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1.
The unimolecular chemistry and structures of self‐assembled complexes containing multiple alkaline‐earth‐metal dications and deprotonated GlyGly ligands are investigated. Singly and doubly charged ions [Mn(GlyGly?H)n‐1]+ (n=2–4), [Mn+1(GlyGly?H)2n]2+ (n=2,4,6), and [M(GlyGly?H)GlyGly]+ were observed. The losses of 132 Da (GlyGly) and 57 Da (determined to be aminoketene) were the major dissociation pathways for singly charged ions. Doubly charged Mg2+ clusters mainly lost GlyGly, whereas those containing Ca2+ or Sr2+ also underwent charge separation. Except for charge separation, no loss of metal cations was observed. Infrared multiple photon dissociation spectra were the most consistent with the computed IR spectra for the lowest energy structures, in which deprotonation occurs at the carboxyl acid groups and all amide and carboxylate oxygen atoms are complexed to the metal cations. The N?H stretch band, observed at 3350 cm?1, is indicative of hydrogen bonding between the amine nitrogen atoms and the amide hydrogen atom. This study represents the first into large self‐assembled multimetallic complexes bound by peptide ligands.  相似文献   

2.
We investigate activation of carbon dioxide by singly charged hydrated magnesium cations Mg .+(H2O)n, through infrared multiple photon dissociation (IRMPD) spectroscopy combined with quantum chemical calculations. The spectra of [MgCO2(H2O)n].+ in the 1250–4000 cm?1 region show a sharp transition from n=2 to n=3 for the position of the CO2 antisymmetric stretching mode. This is evidence for the activation of CO2 via charge transfer from Mg .+ to CO2 for n≥3, while smaller clusters feature linear CO2 coordinated end‐on to the metal center. Starting with n=5, we see a further conformational change, with CO2.? coordination to Mg2+ gradually shifting from bidentate to monodentate, consistent with preferential hexa‐coordination of Mg2+. Our results reveal in detail how hydration promotes CO2 activation by charge transfer at metal centers.  相似文献   

3.
In the title one‐dimensional complex, {[MnIII(C9H10NO2)2]Cl}n, the Schiff base ligand 2‐[(2‐hydroxy­ethyl)­imino­methyl]­phenolate (Hsae) functions as both a bridging and a chelating ligand. The MnIII ion is six‐coordinated by two N and four O atoms from four different Hsae ligands, yielding a distorted MnO4N2 octahedral environment. Each [MnIII(Hsae)2]+ cationic unit has the Mn atom on an inversion centre and each [MnIII(Hsae)2]+ cation lies about another inversion centre. The chain‐like complex is further extended into a three‐dimensional network structure through Cl⋯H—O hydrogen bonds and C—H⋯π contacts involving the Hsae rings.  相似文献   

4.
Coordination Polymeric 1, 2‐Dithiooxalato and 1, 2‐Dithiosquarato Complexes. Syntheses and Structures of [BaCr2(bipy)2(1, 2‐dtox)4(H2O)2], [Ni(cyclam)(1, 2‐dtsq)]·2DMF, [Ni(cyclam)Mn(1, 2‐dtsq)2(H2O)2]·2H22, and [H3O][H5O2][Cu(cyclam)]3[Cu2(1, 2‐dtsq)3]2 1, 2‐Dithioxalate and 1, 2‐dithiosquarate ions have a pair of soft and hard donor centers and thus are suited for the formation of coordination polymeric complexes containing soft and hard metal ions. The structures of four compounds with building blocks containing these ligands are reported: In [BaCr2(bipy)2(1, 2‐dtox)4(H2O)2] Barium ions and pairs of Cr(bipy)(1, 2‐dtox)2 complexes form linear chains by the bisbidentate coordination of the dithiooxalate ligands towards Ba2+ and Cr3+. In [Ni(cyclam)(1, 2‐dtsq)]·2DMF short NÖH···O hydrogen bonds link the NiS2N4‐octahedra with C2v‐symmetry to an infinite chain. In [Ni(cyclam)Mn(1, 2‐dtsq)2(H2O)2]·2H2O the 1, 2‐dithiosquarato ligand shows a rare example of S‐coordination towards manganese(II). The sulfur atoms of cis‐MnO2S4‐polyedra are weakly coordinated towards the axial sites of square‐planar NiN4‐centers, thus forming a zig‐zag‐chain of Mn···Ni···Mn···Ni polyhedra. [H3O][H5O2][Cu (cyclam)]3[Cu2(1, 2‐dtsq)3]2 contains square planar [CuII(cyclam)]2+ ions and dinuclear [CuI2(1, 2‐dtsq)3]4— ions. Here each copper atom is trigonally planar coordinated by S‐donor atoms of the ligands. The Cu…Cu distance is 2.861(4)Å.  相似文献   

