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Melamine–Melem Adduct Phases: Investigating the Thermal Condensation of Melamine
Author(s) -
Sattler Andreas,
Pagano Sandro,
Zeuner Martin,
Zurawski Alexander,
Gunzelmann Daniel,
Senker Jürgen,
MüllerBuschbaum Klaus,
Schnick Wolfgang
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200901518
Subject(s) - melamine , adduct , chemistry , ammonia , crystal structure , crystallography , analytical chemistry (journal) , organic chemistry
By studying the thermal condensation of melamine, we have identified three solid molecular adducts consisting of melamine C 3 N 3 (NH 2 ) 3 and melem C 6 N 7 (NH 2 ) 3 in differing molar ratios. We solved the crystal structure of 2 C 3 N 3 (NH 2 ) 3 ⋅C 6 N 7 (NH 2 ) 3 ( 1 ; C 2/ c ; a =21.526(4), b =12.595(3), c =6.8483(14) Å; β =94.80(3)°; Z =4; V =1850.2(7) Å 3 ), C 3 N 3 (NH 2 ) 3 ⋅C 6 N 7 (NH 2 ) 3 ( 2 ; Pcca ; a =7.3280(2), b =7.4842(2), c =24.9167(8) Å; Z =4; V =1366.54(7) Å 3 ), and C 3 N 3 (NH 2 ) 3 ⋅3 C 6 N 7 (NH 2 ) 3 ( 3 ; C 2/ c ; a =14.370(3), b =25.809(5), c =8.1560(16) Å; β =94.62(3)°; Z =4; V =3015.0(10) Å 3 ) by using single‐crystal XRD. All syntheses were carried out in sealed glass ampoules starting from melamine. By variation of the reaction conditions in terms of temperature, pressure, and the presence of ammonia‐binding metals (europium) we gained a detailed insight into the occurrence of the three adduct phases during the thermal condensation process of melamine leading to melem. A rational bulk synthesis allowed us to realize adduct phases as well as phase separation into melamine and melem under equilibrium conditions. A solid‐state NMR spectroscopic investigation of adduct 1 was conducted.