1 Supporting Information for Nitric oxide reactivity of a Cu(II) complex of an imidazole based ligand: Aromatic Cnitrosation followed by the formation of N nitrosohydroxylaminato complex                Department of Chemistry, Indian Institute of Technology Guwahati, North Guwahati, Assam 781039, India. E%mail:biplab@iitg.ac.in. Phone: +91%361%258%2317. Fax: +91%361%258%2339 Table of Contents Sl. No. Description Page No Figure S1. FT%IR spectrum of the ligand LH in KBr pellet. 03 Figure S2. 1 H%NMR spectrum of the ligand LH in CDCl 3 . 03 Figure S3. 13 C%NMR spectrum of the ligand LH in CDCl 3 . 04 Figure S4. FT%IR spectrum of complex 1 in KBr pellet. 04 Figure S5. UV%visible spectrum of complex 1 in methanol at room temperature. 05 Figure S6. X%band EPR spectrum of complex 1 in acetonitrile:methanol (5:1, v/v) at 77K. 05 Figure S7. ESI%mass spectrum of complex 1 in methanol. Inset shows the simulated (red) and experimental (balck) isotopic distribution pattern. 06 Figure S8. Solution FT%IR spectra of complex 1 (black); Cu(I)%nitrosyl intermediate (blue) just after it’s formation; pink, green and red traces represent the same of Cu(I) nitrosyl intermediate after 5, 10 and 20 hrs , respectively, in acetonitrile:methanol (5:1, v/v) mixture in KBr cell. 06 Figure S9. FT%IR spectrum of complex 2 in KBr pellet. 07 Figure S10. UV%visible spectrum of complex 2 in methanol. 07 Figure S11. ESI%mass spectrum of complex 2 in methanol. Inset shows the simulated (red) and experimental (balck) isotopic distribution pattern. 08 Figure S12. X%band EPR spectrum of complex 2 in methanol at 77 K. 08 Figure S13. FT%IR spectrum of complex 3 in KBr pellet. 09 Figure S14. UV%visible spectrum of complex 3 in methanol. 09 Figure S15. ESI%mass spectrum of complex 3 in methanol. 10 Figure S16. X%band EPR spectrum of complex 3 in methanol at 77 K. 10 Figure S17. FT%IR spectrum of the crude reaction mixture obtained after addition of 11