Two-dimensional hybrid germanium zeotype formed by selective coordination of the trans-1,2-diaminocyclohexane isomer to the ge atom: heterogeneous acid-base bifunctional catalyst

[C 6H 10(NH 2) 2Ge 3O 6] ICMM9 is a two-dimensional germanate in which the metallic atoms are covalently bonded to chelating diamines. Its layered structure having some similitude with that of the pyroxene mineral, presents a totally new topology with two 4-c nodes. The solvothermal synthesis reaction allows the separation in situ of the two 1,2-diaminocyclohexane isomers by selective coordination of the trans isomer to octahedral Ge atoms of the ICMM9 framework. This material behaves as an active and selective heterogeneous acid-base bifunctional catalyst.     

Quality control in residual solvent analysis: the static headspace gas chromatographic method

 Residual solvent testing of raw materials and drug products constitutes part of a quality control programme. Static headspace gas chromatography (HS/GC) is suggested in current pharmacopoeias as a general tool for residual solvent testing. But the main obstacles to using HS/GC procedures are the absence of performance tests, suitable reference solvents and matrix standards, and reference methods. Harmonized regulations for residual solvent testing allow the use of a cumulative approach to estimate the residual solvent content in drug products. The supplier data may be appropriate. Therefore, in a quality control programme the main accent is put on the definition of specification limits (in accordance with toxicological data, and the influence of residual solvents on the physical properties and stability of the product) and supplier qualification. This paper focuses on two main problems linked to supplier qualification: system performance and matrix effect. HS/GC of a mixture containing solvents of different volatility and polarity is proposed as a performance test. The test can be done in three ways in accordance with the residual solvents characteristics, the test sample solubility and the specification levels required. The use of the test as a diagnostic tool is demonstrated and sources of uncertainty of the recovery determination are discussed. Received: 12 December 1998 · Accepted: 25 January 1999     

Large-scale membrane adsorbers.

A new large-scale membrane adsorber system for rapid separation of biomolecules based on a hollow cylindrical module geometry in unitized construction and combined parallel and serial connection of modules is presented. The effectiveness of the concept is demonstrated by breakthrough curves on a 21-m2 pilot plant with hemoglobin as a model substance. Scale-up to the order of 100 m2 and above is easily performed by combining modules in parallel for increasing capacity, and in series for optimizing performance. An estimation of productivity based on these data is presented. Preliminary results of separations by linear salt gradient elution are also given.     

Identification of m-Mentha-3(8),6-diene (Isosylveterpinolene) in Black Pepper Oil

m-Mentha-3(8),6-diene (&sequals n01; isosylveterpinolene; 5 ), which has not been found in nature before, was shown by GC/MS analysis and co-injection with a synthetic sample to be present to the extent of 0.12 – 0.17% in black and green pepper oil. The synthetic reference 5 was prepared by deconjugation of 3-methylcyclohex-2-en-1-one ( 1 ), subsequent alkylation with lithium 2-lithio-2-methylpropanoate, and decarboxylative dehydration of the resulting hydroxycarboxylic acid 3 employing dimethylformamide dimethyl acetal. On polar GC columns, 5 was eluted between p-cymene and terpinolene, and was characterized by an MS similar to that of terpinolene, but with the fragment m/z 121 (59, [M−Me]⁺) being less intense than that of the molecular ion at m/z 136 (67, M⁺). Since m-mentha-3(8),6-diene was also found to the extent of 0.24% in the headspace of ground black peppercorns, it can be considered to be of genuine natural origin, and thus is the first established example of a naturally occurring m-menthadiene.     

N‐Arylated 3,5‐Dihydro‐4H‐dinaphtho[2,1‐c:1′,2′‐e]azepines: Axially Chiral Donors with High Helical Twisting Powers for Nonplanar Push–Pull Chromophores

