1H-Dipyrido[2,3-B:3',2'-D]Pyrrole
|
HS Code |
316548 |
| Chemical Formula | C10H6N4 |
| Appearance | Solid (usually a powder) |
| Color | Typically white to off - white |
| Melting Point | Relatively high, around 300 - 350 °C (approximate, may vary) |
| Boiling Point | Decomposes before boiling under normal conditions |
| Solubility In Water | Poorly soluble in water |
| Solubility In Organic Solvents | Soluble in some polar organic solvents like DMSO |
| Odor | Odorless or very faint odor |
| Crystal Structure | Complex organic molecular crystal structure |
| Pka | No significant acidic or basic pKa values in common pH range |
| Uv Vis Absorption | Absorbs in the ultraviolet region |
As an accredited 1H-Dipyrido[2,3-B:3',2'-D]Pyrrole factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | 100 - gram pack of 1H - Dipyrido[2,3 - B:3',2'-D]Pyrrole in sealed chemical - grade container. |
| Shipping | 1H - Dipyrido[2,3 - B:3',2'-D]Pyrrole is shipped in sealed, corrosion - resistant containers. Strict adherence to hazardous chemical shipping regulations ensures safe transit, with proper labeling and handling throughout the process. |
| Storage | 1H - Dipyrido[2,3 - B:3',2'-D]Pyrrole should be stored in a cool, dry place, away from heat sources and direct sunlight. Keep it in a well - sealed container to prevent exposure to moisture and air, which could potentially cause degradation. Store it separately from incompatible substances to avoid chemical reactions. Ideal storage temperature is typically around 2 - 8 °C if refrigerated storage is recommended by safety data sheets. |
In the fabrication of phosphorescent organic light-emitting diodes (PhOLEDs) where high external quantum efficiency must coexist with a long operational lifetime at practical display brightness levels, the 1H-dipyrido[2,3-b:3',2'-d]pyrrole skeleton serves as an electron-deficient building block for ambipolar host materials. Vacuum-deposited thin films of a typical 5,11-diaryl-substituted derivative doped with 8 wt% fac‑tris(2‑phenylpyridine)iridium(III) [Ir(ppy)₃] produce green electrophosphorescence with a drive voltage at 10 mA cm⁻² regularly falling below 4.2 V when the host is co-deposited with a separate electron-transporting layer such as 2,2′,2″-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi). The dipyrido-pyrrole core lowers the lowest unoccupied molecular orbital (LUMO) to approximately –2.8 eV––3.1 eV without introducing excessive conjugation that would broaden the emission spectrum, thereby confining the exciplex formation zone to the emissive layer–electron transport layer interface. On a Gen‑6 linear cluster evaporation source operating under a base pressure below 5×10⁻⁷ mbar, source preconditioning requires a gradual temperature ramp to 240–260 °C over 45 minutes to avoid sudden decomposition spikes that contaminate shadow masks. During extended campaigns exceeding 200 hours, the quartz crystal microbalance rate monitor shows a drift of less than 0.02 Å s⁻¹ only when the precursor has been validated against ASTM D7515-19 for peroxide-forming potential and has been stored under argon with molecular sieve 4A at –20 °C. A pre-deposition outgassing step at 10⁻⁶ mbar is non-negotiable; residual moisture above 50 ppm in the source material, detectable via Karl Fischer coulometry following ISO 15512:2019, shifts the turn-on voltage upward by 0.3–0.5 V and accelerates luminance decay to LT95 values under 1,000 cd m⁻² that fall below 400 hours in encapsulated devices. The final display-grade amorphous film must exhibit a root-mean-square surface roughness below 0.8 nm as measured by atomic force microscopy over a 5×5 μm² scan area, because larger aggregates nucleate dark spots observable in the aging test prescribed by IEC 62341-5-2:2019 Clause 5.7.
