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Literaturbeleg
In 0 peer-reviewten Publikationen zu Chromatographie, organischer Synthese und Kreuzkupplungsreaktionen zitiert.
Übersicht
m-PEG9-bromide is a PEG derivative containing a bromide group. The bromide (Br) is a very good leaving group for nucleophilic substitution reactions. The hydrophilic PEG spacer increases solubility in aqueous media.
This compound belongs to the class of organic compounds known as dialkyl ethers. These are organic compounds containing the dialkyl ether functional group, with the formula ROR', where R and R' are alkyl groups.
External Descriptors
Not available
1. Djoumbou Feunang Y, Eisner R, Knox C, Chepelev L, Hastings J, Owen G, Fahy E, Steinbeck C, Subramanian S, Bolton E, Greiner R, and Wishart DS. ClassyFire: Automated Chemical Classification With A Comprehensive, Computable Taxonomy. Journal of Cheminformatics, 2016, 8:61.
Zertifikate (CoA, COO, BSE/TSE und Analyse-Diagramm)
C of A & Other Certificates(BSE/TSE, COO):
Analytical Chart:
Chemische und physikalische Eigenschaften
Molekulargewicht
491.400 g/mol
XLogP3
-0.300
Hydrogen Bond Donor Count
0
Hydrogen Bond Acceptor Count
9
Rotatable Bond Count
26
Exact Mass
490.178 Da
Monoisotopic Mass
490.178 Da
Topological Polar Surface Area
83.100 Ų
Heavy Atom Count
29
Formal Charge
0
Complexity
288.000
Isotope Atom Count
0
Defined Atom Stereocenter Count
0
Undefined Atom Stereocenter Count
0
Defined Bond Stereocenter Count
0
Undefined Bond Stereocenter Count
0
The total count of all stereochemical bonds
0
Covalently-Bonded Unit Count
1
Lösungsrechner
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Application Protocols
No application protocols (e.g., WB, IHC, IF, FC) apply to this chemical reagent. For synthetic use, refer to the Reaction Conditions and Synthetic Utility sections for general, literature-based guidance. If you require a stepwise protocol for a specific transformation (e.g., azide substitution, Williamson ether formation, or ATRP macroinitiation), contact Technical Support with your substrate details to obtain a tailored, scale-appropriate procedure.
Biological Roles
This product is a synthetic PEGylation building block rather than a biological macromolecule. The following notes describe general, research-level roles of PEG chains and PEGylation motifs; they are not medical/clinical claims.
PEG as an interface modifier (general): PEG chains are hydrophilic, flexible, and exhibit low protein adsorption due to entropic and hydration-layer effects. Incorporating an m-PEG9 segment can impart “stealth” behavior to surfaces and macromolecules in vitro, reducing nonspecific interactions in biochemical assays and materials testing.
Spacer function: A nine-unit ethylene oxide spacer (~3.5–4.0 nm fully extended; considerably shorter in solution due to coil statistics) can distance bioactive moieties from surfaces or cores, improving accessibility in binding assays and sensor platforms.
Aqueous compatibility: PEG increases solubility of hydrophobic entities in polar media. However, the terminal alkyl bromide is electrophilic and generally unsuitable for direct use in aqueous biological buffers without prior conversion (e.g., to azide, amine, thiol, or click-ready handles) to avoid unintended alkylation.
Biomaterials research: m-PEG9 linkers are frequently used to graft onto nanoparticles, polymers, or hydrogel networks via nucleophilic handles, tuning hydration, fouling resistance, and rheology in cell-free test systems.
For biological or biochemical conjugations, consider converting the –Br to more bio-orthogonal handles (e.g., azide for CuAAC, NHS carbonate for amine coupling) prior to exposure to complex biological media.
Buffer Applications
m-PEG9-bromide is not a buffering agent and does not constitute a defined acid/base pair for pH control. Consequently, it is not typically used to prepare or adjust biological or analytical buffers.
Practical note for researchers: If employing this reagent to modify surfaces or macromolecules that will ultimately be handled in buffers, conduct the alkylation or end-group conversion in suitable anhydrous organic media. After reaction and purification, transfer the PEGylated product to buffer. For aqueous bioconjugation workflows, convert the bromide to a more compatible handle (e.g., azide, NHS, maleimide) before performing reactions in phosphate, HEPES, or other biological buffers.
Green Alternatives
Selecting greener strategies with m-PEG end-group chemistry centers on both the leaving group and the solvent system.
