Syntheses,crystal structures and solvatochromic properties of dinuclear oxalato-bridged copper(II) complexes

Three dinuclear copper(II) complexes, [Cu₂(L¹)₂(μ-ox)](ClO₄)₂?2(CH₃CN), [Cu₂(L²)₂(μ-ox)](ClO₄)₂?H₂O, and [Cu₂(L³)₂(μ-ox)](ClO₄)₂ where ox = oxalato; L = N,N-dimethyl,N′-benzylethane-1,2-diamine, L¹, N,N-diethyl,N′-benzylethane-1,2-diamine, L², N,N-diisoprophyl,N′-benzylethane-1,2-diamine, L³, were prepared and characterized by elemental analyses, spectral (IR, UV–Vis) data and molar conductance measurements. The crystal structures of [Cu₂(L¹)₂(μ-ox)](ClO₄)₂?2(CH₃CN) and [Cu₂(L³)₂(μ-ox)](ClO₄)₂ have been determined by single-crystal X-ray analysis. Solvatochromic behaviors were investigated in various solvents, showing positive solvatochromism. The effect of steric hindrance around the copper ion imposed by N-alkyl groups of the diamine chelates on the solvatochromism property of the complexes is discussed. Solvatochromism was also studied with different solvent parameter models using stepwise multiple linear regression method.     

Highly Efficient Multiphoton‐Pumped Frequency‐Upconversion Stimulated Blue Emission with Ultralow Threshold from Highly Extended Ladder‐Type Oligo(p‐phenylene)s

A series of highly extended π‐conjugated ladder‐type oligo(p‐phenylene)s containing up to 10 phenyl rings with (L)‐Ph(n)‐NPh (n=7–10) or without diphenylamino endcaps (L)‐Ph(n) (n=7 and 8) were synthesized and investigated for their multiphoton absorption properties for frequency upconverted blue ASE/lasing. Extremely large two‐photon absorption (2PA) cross‐sections and highly efficient 2PA ASE/lasing with ultralow threshold were achieved. (L)‐Ph(10)‐NPh exhibits the highest intrinsic 2PA cross‐section of 3643 GM for a blue emissive organic fluorophore reported so far. The record‐high 2PA pumped ASE/lasing efficiency of 2.06 % was obtained by un‐endcapped oligomer, (L)‐Ph(8) rather than that with larger σ₂, suggesting that a molecule with larger σ₂ is not guaranteed to exhibit higher η₂. All of these oligomers exhibit exceptionally ultralow 2PA pumped ASE/lasing thresholds, among which the lowest 2PA pumped threshold of circa 0.26 μJ was achieved by (L)‐Ph(10)‐NPh.     

Dinuclear copper(<Emphasis Type="SmallCaps">II</Emphasis>) complexes with an unsymmetrical exchange fragment

New dinuclear copper(II) complexes with azomethines and hydrazones, which were produced by condensation of substituted salicylaldehyde derivatives with 1,3-diaminopropan-2-ol or carbo(thiocarbo) hydrazide, were studied. The structures of the [Cu₂L(μ-CH₂ClCOO)(CH₃OH)]·(CH₃OH) (L = C₁₇H₁₅N₂O₃) and [Cu₂L²(Cl₃CCO)(CH₃OH)]·H₂O (L² = C₃₂H₄₂N₄O₃) complexes were established by X-ray diffraction. The magnetic properties of these complexes, including the influence of the nature of the substituents in the ligands on exchange interactions, were studied.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 592–596, March, 2005.     

Syntheses,characterization, and crystal structures of ruthenium(II)/(III) complexes with tridentate salicylaldiminato ligands

Treatment of [Ru(PPh₃)₃Cl₂] with one equivalent of tridentate Schiff base 2-[(2-dimethylamino-ethylimino)-methyl]-phenol (HL) in the presence of triethylamine afforded a ruthenium(III) complex [RuCl₃(κ²-N,N-NH₂CH₂CH₂NMe₂)(PPh₃)] as a result of decomposition of HL. Interaction of HL and one equivalent of [RuHCl(CO)(PPh₃)₃], [Ru(CO)₂Cl₂] or [Ru(tht)₄Cl₂] (tht = tetrahydrothiophene) under different conditions led to isolation of the corresponding ruthenium(II) complexes [RuCl(κ³-N,N,O-L)(CO)(PPh₃)] (2), [RuCl(κ³-N,N,O-L)(CO)₂] (3), and a ruthenium(III) complex [RuCl₂(κ³-N,N,O-L)(tht)] (4), respectively. Molecular structures of 1·CH₂Cl₂, 2·CH₂Cl₂, 3 and 4 have been determined by single-crystal X-ray diffraction.     

