Compound characterization data — Keppel et al., 2026

Patrick Keppel, Marek Chovanec, Nikolaus Poremba, Anna Kovalová, Michal Rahm, Hannes Mikula, Milan Vrabel. “Electrostatic attraction unlocks rapid tetrazine–trans-cyclooctene click chemistry in organic solvents.” ChemRxiv (2026). https://doi.org/10.26434/chemrxiv.15007910/v1

TCO-NMe₃⁺
Identifier	1
¹H NMR (400 MHz, CD₃OD)	δ 5.72–5.51 (m, 2H, CH=CH), 4.92–4.85 (m, 1H, OCH), 3.68–3.57 (m, 2H, CH₂NH), 3.56–3.48 (m, 2H, CH₂N⁺), 3.24 (s, 9H, (CH₃)₃N⁺), 2.40–2.19 (m, 4H, TCO CH₂), 2.12–2.05 (m, 1H, TCO CH₂), 1.92–1.66 (m, 3H, TCO CH₂), 1.62–1.48 (m, 1H, TCO CH₂), 1.35–1.25 (m, 1H, TCO CH₂)
¹³C NMR (101 MHz, CD₃OD)	δ 158.4 (OCONH), 136.3 (CH=CH), 132.6 (CH=CH), 72.1 (OCH), 66.2 (t, JC-N = 2.9 Hz, CH₂N⁺), 54.2 (t, JC-N = 3.9 Hz, (CH₃)₃N⁺), 41.9 (TCO CH₂), 36.2 (CH₂NH), 35.2 (TCO CH₂), 33.6 (TCO CH₂), 30.8 (TCO CH₂), 29.1 (TCO CH₂)
LRMS (ESI⁺)	m/z 255.2 [M]⁺
HRMS (ESI⁺)	m/z calcd for C₁₄H₂₇N₂O₂⁺ [M]⁺ 255.2067, found 255.2066

TCO-Arg
Identifier	2
¹H NMR (400 MHz, CD₃OD, mixture of diastereomers)	δ 8.56 (s, 1H, HCO₂⁻), 5.79–5.63 (m, 1H, CH=CH), 5.63–5.49 (m, 1H, CH=CH), 4.84–4.78 (m, 1H, OCH), 4.31–4.13 (m, 1H, NCH), 3.82–3.64 (m, 3H, CO₂CH₃), 3.27–3.12 (m, 2H, NCH₂), 2.47–1.40 (m, 13H, TCO CH₂, CHCH₂CH₂), 1.40–1.21 (m, 1H, TCO CH₂)
¹³C NMR (101 MHz, CD₃OD, mixture of diastereomers)	δ 174.3 (CO₂CH₃), 170.4 (HCO₂⁻), 158.8, 158.7, 158.6, 158.5 (OCONH, C(NH₂)NH₂⁺), 136.5, 136.3 (CH=CH), 132.7, 132.4 (CH=CH), 72.1, 72.0 (OCH), 55.0, 54.8 (NCH), 52.8, 52.7 (CO₂CH₃), 41.9, 41.8 (NCH₂, TCO CH₂), 35.3 (TCO CH₂), 33.7, 33.6 (TCO CH₂), 30.8 (TCO CH₂), 29.7, 29.6 (CH₂), 29.0, 28.8 (TCO CH₂), 26.5 (CH₂); several duplicated/closely spaced resonances arise from the presence of two diastereomers
LRMS (ESI⁺)	m/z 341.2 [M+H]⁺
HRMS (ESI⁺)	m/z calcd for C₁₆H₂₉N₄O₄⁺ [M+H]⁺ 341.2183, found 341.2183

TCO-PEG4
Identifier	3
LRMS (ESI⁺)	m/z (%) 368.2 [M+Na]⁺ (100), 346.2 [M+H]⁺ (5)
HRMS (ESI⁺)	m/z calcd for C₁₇H₃₂NO₆⁺ [M+H]⁺ 346.2224, found 346.2221; calcd for C₁₇H₃₁NO₆Na⁺ [M+Na]⁺ 368.2044, found 368.2041

