The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Adducts of coordination compounds – 12. New hydrogen dinitrates and their structures》. Authors are Al-Zamil, Nabila S.; Evans, E. H. M.; Gillard, R. D.; James, David W.; Jenkins, Tudor E.; Lancashire, Robert J.; Williams, P. A..The article about the compound:cis-Dichlorobis(pyridine)platinum(II)cas:15227-42-6,SMILESS:[Cl-][Pt+2]([N]1=CC=CC=C1)([Cl-])[N]2=CC=CC=C2).Category: tetrahydroisoquinoline. Through the article, more information about this compound (cas:15227-42-6) is conveyed.
The new compounds trans-[Ru(py)4Cl2][H(ONO2)2] and [C13H9NH][H(ONO2)2] were characterized (C13H9N = phenanthridine) and these, with the known compounds trans-[Ir(py)4Cl2][H(ONO2)2], C13H9N.2HNO3.2H2O and [phenH][H(ONO2)2] (phen = 1,10-phenanthroline) shown to involve the H dinitrate ion. The crystal and mol. structure of the Ru complex was determined The orthorhombic unit cell, space group Pbcn has a 7.54, b 21.83, c 14.86 (±0.01) Å, Z = 4. The compound is isomorphous with the analogous Rh(III) complex, but has addnl. disorder involving the nitrate groups owing to loss of HNO3 with time to yield an isostructural mononitrate compound trans-[Ru(py)4Cl2][H(ONO2)2] and trans-[Pt(py)4Cl2](NO3)2 were obtained under conditions previously described as giving rise to nitration of the pyridine ring. In fact, no evidence for the formation of 3-nitropyridine was found during these studies.
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Tetrahydroisoquinoline – Wikipedia,
1,2,3,4-Tetrahydroisoquinoline | C9H11N – PubChem