【作者】 朱慧；

【导师】 郑丽敏；

【作者基本信息】 南京大学 ， 无机化学（专业学位）， 2013， 硕士

【摘要】 金属有机膦酸材料因在吸附、离子交换、传感器、磁性以及非线性光学等领域中的潜在应用前景而得到了迅速的发展。而手性材料在手性识别、手性分离和手性催化等领域具有非常重要的潜在应用前景,因此,将手性信息引入到金属有机膦酸化合物中,成为研究膦酸化学的一个重要课题。在本课题组前期工作的基础上,本文围绕着手性或外消旋的有机膦酸配体展开工作,尝试合成新颖的手性金属有机膦酸化合物。主要研究成果：1、高脯氨酸苯并咪唑膦酸配合物外消旋高脯氨酸苯并咪唑膦酸配体(pbpH2)水热条件下与过渡金属反应得到首例M-pbp金属膦酸化合物：[M(pbp)(H2O)2]·3H2O [M-Ni (1), Co (2)]、 Cu(pbp)-2H2O (3),并对其结构、热稳定性以及磁性等性质进行了研究。其中链状化合物1和2是同构的,八面体配位的金属离子通过O-P-O桥连接形成单一手性的一维线性链,苯并咪唑基团平行排列在链的同一侧,具有不同手性的线性链进一步通过配位水氧(O1W, O2W),晶格水氧(O4W)和膦酸氧(O1)之间形成的氢键构成内消旋的超分子双链,双链之间通过苯并咪唑环上的N(N3),膦酸O(O3)以及晶格水之间的氢键堆积在一起,从而形成一个内消旋的三维超分子化合物。而化合物3中,平面四配位的铜离子通过O-P-O桥连接形成21螺旋链,不同手性的螺旋链在晶格中交替排列,并通过链间的弱相互作用如氢键和π-π作用等形成内消旋的三维超分子结构。化合物1-3的结构不同可以由金属离子不同的配位性质而得以解释。化合物1-3中金属离子之间均存在反铁磁相互作用,其中化合物3的|J|值比化合物1和2都大,这归因于1和2中较长的M…M距离。2、苯甘氨酸膦酸配合物在第二配体4,4’-联吡啶存在下,将外消旋苯甘氨酸膦酸(ppaH3)与过渡金属离子反应,得到首例M-ppa金属膦酸化合物：Co3(ppa)2(4,4’-bpy)2(H2O)4-2H2O (4)和Ni4(ppaH)4(4,4’-bpy)2(H2O)2-2H2O (5).化合物4中ppa3-以五齿形式与钻离子配位,晶体学上相同的两个Co2原子通过来自两个不同对映体配体的O-P-O桥连接,形成内消旋的双核簇,双核簇之间再通过O-P-O桥与Col原子连接形成无限链。相邻两条链通过4,4’-联吡啶交错联接成三维网状结构。化合物5中存在四种晶体学上不等的镍离子、ppaH2-配体,每个膦酸配体上的一个膦氧原子是质子化的,且有四齿和五齿两种配位模式。晶体学上相同的Ni(Ⅱ)离子之间通过两个O-P-O桥联形成双核簇,而不同的Ni(Ⅱ)离子之间(Nil和Ni2, Ni3和Ni4)则通过O-C-O桥联,从而在c-轴方向形成两种交替链(Ⅰ和Ⅱ)。每种链中均包含个数相同的R-/S-两种构型的配体,因而是内消旋的。链Ⅰ和链Ⅱ分别通过4,4’-联吡啶连接形成平行于ac面的二维层状结构。层Ⅰ和层Ⅱ交替堆积,并通过大量的氢键和范德华作用等弱相互作用组装成三维超分子结构。化合物4-5中金属离子之间均存在弱的反铁磁相互作用。3、苯乙胺基甲基膦酸稀土配合物利用单一手性的(R)/(S)-(1-苯基乙胺基)甲基膦酸(pempH2)与稀土离子在水热条件下反应,通过控制不同的反应条件,得到六个单一手性的稀土有机膦酸化合物(R)-和(S)-[Ln(pempH)]·xH2O [Ln=Ho (6,7), Er (8,9)],(R)-[Ln3(pempH)8(pempH2)Cl]·xH2O [Ln=Ho (10), Er (11)]。XRD显示6-9同构,10和11同构。前者与我们课题组得到的R-[Tb(pempH)3]·xH2O是同构的,所以我们可以根据R-[Tb(pempH)3]·xH2O的结构来推测化合物6-9的结构。化合物6-9属于六方晶系,(R)-和(S)-型配合物的空间群分别为P65(No.170)和P61(No.169)。它们具有一维螺旋链的结构,每两个Ln(Ⅲ)之间由一个O-P-O桥、两个μ3-O(P)桥连接。所有的稀土离子都是八配位的,其配位点被来自3个配体膦酸上的氧占据。化合物中每条螺旋链是由三组膦酸基团绕着61螺旋轴形成的手性螺旋链构成的。这些螺旋链通过超分子作用组装成三维结构,沿c方向可观察到填充着晶格水的一维孔道。化合物10和11的单晶结构分析表明,它们结晶于手性空间群P212121,也具有一维链的结构。每个构筑单元中有3个独立的Ln(Ⅲ)原子,两个是八配位的,一个是七配位的。每两个稀土离子之间通过两个μ3-O(P)桥和一个O-P-O桥形成一个Ln3三核单元,相邻两个三核单元通过一个μ3-0(P)桥和两个O-P-O桥连接在一起,进而沿着b轴形成了一维链。Cl-离子作为抗衡阴离子和水一起填充在晶格内的空隙中。对化合物6、8、10、11的磁性研究表明,低温下、外加直流场时,其交流磁化率均出现频率依赖,说明这些化合物可能具有单分子磁体的性质。更多还原

【Abstract】 Metal phosphonates are a class of important inorganic-organic hybrid materials with potential applications in exchange and sorption, optics, catalysis, biotechnology and magnetism. Chiral coordination polymers have attracted intensive current interest mainly due to their potential applications in the areas of enantioselective catalysis, chiral separation and chiral materials. As a result, the incorporation of chiral information into the metal phosphonate compounds becomes an important subject. However, examples of chiral or enantioenriched metal phosphonates are rather few thus far. In this thesis, we shall focus on the assembly of new metal phosphonates