Uncharged Tz
Identifier	S1
¹H NMR (400 MHz, CDCl₃)	δ 8.09 (dd, J = 7.7, 1.7 Hz, 2H, CH), 7.55 (ddd, J = 8.4, 7.4, 1.8 Hz, 2H, CH), 7.23 (td, J = 7.6, 1.0 Hz, 2H, CH), 7.02 (dd, J = 8.5, 1.0 Hz, 2H, CH), 4.68 (s, 4H, OCH₂CO₂tBu), 1.44 (s, 18H, C(CH₃)₃)
¹³C NMR (101 MHz, CDCl₃)	δ 167.8 (2x CO₂tBu), 164.4 (2x Tz C), 157.3 (2x Ph COCH₂CO₂tBu), 133.1 (2x CH), 132.3 (2x CH), 123.2 (2x Ph C-Tz), 122.3 (2x CH), 114.1 (2x CH), 82.6 (2x C(CH₃)₃), 67.2 (2x OCH₂CO₂tBu), 28.1 (2x C(CH₃)₃)
HRMS (ESI⁺)	m/z calcd for C₂₆H₃₁N₄O₆⁺ [M+H]⁺ 495.2238, found 495.2234

Tz dicarboxylate
Identifier	4
¹H NMR (400 MHz, CD₃OD)	δ 8.04 (dd, J = 7.7, 1.7 Hz, 2H, CH), 7.59 (ddd, J = 8.4, 7.4, 1.8 Hz, 2H, CH), 7.25–7.16 (m, 4H, CH), 4.57 (s, 4H, OCH₂CO₂⁻)
¹³C NMR (101 MHz, CD₃OD)	δ 175.7 (2x OCH₂CO₂⁻), 165.7 (2x Tz C), 158.9 (2x Ph COCH₂CO₂⁻), 134.3 (2x CH), 132.9 (2x CH), 123.6 (2x Ph C-Tz), 122.4 (2x CH), 115.1 (2x CH), 69.3 (2x OCH₂CO₂⁻)
HRMS (ESI⁻)	m/z calcd for C₁₈H₁₃N₄O₆⁻ [M−H]⁻ 381.0841, found 381.0843

Compound S2
¹H NMR (400 MHz, CDCl₃)	δ 8.77 (t, J = 5.7 Hz, 1H, NHCO), 8.67 (s, 1H, CH), 7.40 (d, J = 9.0 Hz, 1H, CH), 6.62 (dd, J = 9.0, 2.5 Hz, 1H, CH), 6.47 (d, J = 2.4 Hz, 1H, CH), 4.56 (bs, 1H, NHBoc), 3.49–3.35 (m, 6H, CH₂NHCO, CH₂CH₃), 3.16–2.99 (m, 2H, CH₂NHBoc), 1.63–1.56 (m, 2H, CH₂CH₂CH₂), 1.50–1.33 (m, 15H, CH₂CH₂CH₂, C(CH₃)₃), 1.21 (t, J = 7.1 Hz, 6H, CH₂CH₃)
¹³C NMR (101 MHz, CDCl₃)	δ 163.1 (CONH), 162.9 (CqOO), 157.7 (Cq), 156.1 (CqOOC(CH₃)₃), 152.5 (CqN(CH₂CH₃)₂), 148.1 (CH), 131.2 (CH), 110.5 (Cq), 110.0 (CH), 108.5 (Cq), 96.6 (CH), 79.0 (C(CH₃)₃), 45.2 (2x CH₂CH₃), 40.6 (CH₂NH), 39.6 (CH₂NH), 30.0 (CH₂CH₂CH₂), 29.6 (CH₂CH₂CH₂), 28.5 (2x C(CH₃)₃), 26.8 (CH₂CH₂CH₂), 26.6 (CH₂CH₂CH₂), 12.5 (2x CH₂CH₃)
LRMS (ESI⁺)	m/z (%) 482.3 [M+Na]⁺ (100), 360.2 [M−Boc+2H]⁺ (60), 460.3 [M+H]⁺ (50), 941.5 [2M+Na]⁺ (10)
HRMS (ESI⁺)	m/z calcd for C₂₅H₃₈N₃O₅⁺ [M+H]⁺ 460.2806, found 460.2803; calcd for C₂₅H₃₇N₃O₅Na⁺ [M+Na]⁺ 482.2625, found 482.2621