Why Does This Electron-Deficient Core Reduce Dark Current in Organic Photodetector Blends?When the 1H-dipyrido[2,3-b:3',2'-d]pyrrole unit is incorporated as the central acceptor fragment in a non-fullerene acceptor (NFA) designed for organic photodetector (OPD) bulk heterojunctions, its strong π-stacking propensity and high electron affinity simultaneously increase the external quantum efficiency under reverse bias and reduce the dark current density to levels compatible with indirect-conversion X-ray imagers. In a blade-coated blend with poly[(2,5-bis(2-decyltetradecyl)-3,6-bis(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione-5,5′-diyl)-alt-(thiophen-2,5-diyl)] (PDPP-TT) at a donor : acceptor weight ratio of 1:1.5 deposited from 1,2,4-trimethylbenzene onto indium tin oxide/zinc oxide, the dark current at –2 V drops below 2.1×10⁻⁷ A cm⁻², a value that is roughly one order of magnitude lower than that of comparable ITIC-based devices. This suppression originates from a large injection barrier at the zinc oxide–acceptor interface, as the LUMO of the dipyrido-pyrrole-based NFA sits at –3.9 eV versus –3.7 eV for ITIC, measured via cyclic voltammetry in 0.1 M tetrabutylammonium hexafluorophosphate acetonitrile solution calibrated against the ferrocenium/ferrocene redox couple (E1/2 = +0.40 V vs. SCE). Blade speed is constrained to 15–25 mm s⁻¹ with a gap height of 150 μm to keep the drying front stable; marangoni-driven thickness undulations exceeding ±12 nm cause the noise-equivalent power to deviate beyond the IEC 62906-1-2:2021 acceptance threshold for flat-panel detectors. Post-deposition thermal annealing at 120 °C for 10 minutes under nitrogen flow transforms the film morphology from a mixed face-on/edge-on orientation to a dominant edge-on texture confirmed by grazing-incidence wide-angle X-ray scattering, with the (010) π-stacking peak sharpening from a full width at half maximum of 0.38 Å⁻¹ to 0.21 Å⁻¹; any excursion above 130 °C initiates acceptor microcrystal growth visible as a hazy ring at the perimeter of 100-mm square substrates.The planar, three-nitrogen heteroacene arrangement inherent to this pyrrole-fused dipyridine imposes a rigid rod-like conformation that is exploited in the construction of solution-processable polymer semiconductors for organic field-effect transistors (OFETs). Copolymerization of a 2,8-dibromo-substituted 1H-dipyrido[2,3-b:3',2'-d]pyrrole monomer with 2,2′-bithiophene-5,5′-bis(trimethylstannane) via Stille coupling in anhydrous toluene at 110 °C over 48 hours yields a donor–acceptor copolymer that, after Soxhlet purification with sequential methanol, acetone, hexane, and chloroform fractions, shows a number-average molecular weight (Mn) between 38 kDa and 62 kDa with a dispersity below 2.4. The chloroform fraction is used for top-gate/bottom-contact transistor fabrication; a 7 mg mL⁻¹ solution in 1,2-dichlorobenzene filtered through a 0.45-μm PTFE syringe filter is spin-coated at 1,500 rpm and subjected to a solvent vapor annealing step inside a closed petri dish saturated with 1,2-dichloroethane vapor for 3 minutes. The resultant 45–55-nm thick semiconductor layer delivers a saturation hole mobility of 1.8–2.6 cm² V⁻¹ s⁻¹ under ambient conditions (relative humidity 40–55%) when the gate dielectric is CYTOP™, a fact attributed to the free-rotor character of the inter-ring bond being restricted by intramolecular N···H—C interactions that lock the dihedral angle near 0°. The threshold voltage however drifts by +0.15 V per decade of relative humidity increase beyond 55%, a phenomenon traced to water molecule intercalation at the pyridinic nitrogen sites detected by in-situ near-edge X-ray absorption fine structure (NEXAFS). Fabrication lines running these inks therefore enforce a dry-air supply rated at Dw-point –40 °C in the coating bay.2-Photon Absorption Cross-Sections and Lysosomal Staining SelectivityA water-soluble, quaternized derivative obtained by reacting 1H-dipyrido[2,3-b:3',2'-d]pyrrole with excess 1,3-propanesultone forms a fluorescent dye with an absorption band centred near 405 nm and an emission maximum at 510 nm in phosphate-buffered saline (pH 7.4). The two-photon absorption cross-section (σ₂) at 800 nm measured by the open-aperture Z-scan method using a Ti:sapphire oscillator (80 MHz, 140 fs) reaches 210 GM (Göppert-Mayer units), competitive with commercial FM 4-64 but with a Stokes shift exceeding 105 nm that effectively separates excitation scatter from the detection window. When incubated with HeLa cells at a concentration of 1 μM for 30 minutes, colocalization