title: Melamine-melem adduct phases: investigating the thermal condensation of melamine.
abstract: 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; C2/c; a=21.526(4), b=12.595(3), c=6.8483(14) A; beta=94.80(3) degrees ; Z=4; V=1850.2(7) A(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) A; Z=4; V=1366.54(7) A(3)), and C(3)N(3)(NH(2))(3)3 C(6)N(7)(NH(2))(3) (3; C2/c; a=14.370(3), b=25.809(5), c=8.1560(16) A; beta=94.62(3) degrees ; Z=4; V=3015.0(10) A(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.
authors.affiliation: Department Chemie und Biochemie, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13(D), 81377 München, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Sattler
authors.forename: Sandro
authors.initials: S
authors.lastname: Pagano
authors.forename: Martin
authors.initials: M
authors.lastname: Zeuner
authors.forename: Alexander
authors.initials: A
authors.lastname: Zurawski
authors.forename: Daniel
authors.initials: D
authors.lastname: Gunzelmann
authors.forename: Jürgen
authors.initials: J
authors.lastname: Senker
authors.forename: Klaus
authors.initials: K
authors.lastname: Müller-Buschbaum
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schnick