Compound S3
¹H NMR (400 MHz, DMSO-d₆)	δ 8.68–8.60 (m, 2H, NHCO, CH), 7.78 (bs, 3H, NH₃⁺), 7.67 (d, J = 9.0 Hz, 1H, CH), 6.79 (dd, J = 9.0, 2.4 Hz, 1H, CH), 6.60 (d, J = 2.4 Hz, 1H, CH), 3.47 (q, J = 7.0 Hz, 4H, CH₂CH₃), 3.33–3.25 (m, 2H, CH₂NH), 2.83–2.72 (m, 2H, CH₂NH₃⁺), 1.58–1.47 (m, 4H, CH₂CH₂CH₂), 1.37–1.28 (m, 4H, CH₂CH₂CH₂), 1.13 (t, J = 7.0 Hz, 6H, CH₂CH₃)
¹³C NMR (101 MHz, DMSO-d₆)	δ 162.1 (CONH), 161.8 (CqOO), 158.1 (q, JC-F = 31 Hz, CF₃CO₂⁻), 157.2 (Cq), 152.4 (CqN(CH₂CH₃)₂), 147.6 (CH), 131.5 (CH), 117.2 (q, JC-F = 300 Hz, CF₃CO₂⁻), 110.1 (CH), 109.5 (Cq), 107.7 (Cq), 95.8 (CH), 44.3 (2x CH₂CH₃), 38.7 (CH₂NH, CH₂NH₃⁺, 2 signals), 28.9 (CH₂CH₂CH₂), 26.9 (CH₂CH₂CH₂), 25.9 (CH₂CH₂CH₂), 25.4 (CH₂CH₂CH₂), 12.3 (2x CH₂CH₃)
LRMS (ESI⁺)	m/z (%) 360.2 [M+H]⁺ (100), 382.2 [M+Na]⁺ (10)
HRMS (ESI⁺)	m/z calcd for C₂₀H₃₀N₃O₃⁺ [M+H]⁺ 360.2282, found 360.2280

Compound S4
¹H NMR (400 MHz, DMSO-d₆)	δ 8.15–8.08 (m, 1H, CH), 7.92–7.85 (m, 1H, CH), 7.81 (dd, J = 8.7, 2.2 Hz, 1H, CH), 7.67–7.60 (m, 1H, CH), 7.29–7.10 (m, 3H, CH), 4.86–4.77 (m, 4H, OCH₂CO₂tBu), 1.54–1.21 (m, 18H, C(CH₃)₃)
¹³C NMR (101 MHz, DMSO-d₆)	δ 167.5 (CO₂tBu), 167.3 (CO₂tBu), 164.4 (Tz C), 164.2 (Tz C), 156.4 (Ph COCH₂CO₂tBu), 156.3 (Ph COCH₂CO₂tBu), 141.9 (Ph C-SO₃⁻), 132.9 (CH), 131.7 (CH), 130.1 (CH), 129.2 (CH), 122.5 (Ph C-Tz), 121.5 (CH), 121.3 (Ph C-Tz), 113.6 (CH), 112.8 (CH), 81.6 (C(CH₃)₃), 81.5 (C(CH₃)₃), 65.8 (2x OCH₂CO₂tBu), 27.7 (2x C(CH₃)₃)
HRMS (ESI⁻)	m/z calcd for C₂₆H₂₉N₄O₉S⁻ [M−H]⁻ 573.1661, found 573.1662

