trifluoroacetate ligands afforded [Rh2(μ-O2CCF3)3{μ-(C6H4)PCy2}(CF3COOH)2] (5) and [Rh2(μ-O2CCF3)2{μ-(C6H4)PCy2}2(CF3COOH)2] (7a). Complex 7a without axial ligands, [Rh2(μ-O2CCF3)2{μ-(C6H4)PCy2}2] (7b) was isolated, as well. The crystal structure of complex 5 was determined showing consequences of the bulky cyclohexyl groups on several structural parameters.

The preparation of multimetallic complexes using sterically bulky N-centred tripodal dialkyl phosphino ligands

Sterically bulky monodentate and bidentate phosphines have been widely used as ligands for metal complexation and catalyst formation. Bulky tridentate phosphine ligands are however much rarer and have not been widely investigated even though they may be considered attractive ligands for coordination chemistry studies and catalysis. Here we report the synthesis of two new N-centred tripodal phosphine ligands bearing bulky cyclohexyl and tert-butyl groups. The coordination chemistry of the cyclohexyl triphosphine ligand N(CH 2PCy 2) 3 ( 4) was investigated and found to react with Mo and W hexacarbonyls preferentially forming bidentate metal tetracarbonyl complexes [Mo(CO) 4{N(CH 2PCy 2) 3-κ 2 P}] ( 6) and [W(CO) 4{N(CH 2PCy 2) 3-κ 2 P}] ( 7) over the expected facial capping tridentate complexes. The steric bulk of the cyclohexyl groups on the phosphorus atoms is sufficient to prevent the third arm of the ligand from coordinating and adopting the required geometry for facial coordination. This ‘steric control’ at the metal centre results in the third arm remaining freely available for further metal coordination. The coordination chemistry of this free phosphine arm on complexes 6 and 7 was investigated further and used to prepare a series of gold, platinum and silver multimetallic complexes. The X-ray crystal structures of the resulting mixed bi and trimetallic complexes [W(CO) 4{N(CH 2PCy 2) 3-κ 2 P}AuCl] ( 8), [[Mo(CO) 4{N(CH 2PCy 2) 3-κ 2 P}] 2(μ-PtCl 2)] ( 9) and [[W(CO) 4{N(CH 2PCy 2) 3-κ 2 P}] 2(μ-Ag)]ClO 4 ( 11) are reported.

Solvent Extraction of Indium, Gallium, and Zinc Ions with Acidic Organophosphates having Bulky Alkyl Groups

The extraction equilibria of In3+, Ga3, and Zn2+ with bis(4‐ethylcyclohexyl)phosphoric acid (D4ECHPA), bis(4‐cyclohexylcyclohexyl)phosphoric acid (D4DCHPA), and bis(2‐ethylhexyl)phosphoric acid (D2EHPA) were investigated in acidic aqueous sulfate media. The order of extractability of metal ions is D4DCHPA > D2EHPA > D4ECHPA, which corresponds to the lipophilicity (log P) of the extractants. The separation factors, β(In/Ga) and β(Ga/Zn), of D4ECHPA and D4DCHPA are greater or comparable than that of D2EHPA, because of the steric hindrance of the bulky cyclohexyl groups. In3+ can be therefore separated from simulated liquor containing a high concentration of Zn2+ by D4DCHPA.

Synthesis, structures, and magnetic properties of one-dimensional Fe–M (M = Ni II, Cu II) coordination polymers bridged by nitroprusside

Self-assembling [Fe(CN) 5(NO)] 2− and [M(L)] 2+ (M = Ni, Cu; L = macrocycles) led to one-dimensional coordination polymers, [Ni(L1)][Fe(CN) 5(NO)] · 2H 2O ( 1) with parallel chains and [Cu(L2)][Fe(CN) 5(NO)] · 3H 2O ( 2) exhibiting a slanted chain structure. Compound 1 contains a planar macrocycle L1 coordinated to a slightly distorted octahedral Ni(II) ion in which the planarity of L1 gives rise to piling up chains in parallel. In contrast, a more flexible macrocyclic ligand L2 in 2 that surrounds a Cu center with a tetragonal elongation has bulky cyclohexyl groups together with pendant methyl side groups. The presence of the methyl groups on L2 in a chain makes the cyclohexyl groups in an adjacent chain tilted against the CuN 4 basal plane with the methyl groups, eventually resulting in the slanted chain structure. Magnetic data demonstrate that antiferromagnetic interactions ( J ≈ −0.13 cm −1) are operating although the paramagnetic centers are linked by the long diamagnetic [Fe(CN) 5(NO)] 2− anion.