5.
The title compound, {[Cu(NH3)4][Cu(CN)3]2}n, features a CuI–CuII mixed‐valence CuCN framework based on {[Cu2(CN)3]}n anionic layers and [Cu(NH3)4]2+ cations. The asymmetric unit contains two different CuI ions and one CuII ion which lies on a centre of inversion. Each CuI ion is coordinated to three cyanide ligands with a distorted trigonal–planar geometry, while the CuII ion is ligated by four ammine ligands, with a distorted square‐planar coordination geometry. The interlinkage between CuI ions and cyanide bridges produces a honeycomb‐like {[Cu2(CN)3]}n anionic layer containing 18‐membered planar [Cu(CN)]6 metallocycles. A [Cu(NH3)4]2+ cation fills each metallocyclic cavity within pairs of exactly superimposed {[Cu2(CN)3]}n anionic layers, but there are no cations between the layers of adjacent pairs, which are offset. Pairs of N—H...N hydrogen‐bonding interactions link the N—H groups of the ammine ligands to the N atoms of cyanide ligands.  相似文献   

6.
Cubic [Ta6Br12(H2O)6][CuBr2X2]·10H2O and triclinic [Ta6Br12(H2O)6]X2·trans‐[Ta6Br12(OH)4(H2O)2]·18H2O (X = Cl, Br, NO3) cocrystallize in aqueous solutions of [Ta6Br12]2+ in the presence of Cu2+ ions. The crystal structures of [Ta6Br12(H2O)6]Cl2·trans‐[Ta6Br12(OH)4(H2O)2]·18H2O ( 1 ) and [Ta6Br12(H2O)6]Br2·trans‐[Ta6Br12(OH)4(H2O)2]·18H2O ( 3 )have been solved in the triclinic space group P&1macr; (No. 2). Crystal data: 1 , a = 9.3264(2) Å, b = 9.8272(2) Å, c = 19.0158(4) Å, α = 80.931(1)?, β = 81.772(2)?, γ = 80.691(1)?; 3 , a = 9.3399(2) Å, b = 9.8796(2) Å, c = 19.0494(4) Å; α = 81.037(1)?, β = 81.808(1)?, γ = 80.736(1)?. 1 and 3 consist of two octahedral differently charged cluster entities, [Ta6Br12]2+ in the [Ta6Br12(H2O)6]2+ cation and [Ta6Br12]4+ in trans‐[Ta6Br12(OH)4(H2O)2]. Average bond distances in the [Ta6Br12(H2O)6]2+ cations: 1 , Ta‐Ta, 2.9243 Å; Ta‐Bri , 2.607 Å; Ta‐O, 2.23 Å; 3 , Ta‐Ta, 2.9162 Å; Ta‐Bri , 2.603 Å; Ta‐O, 2.24 Å. Average bond distances in trans‐[Ta6‐Br12(OH)4(H2O)2]: 1 , Ta‐Ta, 3.0133 Å; Ta‐Bri, 2.586 Å; Ta‐O(OH), 2.14 Å; Ta‐O(H2O), 2.258(9) Å; 3 , Ta‐Ta, 3.0113 Å; Ta‐Bri, 2.580 Å; Ta‐O(OH), 2.11 Å; Ta‐O(H2O), 2.23(1) Å. The crystal packing results in short O···O contacts along the c axes. Under the same experimental conditions, [Ta6Cl12]2+ oxidized to [Ta6Cl12]4+ , whereas [Nb6X12]2+ clusters were not affected by the Cu2+ ion.  相似文献   

