[3-(2-Ethylhexyl)-2-thienyl]tributylstannane , CAS No.1235512-21-6

CAS: 1235512-21-6 Cat. No.: E1503680

Storage

Room temperature

Specifications

Storage

Room temperature

Application Protocols

No assay or bioanalytical application protocols are associated with this product. For synthetic use, a generic Stille coupling workflow is provided in Reaction Conditions and Synthetic Utility. Always adjust catalyst, solvent, temperature, and stoichiometry to your specific electrophile and scale.

Biological Roles

This product is a synthetic organotin reagent intended for materials and synthetic chemistry. It does not have established biological roles.

General context (literature; not product-specific):

• Thiophene motifs occur in various bioactive molecules and pharmaceuticals; however, organotin derivatives (particularly SnBu3 species) are not used biologically due to toxicity and lack of physiological relevance.
• Organotin compounds can exhibit significant aquatic toxicity and potential endocrine/disruptive effects in environmental contexts; they are therefore handled strictly as hazardous industrial/lab chemicals, not as biological tools.

For any work intersecting biology (e.g., surface modification of devices), ensure complete removal of tin residues and verify biocompatibility of final materials. This product is for research use only and not for use in humans or animals.

Buffer Applications

Not typically applicable. This compound is a hydrophobic organometallic reagent for carbon–carbon bond formation and does not serve as a buffering agent or component of aqueous buffer systems. For relevant information, see the Reaction & Applications and Synthetic Utility sections.

Green Alternatives

Organostannanes are effective but raise green chemistry concerns (toxicity, waste handling). Consider the following alternatives depending on substrate class (literature):

Comparison (general guidance):

• Suzuki–Miyaura (boron reagents):
  • Pros: lower toxicity, benign byproducts (borates), broad functional group tolerance, aqueous compatibility.
  • Cons: requires base; some boronate instability; may give lower reactivity with certain electrophiles vs Stille.
• Negishi (zinc reagents):
  • Pros: high reactivity and functional group tolerance.
  • Cons: air/moisture sensitivity; organozinc preparation overhead.
• Direct C–H arylation:
  • Pros: atom economy; avoids prefunctionalized organometallics.
  • Cons: regioselectivity challenges; catalyst/condition sensitivity; may impact polymer microstructure.
• Kumada (Grignard):
  • Pros: inexpensive reagents, fast.
  • Cons: poor tolerance of electrophile‑sensitive groups; moisture sensitivity.

Small comparison table (typical):

• Stille (SnBu3): highest robustness with many electrophiles; generates toxic tin waste; excellent for polymerizations.
• Suzuki (B(pin)/B(OH)2): greener waste stream; often comparable performance for aryl–aryl couplings; base needed.

Practical route planning:

• If a matching 3‑(2‑ethylhexyl)‑2‑thienyl boronic ester/acid is available, Suzuki coupling is usually the first green alternative to trial.
• For sensitive motifs, explore direct C–H activation on a 2‑ethylhexyl thiophene precursor to bypass organotin altogether.

Pharmaceutical Uses

Not applicable as an excipient or formulation aid. Organotin compounds are not used in pharmaceutical formulations due to toxicity and regulatory constraints. This product is intended solely for research and synthetic applications (e.g., building conjugated small molecules) and not for any clinical or GMP use.

Physical Properties

Item-specific values from Product Data:

• Appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.

Computed/literature guidance (typical for aryl‑tributylstannanes; not product specifications):

• Physical state: usually high‑boiling, viscous liquids or low‑melting solids; strong hydrophobic character.
• Density: often in the ~1.05–1.20 g/mL range at 20–25 C (literature, varies with substituents).
• Boiling point: organostannanes typically decompose before distillation; purification is usually by chromatography rather than distillation (literature).
• Refractive index: commonly nD ~1.49–1.53 for related SnBu3 aryls (literature).
• Solubility: very soluble in nonpolar and moderately polar aprotic solvents (toluene, xylene, chlorinated solvents, THF, dioxane, DMF); insoluble in water (literature).
• LogP: expected high due to three n‑butyl groups and a branched alkyl side chain (literature).

