Butadiene–isoprene copolymerization with V(acac)3‐MAO. Crystalline and amorphous trans‐1,4 copolymers

Butadiene‐isoprene copolymerization with the system V(acac)₃‐MAO was examined. Crystalline or amorphous copolymers were obtained depending on isoprene content. Both butadiene and isoprene units exhibit a trans‐1,4 structure and are statistically distributed along the polymer chain. Polymer microstructure, comonomer composition, and distribution along the polymer chain were determined by ¹³C and ¹H NMR analysis. The thermal and X‐ray behaviors of the copolymers were also investigated and compared with results from solid‐state ¹³C NMR experiments. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4635–4646, 2007     

Influence of monomer structure on chemo- and stereoselectivity of 1,3-diene polymerization

MAO/CpTiCl₃ is an active catalyst for the polymerization of various types of 1,3-dienes. Butadiene, (E) - and (Z) −1,3-pentadiene, (E) −2-methyl-1,3-pentadiene and 2,3-dimethylbutadiene yield, at room temperature, polymers with a cis-1,4 or a mixed cis/1,2 structure. 4-Methyl-1,3-pentadiene and (E,E) −2,4-hexadiene give, respectively, a 1,2 syndiotactic and a trans-1,4/1,2 polymer. MAO/CpTiCl₂·2THF and MAO/(CpTiCl₂)_n are less active than the CpTiCl₃ catalyst, but give the same type of polymers. A change of stereospecificity with temperature was observed in the polymerization of (Z)-1,3-pentadiene: a cis-1,4 isotactic polymer was obtained at +20°C, and a crystalline 1,2 syndiotactic polymer at −20°C. This effect was attributed to a different mode of coordination of the monomer, which is cis-η⁴ at +20°C and may be trans-η² at −20°C. Results obtained with catalysts from CpTi(OBu)₃ and Ti(OBu)₄ are reported for comparison. An interpretation is given of the formation of cis-1,4 isotactic poly(2-methylpentadiene) and of 1,2 syndiotactic poly(4-methylpentadiene), as well as of syndiotactic polystyrene.     

Polymerization of 2‐pentene with Ni(II) α‐diimine complex/M‐MAO catalyst and structure of the polymer

Polymerization of 2‐pentene with [ArN?C(An)C(An)·NAr)NiBr₂ (Ar?2,6‐iPr₂C₆H₃)] ( 1‐Ni) /M‐MAO catalyst was investigated. A reactivity between trans‐2‐pentene and cis‐2‐pentene on the polymerization was quite different, and trans‐2‐pentene polymerized with 1‐Ni /M‐MAO catalyst to give a high molecular weight polymer. On the other hand, the polymerization of cis‐2‐butene with 1‐Ni /M‐MAO catalyst did not give any polymeric products. In the polymerization of mixture of trans‐ and cis‐2‐pentene with 1‐Ni /M‐MAO catalyst, the M_n of the polymer increased with an increase of the polymer yields. However, the relationship between polymer yield and the M_n of the polymer did not give a strict straight line, and the M_w/M_n also increased with increasing polymer yield. This suggests that side reactions were induced during the polymerization. The structures of the polymer obtained from the polymerization of 2‐ pentene with 1‐Ni /M‐MAO catalyst consists of ? CH₂? CH₂? CH(CH₂CH₃)? , ? CH₂? CH₂? CH₂? CH(CH₃)? , ? CH₂? CH(CH₂CH₂CH₃)? , and methylene sequence ? (CH₂)_n? (n ≥ 5) units, which is related to the chain walking mechanism. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2858–2863, 2008     

Optoeletronic properties of poly(N‐alkenyl‐carbazole)s driven by polymer stereoregularity