based on chiral or racemic phosphonate ligands. The achievements are obtained as follows:1. Racemic metal phosphonates based on1-phosphonomethyl-2-benzimidazol-piperidine phosphonateThe first examples of metal phosphonates based on a racemic1-phosphonomethyl-2-benzimidazol-piperidine (pbpH2) are obtained under hydrothermal conditions, namely,[M(pbp)(H2O)2]·3H2O [M=Ni (1), Co (2)] and Cu(pbp)·2H2O (3). Compounds1and2are isostructural. The metal ions are six-coordinated with a distorted octahedral geometry. The pbp2-behaves as a tetra-dentate ligand. The amino nitrogen (N1) and one benzimidazol nitrogen (N2) atoms chelate the metal atom. Two of the three phosphonate oxygen atoms (O1, O2) bridge the equivalent metal atoms to form a chiral single chain running along the a-axis with the benzimidazol groups arranged on the same side of the chain. The adjacent single chains containing R-pbp2-and S-pbp2-ligands, respectively, are fused together through hydrogen bond interactions, leading to a racemic double chain. The double chains are packed in the lattice thorugh hydrogen bond interactions to form a three-dimensional supramolecular network structure. For compound3, the Cu(II) ion is four-coordinated with a planar geometry. It is chelated by the pbp2-ligand through N1, N2and01atoms, and bridged by the phosphonate group from another equivalent pbp2-ligand. An infinite helical chain is thus constructed with the benzimidazol groups arranged on the two sides of the chain. The chains with opposite helicity are alternatively arranged in the lattice to furnish a final racemic structure. Dominant antiferromagnetic interactions are mediated between the magnetic centers in compounds1-3.2. Racemic metal phosphonates based on2-phenyl-2-(phosphonomethylamino)acetic acidThe first examples of metal phosphonates based on a racemic2-phenyl-2-(phosphonomethylamino)acetic acid (ppaH3) are obtained under hydrothermal conditions, namely, Co3(ppa)2(4,4’-bpy)2(H2O)4-2H2O (4) and Ni4(ppaH)4(4,4’-bpy)2(H2O)2·2H2O (5). Complex4crystallizes in P21/c space group. It contains two crystallographically independent cobalt atoms. The ppa3-behaves as a penta-dentate ligand. The equivalent Co2atoms are bridged by two O-P-0units from R-and S-ppa3-ligands, resulting in a racemic dimer. The dimers are connected by Co1through O-P-0units to form an infinite racemic chain. The chains are cross-linked by4,4’-bpy, leading to a three-dimensional framework structure. In compound5, four crystallographically independent nickel atoms are found. The ppaH2-ligands are either tetra-dentate or penta-dentate. The equivalent Ni atoms are linked by O-P-0into dimers. Neighboring dimers of Nil2and Ni22(or Ni32and Ni42) are connected by O-C-O units, forming infinite chain I (or chain Ⅱ) running