1-甲基-2-咪唑醛肟锰(Ⅲ)配合物的合成、晶体结构及电化学性质研究

采用溶剂扩散法制备了锰(Ⅲ)的两个单核配合物[Mn(Miao)2(H2O)2]ClO4(1)和[Mn(Miao)2(DMF)2]ClO4(2)(HMiao=1-甲基-2-咪唑醛肟,DMF=N,N-二甲基甲酰胺)的晶体.X射线衍射单晶结构表明:两种配合物均属三斜晶系,空间群Pi锰与配体形成变形的八面体结构.采用Gaussian 03W程序计算了HMiao配体的电荷密度,理论计算与实际配位形式完全吻合.测定了两种锰配合物在DMF溶液中的电化学性质,循环伏安法表明两配合物均存在较好的氧化还原性,其氧化还原峰分别为0.75和0.70V,-0.32和-0.50 V,是Mn(Ⅲ)和Mn(Ⅱ)之间的相互转化.     

以2,2′-联吡啶-4,4′-二甲酸和2-甲基吡嗪[3,2-f:2′,3′-h]喹喔啉为配体的三维锰(Ⅱ)配位聚合物的合成、晶体结构和荧光性质(英文)

采用水热法合成了一个锰的配合物[Mn(bpydc)(Medpq)]n(1)(H2bpydc=2,2′-联吡啶-4,4′-二甲酸,Medpq=2-甲基吡嗪[3,2-f:2′,3′-h]喹喔啉),并利用元素分析、红外光谱、紫外可见光谱、热分析和X-射线单晶衍射对其结构进行了表征。单晶结构分析表明配合物1属于单斜晶系,Cc空间群,晶胞参数a=2.031 6(4)nm,b=1.564 5(3)nm,c=0.719 26(14)nm,β=103.97(3)°,V=2.218 5(8)nm3,Z=4。配合物1是一个锰(Ⅱ)离子经由bpydc2-连接形成的三维网络结构。配合物1的固体荧光光谱表明它具有很强的荧光性。应用Gaussian 03W程序,在HF/LANL2DZ水平上对标题化合物的自然键轨道(NBO)进行了分析,结果表明Mn(Ⅱ)与配位原子间的价键类型都属于共价键范畴。     

席夫碱类混价七核锰金属配合物的合成、表征及磁性

以3-乙氧基水杨醛缩乙醇胺席夫碱(H2L)为配体合成了2个新的七核锰配合物[Na2MnⅡMnⅢ6O2(L)6(N3)4(CH3COO)2]·4DMF(1)和[Na2MnⅡMnⅢ6O2(L)6(SCN)4(CH3COO)2]·2DMF (2),并对它们进行红外分析、元素分析、热重分析和单晶结构分析。单晶衍射结果表明,配合物1和2均为混价七核锰配合物,包含1个Mn2+和6个Mn3+。此外还研究了配合物1和2的磁学性质,磁性研究表明配合物1和2都表现出反铁磁作用。     

2,2’-联吡啶-1,1’-二氧化物与Mn(Ⅱ)的三聚体配合物的合成及性能

Mn( )能与许多氮氧化合物形成配合物 ,Wilde对 Mn( )与 2 ,2 -联吡啶及 1 ,1 -二氮杂菲的均配配合物作过详细研究 [1,2 ] ;Mn( )与 2 ,2 -联吡啶 - 1 ,1 -二氧化物 ( bipy O2 )的配合物也有综述 [3] .Mn( )与 bipy O2 的配合物大多是以 Cl O- 4、NO- 3、[Pt Cl4 ]2 -为阴离子 ,少数是卤离子 .它们均形成配位体数目为 3的单核螯合物 ,这些配合物是在水或乙醇中合成的 .Mn( )与 bipy O2 的多核聚合物还未见报道 .本文用 DMF为溶剂 ,以无水 Mn Cl2 和 2 ,2 -联吡啶 - 1 ,1 -二氧化物为原料 ,合成了 Mn( )与bipy O2 的三聚…     

