Tigyer Benjamin R, Zeller Matthias, Zaleski Curtis M
Department of Chemistry, Shippensburg University, 1871 Old Main Dr., Shippensburg, PA 17257, USA.
Acta Crystallogr Sect E Struct Rep Online. 2012 Dec 1;68(Pt 12):m1521-2. doi: 10.1107/S1600536812047228. Epub 2012 Nov 24.
The title compound, [Mn6(C7H4NO3)5(CHO2)2(C3H4N2)5(CH3OH)]·3.36CH3OH·0.65H2O, or Mn(II)(O2CH)215-MCMn(III)N(shi)-55(MeOH)·3.36MeOH·0.65H2O (where MC is metallacrown, shi(3-) is salicyl-hydroximate, Im is imidazole and MeOH is methanol), contains five Mn(III) ions as members of the metallacrown ring and an Mn(II) atom bound in the central cavity. The central Mn(II) atom is seven-coordinate with a geometry best described as between face-capped trigonal-prismatic and face-capped octa-hedral. Three Mn(III) ions of the metallacrown ring are six-coordinate with distorted octa-hedral geometries. Of these six-coordinate Mn(III) ions, two have mirror-plane configurations, while the other has a Δ absolute stereoconfiguration. The remaining two Mn(III) ions have a coordination number of five with a distorted square-pyramidal geometry. The five imidazole ligands are bound to five different Mn(III) ions. Disorder is observed for one of the coordinating imidazole ligands, as the imidazole ligand is disordered over two alternative mutually exclusive positions in a ratio of 0.672 (9) to 0.328 (9). The inter-stitial voids between the main mol-ecules that constitute the structure are mostly filled with methanol mol-ecules that form hydrogen-bonded chains. Some of the sites of the non-coordinated methanol mol-ecules are not fully occupied, with the remainder of the volume either empty or taken up by ill-defined close to amorphous content. One site was refined as being taken up by either two or one methanol mol-ecules, with an occupancy ratio of 0.628 (5) to 0.343 (5). This disorder might thus be correlated with the disorder of the imidazole ring (an N-H⋯O hydrogen bond between the major moieties of the imidazole and the methanol mol-ecules is observed). On the other side of the disordered imidazole ring the chain of partially occupied methanol mol-ecules originates that extends via O-H⋯O hydrogen bonds to the metal-coordinated methanol mol-ecule. The three partially occupied methanol mol-ecules were refined to be disordered with two water mol-ecules to take two residual electron density peaks into account (the exact nature of these weak residual electron density peaks cannot be deduced from the X-ray diffraction data alone, the assignment as water is tentative). The occupancy rate for the methanol mol-ecules refined to 0.480 (7). The occupancy rate of the two water mol-ecules refined to 0.34 (1) and 0.31 (2) for each site.
标题化合物[Mn₆(C₇H₄NO₃)₅(CHO₂)₂(C₃H₄N₂)₅(CH₃OH)]·3.36CH₃OH·0.65H₂O,即Mn(II)(O₂CH)₂15-MCMn(III)N(shi)-5₅(MeOH)·3.36MeOH·0.65H₂O(其中MC为金属冠醚,shi(3-)为水杨醛肟,Im为咪唑,MeOH为甲醇),包含五个作为金属冠醚环成员的Mn(III)离子和一个位于中心腔中的Mn(II)原子。中心Mn(II)原子为七配位,其几何构型最好描述为介于面封顶三棱柱和面封顶八面体之间。金属冠醚环中的三个Mn(III)离子为六配位,具有扭曲的八面体几何构型。在这些六配位的Mn(III)离子中,两个具有镜面构型,而另一个具有Δ绝对立体构型。其余两个Mn(III)离子的配位数为五,具有扭曲的四方锥几何构型。五个咪唑配体与五个不同的Mn(III)离子相连。观察到一个配位咪唑配体存在无序现象,因为该咪唑配体在两个相互排斥的交替位置上无序分布,比例为0.672 (9)比0.328 (9)。构成结构的主要分子之间的间隙大部分被形成氢键链的甲醇分子填充。一些未配位甲醇分子的位置未被完全占据,其余体积要么为空,要么被接近无定形的不明确物质占据。一个位置被精修为被两个或一个甲醇分子占据,占有率为0.628 (5)比0.343 (5)。因此,这种无序可能与咪唑环的无序相关(观察到咪唑主要部分与甲醇分子之间存在N-H⋯O氢键)。在无序咪唑环的另一侧,部分占据的甲醇分子链由此产生,该链通过O-H⋯O氢键延伸至与金属配位的甲醇分子。三个部分占据的甲醇分子被精修为与两个水分子无序分布,以考虑两个残余电子密度峰(仅从X射线衍射数据无法推断这些弱残余电子密度峰的确切性质,将其归为水是暂定的)。甲醇分子的占有率精修为0.480 (7)。每个位置上两个水分子的占有率精修为0.34 (1)和0.31 (2)。