Axially chiral, N‐arylated 3,5‐dihydro‐4H‐dinaphtho[2,1‐c:1′,2′‐e]azepines have been prepared by short synthetic protocols from enantiopure 1,1′‐bi(2,2′‐naphthol) (BINOL) and anilines. Alkynes substituted with two N‐phenyldinaphthazepine donors readily undergo a formal [2+2] cycloaddition, followed by retro‐electrocyclization, with tetracyanoethene (TCNE) to yield donor‐substituted 1,1,4,4‐tetracyanobuta‐1,3‐dienes (TCBDs) featuring intense intramolecular charge‐transfer (CT) interactions. A dicyanovinyl derivative substituted with one N‐phenyldinaphthazepine donor was obtained by a “one‐pot” oxidation/Knoevenagel condensation from the corresponding propargylic alcohol. Comparative electrochemical, X‐ray crystallographic, and UV/Vis studies show that the electron‐donor qualities of N‐phenyldinaphthazepine are similar to those of N,N‐dimethylanilino residues. The circular dichroism (CD) spectrum of a push–pull chromophore incorporating the chiral donor moiety features Cotton effects of exceptional intensity. With their elongated shape and the rigidity of the chiral N‐aryldinaphthazepine donors, these chromophores are effective inducers of twist distortion in nematic liquid crystals (LCs). Thus, a series of the dinaphthazepine derivatives was used as dopants in the nematic LC E7 (Merck) and high helical twisting powers (β) of the order of hundreds of μm^?1 were measured. Theoretical calculations were employed to elucidate the relation between the structure of the dopants and their helical twisting power. For the derivatives with two dinaphthazepine moieties, a strong dependence of the β‐values on the structure and conformation of the linker between them was found.     

Uncertainty in the determination of glucose in aqueous solutions by high‐performance liquid chromatography with evaporative light scattering detection

The determination of glucose and other carbohydrates is the most widespread chemical analysis that is performed within the industries of food, beverage, forage, biomass, pulp and paper, pharmaceuticals among others. Besides that, sugar refineries need to control their products, by‐products and effluents, and furthermore, glucose in the sucrose refining process, is considered an impurity, which shall be controlled. Being HPLC the most currently instrumental technique used for glucose analysis, the evaporative light scattering detector (ELSD) offers advantages (sensitivity, possibility for operating in gradient mode) over the also used refractive index detector. In this work, an HPLC‐ELSD methodology was optimised and validated, aiming the estimate of the uncertainty associated with the results at low levels of concentration of glucose to be measured. Linearity of the response was obtained in the range of glucose concentrations from 20 to 300 mg/L, with an analysis time of 10 min. The global uncertainty was estimated accordingly to the bottom‐up approach used by Eurachem. It was 13% on average for concentrations from 100 to 300 mg/L. For lower concentrations, uncertainty increased significantly up to 30% in the vicinity of the LOD of the method.     

Non-Covalent Interactions in a Nickel(II) Complex with Benzilate and 1,10-Phenanthroline

Abstract  

A new mixed-ligand nickel(II) coordination compound [Ni(bz)₂(phen)₂] (1) (bz = benzilate and phen = 1,10-phenanthroline) has been synthesized by refluxing nickel(II) acetate with benzilic acid and 1,10-phenantholine. Compound 1 has been characterized by elemental analysis, IR and electronic absorption spectroscopy, magnetic measurements, thermogravimetric analysis and single-crystal X-ray diffraction The crystal of 1 belongs to monoclinic crystal system, space group C2/c and its unit cell parameters are a = 25.881(3), b = 11.1728(15), c = 17.609(2) ? and β = 124.104(3)°. The effect of non-covalent interactions, such as π···π and C–H···π, on the 3D supramolecular organization of this molecular complex is analyzed.     

Ab initio potential-energy surface and rovibrational states of the HCN-HCl complex

A four-dimensional intermolecular potential-energy surface has been calculated for the HCN-HCl complex, with the use of the coupled cluster method with single and double excitations and noniterative inclusion of triples. Data for more than 13,000 geometries were represented by an angular expansion in terms of coupled spherical harmonics; the dependence of the expansion coefficients on the intermolecular distance R was described by the reproducing kernel Hilbert space method. The global minimum with De=1565 cm(-1) and Re=7.47a0 has a linear HCN-HCl hydrogen-bonded structure with HCl as the donor. A secondary hydrogen-bonded equilibrium structure with De=564 cm(-1) and Re=8.21a0 has a T-shaped geometry with HCN as the donor and the acceptor HCl molecule nearly perpendicular to the intermolecular axis. This potential surface was used in a variational approach to compute a series of bound states of the isotopomers HCN-H35Cl, DCN-H35Cl, and HCN-H37Cl for total angular momentum J=0,1,2 and spectroscopic parities e, f. The results could be analyzed in terms of the approximate quantum numbers of a linear polyatomic molecule with two coupled bend modes, plus a quantum number for the intermolecular stretch vibration. They are in good agreement with the recent high resolution spectrum of Larsen et al. [Phys. Chem. Chem. Phys. 7, 1953 (2005)] in the region of 330 cm(-1) corresponding to the HCl libration. The (partly anomalous) effects of isotopic substitutions on the properties of the complex were explained with the aid of the calculations.     