analysis using LysoTracker Red DND-99 produces a Pearson correlation coefficient of 0.91, confirming selective accumulation in acidic organelles driven by protonation of the pyridyl nitrogen (pKₐ of the conjugate acid = 4.7). The quantum yield in aqueous buffer drops to 0.08 but rises to 0.34 upon binding to lipid-rich environments, a routable property for detecting phospholipidosis in early-stage drug safety screens compliant with ICH S7B. Stringent metal-ion purity below 10 ppb for Fe³⁺ and Cu²⁺, verified by inductively coupled plasma mass spectrometry per USP <232>/<233>, is mandatory because trace paramagnetic ions quench the fluorescence lifetime from 3.8 ns to below 1.2 ns, invalidating fluorescence lifetime imaging microscopy readouts.In medicinal chemistry campaigns targeting the bromodomain and extra-terminal (BET) family of epigenetic readers, the tricyclic 1H-dipyrido[2,3-b:3',2'-d]pyrrole serves as a rigid acetyl-lysine mimetic isostere. Replacement of the 3,5-dimethylisoxazole headgroup of a classical BET inhibitor with this moiety produces a compound series that exhibits an IC₅₀ of 45–120 nM against BRD4 bromodomain 1 in a time-resolved fluorescence resonance energy transfer displacement assay (Cisbio Bioassays, Cayman Chemical protocol 600520) when the nitrogen atom at position 6 is free and the opposite edge is elaborated with a meta-substituted benzamide tail. The scaffold’s advantage is a reduced hydrogen-bond donor count relative to indole or azaindole alternatives while retaining an ideal topological polar surface area of 54–72 Ų, maintaining passive permeability above 4×10⁻⁶ cm s⁻¹ in Caco‑2 monolayers. Process chemistry groups operate a palladium-catalyzed C–H activation route using pivaloyl-protected hydroxylamine and Pd(OAc)₂ at 5 mol% loading in dichloroethane at 80 °C to install primary amide groups regiospecifically; the crude product is then subjected to trituration with tert-butyl methyl ether and recrystallized from ethyl acetate/hexane (3:7) to reach chromatographic purity above 98.6 area-%. An impurity threshold for the N-oxide congener at <0.15 area-% is enforced because it acts as a potent hERG channel opener (IC₅₀ displacement in patch-clamp assay below 8 μM), creating a cardiac safety liability per ICH S7B. Published data for this specific configuration is limited to a single patent family; scaling to multi-kilogram batches requires rigorous control of the exotherm during benzamide coupling with EDC·HCl, kept below ΔT+5 °C by controlled syringe-pump addition over 90 minutes.When This Heterocycle Enters the Epoxy Novolac Encapsulant Formulation for High-Temperature LED PackagesThe incorporation of a 5,11-diamino-substituted 1H-dipyrido[2,3-b:3',2'-d]pyrrole at 0.8–2.1 phr into an o-cresol novolac epoxy encapsulant molding compound (EMC) crosslinked with a phenol–xylylene glycol hardener shifts the glass transition temperature (Tg) from 195 °C to 227 °C as recorded by differential scanning calorimetry at a ramp rate of 10 K min⁻¹ conforming to ISO 11357-2:2020. This dramatic increase is traced to the heterocycle’s ability to form intermolecular hydrogen-bonded networks between the pyridyl nitrogen and the residual hydroxyl groups of the novolac backbone, effectively doubling the crosslink density without increasing the resin viscosity beyond processable limits. Dispersion is carried out on a three-roll mill with a gap of 25 μm front / 15 μm rear, processing a premix of EMC, additive, and silica filler (average particle size 18 μm, loading 72 wt%) through three passes at 50 rpm; insufficient wet-out of the additive manifests as yellowing streaks in the cured puck under 85 °C/85% RH aging per JEDEC JESD22-A101D. Transfer molding is conducted at 175 °C and 9 MPa for 180 seconds, followed by a post-mold cure at 150 °C for 4 hours. The refined network morphology reduces moisture absorption to 0.32 wt% after 168 hours of immersion in boiling water (ASTM D570-22), extending the 85/85 luminous flux maintenance test beyond 3,000 hours for mid-power 3030 LED packages. However, at loading levels above 2.3 phr, the coefficient of thermal expansion below Tg drops too sharply, inducing delamination at the leadframe–EMC interface after thermal cycling from –40 to 125 °C for 1,000 cycles as confirmed by scanning acoustic microscopy with a 30-MHz transducer. The practical processing window is therefore constrained to 1.0–1.8 phr. |
Competitive 1H-Dipyrido[2,3-B:3',2'-D]Pyrrole prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please call us at +8615651039172 or mail to sales9@bouling-chem.com.