First ionization potentials of amines and electronic effects in their radical cations

The possibility of application of linear free energy relationships for studying the effects of substituents on the first vertical ionization potentials of amines, I(n_N), was substantiated. The I(n_N) values depend on the inductive, resonance, and polarizability effects of substituents and are also affected by hyperconjugation. The _R ⁺ resonance parameters of substituents MR₃ (M = Si, Ge, Sn) and CH₂SiMe₃ bound to the N ^·+ radical cation center were calculated for the first time.     

Deep insights into the hydrolysis of N,N‐dialkylaminoethyl methacrylates in aqueous solution with 1H NMR spectroscopy

N,N‐dialkylaminoethyl methacrylate (DAEA) monomers are extensively used to prepare multi‐responsive polymers. However, these monomers face high risk of hydrolysis in their ester groups when being polymerized in water‐containing medias. Here, NMR spectroscopy was employed to continuously track the hydrolysis and solubility of four widely used DAEA monomers [CH₂CH₂R₁COO(CH₂)₂N(R₂)₂; R₁ = H or CH₃; R₂ = CH₃, CH₂CH₃ or CH(CH₃)₂] under typical polymerization conditions. With this technique, the hydrolysis reactivity and absolute hydrolysis amount of these monomers are separately examined, and then their kinetic correlations with solubility, molecular structure, pH, and temperature are established, so that the hydrolysis of DAEA monomers and even other esters with similar cyclic structure can be predicted. The present efforts are expected to provide a general understanding for the hydrolysis of all the DAEA monomers, benefitting to the optimization of polymerization toward well‐defined DAEA copolymers, as well as the design of smart soft matter for specific applications. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 914–923     

The molecular geometries of some cyclic nitramines in the gas phase

The structural parameters of 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), (CH₂NNO₂)₃, 1,3-dinitro-1,3-diazacyclopentane (DDCP), CH₂(CH₂NNO₂)₂, andN-nitropyrrolidine (NP), (CH₂)₄NNO₂, have been determined by electron diffraction.The six-membered ring of RDX has a chair form with axial positions of the nitro groups and close to planar bond geometry of the amine nitrogen atoms. The overallC ₃ symmetry of the molecule is in agreement with the experimental data.The conformation of the five-membered ring in DDCP is a half-chair ofC ₂ symmetry, while that in NP is an envelope ofC _S symmetry. The nitro groups are in equatorial positions in both molecules. The conformations of pyrrolidine and imidazolidine cycles show interesting features.The pyramidal geometry of the amine nitrogen atom bonds flattens in going from pyrrolidine andN-chloropyrrolidine to NP and DDCP and then to RDX and to dimethylnitramine (DMNA), (CH₃)₂NNO₂.     

Nonclassical urea oligomers. I. Selective reactivity of 1-(N-substituted-carbamyl)aziridine for ring-transformation reactions and ring-opening polymerization

The reaction course of 1-(N-phenyl-carbamyl)aziridine with NaI was found to be highly sensitive to the nature of solvent used; e.g., acetone preferentially gives 1-phenyl-2-imidazolidinone, whereas dimethylformamide (DMF) gives 2-anilino-2-oxazoline. Nuclear magnetic resonance (NMR) study of the solvent effect revealed the relation between the site in the aziridine compound, with which the solvents interact, and the reaction products. From the results obtained by these ring-transformation studies, the use of diethyl sulfate, which is expected to solvate simultaneously at the carbonyl oxygen and the carbamyl–nitrogen atoms, resulted in polymerization of the monomer selectively to the oligomer of type—[CH₂CH₂N(CONHPh)]_n—. The diethyl sulfate was shown to play dual roles as a solvating reagent and an initiator. The oligomer obtained includes relatively definite amount (one molecule per ca. four monomer units) of diethyl sulfate in the “washed” state. The absorbed diethyl sulfate can be removed by treating with aqueous NaOH solution or Amberlite-400 column elution without altering the chemical constitution of the backbone in the polymer. Application of the polymerization procedure to several N-alkyl substituted monomers resulted in oligomers of a similar type. The difference in the monomer reactivity depending on the nature of the substituent groups can be due mainly to steric factors.     