Fire retardancy behavior of PLA based nanocomposites

To understand and improve the fire retardancy behavior of polylactic acid, we have incorporated two structurally different additives, sepiolite and organically modified montmorillonite. A novel approach (combination of electrospinning and extrusion/injection molding) is employed to address critical issues like char enhancement as well as the homogeneity/uniformity of the inorganic barrier during combustion of polymer nanocomposites. Fundamental knowledge is gained on the mechanisms of fire retardancy, particularly with samples of different thicknesses (thermally thin versus thermally intermediate/thick). Volumetric imaging of the residues provided a deeper understanding of the formation or the evolution of the inorganic barrier. Considerable insight on the dependency of biodegradation on the environment (primarily) and on the compromising effect of high aspect ratio nanoparticles is also obtained. This knowledge has a broader scientific impact and is critical to design the new generation of eco-benign flame retardant and biodegradable polymer nanocomposites.     

Chiral information harvesting in helical poly(acetylene) derivatives using oligo(p-phenyleneethynylene)s as spacers

A chiral harvesting transmission mechanism is described in poly(acetylene)s bearing oligo(p-phenyleneethynylene)s (OPEs) used as rigid achiral spacers and derivatized with chiral pendant groups. The chiral moieties induce a positive or negative tilting degree in the stacking of OPE units along the polymer structure, which is further harvested by the polyene backbone adopting either a P or M helix.

A chiral harvesting transmission mechanism is described in poly(acetylene)s bearing oligo(p-phenyleneethynylene)s (OPEs) used as rigid achiral spacers and derivatized with chiral pendant groups.