基于偶氮苯-4,4′-二甲酸配体的锰(Ⅱ)配合物的合成、晶体结构及性质研究(英文)

利用水热反应合成了一种新的锰配合物[Mn(ADB)(phen)(H2O)2]n(1)(H2ADB=偶氮苯-4,4′-二甲酸,phen=邻菲啰啉),运用元素分析、红外光谱、热重分析、电化学等方法对它进行了研究,并通过X射线单晶衍射测定了配合物的单晶结构。晶体结构表明,配合物属三斜晶系,空间群为P1,晶胞参数a=0.762 00(13)nm,b=0.915 30(15)nm,c=1.826 2(2)nm,α=88.467(3)°,β=84.145(2)°,γ=77.542(2)°。配合物1的中心锰离子是六配位,具有扭曲的八面体结构,偶氮苯-4,4′-二甲酸连接相邻的锰离子形成了一维"之"字链,进而链与链之间通过π-π堆积和氢键相互作用拓展成三维超分子结构。磁学性质研究表明该配合物为反铁磁性。     

芳香碘基辅助的配位超分子自组装--锌(Ⅱ)、镉(Ⅱ)与7-碘-8-羟基喹啉-5-磺酸配合物的合成和结构

合成了锌(Ⅱ)、镉(Ⅱ)与7-碘-8羟基喹啉-5-磺酸(IHQS)的两种单晶配合物[Zn(IHQS)(H2O)3]2·4H2O(1)和[Cd-(IHQS)(H2O)2]n·2nH2O(2),用X射线衍射法确定了结构.结果表明,1和2均由一对对映体配合物构成1中两个[Zn-(IHQS)(H2O)3]对映体通过磺酸基-锌(Ⅱ)八面体轴向互补配位形成中心对称双分子聚合体,该聚合体通过分子间磺酸基氧-配位水氢键形成独特的二维层状结构;2的两个[Cd(IHQS)(H2O)2]对映体通过镉(Ⅱ)-磺酸基-镉(Ⅱ)双向互补配位形成一维直线型聚合配位结构.芳香碘基呈现新颖的碘-芳环氢和碘-磺酸基氧等弱相互作用模式,并对上述结构的支撑稳定发挥重要的结构辅助作用.本文展示了芳香碘基、磺酸基和喹啉环三种弱相互作用基团在配位超分子自组装中的形状、空间匹配和协同促进模式.结晶学参数配合物1单斜晶系,C2/c空间群,a=2.2243(7)nm,b=1.0053(3)nm,c=1.3468(4)nm,β=102.267(5)°,V=2.9428(16)nm3和Z=4.配合物2三斜晶系,P1空间群,a=0.6949(2)nm,b=1.0183(3)nm,c=1.0989(3)nm,α=76.069(5)°,β=75.294(5)°,γ=84.747(5)°,V=0.7295(4)nm3和Z=2.     

2-(羟甲基)-N-甲基咪唑桥联Mn_2~ⅡMn_2~Ⅲ四核配合物的合成、结构和磁性

报道了3个2-(羟甲基)-N-甲基咪唑(Hhmmi)桥联的MnⅡ2MnⅢ2四核配合物[Mn4(hmmi)6(DMF)2·(N3)2](ClO4)2(1),[Mn4(hmmi)6(H2O)2(N3)2](ClO4)2(2)和[Mn4(hmmi)6Cl4]·6CH3CN(3·6CH3CN)的合成、晶体结构和磁性.在配合物1~3中,中心结构皆为四核蝶形混合价Mn结构,2个MnⅡ占据蝶形两翼位置,2个MnⅢ占据蝶形中间位置.MnⅢ离子间通过hmmi-上的μ3-烷氧原子桥联,相应MnⅢ—O—MnⅢ键角为101.3°~103.4°;而MnⅢ-MnⅡ离子间通过hmmi-上的μ3-和μ2-烷氧原子桥联,相应MnⅢ—O—MnⅡ键角为92.5°~113.7°.对配合物1~3进行变温磁化率拟合,结果表明,MnⅢ-MnⅢ间呈铁磁相互作用,而MnⅢ-MnⅡ间以及Mn4分子间存在较弱的铁磁或反铁磁耦合.     

