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1,2-Diaminocyclohexane Structure, Formula (C₆H₁₄N₂) & NMR Explained

🔬 Molecular geometry · conformation · spectroscopy for CAS 694-83-7

To truly understand 1,2-diaminocyclohexane (DACH), you have to start with its structure. The molecule is deceptively simple - a six-membered ring with two amine groups - yet that exact geometry is what gives DACH its reactivity, its chirality, and its value as a building block. This guide explains the molecular formula C₆H₁₄N₂, the ring conformation, the stereocenters, and how the molecule shows up in NMR. 🔬

If you have not yet read the basics, see our overview What Is 1,2-Diaminocyclohexane (DACH)? and the numeric data in 1,2-Diaminocyclohexane Properties.

🧪 Molecular Formula & Composition

The molecular formula of 1,2-diaminocyclohexane is C₆H₁₄N₂, sometimes written structurally as (CH₂)₄(CHNH₂)₂ to emphasize the ring. It contains six carbon atoms, fourteen hydrogen atoms, and two nitrogen atoms, giving a molar mass of 114.19 g/mol. ✅

⚛️ Carbon: 6 atoms forming a saturated cyclohexane ring

⚛️ Nitrogen: 2 primary amine (–NH₂) groups on adjacent ring carbons

⚛️ Hydrogen: 14 atoms (ring CH/CH₂ plus the two NH₂ groups)

You can view the canonical 2D and 3D structure on PubChem (CID 4610).

⬡ The Cyclohexane Ring & Adjacent Amine Groups

At the heart of DACH is a fully saturated cyclohexane ring. Two of the ring carbons - at positions 1 and 2, hence the name - each carry an amino group. This 1,2-arrangement places the two –NH₂ groups on neighboring carbons, close enough to act together. 💡

That proximity is the molecule's superpower: the two amines can chelate a single metal ion, bridge two reactive sites in an epoxy network, or condense with two aldehyde groups to form a rigid, ring-closed ligand. It is why DACH outperforms simple monoamines in catalysis and cross-linking.

🪑 Chair Conformation: Axial vs Equatorial

Like all cyclohexanes, DACH's ring prefers the low-energy chair conformation. The two amine groups can occupy axial or equatorial positions, and the preferred arrangement differs between the cis and trans isomers:

🪑 trans isomer: can place both –NH₂ groups equatorial (diequatorial), a particularly stable, low-strain geometry favored in chiral-ligand design.

🪑 cis isomer: must adopt one axial and one equatorial amine, giving it different spatial properties.

These conformational differences underpin why the trans enantiomers are the preferred backbone for salen ligands - a topic covered in DACH-derived chiral ligands.

🧬 Stereocenters & Isomerism

Each of the two carbons bearing an amine group is a stereocenter. This creates three stereoisomers: the meso cis form and the two trans enantiomers, (1R,2R) and (1S,2S). The structural distinction is small on paper but enormous in function - only the resolved trans enantiomers deliver the chirality needed for asymmetric synthesis. 🧬

For a full treatment of the isomers and how to tell them apart, see Cis vs Trans 1,2-Diaminocyclohexane: Isomers & Chirality.

📈 NMR of 1,2-Diaminocyclohexane

NMR spectroscopy is a fast, reliable way to confirm DACH identity and purity. Because the molecule is symmetric, its spectra are simpler than the atom count might suggest:

📊 ¹H NMR: Signals for the ring CH protons adjacent to nitrogen (methine, downfield of the other CH₂ envelope), the remaining ring CH₂ protons (upfield, ~1.0–1.8 ppm), and the exchangeable NH₂ protons (broad).

📊 ¹³C NMR: A small number of carbon environments thanks to molecular symmetry - the C–N methine carbons resolve from the plain ring CH₂ carbons.

For reference spectra and validated physical constants, the NIST Chemistry WebBook is an authoritative source. Exact shifts depend on solvent, concentration, and the cis/trans ratio of your sample.

🧫 Need Identity-Confirmed, High-Purity DACH?

Sinolook Chemical supplies 1,2-diaminocyclohexane (CAS 694-83-7) with COA, including spectral and chromatographic identity data on request.

👉 View DACH Product & Specifications

❓ Frequently Asked Questions

🔹 What is the molecular formula of 1,2-diaminocyclohexane?

It is C₆H₁₄N₂, also written as (CH₂)₄(CHNH₂)₂, with a molar mass of 114.19 g/mol.

🔹 What does the structure of DACH look like?

It is a saturated cyclohexane ring with two primary amine (–NH₂) groups on adjacent carbons (positions 1 and 2). The ring favors a chair conformation.

🔹 Why does DACH have isomers?

The two amine-bearing carbons are stereocenters, producing a cis isomer and two trans enantiomers, (1R,2R) and (1S,2S).

🔹 How is DACH identified by NMR?

Its symmetry gives relatively simple ¹H and ¹³C spectra, distinguishing the C–N methine positions from the plain ring CH₂ environments; exchangeable NH₂ protons appear as a broad signal.