Novel organosilicon monomer for preparing transparent matrices doped with lanthanide complexes

Perfluoroadipic bis(trialkoxysilylpropyl)amide was synthesized as a mixture of five compounds with the general formula (EtO) _n (MeO)_3-n Si(CH₂)₃NHC(O)(CF₂)₄C(O)NH(CH₂)₃-Si(OMe) _n (OEt)_3-n (1, n = 1, 2). Hydrolysis of this product by a specified amount of water (1: 4) gave oligomers EtO[(HO)(EtO)Si(CH₂)₃NH(O)C(CF₂)₄C(O)NH(CH₂)₃Si(OEt)₂O]_nH ( _n = 7–9). From oligomer solutions, transparent glassy thermally stable films were obtained. The film material was studied by IR spectroscopy, atomic force microscopy, transmission electron microscopy, and powder X-ray diffraction. Compound 1 and oligomers can efficiently solvate lanthanide diketonate complexes. They displace water from the metal coordination sphere, and this water is then spent for hydrolysis of trialkoxysilyl groups. The luminescence intensity of matrix films based on the oligomers depends on the concentration of lanthanide complexes and is very low at 7n_exc = 330 nm, whereas the luminescence intensity of the Eu³⁺ cation is very high.     

Alternating copolymerization of cyclohexene oxide and carbon dioxide catalyzed by noncyclopentadienyl rare‐earth metal bis(alkyl) complexes

The syntheses of several dialkyl complexes based on rare‐earth metal were described. Three β‐diimine compounds with varying N‐aryl substituents (HL¹=(2‐CH₃O(C₆H₄))N?C(CH₃)CH?C(CH₃)NH(2‐CH₃O(C₆H₄)), HL² = (2,4,6‐(CH₃)₃ (C₆H₂))N?C(CH₃)CH?C(CH₃)NH(2,4,6‐(CH₃)₃(C₆H₂)), HL³ = PhN?C(CH₃)CH(CH₃) NHPh) were treated with Ln(CH₂SiMe₃)₃(THF)₂ to give dialkyl complexes L¹Ln (CH₂SiMe₃)₂ (Ln = Y ( 1a ), Lu ( 1b ), Sc ( 1c )), L²Ln(CH₂SiMe₃)₂(THF) (Ln = Y ( 2a ), Lu ( 2b )), and L³Lu(CH₂SiMe₃)₂(THF) (3). All these complexes were applied to the copolymerization of cyclohexene oxide (CHO) and carbon dioxide as single‐component catalysts. Systematic investigation revealed that the central metal with larger radii and less steric bulkiness were beneficial for the copolymerization of CHO and CO₂. Thus, methoxy‐modified β‐diiminato yttrium bis(alkyl) complex 1a , L¹Y(CH₂SiMe₃)₂, was identified as the optimal catalyst, which converted CHO and CO₂ to polycarbonate with a TOF of 47.4 h^?1 in 1,4‐dioxane under a 15 bar of CO₂ atmosphere (T_p=130 °C), representing the highest catalytic activity achieved by rare‐earth metal catalyst. The resultant copolymer contained high carbonate linkages (>99%) with molar mass up to 1.9 × 10⁴ as well as narrow molar mass distribution (M_w/M_n = 1.7). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6810–6818, 2008     

Effect of core substituents on the intramolecular exchange interaction in N,N′‐dioxy‐2,6‐diazaadamantane biradical: DFT studies

Density‐functional theory calculations of a series of organic biradicals on the basis of the N,N′‐dioxy‐2,6‐diazaadamantane core with different substituents at carbon atoms adjacent to the nitroxyl groups have been performed by the UB3LYP/6‐311++G(2d,2p) method. Using the breaking symmetry approach, the values of the exchange interaction parameter, J, between the radical centers are calculated. It is shown that the intramolecular exchange interaction for the most part is ferromagnetic in nature, but the J parameter gradually decreases, changing its sign to antiferromagnetic interaction for the last substituent in the following sequence: CF₃(CH₃)COH > CH₂F(H)COH > CH₂OH > H > CBr₃ > CH₂F > CCl₃ > CF₃ > CH₂Br > CH₂Cl > CH₃ > C₂H₅ > C₃H₇ > i‐C₄H₉ > F > Br > OCH₃ > Cl > CH₂C₆H₅. The calculations at the UHSEH1PBE/6‐311++G(2d,2p) level with the most of substituents show nearly the same variation sequence for the J parameter. It is concluded that spin polarization effects in the diazaadamantane cage and a direct through‐space antiferromagnetic exchange interaction between the nitroxyl groups are the main mechanisms contributing to the exchange interaction parameter value in the studied series of compounds. The exchange coupling constant, J, depends on the electronic effects and geometry of the substituents, as well as on their specific interactions with the nitroxyl radical groups.     