Stereoregular polymers like isotactic poly(N‐butenyl‐carbazole) (i‐PBK), isotactic and syndiotactic poly(N‐pentenyl‐carbazole) (i‐PPK and s‐PPK), and poly(N‐hexenyl‐carbazole) (i‐PHK and s‐PHK) are synthesized using the stereospecific homogeneous “single site” Ziegler‐Natta (Z‐N) catalysts: rac‐dimethylsilylbis(1‐indenyl)zirconium dichloride ( 1 )/methylaluminoxane (MAO) and diphenylmethylidene(cyclopentadienyl)‐(9‐fluorenyl)zirconium dichloride ( 2 )/MAO. Catalytic activity is rationalized by density functional theory (DFT) calculations. All synthesized polymers are fully characterized by NMR, thermal, wide‐angle X‐ray diffraction, and fourier transform infrared spectroscopy analysis. Fluorescence measurements on isotactic and syndiotactic polymer films indicate that all polymers give rise to excimers, both “sandwich‐like” and “partially overlapping.” Excimer formation is essentially driven by the polymer tacticity. Isotactic polymers generate both sandwich‐like and partially overlapping excimers, while syndiotactic polymers give rise especially to partially overlapping ones. A theoretical combined molecular dynamics–time dependent DFT approach is also used to support the experimental results. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 242–251     

Polymerization of (E)‐1,3‐Pentadiene and (E)‐2‐methyl‐1,3‐pentadiene with neodymium catalysts: Examination of the factors that affect the stereoselectivity

(E)‐1,3‐Pentadiene (EP) and (E)‐2‐methyl‐1,3‐pentadiene (2MP) were polymerized to cis‐1,4 polymers with homogeneous and heterogeneous neodymium catalysts to examine the influence of the physical state of the catalyst on the polymerization stereoselectivity. Data on the polymerization of (E)‐1,3‐hexadiene (EH) are also reported. EP and EH gave cis‐1,4 isotactic polymers both with the homogeneous and with the heterogeneous system, whereas 2MP gave an isotactic cis‐1,4 polymer with the heterogeneous catalyst and a syndiotactic cis‐1,4 polymer, never reported earlier, with the homogeneous one. For comparison, the results obtained with the soluble CpTiCl₃‐based catalyst (Cp = cyclopentadienyl), which gives cis‐1,4 isotactic poly(2MP), are examined. A tentative interpretation is given for the mechanism of the formation of the stereoregular polymers obtained and a complete NMR characterization of the cis‐1,4‐syndiotactic poly(2MP) is reported. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3227–3232     

Microstructure of Highly Syndiotactic “Living” Poly(propylene)s Produced from a Titanium Complex with Chelating Fluorine‐Containing Phenoxyimine Ligands (an FI Catalyst)

Highly syndiotactic “living” poly(propylene)s were synthesized at 25°C using a bis[N‐(3‐tert‐butylsalicylidene)‐2,3,4,5,6‐pentafluoroanilinato]titanium (IV) dichloride/MAO catalyst system, and microstructures of the polymer were analyzed by means of ¹³C NMR spectroscopy. The syndiotactic poly(propylene) contains isobutyl, isopentyl and propyl end groups, suggesting that the living polymerization of propylene was initiated via 1,2‐insertion, followed by 2,1‐insertion as the principal mode of polymerization. Pentad distribution analysis revealed that the syndiospecific polymerization proceeds under chain‐end control.     

Thermo‐stable 2‐(arylimino)benzylidene‐9‐arylimino‐5,6,7,8‐tetrahydro cyclohepta[b]pyridyliron(II) precatalysts toward ethylene polymerization and highly linear polyethylenes

A series of 2‐(arylimino)benzylidene‐9‐arylimino‐5,6,7,8‐tetrahydrocyclohepta[b] pyridyliron(II) chlorides was synthesized and characterized using FT‐IR and elemental analysis, and the molecular structures of complexes Fe3 and Fe4 have been confirmed by the single‐crystal X‐ray diffraction as a pseudo‐square‐pyramidal or distorted trigonal‐bipyramidal geometry around the iron core. On activation with methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all iron precatalysts exhibited high activities toward ethylene polymerization with a marvelous thermo‐stability and long lifetime. The Fe4 /MAO system showed highest activity of 1.56 × 10⁷ gPE·mol^?1(Fe)·h^?1 at 70 °C, which is one of the highest activities toward ethylene polymerization by iron precatalysts. Even up to 80 °C, Fe3 /MAO system still persist high activity as 6.87 × 10⁶ g(PE)·mol^?1(Fe)·h^?1, demonstrating remarkable thermal stability for industrial polymerizations (80–100 °C). This was mainly attributing to the phenyl modification of the framework of the iron precatalysts. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 830–842     