General structural implications:

• The 2‑ethylhexyl substituent increases solubility in organic media, aiding homogeneous Stille couplings and polymerizations.
• Air/moisture tolerance is better than for many organometallics, but hydrolysis/protodestannylation can occur over time, particularly under acidic or strongly basic conditions.

For exact numeric specifications relevant to your lot (e.g., density, refractive index), please consult the CoA/Spec Sheet.

Quality and Grades

Item-specific quality information:

• Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet.

Context for this class of material:

• Organostannane reagents for Stille coupling are commonly supplied as research‑grade materials. Quality indicators include organic purity (NMR/HPLC/GC), identity (1H/13C NMR; 119Sn NMR optional), and low inorganic residues.
• Trace peroxide content, metal contaminants, and water content are typically not controlling for stannanes; instead, focus is on minimizing protodestannylated arene, tin oxides, and halogenated impurities which can poison catalysts.
• UV cutoffs are generally irrelevant unless the application is analytical.

How to interpret grades (general):

• Research grade: suitable for synthetic chemistry and materials R&D; QA via spectroscopic/analytical methods, but not intended for GMP uses.
• “High‑purity for cross‑coupling” (when stated): emphasizes low polar/tin‑oxide impurities and high assay by 1H NMR; may include inhibitor status. Not specified for this item.

Recommendation:

• Verify suitability by small‑scale test coupling and by inspecting 1H NMR for diagnostic SnBu3 multiplets and aryl signals; consult the CoA for the exact purity definition used for this product.

Reaction and Applications

Primary use: Stille cross‑coupling partner delivering the 3‑(2‑ethylhexyl)‑2‑thienyl fragment to aryl/vinyl halides or pseudohalides.

Typical applications (literature):

• Synthesis of thiophene‑rich small molecules and conjugated polymers used in organic electronics (OPV, OFET, OLED), where the 2‑ethylhexyl side chain enhances processability.
• Installation of the 3‑(2‑ethylhexyl)‑2‑thienyl unit onto electron‑deficient cores (e.g., benzothiadiazoles, diketopyrrolopyrroles, naphthalene diimides) and onto halogenated thiophenes for oligomer growth.
• Step‑growth or chain‑growth polymerizations by Stille polycondensation with di‑halogenated partners.

Mechanistic/practical notes:

• Catalysts: Pd(0/II) sources such as Pd(PPh3)4, Pd2(dba)3/PPh3, Pd(PtBu3)2; phosphine‑ligated catalysts facilitate transmetalation from SnBu3.
• Additives: CuI or LiCl can accelerate couplings in some cases; base is generally not required for Stille.
• Conditions: Anhydrous, oxygen‑reduced environment improves consistency; degas solvents. Elevated temperature often needed for less reactive electrophiles.
• Side reactions: protodestannylation under acidic conditions; homocoupling at high catalyst loadings; tin residues can persist—plan rigorous workup.

Workup/purification tips:

• Scavenge tin by KF or NaF washes, silica gel pretreated with KF, or by oxidative workup (e.g., with H2O2) to convert to insoluble tin oxides followed by filtration. Multiple short silica plugs reduce Sn tailing.

This reagent is not a general solvent or buffer; it is specifically a transfer reagent for the arylthienyl unit via Pd‑catalyzed coupling.

Reaction Conditions

General literature guidance for Stille couplings with aryl‑SnBu3 reagents (illustrative; optimize per substrate):

• Catalysts: Pd(PPh3)4 (1–5 mol%), Pd2(dba)3 (1–2.5 mol%) with PPh3 or tri‑tert‑butylphosphine; for challenging couplings, PdCl2(dppf)·CH2Cl2 (2–5 mol%).
• Additives: CuI (5–20 mol%) or LiCl (1–2 equiv) can accelerate transmetalation; not always necessary.
• Solvents: toluene, xylene, 1,4‑dioxane, THF, DMF, or mixtures; anhydrous, degassed.
• Temperature/time: 60–120 C, 2–24 h depending on electrophile (Ar–I > Ar–Br > Ar–Cl/OTf). Polymerizations often at 90–110 C for 12–48 h.
• Atmosphere: inert (N2/Ar). Degas by sparging or freeze‑pump‑thaw.
• Stoichiometry: ~1.0–1.2 equiv stannane per electrophile; for polymerizations, match functional group balance precisely.
• Workup: cool, dilute, and wash with aqueous KF/NaF or dilute H2O2 to convert tin residues to insoluble oxides; filter and purify by chromatography or precipitation (for polymers).
• Typical outcomes: small‑molecule couplings frequently 60–90% isolated yield; polymer number‑average molecular weights and dispersities depend on catalyst system and monomer purity (literature ranges only).