Preparation of bisdiazoalkane and related complexes from the reactions of diazo compounds with the dinitrogen complexestrans-[M(N2)2(Ph 2PCH2CH2PPh 2)2] (M=Mo or W)

Summary Reactions oftrans-[M(N₂)₂(dppe)₂] (A;M=Mo, W;dppe=Ph ₂PCH₂CH₂PPh ₂) with ethyldiazoacetate, N₂CHCOOEt, yield the bisdiazoalkane speciestrans-[M(N₂CHCOOEt)₂(dppe)₂], upon simple replacement of the dinitrogen ligand by ethyldiazoacetate. However, diazomethane, N₂CH₂, reacts withA with loss of N₂ to give products which we tentatively formulate as containing methylene ligands,trans-[M(CH₂)₂(dppe)₂].

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Herstellung von Bisdiazoalkan- und ähnlichen Komplexen aus den Reaktionen von Diazoverbindungen mit Distickstoffkomplexen des Typstrans-[M(N₂)₂(Ph ₂PCH₂CH₂PPh ₂)₂] mitM=Mo oder W

Zusammenfassung Die Reaktion vontrans-[M(N₂)₂(dppe)₂] (A:dppe=Ph ₂PCH₂CH₂PPh ₂ undM=Mo oder W) mit Ethyldiazoacetat, N₂CHCOOEt, ergab nach einfachem Austausch des Distickstoffliganden mit Ethyldiazoacetat die Bisdiazoalkanetrans-[M(N₂CHCOOEt)₂(dppe)₂]. Diazomethan (N₂CH₂) hingegen reagierte mitA unter Verlust von N₂ zu Produkten, die tentativ alstrans-[M(CH₂)₂(dppe)₂] mit Methylenliganden formuliert wurden.

     

Complexes of [(iPrO)2P(O)NHC(S)NHCH2]2CH2 with Co(II), Ni(II), Zn(II), and Pd(II): Reaction of [(iPrO)2P(O)NHC(S)NHCH2]2 with KOH Leading to the Imidazolidine-2-Imine Derivative

Reaction of O,O′-diisopropylphosphoric acid isothiocyanate (iPrO)₂P(O)NCS with NH₂(CH₂)_nNH₂ (n = 3, 2) leads to the N-phosphorylated bis-thioureas [(iPrO)₂C(S)NHP(O) NH]₂Z (Z = —(CH₂)₃—, H₂L^I ; —(CH₂)₂—, H₂L^II ). Reaction of the potassium salt of H₂L^I with Co(II) and Zn(II) in aqueous EtOH leads to complexes of formula M₂(L-O,S)₂. The metal cation in both complexes is coordinated by two deprotonated ligands through the sulfur atoms of the thiocarbonyl groups and the oxygen atoms of the phosphoryl groups. Reaction of K₂L^I with Ni(II) and Pd(II) in the same conditions leads to M₂(L-N,S)₂ complexes. In both compounds, the metal center is found in a square-planar N₂S₂ environment formed by the C=S sulfur atoms and the P—N nitrogen atoms of two deprotonated ligands L^I . Reaction of H₂L^II with KOH leads to a product of heterocyclization, in which one of the thiourea fragments is retained. Compounds obtained were investigated by IR, UV-Vis, ¹H and ³¹P NMR spectroscopy, and microanalysis.     

Schiff base complexes of dioxouranium(VI). VII. Dioxouranium(VI) acetate complexes with monobasic bidentate and bibasic tridentateSchiff bases

11 and 12 molar reactions of dioxouranium(VI) acetate dihydrate with the monobasic bidentateSchiff bases,o-HOC₆H₄CH=NR oro-HOC₁₀H₆CH=NR (R=C₂H₅,n-C₃H₇,n-C₄H₉ or C₆H₅) and bibasic tridentateSchiff bases,o-HOC₆H₄CH=NR(OH) oro-HOC₁₀H₆CH=NR(OH) (R=–CH₂CH(CH₃)- or —CH₂CH₂CH₂–) have been studied and derivates of the type UO₂(OAc)₂(SBH), UO₂(OAc)₂(SBH)₂, UO₂(OAc)₂(SBH ₂) and UO₂(OAc)₂(SBH ₂)₂ (whereSBH andSBH ₂ represent monobasic bidentate and bibasic tridentateSchiff base molecules respectively) have been isolated. These have been characterized by elemental analysis, conductance measurements and IR spectral studies.