芳香碘基辅助的配位超分子自组装——锌(II)、镉(II)与7-碘-8-羟基喹啉-5-磺酸配合物的合成和结构

合成了锌 (II)、镉 (II)与 7 碘 8 羟基喹啉 5 磺酸 (IHQS)的两种单晶配合物 [Zn(IHQS) (H2 O) 3 ] 2 ·4H2 O ( 1)和 [Cd (IHQS) (H2 O) 2 ] n·2nH2 O ( 2 ) ,用X射线衍射法确定了结构 .结果表明 ,1和 2均由一对对映体配合物构成 :1中两个 [Zn (IHQS) (H2 O) 3 ]对映体通过磺酸基 -锌 (II)八面体轴向互补配位形成中心对称双分子聚合体 ,该聚合体通过分子间磺酸基氧 -配位水氢键形成独特的二维层状结构 ;2的两个 [Cd(IHQS) (H2 O) 2 ]对映体通过镉 (II) 磺酸基 -镉 (II)双向互补配位形成一维直线型聚合配位结构 .芳香碘基呈现新颖的碘 -芳环氢和碘 -磺酸基氧等弱相互作用模式 ,并对上述结构的支撑稳定发挥重要的结构辅助作用 .本文展示了芳香碘基、磺酸基和喹啉环三种弱相互作用基团在配位超分子自组装中的形状、空间匹配和协同促进模式 .结晶学参数配合物 1:单斜晶系 ,C2 /c空间群 ,a =2 2 2 43 ( 7)nm ,b =1 0 0 5 3 ( 3 )nm ,c =1 3 468( 4 )nm ,β =10 2 2 67( 5 )° ,V =2 942 8( 16)nm3 和Z =4.配合物 2 :三斜晶系 ,P1- 空间群 ,a =0 6949( 2 )nm ,b =1 0 183 ( 3 )nm ,c =1 0 989( 3 )nm ,α =76 0 69( 5 )° ,β =75 2 94( 5 )° ,γ =84 747( 5 )° ,V =0 72 95 ( 4 )nm3 和Z =2 .     

2-(5-甲基-1,3,4-噻二唑)-硫乙酸镍(Ⅱ)配合物的合成和晶体结构

本文合成了2个镍配合物[Ni(mtyaa)2(H2O)4]·4(H2O)(1)和[Ni(4,4′-bipy)2(mtyaa)2(H2O)2]·2H2O(2)(Hmtyaa=2-(5-甲基-1,3,4-噻二唑)-硫乙酸;4,4′-bipy=4,4′-联吡啶),用X-射线单晶衍射仪测定了配合物的单晶结构,并对它进行了元素分析、红外光谱、热重和粉末X-射线衍射等表征。配合物1和2的晶体分别属于三斜晶系和单斜晶系,空间群分别为P1和P21/n。X-射线单晶结构分析表明配合物1和2中镍原子均采取六配位扭曲的八面体配位模式。在配合物1中配位水和游离水分子与羧基氧之间的氢键作用将单分子结构连成三维网状结构。配合物2中配位水和游离水分子与羧基氧以及配体中的氮原子之间的氢键作用将链连接成二维层状结构。     

[Mn(phen)3](ClO4)2(H2O)·0.5(azpy)的合成和晶体结构

锰在生物体系的新陈代谢过程中有重要作用。锰有机配合物的研究成为生物无机化学研究领域的一个热点[1]。本文报道用高氯酸锰、1,10 邻菲咯啉和4,4 偶氮联吡啶[2 4]合成的锰配合物[Mn(phen)3](ClO4)2(H2O)·0 5(azpy)的晶体结构。1　实验部分1 1　Mn(Ⅱ)配合物的合成将0 0724g(0 2mmol)Mn(ClO4)2·6H2O溶于8mL水,缓慢加入含有0 1190g(0 6mmol)1,10 邻菲咯啉(phen)和0 0277g(0 15mmol)4,4′ 偶氮联吡啶(azpy)的15mL甲醇溶液,搅拌0 5h,室温下静置,一周后得[Mn(phen)3](ClO4)2(H2O)·0 5(azpy)晶体。元素分析(计算值)/%:C54 19(54 …     

