Let's solve the structure step-by-step using the provided spectral data: --- ## **Step 1: Molecular Formula Determination** **Mass Spectrum:** - Molecular ion [M] = 209 Let's estimate the formula. Assume only C, H, and O (no halogens or N indicated): ### **Degree of Unsaturation** Let’s try C₁₄H₁₁O₂ (just a guess to check): - C: 14 × 12 = 168 - H: 11 × 1 = 11 - O: 2 × 16 = 32 - Total = 168 + 11 + 32 = **211** (a little over) Try C₁₄H₉O₂: - 168 + 9 + 32 = **209** So, **C₁₄H₉O₂** is the likely formula. #### **Degrees of Unsaturation** \[ \text{DoU} = \frac{2C + 2 - H}{2} \] \[ = \frac{2(14) + 2 - 9}{2} = \frac{28 + 2 - 9}{2} = \frac{21}{2} = 10.5 \] Wait, this suggests a miscalculation. Let's revisit: Try C₁₃H₁₁O₂: - 13 × 12 = 156, 11 × 1 = 11, 2 × 16 = 32 → 156 + 11 + 32 = **199** Try C₁₂H₁₃O₄: - 12 × 12 = 144, 13 + 64 = 221 Let’s use C₁₃H₁₁NO₂: - 13 × 12 = 156 + 11 + 14 + 32 = 213 Try C₁₂H₉O₄: - 12 × 12 = 144 + 9 + 64 = 217 Try C₁₁H₉O₄: - 11 × 12 = 132 + 9 + 64 = 205 Try C₁₀H₉O₅: - 10 × 12 = 120 + 9 + 80 = 209 So, **C₁₀H₉O₅** fits: - C: 10 × 12 = 120 - H: 9 - O: 5 × 16 = 80 - **Total = 209** Degrees of Unsaturation: \[ \text{DoU} = \frac{2(10) + 2 - 9}{2} = \frac{20 + 2 - 9}{2} = \frac{13}{2} = 6.5 \] Wait, that's not possible (must be integer). Let's try to move forward with the spectral data. --- ## **Step 2: Analyzing ¹H NMR Spectrum** ### **Chemical Shifts and Integrals** - **7.2–8.2 ppm (5H, multiplet)**: Aromatic protons (monosubstituted benzene ring). - **~4.1 ppm (4H, triplet)**: Two CH₂ groups, each as a triplet; likely –CH₂–CH₂– fragment. - **~2.7 ppm (2H, singlet)**: Methylene (–CH₂–) adjacent to a carbonyl or aromatic ring. ### **Pattern** - 5H multiplet suggests a monosubstituted benzene ring. - Two triplets (each 4H): Likely two –CH₂– groups, each next to another –CH₂– (common in an ethylene glycol or similar fragment). - 2H singlet: Likely isolated methylene. --- ## **Step 3: ¹³C NMR Spectrum** - **~170–180 ppm**: Two signals (likely carbonyl, possibly esters). - **~120–140 ppm**: Multiple signals (aromatic/alkene). - **~65 ppm**: Two signals, likely CH₂ near electronegative atoms (oxygen). - **~30–40 ppm**: Additional CH₂. --- ## **Step 4: IR Spectrum (Functional Groups)** - **3331 cm⁻¹**: O–H/N–H stretch (broad, but not shown; likely O–H as N is unlikely from formula/mass). - **1655, 1601 cm⁻¹**: C=O and aromatic C=C stretches. - **1222 cm⁻¹**: C–O stretch (ester or ether). --- ## **Step 5: Structure Assembly** ### **Aromatic region** - 5H (multiplet) = monosubstituted benzene ring. ### **Oxygenated CH₂s** - Two triplets, 4H each at 4.1 ppm: –CH₂–O–CH₂–, likely on both sides of an aromatic ring. ### **2H singlet** - Methylene group adjacent to two electron-withdrawing groups (aromatic or carbonyl). ### **Overall structure matching** - Mass = 209, fits with a phthalate ester (diethyl phthalate: C₁₂H₁₄O₄, but mass = 222). - Try **benzyl phthalate**: C₁₅H₁₂O₄, mass = 256. ### **Check for ethylene glycol portion** - Two –OCH₂CH₂O– chains (ethylene glycol diester). - Monosubstituted benzene ring: fits with phthalate core. #### **Ethylene glycol phthalate** - C₁₀H₁₀O₄ (phthalate core) + C₄H₈O₂ (ethylene glycol): C₁₄H₁₈O₆, mass = 282. #### **Check for phenyl ester** - Monosubstituted benzene ring suggests a phenyl ester. #### **Try phenyl acetate:** C₈H₈O₂ (mass 136) #### **Try phenyl propionate:** C₉H₁₀O₂ (mass 150) #### **Try benzyl acetate:** C₉H₁₀O₂ (mass 150) #### **Try benzyl ethyl ether:** C₉H₁₂O (mass 136) #### **Try benzyl oxyacetate:** C₉H₁₀O₃ (mass 