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UO₂ ²⁺-Komplexe von Schiff-Basen. VII. Uranylacetat-Komplexe mit monobasischen zweizähnigen und bibasischen dreizähnigen Schiff-Basen

Zusammenfassung Es wurden in 1:1- und 1:2-molaren Reaktionen von UO₂(OAc)₂·2H₂O mitSchiff-Basen (L) Komplexe des Typs UO₂(OAc)₂ L bzw. UO₂(OAc)₂ L ₂ isoliert. Die Komplexe wurden mittels Elementaranalyse, Leitfähigkeitsmessungen und IR-Spektren untersucht.

     

The molecular and electronic structure features of silatranes, germatranes, and their carbon analogs

Molecular geometries of fifty-six metallatranes N(CH₂CH₂Y)₃M-X and fifty-six carbon analogs HC(CH₂CH₂Y)₃M-X (M = Si, Ge; X = H, Me, OH, F; Y = CH₂, O, NH, NMe, NSiMe₃, PH, S) were optimized by the DFT method. Correlations between changes in the bond orbital populations, electron density ρ(r), electron density laplacian ∇²ρ(r), |λ₁|/λ₃ ratio, electronic energy density E(r), bond lengths, and displacement of the central atom from the plane of three equatorial substituents and the nature of substituents X and Y were studied. As the number of electronegative substituents at the central atom increases, the M←N, M-X, and M-Y bond lengths decrease, while the M←N bond strength and the electron density at critical points of the M←N, M-X, and M-Y bonds increase. An increase in electronegativity of a substituent (X or Y) is accompanied by a decrease in the ionicities of the other bonds (M-X, M-Y, and M←N) formed by the central atom (Si, Ge). A new molecular orbital diagram for bond formation is proposed, which takes into account the interaction of all five substituents at the central atom (M = Si, Ge) in atrane molecules. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 448–460, March, 2006.     

Calculation of the molecular exchanging energy of binary surfactants system on the surface monolayer of aqueous solution

By using the binary anionic/cationic surfactants system CH3(CH2)nOSO_3/CH3(CH2)nN (CH3)3 as an ex-ample, the molecular exchanging energy (ε) of adsorption on the surface monolayer of aqueous solu-tion has been studied. ε can be obtained with two methods. One is from the relationship between ε and the molecule interaction parameter (β). This relationship is founded by considering that the adsorption of mixed surfactants on the surface monolayer of solution satisfies the dimensional crystal model condition under which β can be obtained by testing the surface tension of solution. The other is directly from the molecular structure of surfactants with the Lennard-Jones formula. The results for the studied system show that these two methods coincide well.     

Carbofunctional fluorine-containing triethoxysilanes: synthesis,film forming and properties

Novel fluorine-containing carbofunctional organosilicon monomers were synthesized: 3-pentafluorobenzylideneaminopropylethoxysilane (EtO)₃Si(CH₂)₃N=CH-C₆F₅, N-3-methoxydiethoxysilylpropyltrifluoroacetamide (EtO)₂(MeO)Si(CH₂)₃NHC(O)CF₃, and 1,1,5-trihydrooctafluoroamyl N-3-triethoxysilylpropylaminopropanoate (EtO)₃Si(CH₂)₃NH(CH₂)₂C(O)OCH₂(CF₂)₃CHF₂. Compositions for the formation of transparent thermally stable films were prepared from these monomers. The films have low absorbance intensity near 1550 nm, i.e., in the region of photosignal transmission of modern optical communication systems. The compositions can dissolve complexes with organofluorine ligands and produce transparent homogeneous films doped with rare-earth metals. The concentrations of the complexes in the matrices are 3.7–21.4 wt.% (metal concentrations are 0.6–3.7%). Fluorescence and fluorescence excitation spectra of the matrices and electronic absorption spectra of the doped films were studied. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1131–1138, May, 2005.     

