Sagar Belakavadi K, Girisha Marisiddaiah, Yathirajan Hemmige S, Rathore Ravindranath S, Glidewell Christopher
Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysuru 570 006, India.
Centre for Biological Sciences (Bioinformatics), School of Earth, Biological and Environmental Sciences, Central University of South Bihar, Patna 800 014, India.
Acta Crystallogr E Crystallogr Commun. 2017 Aug 8;73(Pt 9):1320-1325. doi: 10.1107/S2056989017011446. eCollection 2017 Sep 1.
In both 2-amino-4,4,7,7-tetra-methyl-4,5,6,7-tetra-hydro-1,3- benzo-thia-zol-3-ium benzoate, CHNS·CHO, (I), and 2-amino-4,4,7,7-tetra-methyl-4,5,6,7-tetra-hydro-1,3-benzo-thia-zol-3-ium picrate (2,4,6-tri-nitro-phenolate), CHNS·CHNO, (II), the cations are conformationally chiral as the six-membered rings adopt half-chair conformations, which are disordered over two sets of atomic sites giving approximately enanti-omeric disorder. For both cations, the bond lengths indicate delocalization of the positive charge comparable to that in an amidinium cation. The bond lengths in the picrate anion in (II) are consistent with extensive delocalization of the negative charge into the ring and onto the nitro groups, in two of which the O atoms are disordered over two sets of sites. In (I), the ionic components are linked by N-H⋯O hydrogen bonds to form a chain of rings, and in (II), the N-H⋯O hydrogen bonds link the components into centrosymmetric four-ion aggregates containing seven hydrogen bonded rings of four different types.
在苯甲酸2-氨基-4,4,7,7-四甲基-4,5,6,7-四氢-1,3-苯并噻唑-3-鎓盐（CHNS·CHO，（I））和苦味酸2-氨基-4,4,7,7-四甲基-4,5,6,7-四氢-1,3-苯并噻唑-3-鎓盐（2,4,6-三硝基苯酚盐）（CHNS·CHNO，（II））中，阳离子构象手性，因为六元环采取半椅式构象，在两组原子位置上无序，产生近似对映体无序。对于这两种阳离子，键长表明正电荷的离域与脒鎓阳离子中的相当。（II）中苦味酸根阴离子的键长与负电荷广泛离域到环上和硝基上一致，其中两个硝基中的O原子在两组位置上无序。在（I）中，离子成分通过N-H⋯O氢键相连形成环链，在（II）中，N-H⋯O氢键将成分连接成含有四种不同类型的七个氢键环的中心对称四离子聚集体。