Uncharged Tz-coumarin conjugate
Identifier	8
¹H NMR (400 MHz, CDCl₃)	δ 8.80 (t, J = 5.9 Hz, 1H, NHCO), 8.74 (s, 1H, CH), 8.61 (d, J = 2.4 Hz, 1H, CH), 8.17–7.97 (m, 2H, CH), 7.56 (ddd, J = 8.7, 7.5, 1.8 Hz, 1H, CH), 7.43 (d, J = 8.9 Hz, 1H, CH), 7.23 (t, J = 7.7 Hz, 1H, CH), 7.07 (d, J = 8.9 Hz, 1H, CH), 7.01 (d, J = 8.4 Hz, 1H, CH), 6.62 (dd, J = 9.0, 2.5 Hz, 1H, CH), 6.48 (d, J = 2.5 Hz, 1H, CH), 5.04 (t, J = 6.2 Hz, 1H, NHSO₂), 4.73 (s, 2H, OCH₂CO₂tBu), 4.68 (s, 2H, OCH₂CO₂tBu), 3.48–3.37 (m, 6H, CH₂CH₃, CH₂NHCO), 3.10–2.96 (m, 2H, CH₂NHSO₂), 1.60–1.44 (m, 20H, CH₂CH₂CH₂, C(CH₃)₃), 1.40–1.32 (m, 4H, CH₂CH₂CH₂), 1.27–1.19 (m, 8H, CH₂CH₂CH₂, CH₂CH₃)
¹³C NMR (101 MHz, CDCl₃)	δ 167.7 (CO₂tBu), 166.8 (CO₂tBu), 164.7 (Tz C), 163.5 (Tz C, CONH, 2 signals), 163.0 (CqOO), 159.9 (Ph COCH₂CO₂tBu), 157.7 (Cq), 157.4 (Ph COCH₂CO₂tBu), 152.6 (CqN(CH₂CH₃)₂), 148.4 (CH), 134.0 (Ph C-SO₂NH), 133.3 (CH), 132.3 (CH), 132.0 (CH), 131.5 (CH), 131.4 (CH), 123.5 (Ph C-Tz), 122.8 (Ph C-Tz), 122.3 (CH), 114.0 (CH), 113.6 (CH), 110.4 (Cq), 110.1 (CH), 108.6 (Cq), 96.7 (CH), 83.2 (C(CH₃)₃), 82.7 (C(CH₃)₃), 67.1 (OCH₂CO₂tBu), 66.7 (OCH₂CO₂tBu), 45.2 (2x CH₂CH₃), 43.1 (CH₂NHSO₂), 39.2 (CH₂NHCO), 29.6 (CH₂CH₂CH₂), 29.5 (CH₂CH₂CH₂), 28.1 (2x C(CH₃)₃), 26.2 (CH₂CH₂CH₂), 25.9 (CH₂CH₂CH₂), 12.6 (2x CH₂CH₃)
LRMS (ESI⁺)	m/z (%) 938.4 [M+Na]⁺ (100), 916.4 [M+H]⁺ (90)
HRMS (ESI⁺)	m/z calcd for C₄₆H₅₈N₇O₁₁S⁺ [M+H]⁺ 916.3910, found 916.3914; calcd for C₄₆H₅₇N₇O₁₁SNa⁺ [M+Na]⁺ 938.3729, found 938.3734