CO2-fixation into carbonate anions for the construction of 3d-4f cluster complexes with salen-type Schiff base ligands: from molecular magnetic refrigerants to luminescent single-molecule magnets

Six new carbonate-bridged Zn₂Ln₂ cluster complexes derived from salen-type Schiff base ligands [H₂L^a = N, N′-bis(3-methoxysalicylidene)-1,3-diaminopropane and H₂L^b = N, N′-bis(3-methoxysalicylidene)- 1,2-diaminoethane] have been synthesized. The bis-imine chain in Schiff base ligands have an obvious influence on the cluster complexes' structures, magnetic and luminescence properties. The carbonate bridging ligand exactly comes from autoimmobilization of carbon dioxide, which may mediate ferromagnetic coupling between Ln³⁺ ions, favoring magnetocaloric effects and single molecule magnet (SMM) properties. Complexes Zn₂Dy₂(μ³-CO₃)₂(L^a)₂(NO₃)₂(MeOH)₂ ( 1 ) and [Zn₂Dy₂(μ³-CO₃)₂(L^b)₂(NO₃)₂]·2MeOH ( 2) show field-induced SMM properties; complexes Zn₂Tb₂(μ³-CO₃)₂(L^a)₂(NO₃)₂(MeOH)₂ ( 3 ) and [Zn₂Tb₂(μ³-CO₃)₂(L^b)₂(NO₃)₂]·2MeOH ( 4 ) display both luminescence and field-induced SMM behaviors; while complexes [Zn₂Gd₂(μ³-CO₃)₂(L^a)₂(NO₃)₂]·2MeOH ( 5 ) and [Zn₂Gd₂(μ³-CO₃)₂(L^b)₂(NO₃)₂]·2MeOH ( 6 ) exhibit medium magnetic entropy changes, which are candidates for cryogenic molecular magnetic refrigerants.     

Synthesis of N‐Substituted (3S,4S)‐ and (3R,4R)‐Pyrrolidine‐3,4‐diols: Search for New Glycosidase Inhibitors

N‐Substituted (3S,4S)‐ and (3R,4R)‐pyrrolidine‐3,4‐diols 9 and 10 , respectively, were derived from (+)‐L ‐ and (?)‐D ‐tartaric acid, respectively. Compounds 9k, 9l , and 9m with the N‐substituents, BnNH(CH₂)₂, 4‐PhC₆H₄CH₂NH(CH₂)₂ and 4‐ClC₆H₄CH₂NH(CH₂)₂, respectively, showed modest inhibitory activities toward α‐D ‐amyloglucosidases from Aspergillus niger and from Rhizopus mold (Table 1). Unexpectedly, several (3R,4R)‐pyrrolidine‐3,4‐diols 10 showed inhibitory activities toward α‐D ‐mannosidases from almonds and from jack bean (Table 3). N‐Substitution by the NH₂(CH₂)₂ group, i.e., 10g , led to the highest potency.     

Well phase separated segmented copolymers via acyclic diene metathesis (ADMET) polymerization

Segmented oligomers consisting of polyoctenylene hard segments and unsaturated polytetrahydrofuran soft segments were prepared using acyclic diene metathesis (ADMET) copolymerization techniques. These are the first such segmented materials prepared via metathesis chemistry. Two different molecular weight α,ω-poly(tetrahydrofuran)diene soft segment monomers of the structure [CH₂CH(CH₂)₄[O(CH₂)₄]-_nO(CH₂)₄CHCH₂] (1) were synthesized by the cationic living polymerization of tetrahydrofuran (THF). Trifluoromethanesulfonic anhydride, (CF₃SO₂)₂O (triflic anhydride) (2), was employed as the initiator, followed by in situ bis-functionalization with 5-hexen-1-ol, [CH₂=CH(CH₂)₄OH] (3), to yield soft segment dienes with vinyl end groups. The functionality of these soft segment monomers was approximately 1.9. These telechelic monomers possessed sufficient functionality to be homopolymerized or copolymerized with 1,9-decadiene (4) to generate well phase separated, segmented oligomers exhibiting hard segment/soft segment thermal behavior. The segmented copolymers were characterized by ¹H-NMR, ¹³C-NMR, and IR spectroscopy, elemental analysis, and TGA and DSC analysis. Average molecular weights were determined by gel permeation chromatography (GPC) and end-group analysis. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3441–3449, 1997