Copolymerization of ethylene with cyclopentene or 2‐butene with half titanocenes‐based catalysts

Half titanocenes (CpCH₂CH₂O)TiCl₂ (1), (CpCH₂CH₂OCH₃)TiCl₃ (2), and CpTiCl₃ (3), activated by methylaluminoxane (MAO) were tested in copolymerization of ethylene with internal olefins such as cyclopentene. All the catalysts were able to give incorporation of cyclopentene in polyethylene matrix. ¹³C NMR analysis of obtained copolymers showed that the catalytic systems have low regiospecificity. In fact, in ethylene–cyclopentene copolymers, cyclic olefin inserts with both 1,2 and 1,3‐enchainment. X‐ray powder diffraction analysis of these copolymers confirmed that 1,2 inserted cyclopentene units are excluded from crystalline phase, whereas 1,3‐cyclopentene units are included, giving rise to expansion of unit cell of crystalline polyethylene. Titanium‐based catalysts were investigated also in the copolymerization of ethylene with E and Z‐2‐butene. Only complex (1) was able to give copolymers and ¹³C NMR analysis of products showed 2‐3, 1‐3, and 1‐2 insertion of 2‐butene. Differential scanning calorimetry analysis displayed that ethylene–cyclopentene, as well as ethylene‐2‐butene, copolymers are crystalline and their melting point decreases by increasing the comonomer content. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4725–4733, 2008     

Stereoselective synthesis and polymerization of Exo‐5‐trimethylsilylnorbornene

Herein the stereoselective two‐step synthesis of pure exo‐5‐trimethylsilylnorbornene is reported. The monomer proved to be highly reactive in both metathesis and addition polymerization. ROMP polymerization was catalyzed by the first‐generation Grubbs catalyst. High‐molecular‐weight saturated addition polymers were prepared using nickel or palladium complexes as precatalysts and Na⁺[B(3,5‐(CF₃)₂C₆H₃)₄]⁻ and/or MAO as cocatalysts. The obtained addition polynorbornenes are highly gas permeable and microporous materials possessing large free volume and BET surface area (up to 540 m²/g). The influence of the substituent orientation (exo‐ vs. exo‐/endo‐mixture) on polymer properties was established. The metathesis polymer based on exo‐isomer exhibits 1.5‐ to 2‐fold increase of permeability coefficients for all gases in comparison to the similar polymer based on the mixture of exo‐ and endo‐isomers. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1234–1248     

[Hg2(μ‐bpe)(μ‐OAc)2(μ‐SCN)2]n,a New Two‐Dimensional Coordination Polymer Involving Three Simultaneously Bridging Ligands: 1,2‐Bis(4‐pyridyle)ethene,Acetate, and Thiocyanate

A new mercury(II) complex of 1,2‐bis(4‐pyridyle)ethene (bpe) with anionic acetate and thiocyanate ligands has been synthesized and characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR spectroscopy. The single crystal X‐ray analysis shows that the complex is a two‐dimensional polymer with simultaneously bridging 1,2‐bis(4‐pyridyle)ethane, acetate and thiocyanate ligands and basic repeating dimeric [Hg₂(μ‐bpe)(μ‐OAc)₂(μ‐SCN)₂] units. The two‐dimensional system forms a three‐dimensional network by packing via π‐π stacking interactions.     

Synthesis, Crystal Structure of Ruthenium 1,2－Naphthoquinone－1－oxime Complex and Its Mediated C－－C Coupling Reactions of Ter－minal Alkynes