166) ### **Let's try to rationalize:** #### **Aromatic ring (5H) + 2x CH₂ (4H each) + 2H singlet** - 5H: Monosubstituted benzene - 4H triplet: OCH₂CH₂O fragment - 2H singlet: Benzyl CH₂ ### **Possibility: Benzyl glycolate (phenylmethyl glycolate)** - Structure: PhCH₂OCOCH₂CH₂O - But mass seems off. ### **Try Benzyl phthalate (monobenzyl phthalate):** - C₁₅H₁₂O₄ (mass 256) ### **Try 1,2-bis(phenoxy)ethane:** - C₁₄H₁₄O₂ (mass 214) ### **Try 1,2-bis(benzyloxy)ethane:** - C₁₆H₁₈O₂ (mass 242) ### **Try 4-(2-phenylethoxy)phenol:** - C₁₄H₁₄O₂ (mass 214) --- ## **Step 6: Re-examine Integration and Splitting** - **5H (multiplet, aromatic)**: Monosubstituted benzene - **4H (triplet, 4.1 ppm)**: Two equivalent CH₂ groups, each next to an oxygen. - **4H (triplet, 4.1 ppm)**: Same as above (two identical signals overlap). - **2H (singlet, 2.7 ppm)**: Methylene not coupled (no neighbors). ### **Likeliest Structure: Dibenzyl ether or related** But the numbers don't add up for simple ethers. --- ## **Step 7: Final Proposal (Based on All Data)** Given the mass 209, let's try **phenoxyethyl acetate**: - C₁₀H₁₀O₃: 10 × 12 = 120 + 10 + 48 = **178** Try **phenyl ethyl ether**: C₈H₁₀O, mass 122 Try **phenoxyacetic acid**: C₈H₈O₃, mass 152 --- ## **Step 8: Check Triethylene Glycol Monobenzoate** - Benzene ring: 5H - CH₂O: 4H (triplet) - CH₂O: 4H (triplet) - CH₂ (singlet): 2H But mass is wrong. --- ## **Step 9: Re-examine Formula and Calculate Exact Mass** Given the pattern and mass, the structure that most closely fits the NMR and integration is **benzyl ethyl ether (C₉H₁₂O)**: - Benzene: 5H - CH₂CH₃: 2H (quartet), 3H (triplet) But not matching with triplets and integrations. --- ## **Step 10: Final Solution** ### **Best Fitting Compound: 1,2-Bis(phenoxy)ethane** - Structure: Ph–O–CH₂–CH₂–O–Ph - Molecular formula: C₁₄H₁₄O₂, MW = 214 (close, but not 209) #### **But the data is best explained by:** - 5H (aromatic) - 2 × 4H (triplet, OCH₂CH₂O) - 2H (singlet, benzylic CH₂) None of the common compounds fit exactly with MW = 209. The closest possible fit is a compound with a monosubstituted benzene ring, two ethylene glycol-type fragments, and an extra CH₂. --- ## **Summary Table** | Signal | Integration | Multiplicity | Assignment | |-----------------|-------------|--------------|--------------------------| | 7.2–8.2 ppm | 5H | m | Monosubstituted benzene | | 4.1 ppm | 4H | t | –OCH₂CH₂O– | | 4.1 ppm | 4H | t | –OCH₂CH₂O– | | 2.7 ppm | 2H | s | Benzylic CH₂ | --- ## **Final Proposed Structure** ### **Name:** **4-(2-phenoxyethoxy)benzaldehyde** or a similar aromatic ether with ethylene glycol linkage. ### **Structure:** - Monosubstituted benzene ring - –CH₂–O–CH₂–CH₂–O– fragment - Benzylic CH₂ ### **Molecular Formula:** **C₁₃H₁₂O₃** (but MW = 216) **Closest fit:** **The exact compound is not perfectly matching the MW = 209, but the NMR data best fits a structure with a monosubstituted benzene ring, an ethylene glycol derived linker, and a benzylic CH₂ group.** --- ## **Conclusion** ### **The structure is most likely:** **Phenoxyethyl benzyl ether** - **Structure:** Ph–O–CH₂–CH₂–O–CH₂–Ph - **NMR matches:** 5H (aromatic), 4H (OCH₂), 4H (OCH₂), 2H (benzylic CH₂) - **Molecular weight:** Close but not exact to 209. --- ### **Final Answer:** **The compound is a phenyl-terminated ethylene glycol ether, likely phenoxyethyl benzyl ether or a very similar structure.** --- **If you have the exact molecular formula, please provide it for confirmation. The NMR data is most consistent with this type of structure.**