7.
The reaction of MnII and [NEt4]CN leads to the isolation of solvated [NEt4]Mn3(CN)7 ( 1 ) and [NEt4]2Mn3(CN)8 ( 2 ), which have hexagonal unit cells [ 1 : R$\bar 3$ m, a=8.0738(1), c=29.086(1) Å; 2 : P$\bar 3$ m1, a=7.9992(3), c=14.014(1) Å] rather than the face centered cubic lattice that is typical of Prussian blue structured materials. The formula units of both 1 and 2 are composed of one low‐ and two high‐spin MnII ions. Each low‐spin, octahedral [MnII(CN)6]4? bonds to six high‐spin tetrahedral MnII ions through the N atoms, and each of the tetrahedral MnII ions are bound to three low‐spin octahedral [MnII(CN)6]4? moieties. For 2 , the fourth cyanide on the tetrahedral MnII site is C bound and is terminal. In contrast, it is orientationally disordered and bridges two tetrahedral MnII centers for 1 forming an extended 3D network structure. The layers of octahedra are separated by 14.01 Å (c axis) for 2 , and 9.70 Å (c/3) for 1 . The [NEt4]+ cations and solvent are disordered and reside between the layers. Both 1 and 2 possess antiferromagnetic superexchange coupling between each low‐spin (S=1/2) octahedral MnII site and two high‐spin (S=5/2) tetrahedral MnII sites within a layer. Analogue 2 orders as a ferrimagnet at 27(±1) K with a coercive field and remanent magnetization of 1140 Oe and 22 800 emuOe mol?1, respectively, and the magnetization approaches saturation of 49 800 emuOe mol?1 at 90 000 Oe. In contrast, the bonding via bridging cyanides between the ferrimagnetic layers leads to antiferromagnetic coupling, and 3D structured 1 has a different magnetic behavior to 2 . Thus, 1 is a Prussian blue analogue with an antiferromagnetic ground state [Tc=27 K from d(χT)/dT].  相似文献   

8.
A series of bis‐chelate pseudooctahedral mononuclear coordination complexes of manganese with the chromophore [MnN4O2]n+ (n=0, 1) have been generated in all three principal oxidation states of this transition‐metal center under ambient conditions by utilizing a readily tunable, versatile phenolic pyridylhydrazone ligand system (i.e., H2(3,5‐R1,R2)‐L; L=ligand). Strategic combinations of the nature and position of a variety of substituent groups afforded selective, spontaneous stabilization of multiple spin states of the manganese center, which, upon close crystallographic scrutiny, appears to be in part due to the occurrence or absence of hydrogen‐bonding interactions that involve the phenolate/phenolic oxygen atom. The divalent complexes are isolable in two forms, namely, molecular [MnII{H(3,5‐R1,R2)‐L}2] and ionic [MnII{H2(3,5‐R1,R2)‐L}{H(3,5‐R1,R2)‐L}]ClO4, with the latter complex converting easily into the former complex on deprotonation. Accessibility of the higher‐valent states is achievable only when the phenolate oxygen atom is sterically hindered from participation in hydrogen bonding. The [MnIII{H(3,5‐tBu2)‐L}2]ClO4 complex is the first example of a hydrazone‐based MnIII complex to exhibit spin crossover. Formation of the tetravalent complexes [MnIV{(3,5‐R1,R2)‐L}2] (R1=tBu, R2=H; R1=R2=tBu) necessitates base‐assisted abstraction of the hydrazinic proton.  相似文献   

9.
Two new complexes, [Ru(phen)2(ppd)]2+ ( 1 ) and [Ru(phen)(ppd)2]2+ ( 2 ) (ppd=pteridino[6,7‐f] [1,10]phenanthroline‐11,13(10H,12H)‐dione, phen=1,10‐phenanthroline) were synthesized and characterized by ES‐MS, 1H‐NMR spectroscopy, and elemental analysis. The intercalative DNA‐binding properties of 1 and 2 were investigated by absorption‐spectroscopy titration, luminescence‐spectroscopy studies, thermal denaturation, and viscosity measurements. The theoretical aspects were further discussed by comparative studies of 1 and 2 by means of DFT calculations and molecular‐orbital theory. Photoactivated cleavage of pBR322 DNA by the two complexes were also studied, and 2 was found to be a much better photocleavage reagent than 1 . The mechanism studies revealed that singlet oxygen and the excited‐states redox potentials of the complex may play an important role in the DNA photocleavage.  相似文献   