Substituted decarbonylation reaction of ruthenium 1,2‐naphthoquinone‐1‐oxime (1‐nqo) complex, cis‐, cis‐[Ru| ζ²‐N(O)C₁₀‐H₆O|₂(CO)₂] (1), with acetonitrile gave cis‐, cis‐[Ru | ζ²‐ N(O)C₁₀H₆O|₂(CO)(NCMe)] (2). Complex 2 was fully characterized by ¹H NMR, FAB MS, IR spectra and single crystal X‐ray analysis. Complex 2 maintains the coordination structure of 1 with the two naphthoquinonic oxygen atoms, as well as the two oximato nitrogen atoms located cis to each other, showing that there is no ligand rearrangement of the 1‐nqo ligands during the substitution reaction. The carbonyl group originally trans to the naphthoquinonic oxygen in one 1‐nqo ligand is left in its original position [O(5)‐Ru‐C(1), 174.0(6)°], while the other one originally trans to the oximato group of the other 1‐nqo ligand is substituted by NCMe [N(1)‐Ru‐N(3), 170.6(6)°]. This shows that the carbonyl trans to oximato group is more labile than the one trans to naphthoquinonic O atom towards substitution. This is probably due to the comparatively stronger ± back bonding from ruthenium metal to the carbonyl group trans to naphthoquinonic O atom, than the one trans to oximato group, resulting in the comparatively weaker Ru–‐CO bond for the latter and consequently easier replacement of this carbonyl. Selected coupling of phenylacetylene mediated by 2 gave a single trans‐dimerization product 3, while 2 mediated coupling reaction of methyl propiolate produced three products: one trans‐dimerization product 4 and two cyclotrimeric products 5 and 6.     

Diastereo‐ and Regioselective Addition of Thioamide Dianions to Imines and Aziridines: Synthesis of N‐Thioacyl‐1,2‐diamines and N‐Thioacyl‐1,3‐diamines

Addition reactions of thioamide dianions that were derived from N‐arylmethyl thioamides to imines and aziridines were carried out. The reactions of imines gave the addition products of N‐thioacyl‐1,2‐diamines in a highly diastereoselective manner in good‐to‐excellent yields. The diastereomeric purity of these N‐thioacyl‐1,2‐diamines could be enriched by simple recrystallization. The reduction of N‐thioacyl‐1,2‐diamines with LiAlH₄ gave their corresponding 1,2‐diamines in moderate‐to‐good yields with retention of their stereochemistry. The oxidative‐desulfurization/cyclization of an N‐thioacyl‐1,2‐diamine in CuCl₂/O₂ and I₂/pyridine systems gave the cyclized product in moderate yield and the trans isomer was obtained as the sole product. On the other hand, a similar cyclization reaction with antiformin (aq. NaClO) as an oxidant gave the cis isomer as the major product. The reactions of N‐tosylaziridines gave the addition products of N‐thioacyl‐1,3‐diamines with low diastereoselectivity but high regioselectivity and in good‐to‐excellent yields. The use of AlMe₃ as an additive improved the efficiency and regioselectivity of the reaction. The stereochemistry of the obtained products was determined by X‐ray diffraction.     

Synthesis and characterization of three dinuclear copper(I) complexes of 1,2‐bis(diphenylphosphino)‐1,2‐dicarba‐closo‐dodecaborane

Three dinuclear copper(I) complexes, [Cu₂(µ‐Cl)₂(1,2‐(PPh₂)₂‐1,2‐C₂B₁₀H₁₀)₂]·2CH₂Cl₂ ( 1 ), [Cu₂(µ‐Br)₂(1,2‐(PPh₂)₂‐1,2‐C₂B₁₀H₁₀)₂]·2THF ( 2 ) and {Cu₂(µ‐I)₂[1,2‐(PPh₂)₂‐1,2‐C₂B₁₀H₁₀]₂} ( 3 ) have been synthesized by the reactions of CuX (X = Cl, Br and I) with the closo ligand 1,2‐(PPh₂)₂‐1,2‐C₂B₁₀H₁₀. All these complexes were characterized by elemental analysis, FT‐IR, ¹H and ¹³C NMR spectroscopy and X‐ray structure determination. Single crystal X‐ray structure determinations show that every complex contained di‐µ‐X‐bridged structure involving a crossed parallelogram plane formed by two Cu atoms and two X atoms (X = Cl, Br, I). The geometry at the Cu atom was a distorted tetrahedron, in which two positions were occupied by two P atoms of the PPh₂ groups connected to the two C atoms of carborane (Cc), and the other two resulted from two X atoms which bridged the other Cu atom at the same time. To the best of our knowledge, this is the first example of copper(I) complexes with 1,2‐diphenylphosphino‐1,2‐dicarba‐closo‐dodecaborane as ligand characterized by X‐ray diffraction. The catalytic property of the complex 3 for the amination of iodobenzene with aniline was also investigated. Copyright © 2005 John Wiley & Sons, Ltd.     