Tz dicarboxylate-coumarin conjugate
Identifier	6
¹H NMR (400 MHz, DMSO-d₆)	δ 8.70–8.53 (m, 2H, NHCO, CH), 8.30 (s, 1H, CH), 7.98 (d, J = 8.9 Hz, 1H, CH), 7.89 (d, J = 7.6 Hz, 1H, CH), 7.73–7.51 (m, 3H, NHSO₂, CH), 7.31 (d, J = 8.9 Hz, 1H, CH), 7.22 (t, J = 7.6 Hz, 1H, CH), 7.16 (d, J = 8.5 Hz, 1H, CH), 6.78 (d, J = 9.0 Hz, 1H, CH), 6.60 (s, 1H, CH), 4.75–4.62 (m, 4H, OCH₂CO₂⁻), 4.09 (bs, 8H, NH₄⁺), 3.47 (q, J = 7.1 Hz, 4H, CH₂CH₃), 3.30–3.21 (m, 2H, CH₂NHCO), 2.85–2.73 (m, 2H, CH₂NHSO₂), 1.51–1.37 (m, 4H, CH₂CH₂CH₂), 1.32–1.22 (m, 4H, CH₂CH₂CH₂), 1.13 (t, J = 7.0 Hz, 6H, CH₂CH₃)
¹³C NMR (101 MHz, DMSO-d₆)	δ 170.0 (OCH₂CO₂⁻), 169.4 (OCH₂CO₂⁻), 164.5 (Tz C), 163.5 (Tz C), 162.0 (CONH), 161.8 (CqOO), 159.5 (Ph COCH₂CO₂⁻), 157.2 (Cq), 156.8 (Ph COCH₂CO₂⁻), 152.4 (CqN(CH₂CH₃)₂), 147.6 (CH), 133.1 (CH), 132.9 (Ph C-SO₂NH), 131.6 (CH, 2 signals), 131.3 (CH), 130.3 (CH), 122.3 (2x Ph C-Tz, 2 signals), 121.4 (CH), 114.3 (CH), 114.1 (CH), 110.1 (CH), 109.5 (Cq), 107.7 (Cq), 95.9 (CH), 66.3 (OCH₂CO₂⁻), 66.0 (OCH₂CO₂⁻), 44.3 (2x CH₂CH₃), 42.6 (CH₂NHSO₂), 38.7 (CH₂NHCO), 29.0 (2x CH₂CH₂CH₂, 2 signals), 26.0 (CH₂CH₂CH₂), 25.8 (CH₂CH₂CH₂), 12.3 (2x CH₂CH₃)
LRMS (ESI⁻)	m/z (%) 400.6 [M−2H]²⁻ (100), 802.3 [M−H]⁻ (35), 824.2 [M−2H+Na]⁻ (5)
HRMS (ESI⁻)	m/z calcd for C₃₈H₃₉N₇O₁₁S²⁻ [M−2H]²⁻ 400.6220, found 400.6218; calcd for C₃₈H₄₀N₇O₁₁S⁻ [M−H]⁻ 802.2512, found 802.2506; calcd for C₃₈H₃₉N₇O₁₁SNa⁻ [M−2H+Na]⁻ 824.2331, found 824.2325

Compound S5
¹H NMR (400 MHz, DMSO-d₆)	δ 8.11 (d, J = 2.2 Hz, 2H, CH), 7.81 (dd, J = 8.7, 2.3 Hz, 2H, CH), 7.16–7.07 (m, 10H, CH, NH₄⁺), 4.81 (s, 4H, OCH₂CO₂tBu), 1.39 (s, 18H, C(CH₃)₃)
¹³C NMR (101 MHz, DMSO-d₆)	δ 167.3 (2x CO₂tBu), 164.2 (2x Tz C), 156.3 (2x Ph COCH₂CO₂tBu), 141.7 (2x Ph C-SO₃⁻), 130.1 (2x CH), 129.2 (2x CH), 121.4 (2x Ph C-Tz), 112.7 (2x CH), 81.6 (2x C(CH₃)₃), 65.8 (2x OCH₂CO₂tBu), 27.7 (2x C(CH₃)₃)
LRMS (ESI⁺)	m/z (%) 677.1 [M+Na]⁺ (100), 699.1 [M−H+2Na]⁺ (35), 655.1 [M+H]⁺ (25)
LRMS (ESI⁻)	m/z (%) 326.1 [M−2H]²⁻ (100), 653.1 [M−H]⁻ (5)
HRMS (ESI⁺)	m/z calcd for C₂₆H₃₁N₄O₁₂S₂⁺ [M+H]⁺ 655.1374, found 655.1379; calcd for C₂₆H₃₀N₄O₁₂S₂Na⁺ [M+Na]⁺ 677.1194, found 677.1197; calcd for C₂₆H₂₉N₄O₁₂S₂Na₂⁺ [M−H+2Na]⁺ 699.1013, found 699.1018
HRMS (ESI⁻)	m/z calcd for C₂₆H₂₉N₄O₁₂S₂⁻ [M−H]⁻ 653.1229, found 653.1224; calcd for C₂₆H₂₈N₄O₁₂S₂²⁻ [M−2H]²⁻ 326.0578, found 326.0576