Structural,spectroscopic, and electrochemical studies of binuclear manganese(II) complexes of bis(pentadentate) ligands derived from bis(1,4,7-triazacyclononane) macrocycles

Structural, electrochemical, ESR, and H2O2 reactivity studies are reported for [Mn(dmptacn)Cl]ClO4 (1, dmptacn = 1,4-bis(2-pyridylmethyl)-1,4,7-triazacyclononane) and binuclear complexes of bis(pentadentate) ligands, generated by attaching 2-pyridylmethyl arms to each secondary nitrogen in bis(1,4,7-triazacyclononane) macrocycles and linked by ethyl (tmpdtne, [Mn2(tmpdtne)Cl2](ClO4)2.2DMF, 2), propyl (tmpdtnp, [Mn2(tmpdtnp)Cl2](ClO4)2.3H2O, 3), butyl (tmpdtnb, [Mn2(tmpdtnb)Cl2](ClO4)2.DMF.2H2O, 4), m-xylyl (tmpdtn-m-X, [Mn2(tmpdtn-m-X)-Cl2](ClO4)2, 5) and 2-propanol (tmpdtnp-OH, [Mn2(tmpdtnp-OH)Cl2](ClO4)2, 6) groups. 1 crystallizes in the orthorhombic space group P2(1)2(1)2(1) (No. 19) with a = 7.959(7) A, b = 12.30(1) A, and c = 21.72(2) A; 2, in the monoclinic space group P2(1)/c (No. 14) with a = 11.455(4) A, b = 15.037(6) A, c = 15.887(4) A, and beta = 96.48(2) degrees; 3, in the monoclinic space group P2(1)/c (No. 14) with a = 13.334(2) A, b = 19.926(2) A, c = 18.799(1) A, and beta = 104.328(8) degrees; and [Mn2(tmpdtnb)Cl2](ClO4)2.4DMF.3H2O (4'), in the monoclinic space group P2(1)/n (No. 14) with a = 13.361(3) A, b = 16.807(5) A, c = 14.339(4) A, and beta = 111.14(2) degrees. Significant distortion of the Mn(II) geometry is evident from the angle subtended by the five-membered chelate (ca. 75 degrees) and the angles spanned by trans donor atoms (< 160 degrees). The Mn geometry is intermediate between octahedral and trigonal prismatic, and for complexes 2-4, there is a systematic increase in M...M distance with the length of the alkyl chain. Cyclic and square-wave voltammetric studies indicate that 1 undergoes a 1e- oxidation from Mn(II) to Mn(III) followed by a further oxidation to MnIV at a significantly more positive potential. The binuclear Mn(II) complexes 2-5 are oxidized to the Mn(III) state in two unresolved 1e- processes [MnII2-->MnIIMnIII-->MnIII2] and then to the MnIV state [MnIII2-->MnIIIMnIV-->MnIV2]. For 2, the second oxidation process was partially resolved into two 1e- oxidation processes under the conditions of square-wave voltammetry. In the case of 6, initial oxidation to the MnIII2 state occurs in two overlapping 1e- processes as was found for 2-5, but this complex then undergoes two further clearly separated 1e- oxidation processes to the MnIIIMnIV state at +0.89 V and the MnIV2 state at +1.33 V (vs Fc/Fc+). This behavior is attributed to formation of an alkoxo-bridged complex. Complexes 1-6 were found to catalyze the disproportionation of H2O2. Addition of H2O2 to 2 generated an oxo-bridged mixed-valent MnIIIMnIV intermediate with a characteristic 16-line ESR signal.     