During the last years, dynamic helical polymers have attracted the attention of the scientific community due to the possibility of tuning the helical sense and/or the elongation of the helical structure by using external stimuli.^1–14In the case of a chiral dynamic helical polymer, modifications in its structure—helical sense enhancement or helix inversion—arise from conformational changes induced at its chiral pendants—usually, with just one stereocenter—, by stimuli such as variations in solvent polarity or temperature, the addition of certain ions, and so on (Fig. 1a).¹⁵ On the other hand, if a helical polymer is achiral (i.e., bearing achiral pendants), the chiral amplification phenomena can emerge from interactions between the polymer and external chiral molecules.¹⁶ In both the above cases, the changes produced in the helical structures are related to the spatial dispositions adopted by the substituents or associated species at the pendant groups.^17–19Open in a separate windowFig. 1Several scenarios depicting conceptual representations of the transmission of chiral information. (a) Helical switch via chiral tele-induction. (b) Effect of distance on chiral tele-induction from multichiral pendants. (c) Helicity controlled by the conformational composition of achiral spacers.A step forward in the helical sense control of poly(phenylacetylene)s (PPA)s is to study different mechanisms of transmission of chiral information from the pendant to the polyene backbone by introducing achiral spacers. The goal is to demonstrate how far it is possible to place the chiral center and still have an effective chiral induction on the polyene backbone. Therefore, transmission of the chiral information from a remote position can occur through space, thus overpassing the distance generated by the spacer—tele-induction—(Fig. 1b),^20–28 or through the achiral spacer itself, producing in it a preferred structure, such as a helical structure and where the orientation of the achiral helix is further transmitted to the polyene backbone—conformational switch—(Fig. 1c).^29–31For the first mechanism—chiral tele-induction—, both flexible and rigid spacers have been designed.^20–28 In all cases, supramolecular interactions, such as H bonding or π–π stacking, generate organized structures. As a result, the chiral center is located into a specific orientation, producing an effective helical induction. Additionally, those studies allow evaluating how distances and sizes have an effect on this phenomenon.In the second strategy, the helix induction is transmitted through conformational changes along an achiral spacer which is harvested by the polyene. For instance, an achiral peptide or an achiral polymeric helix derivatized at one end with a chiral residue and linked to the polymer main chain at the other end. In such cases, changes in the absolute configuration or even just a conformational change at the chiral center can induce an opposite helical structure into the achiral spacer, which in turn will be harvested by the polymer main chain (Fig. 1c).^29–31Herein we will demonstrate another remote chiral induction mechanism based on a different chiral harvesting process. In this case, the chiral center does not produce a conformational change at the achiral spacer, but affects its array within the helical scaffold. Thus, to perform these studies we decided to introduce the use of oligo(p-phenyleneethynylene)s (m = 1, 2, 3) (OPEs) as rigid spacers to separate the distant chiral center from the polyene backbone. These OPE units have been used in the formation of benzene-1,3,5-tricarboxamide (BTA) based supramolecular helical polymers, demonstrating their ability to stack with a certain tilting degree commanded by the chiral center.^32–34Hence, in our design, the chiral moiety will determine the supramolecular chiral orientation of the OPE groups used as spacers, which is further harvested by the polyene backbone. The overall process yields a helix with a preferred screw sense (Fig. 2).Open in a separate windowFig. 2Conceptual side view and top view of the chiral information transmission mechanism from stereocenters at the far end of oligo(p-phenyleneethynylene) spacers to the polyene backbone via chiral harvesting.To perform these studies, we used as model compounds two PPAs—poly-(R)-1 and poly-(S)-1—derived from the 4-ethynylanilide of (S)- and (R)-α-methoxy-α-phenylacetic acid (MPA, m-(S/R)-1), whose helical structures and dynamic behaviors have been deeply studied by our group—poly-(R)-1 and poly-(S)-1—(Fig. 3).^35–46 By using these polymers as reference materials, four novel PPAs were designed introducing two OPE spacers—4-[(p-phenyleneethynylene)_n]ethynylanilide (n = 1, 2)—between the phenyl acetylene group and the (S)- or (R)-α-methoxy-α-phenylacetic acid (MPA) chiral group. Thus, monomers m-(S)- and m-(R)-2 and m-(S)- and m-(R)-3 (Fig. 3a) were prepared and submitted to polymerization by using a Rh(i) catalyst poly-(S)- and poly-(R)-2 and poly-(S)- and poly-(R)-3 (Fig. 3b) were obtained in high yield and showed Raman spectra characteristic of cis polyene backbones (see Fig. S11 and S12^†).Open in a separate windowFig. 3(a) Monomers and (b) polymers synthetized in this study.X-ray structures of the monomers show a preferred antiperiplanar (ap) orientation between the carbonyl and methoxy groups (O C–C–OMe) for m-(R)-2 and m-(S)-3, whereas in the case of m-(S)-1 a synperiplanar (sp) geometry is favoured (Fig. 4a).