along the c-axis. Each chain contains equal amount of R-and S-ppa3-ligands, thus is racemic. Chains Ⅰ and Ⅱ are each linked by4,4’-bpy, resulting in layers Ⅰ and Ⅱ, respectively, in the ac plane. These layers are packed alternatively along the b-axis with weak inter-layer hydrogen bond and van del Waals interactions, thus forming a3D supramolecular structure. The magnetic properties of4and5are studied, which show dominant antiferromagnetic interactions.3. Homochiral lanthanide phosphonates based on (1-phenylethylamino)methylphosphonic acidHomochiral lanthanide phosphonates (R)-or (S)-[Ln(pempH)3]·xH2O [Ln=Ho (6,7), Er (8,9)],(R)-[Tb3(pempH)8(pempH2)Cl]-xH2O [Ln=Ho (10), Er (11)] are obtained through reactions of (R)/(S)-(1-phenylethylamino)methylphosphonic acid (pempH2) and Ln(NO3)3under hydrothermal conditions. Compounds6and7,8and9are enatiomers, respectively. Although single crystals suitable for structural determination cannot be obtained for compounds6-9, they are isostructural to compounds (R)-and (S)-[Tb(pempH)3]·xH2O based on their powder XRD patterns. Accordingly, the crystal structures of6-9can be described as below:(R)/(S)-[Ln(pempH)3]·xH2O (Ln=Ho, Er) crystallize in hexagonal space group P65and P61, respectively. Each shows a ID helical chain structure, where the equivalent Ln(III) ions are triply bridged by two μ3-O(P) and one O-P-0units. Each Ln(III) ion is eight-coordinated with the eight coordination sites provided by the phosphonate oxygen atoms from three pairs of pempH-ligands. Each helical chain is constructed by right-or left-handed triple-strands formed from three phosphonate groups of three pempH-species which bridge two adjacent Ln(III) ions along the crystallographic61screw axis. The helical chains are packed through supramolecular interactions, generating channels running along the c-axis where the lattice water molecules reside.Compounds10and11are also enantiomers. Single crystal structural determination reveals that both crystallize in orthorhombic chiral space group P212121and show a chain structure. In this case, there are three crystallographically distinguished Er(Ⅲ) ions in the asymmetric unit, two of which are eight-coordinated and the third one is seven-coordinated. They are triply bridged by two μ3-O(P) and one O-P-O units, forming a Er3trimer. The neighboring trimers are further connected by one μ3-O(P) and two O-P-O units, thus leading to an infinite helical chain running along the b-axis. The Cl-anions serve as counterions and reside in the interchain spaces together with the lattice water molecules. Magnetic properties of compounds6,8,10and11are investigated. Slow magnetization relaxation is observed in all cases under a dc field at low temperature, indicating single molecular magnet behaviors.更多还原