Cautions:

• Avoid strong acids/bases and protic solvents that induce protodestannylation.
• Chlorinated solvents can aid solubility but consider environmental and safety profiles.

Note: These are literature guidelines, not item specifications. Conduct substrate‑specific optimization.

Safety and Handling

Authoritative safety information must be obtained from the product SDS for your lot.

Item-specific hazard fields in Product Data:

• Signal word: Not specified for this item; refer to SDS.
• H‑statements: Not specified for this item; refer to SDS.
• GHS classification/pictograms: Not specified for this item; refer to SDS.

General safety guidance for organotin aryl‑tributylstannanes (literature; not product-specific):

• Hazards: Organotin compounds can be harmful if inhaled, swallowed, or absorbed through skin; many are toxic to aquatic life with long‑lasting effects. Avoid environmental release.
• PPE: Use chemical‑resistant gloves (e.g., nitrile), lab coat, and splash goggles. Handle in a fume hood to minimize inhalation of vapors/aerosols.
• Incompatibilities: Strong acids and bases may accelerate protodestannylation/hydrolysis; strong oxidizers; halogens. Avoid prolonged exposure to moisture and light.
• First aid: If on skin, wash with soap/water. If in eyes, rinse cautiously with water for several minutes; remove contact lenses if present/easy. If inhaled, move to fresh air. If ingested, rinse mouth; seek medical attention. Consult SDS for detailed instructions.
• Fire: Combustible organic; use dry chemical, CO2, or foam. Combustion may produce tin oxides and sulfur oxides.
• Waste: Collect organotin residues and tin‑contaminated silica as hazardous waste. Consider fluoride or oxidizing scrubs during workup to immobilize/remove tin residues; never discharge to drain.

Always defer to the SDS and your institutional EHS policies.

Solvent Selection

This reagent is a highly lipophilic aryl‑tributylstannane.

General solvent compatibility (literature):

• Excellent solubility: toluene, xylene, chlorobenzene, dichlorobenzene, chloroform, dichloromethane, THF, 1,4‑dioxane, DMF, DMAc, NMP.
• Poor/insoluble: water; very polar protic solvents.
• Dielectric considerations: choice is driven by the coupling partner and catalyst; Stille couplings perform well in toluene/xylene (high‑T), dioxane/THF (moderate‑T), or DMF (lower‑T, polar substrates).

When to choose which solvent (typical for Stille):

• Toluene/xylene: aryl/vinyl halides at elevated temperatures; good for polymerizations targeting high molecular weight and film‑forming materials.
• 1,4‑Dioxane or THF: milder conditions, better for base‑sensitive partners.
• DMF/DMAc: enhances rates with less reactive electrophiles; aids polar substrate solubility.

Quick comparison (literature):

• Toluene: nonpolar, bp 111 C; balances solubility and volatility.
• 1,4‑Dioxane: ether, bp 101 C; miscible with many reagents; consider peroxide control.
• DMF: polar aprotic, bp 153 C; hygroscopic; facilitates room‑temp to moderate‑temp couplings.

Note: Exact solubility parameters for this specific item are not specified; confirm experimentally on small scale.

Storage and Reconstitution

Item-specific storage from Product Data:

• Storage conditions: Room temperature
• Shipped in: Not specified for this item; refer to CoA/Spec Sheet.
• Appearance: Not specified for this item; refer to CoA/Spec Sheet.