Synthesis, structures, and magnetic properties of a series of cyano-bridged Fe-Mn bimetallic complexes

The preparation and crystal structures of five cyano-bridged Fe-Mn complexes, [(bipy)2Fe(II)(CN)2Mn(II)(bipy)2]2(ClO4)4 (1), [(bipy)2Fe(II)(CN)2Mn(II)(DMF)3(H2O)]2(ClO4)4 (2), {[(Tp)Fe(III)(CN)3]2Mn(II)(DMF)2(H2O)}2 (3), {[(Tp)Fe(III)(CN)3]2Mn(II)(DMF)2}n (4), and Na2[Mn(II)Fe(II)(CN)6] (5) (bipy = 2,2'-bipyridine, Tp = tris(pyrazolyl)hydroborate), are reported here. Compounds 1-4 contain the basic Fe2(CN)4Mn2 square building units, of which 1-3 show the motif of discrete molecular squares of Fe2(CN)4Mn2 and 4 possesses a 1D double-zigzag chain-like structure, while compound 5 is a 3D cubic framework analogous to that of Prussian blue. Compounds 1 and 2 show weak ferromagnetic interactions between two Mn(II) ions through the bent -NC-Fe(II)-CN- bridges. Compound 3 shows weak antiferromagnetic coupling between the Fe(III) and Mn(II) ions, while compound 4 displays a metamagnetic-like behavior with TN = 5.2 K and Hc = 10.5 kOe. Compound 5 exhibits a ferromagnetic ordering with Tc= 3.5 K, coercive field, Hc, = 330 G, and a remnant magnetization of 503 cm3 Oe mol(-1).     

Dimetallic complexes of a structurally versatile pyridazine-containing Schiff-base macrocyclic ligand with pendant pyridine arms

The new [2 + 2] Schiff-base macrocyclic ligand L2, containing pyridazine head units and pyridine pendant arms, was synthesised as [Ba(II)2L2(ClO4)4(OH2)] 1 from the barium(II) ion templated condensation reaction of 3,6-diformylpyridazine and N1-(2-aminoethyl)-N1-(methylene-2-pyridyl)-ethane-1,2-diamine. Subsequent transmetallation reactions of 1 with copper(II), iron(II) and manganese(II) perchlorates led to the formation of [Cu(II)2L2](ClO4)4.2MeCN 2, [Fe(II)2L2(MeCN)2](ClO4)4 3 and two manganese complexes, 4 and 5, with the same formula, [Mn(II)2L2(MeCN)(OH2)](ClO4)4, but slightly different crystal structures, respectively. Single-crystal X-ray structural analyses reveal the variety of structures which can be supported by L2 in order to meet the coordination environment preferences of the incorporated metal ions. The barium(II) ions in 1 have an irregular ten-coordinate geometry whereas the copper(II) ions in 2 have a square pyramidal geometry and the iron(II) ions in 3 have an octahedral geometry, while in 4 and 5 every manganese(II) ion is seven-coordinate and the environment can be best described as distorted pentagonal bipyramidal. In 1, 4 and 5 the pyridazine moieties bridge the metal centres [Ba(1)...Ba(2) 4.9557(3)A 1; Mn(1)...Mn(2) 4.520(1)A 4; Mn(1)[dot dot dot]Mn(2) 4.3707(8)A 5] but this is not observed in the copper(II) and iron(II) complexes, 2 and 3, in which the metal ions are well separated [Cu(1)...Cu(2) 5.9378(6)A 2; Fe(1)...Fe(2) 5.7407(12)A 3]. In the cyclic voltammogram of [Cu2(II)L2](ClO4)4.2MeCN 2 in MeCN vs. Ag/AgCl two separate reversible one-electron transfer steps are observed [E(1/2)=0.04 V, DeltaE= 0.12 V and E(1/2)= 0.20 V, DeltaE=0.12 V; K(c)=510; in this system E(1/2)(Fc+/Fc)=0.42 V and DeltaE(Fc+/Fc)=0.08 V]. The other complexes cannot be reversibly reduced/oxidised.     