Leaving group considerations:
m-PEG–OTs/OMs (tosylate/mesylate) are viable alternatives to –Br, often offering comparable or better solubility and reduced concerns about alkyl bromide volatility/toxicity. They can be prepared or purchased and displaced under similar SN2 conditions.
m-PEG–I is more reactive but increases halogen hazard; generally not greener.
Carbonate-based activating groups (e.g., m-PEG–O–CO–R) enable subsequent, milder displacements, though they may narrow substrate scope.
Solvent selection (greener media vs. conventional):
Greener choice | Conventional | Comment (literature/general)
---------------|-------------|------------------------------
2-MeTHF | THF | Bio-based, higher bp, moisture tolerant; good for K2CO3-mediated SN2.
CPME | Dioxane | Low peroxide tendency; broader safety envelope.
MeCN (ACS GPC) | DMF/DMSO | Easier removal, lower toxicity; may require higher temperature.
Propylene carbonate | CH2Cl2 | High dielectric, non-volatile; viscosity can slow mass transfer.
Ethyl acetate | CH2Cl2 | Useful for extractions and some PTC systems.
Process tips:
Use solid bases (K2CO3, Cs2CO3) and azeotropic drying to avoid DMF/DMSO when feasible.
Implement solvent recycling (MeCN, acetone, 2-MeTHF) and minimize halogenated waste.
Consider heterogeneous or continuous-flow PTC to reduce solvent volumes and improve safety.
Tradeoffs: Highly polar aprotic solvents (DMF/DMSO) often deliver the fastest SN2 rates; greener alternatives may require longer times or elevated temperature. Optimize on small scale before scale-up.
Pharmaceutical Uses
No therapeutic or clinical claims are made. The information below concerns research/formulation contexts only.
Excipients and materials research: PEG segments are widely used to tune solubility, viscosity, and interfacial behavior in prototype formulations. m-PEG9-bromide itself is a reactive intermediate rather than a finished excipient; it is typically transformed to a more stable or bio-orthogonal end group (e.g., mPEG–N3, mPEG–NHS) prior to any formulation-related research.
Conjugation precursor: In pre-formulation or delivery-system research (e.g., nanoparticles, micelles, polymer–drug conjugates), m-PEG9-bromide can serve as a starting point to synthesize amphiphiles or surface ligands, after which the final, neutral PEGylated surface reduces non-specific adsorption in vitro.
Regulatory status: Not specified for this item; refer to CoA/Spec Sheet. m-PEG bromides are not typically compendial excipients in their reactive form.
Manufacturing/process notes (research scale):
The bromide group may be corrosive/reactive; handle under inert atmosphere to maintain purity and to minimize side reactions.
After end-group conversion, thorough removal of residual halides and low-MW PEG species is recommended (dialysis, ultrafiltration, or silica/size-exclusion chromatography) to meet analytical targets relevant to formulation studies.
Physical Properties
Item-specific physicochemical specifications are not provided. The following notes reflect general/literature characteristics of short mPEG bromides; confirm exact values on the CoA/Spec Sheet for SKU M595488.
Appearance: Not specified for this item; refer to CoA/Spec Sheet. (Short mPEG oligomers commonly appear as colorless to pale viscous oils or waxy solids.)
Molecular weight and formula: Not specified for this item; refer to CoA/Spec Sheet.
Melting/softening behavior (literature): mPEG oligomers in the n≈6–12 range often exhibit broad softening ranges rather than sharp melting points due to conformational and microcrystalline domains.
Boiling point (literature): Not typically reported; polyethers of this size have very low volatility and are commonly dried under high vacuum at moderate temperatures (e.g., 30–60 °C) rather than distilled.
Density (literature): PEG oligomers typically ~1.05–1.13 g/mL at 20–25 °C; actual value depends on chain length and end-group.
Solubility (literature/experience):
Highly soluble in polar organic solvents (DMF, DMSO, MeCN, acetone, THF, dioxane, CH2Cl2) and miscible with alcohols.
Miscible or highly soluble in water depending on terminal hydrophobic segment length; m-PEG9 generally exhibits good aqueous compatibility but terminal –Br reduces water reactivity handling.
LogP and pKa: Not applicable/typically not reported for non-ionic polyethers; terminal alkyl bromide is not ionizable.
Refractive index/UV cutoff: Not specified for this item; refer to CoA/Spec Sheet.