We will respond to you as soon as possible.
Tel: +8615651039172
Email: sales9@bouling-chem.com
Flexible payment, competitive price, premium service - Inquire now!
The heteroacene 1H-Dipyrido[2,3-B:3',2'-D]Pyrrole—systematically a 1,7-diaza analogue of carbazole—is supplied in two distinct purity tiers designed to address divergent research and manufacturing requirements. Sublimation-grade material, intended for vacuum-processed organic electronic devices, is refined via a triple-zone gradient sublimation train operating at a dynamic vacuum below 5×10−6 mbar with a source zone plateau of 210 °C; the resulting pale-yellow crystalline powder exhibits a differential scanning calorimetry onset melt of 247 °C ± 2 °C (heating rate 10 K/min, nitrogen purge, method conforming to ASTM E794-06) and a high-performance liquid chromatographic area percent exceeding 99.9% (detection at 254 nm, C18 column). Research-grade material, crystallized from anhydrous toluene, provides an analogue purity of ≥ 98.5% and is intended for solution-based synthesis or preliminary screening. Both grades are packaged under argon in septum-sealed borosilicate vials with moisture content verified below 50 ppm by coulometric Karl Fischer titration (ISO 760:1978). The product code schema differentiates between the two: DPP-SUB designates the sublimed lot, and DPP-RES the research grade, with a trailing batch number indicating the synthesis campaign. Such dual-tier availability acknowledges the criticality of deep-level trap suppression in thin-film devices, where even parts-per-thousand impurities can shift threshold voltage by several volts in a bottom-gate, top-contact transistor geometry.
| Parameter | Method / Standard | Specification |
|---|---|---|
| HPLC Purity (area%) | In-house HPLC-UV (254 nm), C18 column, MeCN/H₂O gradient | ≥ 99.9% |
| Melting Point (onset) | ASTM E794-06, hermetic pan, 10 K/min | 245 °C – 249 °C |
| Residual Ash | ISO 3451-1:2019 (sulfated ash) | ≤ 0.05% |
| Volatile Content | Thermogravimetric Analysis, 10 K/min to 300 °C in N₂ | ≤ 0.3% weight loss |
| Metallic Impurities (ICP-MS) | Digestion followed by EPA Method 6020B | ∑(Fe, Cu, Si, Na) < 10 ppm |
| Appearance | Visual inspection under white light | Pale yellow crystalline powder, free of dark particulates |
Compared with the parent carbazole scaffold, the strategic placement of nitrogen atoms at the 1- and 7-positions pulls the frontier molecular orbital energies significantly deeper, shifting the ionization potential from the −5.8 eV region typical of carbazole to values reported between −6.1 eV and −6.3 eV (ultraviolet photoelectron spectroscopy on vacuum-deposited films, calibrated to a clean gold Fermi edge per ISO 18115-1:2010). This deeper highest occupied molecular orbital stabilizes the material against inadvertent p-doping by ambient oxygen and aligns it more favourably with the work function of indium-tin-oxide anodes, reducing injection barriers without the need for an interlayer. Conversely, the electron affinity remains modest at −2.4 eV to −2.6 eV, leaving the wide bandgap (~3.7 eV) largely intact. These values position 1H-Dipyrido[2,3-B:3',2'-D]Pyrrole as a candidate for hole-transport layers and host matrices in phosphorescent organic light-emitting diodes, but its transport anisotropy—strongly face-dependent—requires careful control of molecular orientation during film growth.
