Freire Eleonora, Vega Daniel R, Baggio Ricardo
Gerencia de Investigación y Aplicaciones, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina.
Acta Crystallogr C. 2010 Jun;66(Pt 6):m166-70. doi: 10.1107/S0108270110017634. Epub 2010 May 29.
Diaquabis[dihydrogen 1-hydroxy-2-(imidazol-3-ium-1-yl)ethylidene-1,1-diphosphonato-kappa(2)O,O']magnesium(II), [Mg(C(5)H(9)N(2)O(7)P(2))(2)(H(2)O)(2)], consists of isolated dimeric units built up around an inversion centre and tightly interconnected by hydrogen bonding. The Mg(II) cation resides at the symmetry centre, surrounded in a rather regular octahedral geometry by two chelating zwitterionic zoledronate(1-) [or dihydrogen 1-hydroxy-2-(imidazol-3-ium-1-yl)ethylidene-1,1-diphosphonate] anions and two water molecules, in a pattern already found in a few reported isologues where the anion is bound to transition metals (Co, Zn and Ni). catena-Poly[[aquacalcium(II)]-mu(3)-[hydrogen 1-hydroxy-2-(imidazol-3-ium-1-yl)ethylidene-1,1-diphosphonato]-kappa(5)O:O,O':O',O''], Ca(C(5)H(8)N(2)O(7)P(2))(H(2)O), consists instead of a Ca(II) cation in a general position, a zwitterionic zoledronate(2-) anion and a coordinated water molecule. The geometry around the Ca(II) atom, provided by six bisphosphonate O atoms and one water ligand, is that of a pentagonal bipyramid with the Ca(II) atom displaced by 0.19 A out of the equatorial plane. These Ca(II) coordination polyhedra are ;threaded' by the 2(1) axis so that successive polyhedra share edges of their pentagonal basal planes. This results in a strongly coupled rhomboidal Ca(2)-O(2) chain which runs along [010]. These chains are in turn linked by an apical O atom from a -PO(3) group in a neighbouring chain. This O-atom, shared between chains, generates strong covalently bonded planar arrays parallel to (100). Finally, these sheets are linked by hydrogen bonds into a three-dimensional structure. Owing to the extreme affinity of zoledronic acid for bone tissue, in general, and with calcium as one of the major constituents of bone, it is expected that this structure will be useful in modelling some of the biologically interesting processes in which the drug takes part.
二水合双[二氢-1-羟基-2-(咪唑-3-鎓-1-基)亚乙基-1,1-二膦酸根合-κ(2)O,O']镁(II)，[Mg(C₅H₉N₂O₇P₂)₂(H₂O)₂]，由围绕一个反演中心构建的孤立二聚体单元组成，并通过氢键紧密相连。Mg(II)阳离子位于对称中心，以相当规则的八面体几何构型被两个螯合的两性离子唑来膦酸根(1-) [或二氢-1-羟基-2-(咪唑-3-鎓-1-基)亚乙基-1,1-二膦酸]阴离子和两个水分子包围，这种模式已在一些已报道的同构物中发现，其中该阴离子与过渡金属(Co、Zn和Ni)结合。链状聚[[水合钙(II)]-μ(3)-[氢-1-羟基-2-(咪唑-3-鎓-1-基)亚乙基-1,1-二膦酸根合]-κ(5)O:O,O':O',O'']，[Ca(C₅H₈N₂O₇P₂)(H₂O)]ₙ，相反，由处于一般位置的Ca(II)阳离子、一个两性离子唑来膦酸根(2-)阴离子和一个配位水分子组成。由六个双膦酸根O原子和一个水配体提供的围绕Ca(II)原子的几何构型是一个五角双锥，Ca(II)原子偏离赤道平面0.19 Å。这些Ca(II)配位多面体由2(1)轴“贯穿”，使得连续的多面体共享它们五角形底面的边。这导致了一个沿着[010]方向延伸的强耦合菱形Ca₂-O₂链。这些链又通过相邻链中一个 -PO₃基团的顶端O原子相连。这个在链之间共享的O原子产生了平行于(100)的强共价键合平面阵列。最后，这些片层通过氢键连接成三维结构。由于唑来膦酸一般对骨组织具有极高的亲和力，并且钙是骨的主要成分之一，预计这种结构将有助于模拟该药物参与的一些生物学上有趣的过程。