Hygroscopicity (literature): PEG oligomers are hygroscopic; water uptake can impact reactivity in moisture-sensitive transformations.
Quality and Grades
Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet.
What to expect with m-PEG reagents:
Discrete oligomer vs. distribution: m-PEG9-bromide can be offered as a monodisperse, well-defined length (n=9) or as a narrow distribution centered near n=9. Verify by lot-specific CoA (1H NMR end-group integration, MALDI-TOF/ESI-MS, GPC).
End-group fidelity: High end-group conversion is critical for reproducible coupling. CoA typically reports >95% end-group functionalization by NMR; confirm for this SKU/lot.
Residuals: Common impurities include unreacted m-PEG-OH/OMs/OTs, hydrolyzed alcohol end, and inorganic salts from halide exchange. Low residual solvents/salts improve downstream reactions and analytical clarity.
Analytical characterization (typical expectations; not item-specific):
1H/13C NMR in CDCl3 or DMSO-d6 showing PEG methylene envelope (~3.35–3.75 ppm) and terminal methoxy singlet (~3.35 ppm); disappearance of tosylate/mesylate signals if used as precursors.
MS showing the expected [M+Na]+ series for the oligomer distribution.
Karl Fischer water and residual halide/anion tests may be provided for moisture-sensitive applications; request if needed.
Stabilizers: Not specified for this item; refer to CoA/Spec Sheet. (mPEG bromides generally do not require stabilizers; inert-atmosphere storage minimizes hydrolysis.)
Suitability notes: For nucleophilic substitutions and ATRP macroinitiators, low water content and verified bromide end-group integrity are central to performance. Request CoA/SDS before critical work.
Reaction and Applications
m-PEG9-bromide is a versatile electrophile used to introduce a hydrophilic, methoxy-terminated PEG spacer onto nucleophilic substrates and to initiate controlled radical polymerizations.
Nucleophilic substitutions (literature):
O-alkylation (Williamson ether): Reaction with phenols/alkoxides to afford m-PEG9–O–R ethers; K2CO3 or NaH in acetone, MeCN, or DMF; typically 25–80 °C.
S-alkylation: Thiolate displacement to form thioether-linked PEG conjugates, useful for small-molecule and surface tethering; bases as above.
N-alkylation: Primary amines yield secondary/tertiary ammonium salts by alkylation; often less selective in complex settings—azide displacement to mPEG–N3 followed by Staudinger reduction or CuAAC is commonly preferred for amine targeting.
Carboxylate alkylation: Formation of PEG-containing esters from carboxylate salts (e.g., cesium carboxylates) under SN2 conditions.
Macroinitiator for polymerizations:
ATRP: mPEG–Br acts as a macroinitiator for methacrylates/acrylates/styrenics, yielding PEG–block–polymer architectures (e.g., PEG-b-PMMA). Typical systems use CuBr/ligand (e.g., PMDETA, bpy) in anisole or DMF.
NMP/RAFT pathways are also accessible after converting the bromide to appropriate initiating/RAFT end-groups.
Materials and surface science:
PEGylation of nanoparticles, pigments, and oxide surfaces via nucleophilic handles (e.g., phenolic/silanol derivatization), imparting protein-repellent, antifouling character and improved dispersion in polar media.
Spacer installation in linkers for solid-phase synthesis and diagnostics.
Practical notes:
End-group integrity dictates performance; verify by NMR/MS before critical couplings.
Use minimal excess of reagent to simplify purification; PEG chains aid phase separation and can be removed by dialysis/ultrafiltration in materials workflows.
Reaction Conditions
The following conditions are representative literature/general practices for m-PEG alkyl bromides; optimize per substrate.
Williamson ether synthesis (phenols/alcohols):
Base: K2CO3 (2–3 equiv) or NaH (1.1–1.5 equiv for alcohols); catalytic KI may accelerate.
Solvent: acetone or MeCN (reflux, 2–24 h) or DMF (25–70 °C, 1–16 h) for less soluble nucleophiles.
Stoichiometry: m-PEG9–Br (1.0–1.3 equiv) relative to nucleophile; higher excess can drive to completion but complicates purification.
Thiolate alkylation:
Base: NaH, K2CO3, Cs2CO3, or DBU to generate RS− in situ.
Solvent: dry DMF, DMSO, MeCN, or acetone; 20–60 °C, 0.5–8 h.
Solvent: anisole, toluene, DMF, or mixtures; 25–90 °C depending on monomer.
