title: Cocrystal of the [MnIVC2H7N5)3]4+ ion and biguanidium: a double hydrogen-bond interaction with guanidinium-recognizing anions.
abstract: Biguanidium tris(biguanide-kappa(2)N(2),N(4))manganese(IV) hexanitrate, (C(2)H(9)N(5))[Mn(C(2)H(7)N(5))(3)](NO(3))(6), is a cocrystal of the [Mn(IV)(C(2)H(7)N(5))(3)](4+) ion and biguanidium. The cocrystal exhibits a double hydrogen-bonding interaction between the biguanide and nitrate groups, which is rarely observed in crystal structures but is proposed as a recognition mode for guanidinium-recognizing anionic groups in biological systems. In this cocrystal structure, biguanide moieties exist both as divalent cations and as neutral molecules.
authors.affiliation: Institute of Molecular Science, Chemical Biology and Molecular Engineering Laboratory of Education Ministry, Shanxi University, Taiyuan, Shanxi 030006, People's Republic of China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Lu
authors.forename: Miao -Li
authors.initials: M-
authors.lastname: Zhu
authors.forename: Pin
authors.initials: P
authors.lastname: Yang