(Di)-aminoguanidine Functionalization through Transamination: An Avenue to an Auspicious Class of Supramolecular Synthons

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• 作者：Anil D. Naik ; Bernard Tinant ; Alexandre Le虂onard ; Jacqueline Marchand-Brynaert ; Bao-Lian Su ; Yann Garcia
• 刊名：Crystal Growth & Design
• 出版年：2011
• 出版时间：September 7, 2011
• 年：2011
• 卷：11
• 期：9
• 页码：4034-4043
• 全文大小：1056K
• 年卷期：v.11,no.9(September 7, 2011)
• ISSN：1528-7505

文摘

N-4H-1,2,4-Triazol-4-yl-guanidine hydrochloride (L1) and a heterocyclized 3,4-diamino-4H-1,2,4-triazole hydrochloride (L2) were synthesized in good yields thanks to a transamination reaction of aminoguanidine and diaminoguanidine hydrochlorides, whose mechanism is presented. L1 and L2 crystallize in monoclinic (P2₁/a) and triclinic (P1̅) space groups, respectively. Hydrogen bonding interactions dictated by H-donor, acceptor rich ligand framework together with lattice chloride ions in L1 and L2 organize the crystal packing into a three-dimensional (3D) supramolecular network. The crystal structure of L1 is the first one for a 1,2,4-triazole ligand constructed from aminoguanidine. Both L1 and L2 that exist in monocationic form were introduced as supramolecular synthons to prepare Zn(II) complexes. Scanning electron microscopy (SEM) images on a bulk sample of [Zn(L1)₂Cl₂]Cl₂路H₂O (1) reveals a spontaneous aggregation of porous balls of coccolith morphology with surface decorated sickle-shaped particles of 100 nm thickness, whereas a powder sample of [Zn(L2)₂Cl₂]路H₂O (2) shows neat rectangular blocks of 470 nm thickness. Colorless crystals of 2 crystallize in a monoclinic space group (C2/c). Zn(II) ions bound chloride with NH6B路路路Cl(1) = 2.495(2) 脜 and N路路路H type bonding (N6路路路H3C3 = 2.743(2) 脜; N2路路路H7N7 = 1.989(2) 脜) affording a 3D supramolecular network. The degree of pyramidality, 危N = 38掳, observed at one of the terminal amines in L2 is still retained in 2, but 鈥渇lipping鈥?of orientation of attached protons due to directional H-bonding is observed too. Porosity partitioning by mercury porosimetry measurements on 1 and 2 reveals interparticular porosities between 7 and 15 渭m. N_2(g) and H_2(g) gas adsorption capacities of 1 and 2 were measured by BET which shows no preference for N_2(g) but a low irreversible H_2(g) uptake of 3 cm³/g.