Typical conversions: high control over Mn and Đ with appropriate feed ratios and deoxygenation.
General tips:
Dry all components; water suppresses base strength and promotes hydrolysis.
Monitor by 1H NMR (end-group region) or LC/MS (for low-MW conjugates).
For greener workflows, consider 2-MeTHF or MeCN and solid inorganic bases; extend time or temperature as needed.
Safety and Handling
GHS classification, signal word, pictograms, and H-statements: Not specified for this item; refer to the SDS for authoritative safety information.
General hazards (literature/practice):
Terminal alkyl bromides can act as alkylating agents and may be irritating to skin, eyes, and respiratory tract; avoid inhalation of aerosols and contact with skin or eyes.
Polyether matrices may slowly form peroxides upon prolonged air/oxygen exposure, especially in light; while risk is much lower than for low-MW cyclic ethers, store under recommended conditions and minimize air/light exposure.
Recommended PPE: lab coat, safety glasses or splash goggles, and appropriate chemical-resistant gloves (e.g., nitrile). Use in a fume hood when handling powders/aerosols or during reactions that can release HBr.
Handling practices:
Keep dry; moisture can hydrolyze reactive intermediates and quench bases/nucleophiles used with this reagent.
Purge containers with inert gas after opening when feasible; re-cap promptly.
Avoid strong nucleophiles/bases in confined vessels unless pressure relief is provided (possible gas evolution or exotherm in derivatizations).
Incompatibilities (general): strong bases and nucleophiles may react vigorously; avoid strong oxidizers. Alkyl bromides can undergo substitution with metals/nucleophiles; segregate from amines during storage.
First aid (overview; see SDS): flush eyes/skin with water for 15 minutes; remove contaminated clothing; seek medical attention if irritation persists; if inhaled, move to fresh air; if ingested, rinse mouth and seek medical advice.
Waste: Collect halogenated organic waste according to institutional procedures.
Solvent Selection
As an electrophilic mPEG reagent used primarily in SN2 and initiation chemistries, solvent choice should balance nucleophile solvation, substrate solubility, and suppression of side reactions.
Polarity/miscibility (general):
Highly soluble in polar aprotic media: DMF, DMSO, NMP, DMAc, MeCN, acetone; also soluble in moderately polar ethers (THF, dioxane) and chlorinated solvents (CH2Cl2, CHCl3).
Often miscible with alcohols (MeOH, EtOH); alcohols may reduce alkylation efficiency due to competing solvent nucleophilicity.
Preferred media by transformation (literature guidance):
Williamson ether synthesis with phenoxides/alkoxides: acetone (reflux) or MeCN with K2CO3; alternatively DMF/DMSO at 25–80 °C for less soluble substrates.
Thiolate alkylation: dry DMF, DMSO, MeCN, or acetone; strong, non-nucleophilic bases (NaH, K2CO3, Cs2CO3) under anhydrous conditions.
Azide displacement (for end-group conversion to mPEG–N3): DMF or DMSO, 40–80 °C with NaN3.
DMF/DMSO maximize SN2 rates but complicate workup; acetone/MeCN ease removal and favor phase separations.
2-MeTHF or CPME provide greener alternatives to THF/DCM for less polar systems.
Practical tips:
Ensure all solvents are anhydrous (molecular sieves or fresh solvent). Water suppresses nucleophile generation and can hydrolyze reactive intermediates.
For poorly soluble nucleophiles, biphasic PTC systems (toluene or DCM with aqueous base and TBAB/TBAHS) can be effective, but monitor for PEG partitioning and quaternary ammonium contamination.
Storage and Reconstitution
Storage (from Product Data): Store at −20 °C. Shipped in an ice chest with ice pads.
Container and atmosphere: Keep tightly closed under inert gas (argon or nitrogen) with a desiccant. Minimize headspace and light exposure to limit oxidative/peroxide processes typical of polyethers over long storage.
Moisture control: Hygroscopic; handle quickly in a dry box or under a dry nitrogen purge. Reseal promptly after use.
Stability notes (general): Terminal alkyl bromides can slowly hydrolyze to alcohols in the presence of moisture and may undergo substitution with adventitious nucleophiles. Cold, dry, inert storage helps preserve end-group fidelity.
Readily dissolves in dry DMF, DMSO, MeCN, acetone, THF, dioxane, and CH2Cl2. For aqueous handling, convert –Br to a more stable/compatible handle first (e.g., azide or alcohol), then dissolve in buffer.