Asymmetric fluorogenic organophosphates for the development of active organophosphate hydrolases with reversed stereoselectivity

In order to enhance the enzymatic detoxification rate of organophosphorus (OP) nerve agents we have searched for more active variants of recombinant mammalian paraoxonase (PON1). We have previously identified three key positions in PON1 that affect OP hydrolysis: Leu69, Val346 and His115, that significantly enhance the hydrolysis of cyclosarin (GF), soman, chlorpyrifos-oxon (ChPo), O-isopropyl- O-( p-nitrophenyl)methylphosphonate (IMP- pNP) and diisopropyl fluorophosphate (DFP). GC/FPD analysis compared to residual AChE inhibition assay displayed stereoselective hydrolysis of GF, soman and IMP- pNP, indicating that wild type PON1 and its variant V346A are more active toward the less toxic P(+) optical isomer. In order to obtain new PON1 variants with reversed stereoselectivity, displaying augmented activity toward the more toxic isomer P(−) of nerve agents, we synthesized new asymmetric fluorogenic OPs (Flu-OPs). Six Flu-OPs were prepared containing either ethyl (E), cyclohexyl (C) or pinacolyl (P) alkyl radicals attached to methyl-phosphonyl (MP) moiety analogous to the structure of VX, GF and soman, respectively. The fluorescent moieties are either 3-cyano-4-methyl-7-hydroxy coumarin (MeCyC) or 1,3-dichloro-7-hydroxy-9,9-dimethyl-9 H-acridin-2-one (DDAO). The kinetics of AChE and BChE inhibition by these new Flu-OPs display k i values 8.5 × 10 4 to 8.5 × 10 7 and 5 × 10 4 to 2 × 10 6 M −1 min −1, respectively. EMP–MeCyC and EMP–DDAO are the most active inhibitors of AChE whereas CMP–MeCyC and CMP–DDAO are better inhibitors of BChE than AChE, indicating accommodation of bulky cyclohexyl group inside the active site of BChE. PMP–MeCyC and PMP–DDAO are the least active inhibitors of both AChE and BChE. CMP–MeCyC and CMP–DDAO were significantly detoxified only by the five-site mutations PON1 variant L69V/S138L/S193P/N287D/V346A. Degradation kinetics of Flu-OPs measured by increase in absorbance of the released fluorogenic group was fit by a two exponential function, indicating faster hydrolysis of the less toxic optical isomer. Interestingly, wt PON1 caused only 50% degradation of racemic EMP–MeCyC, CMP–MeCyC and CMP–DDAO indicating complete hydrolysis of P(+) isomer. This remarkable stereoselectivity was used for the enzymatic separation of the P(−) isomer of CMP–MeCyC. The bimolecular rate constant k i for human AChE inhibition by the isolated P(−) isomer of CMP–MeCyC is five-fold larger than that of its P(+) isomer. The marked preference of wt PON1 toward P(+) stereo-isomer of CMP–MeCyC and CMP–DDAO renders their P(−) stereo-isomers suitable for the selection of new OP hydrolase variants with reversed stereoselectivity.

Basicity of Amines in the Gas Phase – Analysis of the Base‐Strengthening Effect of an N‐Trityl Group by Use of a Triadic Formula