Trianionic Tz-coumarin conjugate
Identifier	7
¹H NMR (400 MHz, DMSO-d₆)	δ 8.66–8.58 (m, 2H, NHCO, CH), 8.29 (d, J = 2.5 Hz, 1H, CH), 8.12 (d, J = 2.2 Hz, 1H, CH), 7.99 (dd, J = 8.9, 2.5 Hz, 1H, CH), 7.80 (dd, J = 8.7, 2.3 Hz, 1H, CH), 7.69–7.61 (m, 2H, NHSO₂, CH), 7.36 (d, J = 9.0 Hz, 1H, CH), 7.13 (d, J = 8.8 Hz, 1H, CH), 6.82–6.77 (m, 1H, CH), 6.63–6.59 (m, 1H, CH), 4.83 (s, 2H, OCH₂CO₂⁻), 4.76 (s, 2H, OCH₂CO₂⁻), 3.47 (q, J = 7.0 Hz, 4H, CH₂CH₃), 3.28–3.23 (m, 2H, CH₂NHCO), 2.83–2.74 (m, 2H, CH₂NHSO₂), 1.48–1.36 (m, 4H, CH₂CH₂CH₂), 1.30–1.23 (m, 4H, CH₂CH₂CH₂), 1.13 (t, J = 7.0 Hz, 6H, CH₂CH₃)
¹³C NMR (101 MHz, DMSO-d₆)	δ 169.8 (OCH₂CO₂⁻), 169.4 (OCH₂CO₂⁻), 164.4 (Tz C), 163.5 (Tz C), 162.0 (CONH), 161.8 (CqOO), 159.4 (Ph COCH₂CO₂⁻), 157.2 (Cq), 156.7 (Ph COCH₂CO₂⁻), 152.4 (CqN(CH₂CH₃)₂), 147.6 (CH), 141.8 (Ph C-SO₃⁻), 133.0 (Ph C-SO₂NH), 131.5 (CH), 131.2 (CH), 130.3 (CH), 130.2 (CH), 129.2 (CH), 122.5 (Ph C-Tz), 121.1 (Ph C-Tz), 114.2 (CH), 113.1 (CH), 110.1 (CH), 109.5 (Cq), 107.7 (Cq), 95.9 (CH), 66.2 (OCH₂CO₂⁻), 65.9 (OCH₂CO₂⁻), 44.3 (2x CH₂CH₃), 42.6 (CH₂NHSO₂), 38.7 (CH₂NHCO), 29.0 (2x CH₂CH₂CH₂), 26.0 (CH₂CH₂CH₂), 25.8 (CH₂CH₂CH₂), 12.3 (2x CH₂CH₃)
LRMS (ESI⁻)	m/z (%) 440.6 [M−2H]²⁻ (100), 293.4 [M−3H]³⁻ (95), 882.2 [M−H]⁻ (20)
HRMS (ESI⁻)	m/z calcd for C₃₈H₃₉N₇O₁₄S₂²⁻ [M−2H]²⁻ 440.6004, found 440.6001; calcd for C₃₈H₄₀N₇O₁₄S₂⁻ [M−H]⁻ 882.2080, found 882.2078