10.
Under hydrothermal conditions, replacement of the water molecules in the [MnIII4MnII2O4(H2O)4]8+ cluster of mixed‐valent Mn6 sandwiched silicotungstate [(B‐α‐SiW9O34)2MnIII4MnII2O4(H2O)4]12? ( 1 a ) with organic N ligands led to the isolation of five organic–inorganic hybrid, Mn6‐substituted polyoxometalates (POMs) 2 – 6 . They were all structurally characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, diffuse‐reflectance spectroscopy, and powder and single‐crystal X‐ray diffraction. Compounds 2 – 6 represent the first series of mixed‐valent {MnIII4MnII2O4(H2O)4?n(L)n} sandwiched POMs covalently functionalized by organic ligands. The preparation of 1 – 6 not only indicates that the double‐cubane {MnIII4MnII2O4(H2O)4?n(L)n} clusters are very stable fragments in both conventional aqueous solution and hydrothermal systems and that organic functionalization of the [MnIII4MnII2O4(H2O)4]8+ cluster by substitution reactions is feasible, but also demonstrates that hydrothermal environments can promote and facilitate the occurrence of this substitution reaction. This work confirms that hydrothermal synthesis is effective for making novel mixed‐valent POMs substituted with transition‐metal (TM) clusters by combining lacunary Keggin precursors with TM cations and tunable organic ligands. Furthermore, magnetic measurements reveal that 3 and 6 exhibit single‐molecule magnet behavior.  相似文献   

11.
The solid‐state structure of the title compound, [Na2Mn2(C32H56N2OSi2)2O2] or [1,8‐C10H6(NSiiPr3)2Mn(μ3‐O)Na(THF)]2, which lies across a crystallographic twofold axis, exhibits a central [Mn2O2Na2]4+ core, with two oxide groups, each triply bridging between the two MnIII ions and an Na+ ion. Additional coordination is provided to each MnIII centre by a 1,8‐C10H6(NSiiPr3)2 [1,8‐bis(triisopropylsilylamido)naphthalene] ligand and to the Na+ centres by a tetrahydrofuran molecule. The presence of an additional Na...H—C agostic interaction potentially contributes to the distortion around the bridging oxide group.  相似文献   

12.
The novel oxothiomolybdate Mn2(tren)3[Mo2O2S6]2·1.3H2O [tren = tris(2-aminoethyl)amine], synthesized under solvothermal conditions, consists of one-dimensional novel [Mn2(tren)3] n 4+ chains and discrete [Mo2O2S6]2– anions. There are two crystallographically independent chains and four [Mo2O2S6]2– anions in the asymmetric unit. Each Mn atom in the cationic chains is sixfold coordinated by N atoms of the chelating tren molecules. Two of the four crystallographically independent Mn atoms are tridentately coordinated by two tren molecules, whereas the other two are coordinated tetradentately by one tren molecule and monodentately by the remaining primary amino groups from the tren molecules that act as tridentate ligands. The tren ligand bonding modes lead to the formation of the polymeric [Mn2(tren)3] n 4+ chain. One of the four Mn atoms is in the unusual trigonal prismatic coordination state with six surrounding N atoms.  相似文献   

13.
Self‐assembly of the [Mo(CN)7]4– anion and the Mn2+ ion in the aqueous solution containing ammonium formate results in a new coordination polymer, {(NH4)3[(H2O)Mn3(HCOO)][Mo(CN)7]2·4H2O}n. Single crystal X‐ray analysis revealed a very complicated three‐dimensional (3D) framework, where both the [Mo(CN)7]4– and the formate anions act as bridges between the MnII centers. Magnetic measurements revealed that this compound displays ferrimagnetic ordering below 70 K. Competing antiferromagnetic interactions between the spin carriers might lead to spin frustration and non‐linear alignment of the magnetic moments. Specifically, this compound is the first mixed [Mo(CN)7]4–/HCOO bridged molecule magnet.  相似文献   