AbstractAn ab initio theoretical method based on a triadic formula has been employed to calculate changes in proton affinities (PAs) after sequential substitution of C–H by C–phenyl in methylamine and in the N‐methyl component of N‐methylacetamide. The overall objective was to investigate the cause of the recently reported unexpected basicity‐enhancing effect of the N‐trityl group in several amines and in acetamide. The triadic method indicates that the increase in PA from NH3 to CH3NH2 is principally due to destabilisation of the lone pair, compensated to some degree by a smaller bond energy term. The increasing PAs along the series CH3NH2, PhCH2NH2, Ph2CHNH2 and Ph3CNH2 are mainly due to an increasing relaxation energy effect following increasing phenyl substitution, supported by increasing bond energy terms. Introduction of para‐methoxy substituents in tritylamine would be calculated to result in small incremental increases in PA, in agreement with experimental findings. The PA of tricyclohexylmethylamine (233.6 kcal·mol–1) is calculated to be similar to that of trimethoxytritylamine (233.5 kcal·mol–1), a consequence of the destabilisation of the lone pair on nitrogen by the three bulky cyclohexyl groups. Results for acetamide indicate that protonation on oxygen is more favourable than on nitrogen, which supports the intuitive argument that conventional π‐electron resonance stabilisation of the O‐protonated cation should be appreciably greater than hyperconjugative stabilisation of the N‐protonated isomer. The increase in PA along the series MeCONHCH3, MeCONHCH2Ph, MeCONHCHPh2 and MeCONHCPh3 parallels the increase from CH3NH2 to Ph3CNH2 and is again principally a consequence of the increasing relaxation energies, which dominate the negative bond energy term contributions. Prior to protonation, the nitrogen atom of MeNHAc is perfectly planar, consistently with resonance delocalisation of the nitrogen lone pair into the carbonyl group. In contrast, there is a 6.5 % degree of pyramidalisation at the nitrogen in TrNHAc [calculated at the B3LYP/6‐31G(d) level], indicating a reduced resonance interaction due to steric crowding, in support of a previous suggestion. Finally, the computed PAs and predicted first adiabatic ionisation energies are in satisfactory agreement with experimental results where these are available.(© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2006)

Synthesis and characterization of bis[4-N-(cyclohexylimino)-2-pentanonato]magnesium(II)

A novel β-ketoimine, 4-N-(cyclohexylimino)-2-pentanone, was synthesized and reacted with dibutyl magnesium to afford the desired magnesium bis(β-ketoiminate). The complex, bis[4-N-(cyclohexylimino)-2-pentanonato]magnesium(II), has been structurally characterized by single-crystal X-ray diffraction methods. Crystallographic analysis shows the four-coordinate complex to be homoleptic and monomeric in the solid state. The geometry around the Mg(II) atom is a distorted tetrahedron. The bulky cyclohexyl groups provide enough steric bulk about magnesium to inhibit intermolecular interactions. The crystal structure of the complex is triclinic, space group , with a = 8.301(3), b = 11.301(4), c = 12.023(4) Å, α = 75.840(6), β = 88.867(6), γ = 84.611(6)°, Z = 2. The two normal Mg–O and Mg–N bond lengths are, respectively, 1.9162(11), 1.9265(11) and 2.0699(13), 2.0822(12) Å.

Synthesis and electroluminescent properties of cyclohexyl-substituted polyfluorenes

To lessen the excimer formation often observed in many poly(dialkylfluorene) derivatives, various lengths of alkyl chains containing bulky cyclohexyl groups were substituted to polyfluorenes at the C-9 position. Three polymers were synthesized by Ni(0)-mediated polymerization. PF1CY has very poor solubility because of the rigidness of the backbone caused by the closely lying bulky cyclohexyl substituents, and therefore the soluble fraction showed oligomeric properties. PF4CY displayed green electroluminescence (EL) of an excimer emission; insulation of backbones by such a length of substituents is not effective enough to prevent the excimer formation. However, PF7CY was able to suppress excimer formation by effective aggregation. Efficient blue EL was obtainable with PF7CY.