Compound S6
¹H NMR (400 MHz, CDCl₃)	δ 5.66–5.47 (m, 2H, CH=CH), 5.16 (bs, 1H, OCONH), 5.00–4.83 (m, 1H, OCH), 3.32–3.22 (m, 2H, CH₂NH), 2.42 (t, J = 6.0 Hz, 2H, CH₂N(CH₃)₂), 2.39–2.16 (m, 10H, CH₂N(CH₃)₂, TCO CH₂), 2.16–2.03 (m, 1H, TCO CH₂), 1.90–1.71 (m, 2H, TCO CH₂), 1.72–1.48 (m, 2H, TCO CH₂), 1.26–1.14 (m, 1H, TCO CH₂)
¹³C NMR (101 MHz, CDCl₃)	δ 156.5 (OCONH), 135.5 (CH=CH), 131.9 (CH=CH), 70.2 (OCH), 58.5 (CH₂N(CH₃)₂), 45.4 (CH₂N(CH₃)₂), 41.3 (TCO CH₂), 38.5 (CH₂NH), 34.5 (TCO CH₂), 32.8 (TCO CH₂), 30.1 (TCO CH₂), 28.1 (TCO CH₂)
LRMS (ESI⁺)	m/z (%) 241.2 [M+H]⁺ (100), 263.2 [M+Na]⁺ (20)
HRMS (ESI⁺)	m/z calcd for C₁₃H₂₅N₂O₂⁺ [M+H]⁺ 241.1911, found 241.1909; calcd for C₁₃H₂₄N₂O₂Na⁺ [M+Na]⁺ 263.1730, found 263.1728

Compound S7
¹H NMR (400 MHz, CD₂Cl₂)	δ 6.63 (bs, 1H, OCONH), 5.85–5.60 (m, 1H, CH=CH), 5.60–5.40 (m, 1H, CH=CH), 4.96–4.77 (m, 1H, OCH), 3.91–3.67 (m, 4H, CH₂NH, CH₂N⁺), 3.63 (s, 3H, OCH₃), 3.61–3.49 (m, 2H, CH₂N⁺), 3.34 (s, 6H, (CH₃)₂N⁺), 2.36–2.03 (m, 7H, CH₂CO₂CH₃, TCO CH₂), 1.88–1.59 (m, 7H, CH₂, TCO CH₂), 1.59–1.38 (m, 3H, CH₂, TCO CH₂), 1.28–1.15 (m, 1H, TCO CH₂)
¹³C NMR (101 MHz, CD₂Cl₂)	δ 173.9 (CO₂CH₃), 156.7 (OCONH), 136.0 (CH=CH), 131.8 (CH=CH), 70.9 (OCH), 65.6 (CH₂N⁺), 63.2 (CH₂N⁺), 52.4 ((CH₃)₂N⁺), 51.8 (CO₂CH₃), 41.3 (TCO CH₂), 35.7 (CH₂NH), 34.6 (TCO CH₂), 33.8 (CH₂CO₂CH₃), 32.9 (TCO CH₂), 30.2 (TCO CH₂), 28.4 (TCO CH₂), 25.9 (CH₂), 24.6 (CH₂), 22.9 (CH₂)
HRMS (ESI⁺)	m/z calcd for C₂₀H₃₇N₂O₄⁺ [M]⁺ 369.2748, found 369.2750

Compound S8
¹H NMR (400 MHz, DMSO-d₆)	δ 8.41–8.31 (m, 1H, OCONH), 5.73–5.56 (m, 1H, CH=CH), 5.56–5.42 (m, 1H, CH=CH), 4.84–4.69 (m, 1H, OCH), 3.45–3.36 (m, 4H, CH₂NH, CH₂N⁺), 3.36–3.27 (m, 2H, CH₂N⁺), 3.07 (s, 6H, (CH₃)₂N⁺), 2.31–1.95 (m, 5H, TCO CH₂), 1.91–1.57 (m, 7H, CH₂CO₂H, CH₂, TCO CH₂), 1.52–1.39 (m, 3H, CH₂, TCO CH₂), 1.29–1.13 (m, 3H, CH₂, TCO CH₂)
¹³C NMR (101 MHz, DMSO-d₆)	δ 175.5 (CO₂H), 156.1 (OCONH), 135.1 (CH=CH), 131.5 (CH=CH), 68.8 (OCH), 63.3 (CH₂N⁺), 61.3 (CH₂N⁺), 50.5 ((CH₃)₂N⁺), 40.5 (TCO CH₂), 38.4 (CH₂CO₂H), 34.5 (CH₂NH), 34.0 (TCO CH₂), 32.2 (TCO CH₂), 29.6 (TCO CH₂), 27.5 (TCO CH₂), 26.2 (CH₂), 25.9 (CH₂), 21.7 (CH₂)
LRMS (ESI⁺)	m/z (%) 355.3 [M]⁺ (100), 377.2 [M−H+Na]⁺ (10)
HRMS (ESI⁺)	m/z calcd for C₁₉H₃₅N₂O₄⁺ [M]⁺ 355.2591, found 355.2590; calcd for C₁₉H₃₄N₂O₄Na⁺ [M−H+Na]⁺ 377.2411, found 377.2409