14.
Polynuclear Pd(II) and Ni(II) complexes of macrocyclic polyamine 3,6,9,16,19,22‐hexaazatricyclo[22.2.2.211,14]‐triaconta 11,13,24,26(l),27,29‐hexaene (L) in solution were investigated by electrospray ionization mass spectrometry (ESIMS). For methanol solution of complexes M2LX4 (M = Pd(II) and Ni(II), X= Cl and I), two main clusters of peaks were observed which can be assigned to [M2LX3]+ and [M2LX2]2+. When Pd2LCl4 was treated with 2 or 4 mol of AgNO3, it gave rise formation of Pd2LCl2 (NO3)2 · H2O and [Pd2L(H2O)m(NO3)n](4‐n)+, respectively. ESMS spectra show that the dissociation of the former in the ionization process gave peaks of [Pd2LCl2]2+ and [(Pd2LCl2)NO3]+, while dissociation of the later gave the peaks of [Pd2L(CH3CO2)2]2+ and [Pd2L(CH3CO2)2](NO3) + in the presence of acetic acid. Similar species were observed for Pd2LI4 when treated with 4 mol of AgNO3. When [Pd2L · (H2O)m(NO3)n](4‐n)+ reacted with 2 mol of oxalate anions at 40°C, [Pd4L2(C2O4)2(NO3)2]2+ and [Pd4L2(C2O4)2 (NO3)]3+ were detected. This implies the formation of square‐planar molecular box Pd4L2(C2O4)2(NO3)4 in which C2O4? may act as bridging ligands as confirmed by crystal structure analysis. The dissociation form and the stability of complex cations in gaseous state are also discussed. This work provides an excellent example of the usefulness of ESIMS in the identification of metal complexes in solution.  相似文献   

15.
The title racemic heterometallic dinuclear compound, [MnSn(C2H2O2S)3(H2O)5], (I), contains one main group SnIV metal centre and one transition metal MnII centre, and, by design, links the MnII centre to the building unit of the (Δ/Λ) [SnL3]2− complex anion (L is the 2‐sulfidoacetate dianion). In this cluster, the SnIV centre of the (Δ/Λ) [SnL3]2− unit is coordinated by three O atoms and three S atoms from three L ligands to form an [SnO3S3] octahedral coordination environment. The MnII centre is in an [MnO6] octahedral coordination environment, with five O atoms from five water molecules and the sixth from the μ2L ligand of the (Δ/Λ) [SnL3]2− unit. Between adjacent dinuclear molecules, there are many hydrogen‐bond interactions of O—H...O, O—H...S, C—H...O and C—H...S types. Of these, eight pairs of O—H...O hydrogen bonds fuse all the dinuclear molecules into two‐dimensional supramolecular sheets along the bc plane. Adjacent supramolecular sheets are further connected through O—H...S hydrogen bonds to give a three‐dimensional supramolecular network.  相似文献   

16.
将过渡金属配合物阳离子([M(DETA)2]n+(M=Cu2+,Ni2+,Co3+;DETA=Diethylenetriamine,二乙烯三胺)作为客体插入层状MnPS3层间得到了相应的3个夹层化合物。通过X-射线粉末衍射、元素分析和红外光谱对夹层化合物的结构进行了表征。结果表明,与主体MnPS3 0.65 nm的层间距相比较,夹层化合物(Mn0.88PS3[Cu(DETA)2]0.12)的层间距扩大了0.32 nm,由此推测客体[Cu(DETA)2]2+在层间以平面四方的配位形式存在,而另2个夹层化合物(Mn0.79PS3[Ni(DETA)2]0.21和Mn0.74PS3[Co(DETA)2]0.17)的层间距扩大了0.48 nm,说明客体[(M(DETA)2]n+,M=Co3+,Ni2+) 在主体层间以八面体配位形式存在。磁性测试结果表明过渡金属离子[(M(DETA)2]n+(M=Cu2+,Co3+)的插入能引起主体MnPS3的磁性在35~40 K发生由顺磁向亚铁磁性的转变并表现自发磁化,而客体[Ni(DETA)2]2+却使夹层化合物的反铁磁相互作用增强,抑制了自发磁化的发生。  相似文献   