Crystal structures and magnetic properties of two low-dimensional materials constructed from [Mn(III)(salen)H2O]+ and [M(CN)8](3-/4-) (M = Mo or W) precursors

The syntheses, X-ray structures, and magnetic behaviors of two new cyano-bridged assemblies, the molecular [Mn(III)(salen)H2O]3[W(V)(CN)8].H2O (1) and one-dimensional [Mn(salen)(H2O)2]2[[Mn(salen)(H2O)][Mn(salen)]2[Mo(CN)(8)]].0.5ClO4.0.5OH.4.5H2O (2), are presented. Compound 1 crystallizes in the monoclinic system, has space group P2(1)/c, and has unit cell constants a = 13.7210(2) A, b = 20.6840(4) A, c = 20.6370(2) A, and Z = 4. Compound 2 crystallizes in the triclinic system, has space group P, and has unit cell dimensions a = 18.428(4) A, b = 18.521(3) A, c = 18.567(4) A, and Z = 2. The structure of 1 consists of the asymmetric V-shaped Mn-NC-W-NC-Mn-O(phenolate)-Mn molecules, where W(V) coordinates with [Mn(salen)H2O] and singly phenolate-bridged [Mn(salen)H2O]2 moieties through the neighboring cyano bridges. The [W(V)(CN)8]3- ion displays distorted square-antiprism geometry. The structure of 2 consists of the cyano-bridged [Mn3(III)Mo(IV)]n- repeating units linked by double phenolate bridges into one-dimensional zigzag chains. The Mn(III) centers are bound to Mo(IV) of square-antiprism geometry through the neighboring cyano bridges. The magnetic studies of 1 reveal the antiferromagnetic intramolecular interactions through the CN and phenolate bridges and the relatively weak intermolecular interactions. Compound 1 becomes antiferromagnetically ordered below TN = 4.6 K. The presence of the magnetic anisotropy is documented with the MH measurements carried out for both polycrystalline and single-crystal samples. At T = 1.9 K, the spin-flop transition is observed in the field of 18 kOe applied parallel to the bc plane, which is the easy plane of magnetization. Field dependence of magnetization of 1 shows field-induced metamagnetic behavior from the antiferromagnetic ground state of ST = 3/2 to the state of ST = 5/2. The magnetic properties of 2 indicate a weak antiferromagnetic interaction between Mn(III) centers in double-phenolate-bridged [Mn(III)(salen)]2 dinuclear subunits and a very weak ferromagnetic interaction between them through the diamagnetic [Mo(IV)(CN)8]4- spacer.     

Synthesis and structure of manganese(ii) coordination polymers with 1,4-diazabicyclo[2.2.2]octane N,N′-dioxide: solvent and template effects

Russian Chemical Bulletin - New metal-organic frameworks [Mn(DMF)2(odabco)2](ClO4)2 · H2O (1), [Mn(H2O)2? (HCOO)2] · odabco (2), and [Mn(Hodabco)2(odabco)3](NO3)4 (3) were...     

新型二维异核配位聚合物{[NdBi(cydta)(NO3)2(H2O)4]&#8226;2.5H2O}n的 晶体结构与热分解

由Bi(Hcydta)&#8226;5H2O和Nd(NO3)&#8226;6H2O按1︰1的物质的量比, 在水溶液中合成了含Bi(III)-Nd(III)的异核配位聚合物{[(NO3)Nd(H2O)4(μ3-cydta)Bi(μ-ONO2)]&#8226;2.5H2O}n. 用元素分析、红外光谱、热重-差热和X射线单晶衍射等手段对标题配合物的组成和结构进行了表征. 该配合物属三斜晶系, 空间群 , 晶胞参数: a＝0.9235(3) nm, b＝1.0902(4) nm, c＝1.4253(5) nm, α＝71.840(4)°, β＝86.877(4)°, γ＝76.991(4)°, Z＝2, Mr＝936.65, V＝1.3284(8) nm3, Dc＝2.342 g&#8226; cm－3, μ＝8.646 mm－1, F(000)＝900, 最终偏离因子R1＝0.0406, wR2＝0.1124. 在该配合物中, 铋(III)与配体cydta4－的4O2N和1个硝酸根中1个O原子以及邻位分子的硝酸根形成8配位的畸变双帽三棱柱. 钕(III)与4个水分子的O, 1个硝酸根中2个O以及来自3个不同配体cydta4－的桥联羧基O结合, 形成9配位的三帽三棱柱构型. 羧酸根在Bi—Nd和硝酸根在Bi—Bi间的桥联作用, 使得整个配合物分子连接成无限二维框架结构. 热分析以及分解产物的红外光谱表明配合物热分解经历脱水、配体热分解、硝酸盐转变成氧化物等多步连续分解过程, 最后在625 ℃失重恒定.     