TCO-lipid
Identifier	9
¹H NMR (500 MHz, CDCl₃, mixture of isomers)	δ 7.19–7.06 (m, 1H, OCONH), 5.75–5.46 (m, 2H, CH=CH), 5.29–5.17 (m, 1H, glycerol OCH), 4.99–4.63 (m, 1H, TCO OCH), 4.35–4.24 (m, 2H, glycerol OCH₂), 4.17–4.09 (m, 2H, glycerol OCH₂), 4.01–3.69 (m, 4H, CH₂NH, CH₂N⁺), 3.60–3.43 (m, 2H, CH₂N⁺), 3.43–3.24 (m, 6H, (CH₃)₂N⁺), 2.40–2.04 (m, 11H, CH₂CO₂R, TCO CH₂), 1.93–1.25 (m, 55H, myristoyl CH₂, hexyl CH₂, TCO CH₂), 0.87 (t, J = 7.0 Hz, 6H, myristoyl CH₂CH₃)
¹³C NMR (126 MHz, CDCl₃, mixture of isomers)	δ 173.6 (CO₂R), 173.1 (CO₂R), 172.7 (CO₂R), 157.0 (OCONH), 135.8 (CH=CH), 131.5 (CH=CH), 71.0 (TCO OCH), 68.9 (glycerol OCH), 65.4 (CH₂N⁺), 63.0 (CH₂N⁺), 62.5 (glycerol OCH₂), 62.2 (glycerol OCH₂), 51.8 ((CH₃)₂N⁺), 41.2 (TCO CH₂), 35.7 (CH₂NH), 34.5 (TCO CH₂), 34.4 (CH₂CO₂R), 34.2 (CH₂CO₂R), 33.5 (CH₂CO₂R), 32.9 (TCO CH₂), 32.1 (2x myristoyl CH₂CH₂CH₃), 30.0 (TCO CH₂), 29.8–29.2 (myristoyl CH₂), 28.1 (TCO CH₂), 25.7 (hexyl CH₂), 25.1 (myristoyl CH₂CH₂CO₂R), 25.0 (myristoyl CH₂CH₂CO₂R), 24.2 (hexyl CH₂), 22.8 (2x myristoyl CH₂CH₃), 22.6 (hexyl CH₂), 14.3 (2x myristoyl CH₂CH₃)
LRMS (ESI⁺)	m/z 849.7 [M]⁺
HRMS (ESI⁺)	m/z calcd for C₅₀H₉₃N₂O₈⁺ [M]⁺ 849.6926, found 849.6928

TCO-HER2
Identifier	10
HRMS (ESI⁺)	m/z calcd for C₅₆H₇₉N₁₀O₁₅⁺ [M+H]⁺ 1131.5721, found 1131.5727

TCO-LysMe₃⁺-HER2
Identifier	11
HRMS (ESI⁺)	m/z calcd for C₆₅H₉₇N₁₂O₁₆⁺ [M]⁺ 1301.7140, found 1301.7152

TCO-Arg-HER2
Identifier	12
HRMS (ESI⁺)	m/z calcd for C₆₂H₉₁N₁₄O₁₆⁺ [M+H]⁺ 1287.6732, found 1287.6744

TCO-NMe₃⁺, TCO-Arg, uncharged Tz, Tz dicarboxylate, Compounds S2–S8, uncharged Tz-coumarin conjugate, Tz dicarboxylate-coumarin conjugate, trianionic Tz-coumarin conjugate and TCO-lipid
¹H and ¹³C NMR spectra	Image data were not transcribed

TCO-HER2, TCO-LysMe₃⁺-HER2 and TCO-Arg-HER2
HPLC and mass spectrometry	Image data were not transcribed