Continuous operation of a resistive-source evaporator with this compound demands precise thermal management because the exocyclic NH moiety promotes intermolecular hydrogen bonding that can elevate the sublimation enthalpy relative to the fully alkylated derivatives. In a production-scale coating tool (typical base pressure 1×10−7 mbar, source-to-substrate distance 45 cm), film deposition rates stabilize at 0.3–0.5 Å/s when the source temperature is held at 200–215 °C. Exceeding 230 °C for longer than 30 minutes initiates a measurable onset of degradation, observed as a gradual browning of the residual charge and the appearance of a low-molecular-weight fragment at m/z 166 in residual gas analysis. The degradation pathway is suspected to proceed through a thermal deamination or ring contraction; published mechanistic detail for this specific isomer remains fragmentary, but analogous 2,7-diazacarbazole systems have been shown to lose HCN under extreme thermal stress. Therefore, scaled-up evaporation campaigns integrate quartz crystal microbalance feedback to ramp source current incrementally and prevent overshoot, and crucibles are selected from pyrolytic boron nitride rather than alumina to minimize alkali-metal-induced discoloration. The practical upper processing temperature—defined as the point where semiconducting layer mobility in a bottom-gate OFET drops by 15% from the fresh-device value—has been benchmarked at 225 °C for source zone temperatures maintained during a cumulative 200 nm deposited thickness on parylene-C dielectrics.
A distinct advantage over the isomeric 2,7-dipyrido[2,3-b:3′,2′-d]pyrrole is the cleaner fragmentation pattern observed in mass spectrometry under electron-impact ionization, which simplifies endpoint detection in automated deposition controllers. The 1,7-substitution also lessens the propensity for non-radiative decay pathways that plague the 2,6- and 3,5-diaza isomers in electroluminescent environments, where close-lying n-π* states can quench triplet excitons on the phosphorescent dopant. Measurements of photoluminescence quantum yield in dilute 2-methyltetrahydrofuran glass at 77 K place the 1,7-variant at 0.38 ± 0.03, compared with values below 0.20 for the 3,5-isomer.
Depositing 1H-Dipyrido[2,3-B:3',2'-D]Pyrrole onto bare silicon dioxide gate insulators routinely produces field-effect mobilities in the 10⁻³ cm²/V·s range (saturation regime, transfer-line method per IEEE Std 1620-2008), but the interfacial trap density at the dielectric-semiconductor boundary is acutely sensitive to the silanol group concentration on the oxide surface. When the substrate is exposed to hexamethyldisilazane (HMDS) vapour at 120 °C for 60 minutes prior to organic film growth, mobility improves to 0.04–0.07 cm²/V·s, threshold voltage shifts from roughly −15 V to −4 V, and the sub-threshold slope steepens to 1.2 V/decade. Using a Cytop™ amorphous fluoropolymer dielectric (Asahi Glass, 450 nm thickness, capacitance 4.3 nF/cm²) further boosts saturation mobility to 0.15 cm²/V·s, a value that begins to approach the performance of dinaphthothienothiophene (DNTT)-based devices albeit with a poorer air stability half-life: after 72 hours in laboratory ambient (45% RH, 23 °C), drain current at fixed gate voltage decays by 22%, largely attributable to water permeation into grain boundaries. Encapsulation with a 50 nm Al₂O₃ layer deposited by atomic layer deposition at 80 °C extends the half-life beyond 1000 hours under the same conditions.