To prepare an anhydrous stock solution, weigh quickly, dissolve in pre-dried solvent (molecular sieves or freshly opened anhydrous grade), and aliquot under inert gas into amber vials; store at −20 °C.
Freeze–thaw: Avoid repeated freeze–thaw of solutions; dispense single-use aliquots. For solids/semi-solids, warm gently to room temperature in a desiccator before opening to prevent moisture condensation.
Shelf life: Not specified for this item; refer to CoA/Spec Sheet.
Research Use Note: For research use only.
Structure and Identity
m-PEG9-bromide is a monofunctional polyethylene glycol (PEG) oligomer bearing a terminal alkyl bromide and a methoxy-terminated opposite end, enabling SN2-type alkylation chemistry while retaining PEG’s solubilizing, hydrophilic character.
Product identifiers (from Product Data)
CAS: 125562-30-3
PubChem CID: 19822384
InChIKey: 370505 (as provided)
SMILES: Not specified for this item; refer to CoA/Spec Sheet.
Composition and features (general/literature description)
Discrete oligomer with approximately nine ethylene oxide (–CH2–CH2–O–) repeat units.
One terminus is methoxy-capped (–O–(CH2CH2O)9–CH3); the other terminus is a primary alkyl bromide (–(CH2)n–Br; typically ω-bromo-PEG methyl ether).
Structural motif (2D description): a linear, flexible polyether backbone consisting of nine repeating –CH2–CH2–O– units; the left end terminated with –O–CH3 (methoxy), the right end terminated with –CH2–CH2–Br (primary bromoalkyl). No rings or stereocenters.
Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.
Molecular weight: Not specified for this item; refer to CoA/Spec Sheet. (Note: m-PEG oligomers can be provided as discrete-length materials; verify exact MW on the CoA.)
Converts phenols/alkoxides to mPEG9-aryl/alkyl ethers (Williamson ether synthesis), introducing a hydrophilic spacer without altering aromatic frameworks.
Alkylates thiolates to yield thioether-linked PEG conjugates, advantageous for sulfur-containing ligands and soft-surface tethering.
Enables ester formation from carboxylate salts, furnishing PEG-appended esters that enhance solubility or provide handles for further transformations.
Direct amine alkylation is possible but can lead to mixtures; alternative two-step routes (Br→N3→NH2) often improve selectivity.
Macroinitiator role:
Initiates ATRP of methacrylates/acrylates to build amphiphilic block copolymers (PEG-b-PMMA, PEG-b-PS, etc.) with controlled molecular weights and narrow dispersities.
End-group interconversions:
Br→I (Finkelstein) to increase leaving-group reactivity; Br→N3 (NaN3) for click chemistry; Br→SH (via thioacetate then hydrolysis); Br→OH (hydrolysis) for regeneration of mPEG–OH; Br→NHS carbonate via intermediate alcohol/activated carbonate.
Retrosynthetic value:
Serves as a convergent PEGylation synthon—install spacer late in a sequence to enhance solubility and purification, then unveil the final functionality at the distal end as needed.
Practical guidance:
Verify end-group fidelity by 1H NMR (methoxy integration vs. PEG envelope) and MS before committing valuable substrates.
Use stoichiometric control and phase behavior (e.g., selective precipitation in MTBE/Et2O or trituration) to simplify isolation of PEGylated products.
Drying (vacuum, gentle heat) prior to reactions increases yields in base-sensitive SN2 steps.
Target Specificity
Not applicable. This product is a small-molecule/oligomeric reagent (m-PEG9-bromide) and is not an antibody, protein, or assay-directed probe. It does not possess biological “target specificity” parameters such as antigen, epitope, clone, isotype, or species reactivity.
Häufig gestellte Fragen
What is the purity of this product?
This product is supplied at ≥98% purity (chemical assay). Lot-specific values are stated on the Certificate of Analysis.
How should this product be stored?
Store at ?20 °C. Freezer storage is required to maintain the specified shelf life.
How is this product shipped?
This product ships in an insulated container with ice pads. Unpack on arrival and transfer it to the storage condition stated above.
What are the CAS number, molecular formula and molecular weight?
The CAS Number is 125562-30-3, the molecular formula is C19H39BrO9, and the molecular weight is 491.4 g/mol. InChIKey UVVCGSZTSMUNGX-UHFFFAOYSA-N.
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.
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