2-（羟甲基）-N-甲基咪唑桥联Mn2ⅡMn2Ⅲ四核配合物的合成、结构和磁性简

报道了3个2-(羟甲基)-N-甲基咪唑(Hhmmi)桥联的Mn2ⅡMn2Ⅲ四核配合物[Mn4(hmmi)6(DMF)2·(N3)2](ClO4)2(1),[Mn4(hmmi)6(H2O)2(N3)2](ClO4)2(2)和[Mn4(hmmi)6Cl4]·6CH3CN(3·6CH3CN)的合成、晶体结构和磁性. 在配合物1~3中,中心结构皆为四核蝶形混合价Mn结构,2个MnⅡ占据蝶形两翼位置,2个MnⅢ占据蝶形中间位置. MnⅢ离子间通过hmmi-上的μ3-烷氧原子桥联,相应MnⅢ-O-MnⅢ键角为101.3°~103.4°;而MnⅢ-MnⅡ离子间通过hmmi-上的μ3-和μ2-烷氧原子桥联,相应MnⅢ-O-MnⅡ键角为92.5°~113.7°. 对配合物1~3进行变温磁化率拟合,结果表明,MnⅢ-MnⅢ间呈铁磁相互作用,而MnⅢ-MnⅡ间以及Mn4分子间存在较弱的铁磁或反铁磁耦合.     

A geometrically constraining bis(benzimidazole) ligand and its nearly tetrahedral complexes with Fe(II) and Mn(II)

2,2'-Bis[2-(1-propylbenzimidazol-2-yl)]biphenyl), 4, and its bis complexes with Fe(II) and Mn(II) have been prepared and characterized structurally and spectroscopically. Ligand 4 adopts an open, "trans" conformation in the solid state with the benzimidazole (BzIm) groups on opposite sides of the biphenyl unit. In its complexes with metal ions, a "cis" conformation is observed, and 4 behaves as a geometrically constraining bidentate ligand with four planar groups connected by three "hinges". Reaction of 4 with Fe(II) or Mn(II) yielded isomorphous crystals (space group Pnn2) of Fe(II)(4)2.(ClO4)2 and Mn(II)(4)2.(ClO4)2, in which the M(II)(4)2 cations exhibit distorted-tetrahedral coordination geometries (N-M-N angles, 109 +/- 11 degrees ) enforced by rigid, chiral nine-membered M(4) rings in the twist-boat-boat conformation. Individually, the cations show R,R or S,S stereochemistry, and the crystals are racemates. Mn(II)(4)2.(ClO4)2 exhibits a quasi-reversible Mn(II) --> Mn(III) oxidation at E(1/2) = 0.64 V; the corresponding Fe(II) --> Fe(III) oxidation occurs at E(1/2) = 1.76 V. The electrochemical stability of the Fe(III) oxidation state in this system suggests the possibility of isolating an unusual pseudotetrahedral Fe(III)N(BzIm)(4) species. Ultraviolet spectra of the iron and manganese complexes are dominated by absorptions of the ligand 4 blue-shifted by approximately 2000-3000 cm(-1). Ligand-field absorptions were observed for the Fe(II) complex; those for the Mn(II) complex were obscured by tailing ultraviolet absorptions. Electron paramagnetic resonance and magnetic susceptibility measurements are consistent with a high-spin Mn(II) complex, while for the Fe(II) complex, the falloff of the magnetic moment with decreasing temperature is indicative of zero-field splitting with D approximately 4 cm(-1).     