Syntheses of Halogenated Polyhedral Phosphaboranes: Crystal Structure of conjuncto‐3,3′‐(closo‐1,2‐P2B4Br3)2

Co‐pyrolysis of B₂Br₄ with PBr₃ at 480 °C gave, in addition to the main product closo‐1,2‐P₂B₄Br₄, conjuncto‐3,3′‐(1,2‐P₂B₄Br₃)₂ ( 1 ) and the twelve‐vertex closo‐1,7‐P₂B₁₀Br₁₀ ( 2 ), both in low yields. X‐ray structure determination for 1 [triclinic, space‐group P1 with a = 7.220(2) Å, b = 7.232(2) Å, c = 8.5839(15) Å, α = 97.213(15)°, β = 96.81(2)°, γ = 94.07(2)° and Z = 1] confirmed that 1 adopts a structure consisting of two symmetrically boron–boron linked distorted octahedra with the bridging boron atoms in the 3,3′‐positions and the phosphorus atoms in the 1,2‐positions. The intercluster 2e/2c B–B bond length is 1.61(3) Å. The shortest boron–boron bond within the cluster framework is 1.68(2) Å located between the boron atoms antipodal to the phosphorus atoms. The icosahedral phosphaborane 2 was characterized by ¹¹B‐¹¹B COSY NMR spectroscopy showing cross peaks indicative for the isomer with the phosphorus atoms in 1,7‐positions. Both the X‐ray data of 1 and the NMR spectroscopic data of 1 and 2 give further evidence for the influence of an antipodal effect of heteroatoms to cross‐cage boron atoms and, vice versa, of an additional shielding of the phosphorus atoms caused by B‐Hal substitution at the boron positions trans to phosphorus.     

1,2‐dichloroethane conformation and molecular organization in syndiotactic polystyrene gels

The conformational equilibrium of 1,2‐dichloroethane (DCE) in syndiotactic polystyrene (sPS)/DCE gels has been investigated by using Fourier transform infrared spectroscopy. Results show that the fraction of DCE in the trans conformation (X_T) increases with increasing polymer concentration. From these X_T values, by assuming that the crystalline phase in the gel presents the clathrate structure, the amount of DCE included in the crystalline phase and the fraction of polymer included in the crystalline phase were evaluated as a function of the gel composition.     

Stereospecific and molecular weight‐controlled polymerization of 1,3‐butadiene with Co(acac)3‐MAO catalyst

The polymerization of butadiene (Bd) with Co(acac)₃ in combination with methylaluminoxane (MAO) was investigated. The polymerization of Bd with Co(acac)₃‐MAO catalysts proceeded to give cis‐1,4 polymers (94 – 97%) bearing high molecular weights (40 × 10⁴) with relatively narrow molecular weight distributions (M_w's/M_n's). The molecular weight of the polymers increased linearly with the polymer yield, and the line passed through an original point. The polydispersities of the polymers kept almost constant during reaction time. This indicates that the microstructure and molecular weight of the polymers can be controlled in the polymerization of Bd with the Co(acac)₃‐MAO catalyst. The effects of reaction temperature, Bd concentration, and the MAO/Co molar ratio on the cis‐1,4 microstructure and high molecular weight polymer in the polymerization of Bd with Co(acac)₃‐MAO catalyst were observed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2793–2798, 2001     

Syndiotactic 1,2-polybutadiene with Co-CS2 catalyst system. I. Preparation,properties, and application of highly crystalline syndiotactic 1,2-polybutadiene

Highly crystalline syndiotactic 1,2-polybutadiene (s-PB) having melting point (mp) up to 216°C was obtained by using a Co(acac)₃-AIEt₃-CS₂ catalyst. The polymer with mp 208°C was found to have 99.7% 1,2 content and 99.6% syndiotacticity by ¹H and ¹³C-NMR measurements. The s-PB can be molded by addition of a stabilizer such as 2,6-di-t-butyl-4-hydroxymethylphenol into fiber, film, and various shaped articles. The physical properties presented in the present article include stress-strain and dynamic mechanical behavior. The highly crystalline syndiotactic 1,2-polybutadiene was applied to a carbon fiber and UBEPOL VCR (cis-1,4-polybutadiene reinforced by fibrous syndiotactic 1,2-polybutadiene).     