³⁵ In complementary studies, CD spectra of monomers m-(S)-[1–3] in CHCl₃ show negative Cotton effects, indicative of major ap conformations in solution (Fig. 4b),³⁵ further corroborated by theoretical calculations (see Fig. S10^†). Interestingly, the maximums of the Cotton effects in CD undergo a bathochromic shift—from 266 nm in m-1 to 327 nm in m-3—due to a larger conjugation of the π electrons (from the anilide to the alkyne group) when the length of the spacer increases (Fig. 4b).Open in a separate windowFig. 4(a) X-ray structures of m-(S)-1, m-(R)-2 and m-(S)-3. (b) CD traces of m-(S)- and m-(R)-1; m-(S)- and m-(R)-2; m-(S)- and m-(R)-3 in CHCl₃ (0.1 mg mL⁻¹). (c) CD spectra for poly-(S)- and poly-(R)-1 in CHCl₃ (0.1 mg mL⁻¹); poly-(S)- and poly-(R)-2 in DMSO (0.1 mg mL⁻¹); poly-(S)- and poly-(R)-3 in DMSO (0.1 mg mL⁻¹).CD studies of the polymer series bearing OPE spacers—poly-(R)- and poly-(S)-[2–3]—in different solvents show the formation of a PPA helical structure with a preferred helical sense, while the parent polymer, poly-1, devoid of the OPE unit, has a poor CD. This is a very interesting phenomena that indicates that the OPE spacers work as transmitters of the chiral information from remote chiral centers to the polyene backbone—placed at 1.7 nm for poly-2 and at 2.4 nm for poly-3—(Fig. 4a). These large distances between the chiral center and the polymer main chain mean that other mechanisms of chiral induction, such as chiral tele-induction effect, should be almost null in these cases.In these two polymers (poly-2 and poly-3), the chiral information transmission mechanism must occur in different sequential steps. First, the chiral centers possessing a major (ap) conformation induce a certain tilting degree (θ) in the achiral spacer array. This step resembles the helical induction mechanism found in supramolecular helical polymers bearing OPE units.^32–34 Next, the chiral array induced in the OPE units is harvested by the polyene backbone, resulting in an effective P or M helix induction (Fig. 2).^34,47Additional structural studies were carried out in poly-(S)-2 and poly-(S)-3 to obtain an approximated secondary structure of these polymers and determine their dynamic behaviour.From literature it is known that the conformational equilibrium of poly-1 can be altered in solution by the presence of metal ions. The addition of monovalent ions (e.g., Li⁺) stabilizes the ap conformer at the pendant group by cation–π interactions, while divalent ions (e.g., Ca²⁺) stabilize the sp conformations by chelation with the methoxy and carbonyl groups.^36,38,39,43 As a result, both the P or M helical senses can be selectively induced in poly-1 by the action of metal ions.Therefore, we decided to add different perchlorates of monovalent and divalent metal ions to solutions of poly-(S)-2 and poly-(S)-3 with the aim of determining the conformational composition at the pendant groups. Thus, when monovalent metal ions (Li⁺, Ag⁺ and Na⁺) are added to a chloroform solution of poly-(S)-2, a chiral enhancement is observed (Fig. 5d for Li⁺ and Fig. S16^† for Na⁺ and Ag⁺). IR and ⁷Li-NMR studies show that those ions stabilize the ap conformer at the pendant group in a similar fashion to poly-1, this is by coordination to the carbonyl group of the MPA (Fig. 5g) and the presence of a cation–π interaction with the aryl ring of the chiral (|Δδ| ⁷Li ca., 3.75 ppm) (Fig. 5f and ESI^†). Therefore, addition of Li⁺ produces a larger number of pendant groups with ap conformation among poly-2, which triggers a chiral enhancement effect through a cooperative process.Open in a separate windowFig. 5(a) Conceptual representation of the chiral information harvesting and top view of the 3D model for poly-(S)-2. (b) CD spectra of poly-(S)-2 (0.2 mg mL⁻¹) in DMSO vs. calculated ECD spectra. Full width at half-maximum (FWHM) equals 20 nm. (c) Low-resolution AFM image from a poly-(S)-2 monolayer and profile depicting the chain separation of the yellow highlighted area in the AFM image. (d) CD spectra showing the chiral enhancement after the addition of Li⁺ (50 mg mL⁻¹, THF) to a poly-(S)-2 solution (0.1 mg mL⁻¹, THF). (e) CD trace of poly-(S)-2 before and after the addition of a Ca²⁺ solution (50 mg mL⁻¹, THF). (f) ⁷Li-NMR spectra substantiating the cation–π interaction. (g) IR shifts observed for carbonyl and methoxy groups after the addition of LiClO₄ and Ca(ClO₄)₂ (50 mg mL⁻¹, THF) to a poly-(S)-2 solution (3 mg mL⁻¹, CHCl₃). The coordination modes of the MPA moiety with Li⁺ and Ca²⁺ are shown vertically in the middle of the figure.On the contrary, the addition of perchlorates of divalent metal ions, such as Ca²⁺and Zn²⁺, produced an inversion of the third Cotton band—310 nm—associated to the MPA moiety and the disappearance of both first and second Cotton effects (Fig. 5e for Ca²⁺ and Fig. S17^† for Zn²⁺). This is a very interesting outcome because, although the conformational equilibrium at the MPA group changes from ap to sp after the addition of Ca²⁺, the number of pendant groups with sp conformation do not reach the number needed to trigger the helix inversion process and in fact, a mixture of P and M helices at the polyene backbone is obtained.The helical structures adopted by both polymer systems, PPAs (poly-1) and poly[oligo(p-phenyleneethynylene)phenylacetylene]s (POPEPAs) (poly-2 and poly-3), are defined by two coaxial helices, one formed by the polyene backbone (internal helix, CD active) and the other constituted by the pendants (external helix, observed by AFM).These two helices can rotate in either the same or the opposite sense, depending on the dihedral angle between conjugated double bonds. Thus, internal and external helices rotate in the same direction in cis-cisoidal polymers, while they rotate in opposite directions in cis-transoidal ones.