General handling guidance for aryl‑SnBu3 stannanes (literature; not product specifications):

• Store tightly closed under inert gas (N2/Ar) in a dry place, protected from light to minimize slow oxidation and protodestannylation. Room temperature storage is typically acceptable; refrigeration is not required unless specified on the CoA.
• If supplied as a viscous oil, dispense with dry glass or PTFE syringes. For semi‑solid materials, gently warm (e.g., 30–40 C) to homogenize before use; avoid prolonged heating.
• Minimize headspace and moisture ingress; consider using septum‑cap bottles for repeated access.
• Do not store near acids, bases, or oxidizers.

Stability notes:

• Organostannanes are generally air‑stable but can slowly hydrolyze; perform critical reactions with freshly opened or verified‑pure material.
• No reconstitution is required; use as received. If dilution is desired for dosing, prepare anhydrous stock solutions in toluene, THF, or dioxane under inert atmosphere and use promptly.

Always follow the CoA/SDS for lot-specific guidance.

Structure and Identity

Organotin cross-coupling reagent bearing a 3-(2-ethylhexyl)-2-thienyl group on tin, designed for Stille-type C–C bond formation.

• SKU: E1503680
• Product name: [3-(2-Ethylhexyl)-2-thienyl]tributylstannane
• CAS: 1235512-21-6
• Category: Materials Science (research use only)

Item-specific identifiers (from Product Data):

• Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.
• Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.
• SMILES: Not specified for this item; refer to CoA/Spec Sheet.
• InChIKey: Not specified for this item; refer to CoA/Spec Sheet.

Computed/literature descriptors (informational, not product specifications):

• Approximate formula (computed from the structure name): C24H46SSn
• Approximate molecular weight: ~485.41 g/mol
• Core structural features: a thiophene ring (five-membered aromatic, one sulfur) substituted at C-3 with a branched alkyl chain (2‑ethylhexyl) and at C-2 bonded to tin; tin bears three n‑butyl ligands (SnBu3).
• 2D description: a thiophene ring with adjacent substituents at positions 2 (SnBu3) and 3 (–CH(C2H5)–(CH2)3CH3 on a secondary carbon), giving a sterically demanding, lipophilic arylstannane.

Notes:

• The 2‑ethylhexyl side chain enhances solubility in nonpolar media and is common in conjugated polymer building blocks.
• Organotin center is tetravalent (SnIV) with four σ‑bonds (sp3 around Sn).

Synthetic Utility

Functional group and reactivity profile:

• Transfer of a 3‑(2‑ethylhexyl)‑2‑thienyl unit under Pd catalysis via Stille cross‑coupling to aryl/vinyl electrophiles (I, Br, OTf).
• Robust toward many functional groups on the electrophile (esters, nitriles, ketones, amides); generally tolerant of moderately acidic protons but avoid strong acids/bases that promote protodestannylation.

Retrosynthetic value:

• Enables late‑stage installation of a solubilizing 2‑ethylhexyl‑thiophene fragment onto electron‑deficient cores to tune HOMO/LUMO and solubility in organic electronic materials.
• In polymer synthesis, facilitates AB/AA–BB Stille polycondensation with dihalogenated partners to access regioregular oligothiophenes and donor–acceptor backbones.

Named reactions and variants:

• Stille coupling (Pd‑catalyzed transmetalation from Sn to Pd, followed by reductive elimination).
• Migita–Kosugi–Stille conditions; copper co‑catalysis (Stille–Migita) for enhanced rates with less reactive partners.

Practical guidance:

• Monitor by GC/MS or 1H NMR; disappearance of SnBu3 resonances (~0.8–1.6 ppm) and growth of product signals.
• To minimize tin residues, employ fluoride scrubs (KF), scavenger resins, or oxidative workups; thorough filtration over celite/silica is recommended.
• If scaling polymerizations, ensure rigorous degassing and control of stoichiometry to manage molecular weight and dispersity.

Target Specificity

Not applicable. This product is a small‑molecule organotin reagent and is not an antibody, probe, or bioactive ligand with defined biological targets.

Frequently Asked Questions

What are the CAS number, molecular formula and molecular weight?

The CAS Number is 1235512-21-6.

How should this product be stored?

Store at room temperature.

What documentation is provided?

Available product documentation, including Certificates of Analysis (COA), Safety Data Sheets (SDS), and specification sheets, is shown in the product document area. Document availability and access follow the current site policy.