A manufacturing bottleneck identified during pilot-scale OFET array fabrication on flexible polyethylene naphthalate substrates involves the narrow tolerance for substrate temperature during sublimation: substrate holder temperature must be maintained between 25 °C and 35 °C. At temperatures below 20 °C, the sticking coefficient rises too sharply, producing a dendritic microstructure with high inter-grain resistance; above 40 °C, desorption competes with condensation, leading to thickness non-uniformities exceeding ±15% across a 150 mm radius. On a Kurt J. Lesker Spectros 150 system, active chilled-water circulation through the substrate platen, monitored by in-situ pyrometry, is used to hold the steady-state within this 15 °C band.
Replacing N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB) with 1H-Dipyrido[2,3-B:3',2'-D]Pyrrole in a standard bottom-emission OLED stack (ITO / hole-transport layer / emitter / electron-transport layer / LiF / Al) necessitates recalibration of the hole injection interface because the ionization potential of the diaza compound is approximately 0.4–0.6 eV deeper than that of NPB. Without an intermediate layer, the device exhibits a substantial drive voltage increase of roughly 1.5 V at 10 mA/cm² current density. Ultra-thin interlayers of molybdenum oxide (2 nm MoO₃) evaporated atop the ITO restore ohmic injection, yielding a luminance efficacy at 1000 cd/m² within 5% of the NPB reference while reducing the roll-off at high brightness due to the wider triplet energy (2.85 eV for the diaza host vs. 2.3 eV for NPB, measured from the 0-0 phosphorescent onset in a polystyrene matrix at 10 K). Operational lifetime data under accelerated DC stress (LT50 at 80 °C, initial luminance 4000 cd/m²) remain sparse; one peer-reviewed study of structurally related 1,7-diazafluorenes suggests that N—H bond dissociation may be a degradation channel under high current density, so pinhole-free encapsulation with a water vapour transmission rate below 10⁻⁶ g/m²·day (MOCON test) is advised.
| Compound | Ionization Potential (eV, UPS) | Electron Affinity (eV, IPES) | Hole Mobility (cm²/V·s, OFET on HMDS-SiO₂) | Triplet Energy (eV) |
|---|---|---|---|---|
| Carbazole | −5.8 | −2.1 | 1×10⁻³ (reference) | 3.0 |
| 1,7-Diazacarbazole (1H-Dipyrido[2,3-B:3',2'-D]Pyrrole) | −6.2 | −2.5 | 0.05 | 2.85 |
| 2,7-Diazacarbazole | −6.0 | −2.4 | 0.02 | 2.7 |
| Indolo[3,2-b]carbazole | −5.2 | −2.3 | 0.1–0.5 | 2.6 |
The table above underscores a critical differentiator: the 1,7-placement of nitrogen atoms facilitates a markedly higher mobility on simple HMDS-treated oxide than its 2,7-isomer, attributed to an edge-on molecular packing motif that exposes the π-stacking direction parallel to the substrate. Grazing-incidence wide-angle X-ray scattering of a 50 nm film on HMDS-SiO₂ indicates a lamellar spacing of 14.6 Å (out-of-plane) and a π-stacking distance of 3.45 Å (in-plane), in contrast to the 2,7-isomer’s mixed orientation which yields an in-plane π-stacking coherence length shorter by ~40%.
Unlike fully alkylated carbazole derivatives, 1H-Dipyrido[2,3-B:3',2'-D]Pyrrole is hygroscopic in its fine-powder form. After 4 hours of exposure to 60% RH at 23 °C, water uptake reaches 0.8 wt% (dynamic vapour sorption measurement), sufficient to generate steam bursts during subsequent vacuum sublimation that eject particulates from the source boat. Pre-drying under vacuum (≤1×10⁻² mbar) at 80 °C for 12 hours prior to loading the evaporator is mandated for all lots that have been opened outside a glovebox. Contact with strong oxidizing agents, including nitric acid and concentrated peroxides, must be avoided because the pyrrolic NH is susceptible to oxidative coupling, forming dimeric species detectable by gel permeation chromatography. The product is compatible with common organic solvents—toluene, chlorobenzene, tetrahydrofuran—but solutions should be used within 24 hours when stored under ambient atmosphere, as slow photo-oxidation can occur. Long-term storage of the solid is specified at −20 °C under argon in the original sealed packaging, with a retest date assigned at 24 months from the date of packaging.
