A 1H, 13C and 15N NMR investigation of three substituted DMAN derivatives and their monoprotonated salts

✍ Scribed by Mariusz Pietrzak; Lech Stefaniak; Alexander F. Pozharskii; Valery A. Ozeryanskii; Joanna Nowicka-Scheibe; Eugeniusz Grech; Graham A. Webb

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 52 KB
• Volume: 13
• Category: Article
• ISSN: 0894-3230
• DOI: 10.1002/(sici)1099-1395(200001)13:1<35::aid-poc202>3.0.co;2-n

✦ Synopsis

We report a 1 H, 13 C and 15 N NMR investigation of one symmetrically substituted 2,7-dichloro and two unsymmetrically substituted 2-chloro and 4-bromo DMAN [1,8-bis(dimethylamino)naphthalene] proton sponges and their protonated salts. From a consideration of the NMR data reported we conclude, that the most sensitive parameters for investigating compounds of this kind are 1 J ( 15 N-1 H) and 15 N and 1 H chemical shifts for the nuclei in the [N8-H-N1] bridge. A further significant NMR parameter is 3 J ( 1 H-1 H) for the bridging proton and the N(CH 3 ) 2 protons. An analysis of the values of 1 J ( 15 N-1 H) for the studied compounds is consistent with the view that in the investigated system equilibrium between two tautomeric forms occurs. A study at temperatures between 27 and À40 °C, and a change of solvent, show that the values of the 15 N chemical shifts and couplings 1 J ( 15 N-1 H) and 3 J ( 1 H-1 H) for the [N8-H-N1] bridge are essentially unchanged. This shows that the bonding arrangements of the bridge atoms are stable under these experimental conditions.