17.
[Mn(H2O)4(C4N2H4)][C6H4(COO)2] – An One‐Dimensional Coordination Polymer with Chain‐like [Mn(H2O)4(C4N2H4)]n2n+ Polycations Orthorhombic single crystals of [Mn(H2O)4(C4N2H4)][C6H4(COO)2] have been prepared in aqueous solution at room temperature. Space group Imm2 (no. 44), a = 1039.00(6) pm, b = 954.46(13) pm, c = 737.86(5) pm, V = 0.73172(12) nm3, Z = 2. Mn2+ is coordinated in a octahedral manner by four water molecules and two nitrogen atoms stemming from the pyrazine molecules (Mn–O 215.02(11) pm; Mn–N 228.7(4), 230.7(4) pm). Mn2+ and pyrazine molecules form chain‐like polycations with [Mn(H2O)4(C4N2H4)]n2n+ composition. The positive charge of the polycationic chains is compensated for by phthalate anions, which are accomodated between the chains. The phthalate anions are linked by hydrogen bonds to the polycationic chains. Thermogravimetric analysis in air revealed that the loss of water of crystallisation and pyrazine occurs in two steps between 130 and 245 °C. The resulting sample was stable up to 360 °C. Further decomposition yielded Mn2O3.  相似文献   

18.
The zinc(II) coordination polymer [Zn3(BPT)22‐H2O)2(H2O)2]n · n(DMA) ( 1 ) (H3BPT = biphenyl‐3,4′,5‐tricarboxylic acid, DMA = N,N′‐dimethylactamide) was obtained by the solvothermal reaction of H3BPT with Zn(NO3)2 in DMA/H2O mixed solvent. Single crystal X‐ray analysis reveals that compound 1 has a complicated 3D framework containing linear trinuclear [Zn3(COO)42‐H2O)2] clusters as building subunits, which can be simplified into a (3,6)‐connected rtl topological network with the Schläfli symbol {4.62}2{42.610.83}. The calculated results of total and partial density of states (DOS) indicate that the luminescence of 1 mainly originates from intraligand charge transfer.  相似文献   

19.
We have investigated the single‐molecule magnets [MnIII2(5‐Brsalen)2(MeOH)2MIII(CN)6]NEt4 (M=Os ( 1 ) and Ru ( 2 ); 5‐Brsalen=N,N′‐ethylenebis(5‐bromosalicylidene)iminate) by frequency‐domain Fourier‐transform terahertz electron paramagnetic resonance (THz‐EPR), inelastic neutron scattering, and superconducting quantum interference device (SQUID) magnetometry. The combination of all three techniques allows for the unambiguous experimental determination of the three‐axis anisotropic magnetic exchange coupling between MnIII and RuIII or OsIII ions, respectively. Analysis by means of a spin‐Hamiltonian parameterization yields excellent agreement with all experimental data. Furthermore, analytical calculations show that the observed exchange anisotropy is due to the bent geometry encountered in both 1 and 2 , whereas a linear geometry would lead to an Ising‐type exchange coupling.  相似文献   

20.
Metal Salts of Benzene‐1, 2‐di(sulfonyl)amine. 8. Lamellar Layers Based upon Hydrogen Bonding and π‐Stacking: Crystal Structures of the Complexes [Mg(H2O)6]Z2 and [Be(H2O)4]Z2�2 H2O, where Z is C6H4(SO2)2N The crystal structures of the title complexes (both triclinic, space group P1¯, Z = 1 for M = Mg, Z = 2 for M = Be) have been determined by low‐temperature X‐ray diffraction. They consist of non‐coordinating ortho‐benzenedisulfonimide anions and, respectively, inversion‐symmetric octahedral [Mg(H2O)6]2+ cations or tetrahedral [Be(H2O)4]2+ cations and two non‐coordinating water molecules. In both structures, all O—H hydrogen bond donor groups are used to associate the components into two‐dimensional assemblies comprising an internal polar lamella of metal cations, (SO2)2N groups and water molecules, and hydrophobic peripheral regions consisting of vertically protruding benzo rings. Carbocycles drawn alternatingly from adjacent layers form π‐stacking arrays, whereby the aromatic rings display intercentroid distances in the range 340—370 pm. Several short C—H ⃜O contacts, which may be viewed as weak hydrogen bonds, occur within and between the layers.  相似文献   

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