^14,42,48,49In order to find out an approximated helical structure for poly-(S)-2, DSC studies were performed. The thermogram shows a compressed cis-cisoidal polyene skeleton (see Fig. S13a^†), similar to the one obtained for poly-1.⁴² Moreover, AFM studies on a 2D crystal of poly-(S)-2 did not produce high-resolution AFM images, although some parameters such as helical pitch (c.a., 2.8 nm) and packing distance between helices of (c.a., 6 nm) could be extracted from the well-ordered monolayer analyzed (Fig. 5c).Previous structural studies in PPAs found that it is possible to correlate the internal helical sense with the Cotton band associated to the polyene backbone—CD (+), P_int; CD (−), M_int—.^50,51 Herein, the positive Cotton effect observed for the polyene backbone [CD_{365 nm} = (+)] in poly-(S)-2 is indicative of a P orientation of the internal helix, which correlates with a P orientation of the external helix in a cis-cisoidal polyene scaffold. To summarize, DSC, AFM and CD studies agree that poly-(S)-2 is made up of a cis-cisoidal framework with P_int and P_ext helicities (Fig. 5a).Computational studies [TD-DFT(CAM-B3LYP)/3-21G] were carried out on a P helix of an n = 9 oligomer of poly-(S)-2, possessing a cis-cisoidal polyene skeleton (ω₁ = +50°, ω₃ = −40°) and an antiperiplanar orientation of the carbonyl and methoxy groups at the pendants. The theoretical ECD spectrum obtained from these studies (Fig. 5b and see ESI^† for additional information) is in good agreement with the experimental one, indicating that our model structure is a good approximation of the helical structure adopted by poly-(S)-2.Next, a similar set of DSC and AFM studies were carried out for poly-(S)-3, that bears an OPE spacer with n = 2. The data showed that this polymer presents a compressed cis-cisoidal polyene skeleton, similar to those obtained for poly-1 and poly-2 (see Fig. S13b^†), with a helical pitch of 3.8 nm and a P_ext helical sense (Fig. 6a and c).Open in a separate windowFig. 6(a) Conceptual representation of the chiral information harvesting and top view of the 3D model for poly-(S)-3. (b) CD spectrum of poly-(S)-3 in THF (0.2 mg mL⁻¹) and comparison to the calculated ECD spectra. Full width at half-maximum (FWHM) equals 20 nm. (c) AFM image obtained from a poly-(S)-3 monolayer. (d) CD traces for poly-(S)-3 in THF polymerized at different temperatures.UV studies indicate that, in poly-(S)-3, the polyene backbone absorbs at ca. 380 nm, coincident with the first Cotton effect, that is positive (see Fig. S15b^†). Therefore, it reveals that poly-(S)-3 adopts a P_int helicity (Fig. 6b). Thus, as expected for cis-cisoidal scaffolds, the orientations of the two coaxial helices are coincident.Computational studies [TD-DFT(CAM-B3LYP)/3-21G] were carried out on a P helix of an n = 9 oligomer of poly-(S)-3, possessing a cis-cisoidal polyene skeleton (ω₁ = +63°, ω₃ = −40°) and an antiperiplanar orientation of the carbonyl and methoxy groups at the pendants. The theoretical results (Fig. 6b and see ESI^† for additional information) match with the experimental data, indicating that our model structure is a good approximation to the helical structure adopted by poly-(S)-3.Finally, the stimuli response properties of poly-(S)-3 were explored by CD. These experiments revealed that the addition of monovalent or divalent metal ions to a chloroform solution of poly-(S)-3 does not produce any significant effect in the structural equilibrium of this polymer (see Fig. S18^†). This fact, in addition to the previous results obtained from the interaction of poly-(S)-2 with divalent metal ions, corroborates the decrease of the dynamic character of helical PPAs when large OPEs are used as spacers.The poor dynamic behaviour was further demonstrated by polymerizing m-(S)-3 at a lower temperature (0 °C) (Fig. 6d). In this case, the region around 240–350 nm remains unaffected, indicating that the pendant is ordered in a similar manner in both batches of polymers, regardless of the temperature at which they were synthesized (20 °C and 0 °C). Interestingly, the magnitude of the first Cotton band is duplicated when the polymer is obtained at low temperature due to a stronger helical sense induction at the polyene backbone. This result indicates that a preorganization process may occur during polymerization, affecting the screw sense excess of the PPA.In conclusion, a novel chiral harvesting transmission mechanism has been described in poly(acetylene)s bearing oligo(p-phenylenethynylene)s as rigid spacers that place the chiral pendant group away from the polyene backbone, at a distance around ca. 1.7 nm for poly-2, and 2.4 nm for poly-3. Hence, the disposition of the chiral moiety affects the stacking of the OPE units within the helical structure, inducing a specific positive or negative tilting degree, which is further harvested by the polyene backbone inducing either a P or M internal helix.We believe that these results open new horizons in the development of novel helical structures by combining information from the helical polymers and supramolecular helical polymers fields, which leads to the formation of novel materials with applications in important fields such as asymmetric synthesis, chiral recognition or chiral stationary phases among others.