Synthesis and Characterization of New Orange-Red Light-Emitting PPV Derivatives With Bulky Cyclohexyl Groups

A series of 2,5-dialkoxy substituted poly(1,4-phenylenevinylene) derivatives containing a rigid and bulky cyclohexyl group in the side chain, poly[2-(7-cyclohexylheptyloxy)-5-butoxy-1,4-phenylenevinylene] (PBCyHpPV), Poly[2-(6-cyclohexylmethoxyhexyloxy)-5-butoxy-1,4-phenylenevinylene] (PBCyHxPV), Poly [2,5-di-(6-cyclohexylmethoxy-hexyloxy)-1,4-phenylenevinylene] (PDCyHxPV) were synthesized via the Gilch polymerization. The synthesized polymers were soluble in common organic solvents and showed good thermal stability up to 370 °C. The maximum absorption of PBCyHpPV, PBCyHxPV and PDCyHxPV as thin films was at 513 nm, 515 nm, 511 nm, respectively. Photoluminescence maximum emission of above polymers appeared at 590 nm, 597 nm, 590 nm, respectively. The electroluminescence (EL) maxima of the polymers appeared around 585-590 nm, and also showed another shoulder around 630 nm strongly. PDCyHxPV showed the highest EL efficiency and EL power than those of other polymers due to the dilution effect of the two rigid and bulky cyclohexyl groups.

Gas permeabilities of polymers with indan groups in the main chain.: 2: Polyimides

Permeability coefficients and ideal selectivities for H 2, CO 2, O 2, and N 2 were determined for two series of polyimides with indan groups in the main chain. The bulkiness of the indan group was varied by replacing methyl groups at the indan ring system by bulky cyclohexyl groups. The effects of the linking group in the dianhydride part of the polymer repeating unit could be explained on the basis of bulkiness and flexibility. However, the introduction of two cyclohexyl substituents at the indan group to increase the bulkiness of this structural element had no uniform effect on permeability coefficients and selectivities. Positive or negative effects were observed, depending on the linking group in the dianhydride moiety. This was tentatively attributed to the conformational flexibility of the cyclohexyl rings, which can result in different sterical requirements.

Miscible polymer mixture driven by segmental microconformations

It is shown that polystyrene and poly(cyclohexyl acrylate) form a partially miscible blend with a reversible lower critical solution temperature. Preliminary results show that the bulky cyclohexyl group severely limits the segment to finite rotational states and, as a result, enhances the weak dipole-induced dipole interaction

The preparation and characterization of phosphorus-terminated poly-1,3-butadiene: new telechelic ionomers

Polybutadienyllithium systems, with high 1,4-microstructure, low polydispersity and M ̄ n in the range (2–10) × 10 3, have been produced in hydrocarbon solvents by using n-butyllithium or 3-dimethylamino-propyllithium as initiator. Termination of these ‘living’ polymers with chlorophosphine, ClPR 2 (R = Ph, Et or Cy), occurs to give oxidatively unstable phosphine derivatives Y-(C 4H 6) n -PR 2, in up to 93% efficiency. Oxidation products include the related phosphine oxides. Quaternization of the phosphinated polymers in situ with iodomethane gives a quantitative conversion into the cationomeric polymers Y′-(C 4H 6) n -PR 2Me +I −, including the novel dicationic telechelic systems with Y′ = I +NMe 3(CH 2) 3, which show thermoplastic elastomeric properties. The products have been characterized by gel permeation chromatography, end-group analysis and 1H, 13C and 31P nuclear magnetic resonance spectroscopy. Model quaternary phosphonium derivatives, trans- and cis-t-BuCH 2CHCHCH 2PR 2Me +I − and t-BuCH 2CH(CHCH 2)PR 2Me +I −, are reported and help establish the terminal geometry of the quaternary phosphonium-capped polybutadienes: the addition of phosphorus to the terminal butadienyl follows the order cis-1,4> trans-1,4>1,2 with the amount of 1,2-termination being smallest when R is the bulky cyclohexyl group.

Gas transport in poly(vinyl cyclohexanecarboxylate)

AbstractLow‐pressure gas permeation measurements were performed on poly(vinyl cyclohexanecarboxylate) to evaluate its transport characteristics. The transport data of CO2, O2, N2, He, and Ar, were presented as a function of temperature ranging from 15 to 85°C. The apparent transport parameters were determined by the time lag method above and below the glass transition temperature and they were compared with other polymers of similar chemical structures. The side chain of the polymer has a bulky cyclohexyl group, which seemed to increase gas diffusivity. The activation energy for diffusion seemed to be related with the polarity of side chain. The relationships between gas diffusivity, physical properties, and chemical structure were qualitatively discussed in comparison with the data on poly(vinyl benzoate) and poly(vinyl acetate).