Studies of a dinuclear manganese complex with phenoxo and bis-acetato bridging in the Mn2(II,II) and Mn2(II,III) states: Coordination structural shifts and oxidation state control in bridged dinuclear complexes

The dinucleating ligand, 2,6-bis{[(2-(2-pyridyl)ethyl)(2-pyridylmethyl)-amino]-methyl}-4-methylphenol) (L1OH) reacts with Mn(ClO4)2.6H2O to form the dinuclear complex [Mn2(II,II)(L1O)(mu-OOCCH3)2]ClO4 (1). The electrolytic oxidation of 1 at 0.7 V (vs Ag/AgCl) produces the mixed valent complex [Mn2(II,III)(L1O)(mu-OOCCH3)2](ClO4)2 (1ox) quantitatively, while electrolysis at 0.20 V converts 1ox back to 1. X-ray crystallographic structures show that both 1 and 1ox are dinuclear complexes in which the two manganese ions are each in distorted octahedral coordination environments bridged by the phenoxo oxygen and two acetate ions. The structural changes that occur upon the oxidation 1 to 1ox suggest an extended pi-bonding system involving the phenoxo ring C-O(phenoxo)-Mn(II)-N(pyridyl) chain. In addition, as 1 is oxidized to 1ox, the rearrangements in the coordination sphere resulting from the oxidation of one Mn(II) ion to Mn(III) are transmitted via the bridging Mn-O(phenoxo) bonds and cause structural changes that render the site of the second manganese ion unfit for the +3 state and hence unstable to reduction. Thus the electrolytic oxidation of 1ox in acetonitrile at 1.20 V takes up slightly greater than 1 F of charge/mol of 1ox, but the starting complex, 1ox, is recovered, showing the instability of the Mn2(III,III) state that is formed with respect to reduction to 1ox. Variable-temperature magnetic susceptibility measurements of 1 and 1ox over the temperature range from 1.8 to 300 K can be modeled with magnetic coupling constants J = -4.3 and -4.1 cm(-1), respectively showing the weak antiferromagnetic coupling between the two manganese ions in each dinuclear complex, which is commonly observed among similar phenoxo- and bis-1,3-carboxylato-bridged dinuclear Mn2(II,II) and Mn2(II,III) complexes.     

Reductive nitrosylation and proton-assisted bridge splitting of a (mu-oxo)dimanganese(III) complex derived from a polypyridine ligand with one carboxamide group

Aerobic oxidation of the Mn(II) complex [Mn(Papy3)(H2O)](ClO4) (1, PaPy3- is the anion of the designed ligand N,N-bis(2-pyridylmethyl)amine-N-ethyl-2-pyridine-2-carboxamide) in acetonitrile affords the (mu-oxo)dimanganese(III) complex [(Mn(PaPy3))2(mu-O)](ClO4)2 (3) in high yield. The unsupported single oxo bridge between the two high-spin Mn(III) centers in 3 is readily cleaved upon addition of proton sources such as phenol, acetic acid, and benzoic acid, and complexes of the type [Mn(PaPy3)(L)](ClO4) (5, L = PhO-; 6, L = AcO-; 7, L = BzO-) are formed. The basicity of the bridge is evident by the fact that simple addition of methanol to a solution of 3 in acetonitrile affords the methoxide complex [Mn(PaPy3)(OMe)](ClO4) (4). The structures of 3-5 and 7 have been determined. Passage of NO through a solution of 3 in acetonitrile produces the [Mn-NO]6 nitrosyl [Mn(PaPy3)(NO)](ClO4) (2) via reductive nitrosylation. Complexes 4-7 also afford the [Mn-NO]6 nitrosyl 2 upon reaction with NO. In the latter case, the anionic O-based ligands (such as MeO- and PhO-) act as built-in bases and promote reductive nitrosylation of the Mn(III) complexes.