Propylene polymerizations with a binary metallocene system—Chain shuttling caused by trimethylaluminium between active catalyst centers

Propylene was polymerized at varying trimethylaluminium (TMA) concentration with a homogeneous binary metallocene catalyst system activated by methylaluminoxane (MAO) in an attempt to better understand interactions between active catalyst sites and to clarify the role of the TMA as a chain shuttling agent. TMA‐free polymerization conditions were obtained by chemical treatment of MAO solution with 2,6‐di‐tert‐butyl‐4‐methylphenol (BHT). A binary catalyst system consisting of catalyst precursors diphenylmethyl(cyclopentadienyl)(9‐fluorenyl)zirconium dichloride ( 1 ) producing high M_w syndiotactic polypropylene and rac‐dimethylsilylbis(4‐tert‐butyl‐2‐methyl‐cyclopentadienyl)zirconium dichloride ( 2 ) producing low M_w isotactic polypropylene was investigated. At the studied polymerization conditions, chain shuttling between the active catalysts caused by TMA was confirmed. The chain shuttling reactions caused changes in catalyst activity, molecular weights, melting behavior, and polymer microstructure. We propose that TMA is capable to transfer a growing polymer chain from catalyst 2 to catalyst 1 , and a stereoblock copolymer is formed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1364–1376, 2007     

Synthesis,characterization, and photoresponsive behavior of new azobenzene‐containing polyethers

Two new polyethers, bearing azobenzene moiety in the side chain, were synthesized in excellent yields by means of anionic polymerization of 4‐glycidyloxyazobenzene and 4‐cyano‐4′‐glycidyloxyazobenzene (leading to azo‐P1 and azo‐P2 polymers, respectively) with the system polyiminophosphazene base t‐Bu‐P₄/3,5‐di‐tert‐butylphenol as initiator. The polymers were characterized with respect to their molecular weights, structure, and calorimetric features. The polyether bearing cyanoazobenzene group in the side chain was found to exhibit nematic phase up to 200 °C. E–Z isomerization of both polymers in tetrahydrofuran solution, after irradiating with UV light at 364 nm for 15 min, was investigated by means of UV–visible absorption spectroscopy. In the case of glycidylic monomers as well as the resulting polymers, E–Z isomerization was also investigated by means of ¹H NMR, by direct irradiation in the NMR probe in deuterated 1,1,2,2‐tetrachloroethane solution. By this technique, in the case of 4‐cyano‐4′‐glycidyloxyazobenzene, it was found that irradiation led to a photostationary state corresponding to an amount of Z isomer equal to 25%. For azo‐P1 polymer, Z–E or “reverse” isomerization was investigated at 60, 70, or 80 °C directly in the NMR probe; as expected, the process followed a first‐order rate law. The kinetic constants as well as the activation energy for the process were determined in this temperature range. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5426–5436, 2009     

Efficient Separation of cis‐ and trans‐1,2‐Dichloroethene Isomers by Adaptive Biphen[3]arene Crystals

Reported here is the highly efficient separation of industrially important cis‐ and trans‐1,2‐dichloroethene (cis‐DCE and trans‐DCE) isomers by activated crystalline 2,2′,4,4′‐tetramethoxyl biphen[3]arene (MeBP3) materials, MeBP3α. MeBP3 can be synthesized in excellent yield (99 %), and a cyclic pentamer is also obtained when using 1,2‐dichloroethane as the solvent. The structure of MeBP3 in the CH₃CN@MeBP3 crystal displays a triangle‐shape topology, forming 1D channels through window‐to‐window packing. Desolvated crystalline MeBP3 materials, MeBP3α, preferentially adsorb cis‐DCE vapors over its trans isomer. MeBP3α is able to separate cis‐DCE from a 50:50 (v/v) cis/trans‐isomer mixture, yielding cis‐DCE with a purity of 96.4 % in a single adsorption cycle. Single‐crystal structures and powder X‐ray diffraction patterns indicate that the uptake of cis‐DCE triggers a solid‐state structural transformation of MeBP3, suggesting the adaptivity of MeBP3α materials during the sorption process. Moreover, the separation can be performed over multiple cycles without loss of separation selectivity and capacity.