Lingqian Kong

Structures and magnetism of two manganese crowns assembled with 2,4-dihydroxyacetophenone oxime

Reactions of 2,4-dihydroxyacetophenone oxime with manganese salts yielded two manganese crowns, [Mn3(μ 3-O)(4-OH-Me-sao)3(HCOO)(MeOH)5]·MeOH (1) and [Mn3(μ 3-O)(4-OH-Me-sao)3(CH3COO)(MeOH)5]·MeOH (2) (4-OH-Me-saoH2=2,4-dihydroxyacetophenone oxime). Both compounds possess [MnIII 3(μ 3-O)]7+ cores which contain 9-MC-3 metallacrown (MC) rings with the repeating pattern [–Mn–N–O–]. However, the difference in the structures of both compounds is coordinated carboxylates. In 1 and 2, the MC molecules are connected with each other through intermolecular hydrogen bonds, generating similar 3-D supramolecular networks. Magnetic properties reveal that in 1 and 2 the metal ions exhibit ferromagnetic exchange coupling.

Synthesis, crystal structures, and magnetic properties of three pairs of chiral cyanide-bridged Fe(III)–Cu(II) enantiomeric complexes

With three trans-dicyanideiron(III) precursors K[Fe(L)(CN)2] as building blocks (L = bpb2−, bpmb2−, bpdmb2−; bpb2− = 1,2-bis(pyridine-2-carboxamido)-4,5-enzenate, bpmb2− = 1,2-bis(pyridine-2-carboxamido)-4-methylbenzenate, bpdmb2− = 1,2-bis(pyridine-2-carboxamido)-4,5-dimethylbenzenate) and two chiral copper(II) compounds Cu[(S,S/R,R-dpen)2](ClO4)2 (S,S/R,R-dpen = S,S/R,R-1,2-diphenylethylenediamine) as assembly segments, three pairs of cyanide-bridged enantiomers, {[(S,S/R,R-dpen)2Cu(μ-CN)Fe(bpb)(CN)]ClO4}2 (1,2), {[(S,S/R,R-dpen)2Cu(μ-CN)Fe(bpmb)(CN)]}ClO4 (3,4), and {[(S,S/R,R-dpen)2Cu(μ-CN)Fe(bpdmb)(CN)]}ClO4 (5,6), have been obtained and characterized by elemental analysis, IR spectroscopy, and X-ray structure determination. Single X-ray diffraction analysis shows their similar binuclear structures, in which the cyanide-containing building blocks acting as a monodentate ligand through one of the two cyanide groups are linked to the five-coordinate Cu(II) ion, for which the four amine N complete the additional coordination positions. Investigation of magnetic properties of 1–6 reveals weak ferromagnetic magnetic exchange between the neighboring Fe(III) and Cu(II) ions through the bridging cyanide. Graphical abstract

A new linear trinuclear cobalt complex bearing oximato and azido ligands: synthesis, structure, and magnetic characterization

The reaction of CoCl2 · 6H2O, mpkoH (methyl 2-pyridyl ketone oxime), NEt3, and NaN3 in a 1 : 1 : 2 : 1 molar ratio affords a linear trinuclear complex, [ CoII(mpko)4(N3)4(H2O)2] (1). Complex 1 has been characterized by single-crystal X-ray diffraction, elemental analysis, and infrared spectrum. Three cobalt ions are in the center of distorted octahedra, which are connected by two μ-1,1 azides and two oxime oxygen atoms to form a linear trinuclear structure. Discrete units of 1 are connected to form a stable 3-D supramolecular network by C–H···O and C–H···N weak interactions. Variable temperature magnetic susceptibility measurements reveal that 1 exhibits antiferromagnetic behavior.

Synthesis, Crystal Structures, and Magnetic Properties of Two [Cu(cyclm)]2+-Based One-Dimensional Chain Complexes

With polyimine macrocyclic compound [Cu(cyclm)]2+ as assembly segment, two 1D coordination polymers, {[Cu(cyclm)Br][Ru(acac)2(CN)2]}n∙nCH3OH (1) and {[Cu(cyclm)Br]ClO4}n∙nCH3CN∙nH2O (2), have been synthesized and structurally characterized. Single-crystal X-ray diffraction analysis shows their 1D cationic structure comprised by the repeating unit [Cu(cyclm)Br]+ with [Ru(acac)2(CN)2]− or ClO4− as balance anion (cyclm = 1,4,8,11-tetraazacyclotetradecane, acac = acetylaceto). Investigation of the magnetic properties of these two complexes reveals the weak antiferromagnetic magnetic coupling between the neighboring Cu(II) bridged by bromide ions. A best fit to the magnetic susceptibilities of complexes 1 and 2 leads to the magnetic coupling constants J = 1.02(2) (1) and 1.05(2) cm−1 (2), respectively.

Synthesis, crystal structure and magnetic characterization of a cyanide-bridged Mo–Ni nanosized molecular wheel

Abstract By using K4[Mo(CN)8] and [Ni(L)(H2O)2][ClO4]2 as reagents (L = 2,12-dimethyl-3,7,11,17-tetraazabicyclo [11.3.1]heptadeca-1(17),13,15-triene), a new cyanide-bridged Mo–Ni complex containing the building blocks [Ni(H2O)(L)]2+ and [Ni(L)]2+ bridged by [Mo(CN)8]4− units has been obtained. The complex with the formula {[Ni(H2O)(L)][Ni(L)][Mo(CN)8]}6 · 36H2O · 2CH3OH (1) was characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The structure determination reveals an octadecanuclear cluster in the form of a 36-membered macrocycle, in which the largest intramolecular W···W and Ni···Ni distances are 16.5 and 14.4 Å, respectively, indicating that complex 1 is a nanosized molecular wheel. Investigation of its magnetic properties has shown weak antiferromagnetic coupling between the adjacent Ni(II) ions bridged by the diamagnetic [Mo(CN)8]4− ions.

Synthesis, crystal structure, and magnetic characterization of chiral Schiff-base manganese(III) complex containing cocrystallized crown ether molecule

A chiral Schiff-base Mn(III) compound containing cocrystallized crown ether {Mn[(R,R)-Salcy]·(H2O)2}2(ClO4)2·18-Crown-6 (I), where (R,R)-Salcy = (R,R)-N, N′-(1,2-cyclohexanediylethylene)bis(salicylideneiminato) dianion, has been synthesized by the reaction of {Mn[(R,R)-Salcy](H2O)2}ClO4 with 18-crown-6 ether and K4[Mo(CN)8]. X-ray diffraction analysis revealed that the cationic mononuclear Mn(III) Schiff-base compounds were self-complementary via intermolecular O-H⋯O H-bond formed by coordinated aqua ligand of one molecule and phenolic oxygen atoms of the neighboring molecule, giving supramolecular dimeric structure. The H-bond between O atoms of the cocrystallized crown molecule and that of the mentioned above dimer supported formation of one-dimensional supramolecular chain structure which can be linked to two-dimensional supramolecular network based on intermolecular O-H⋯Cl weak interactions. Our study of its magnetic properties revealed weak antiferromagnetic coupling between the adjacent Mn(III) ions.

CCDC 819542: Experimental Crystal Structure Determination

Related Article: Lingqian Kong, Daopeng Zhang, Fangfang Su, Dacheng Li, Jianmin Dou|2011|Bull.Korean Chem.Soc.|32|2249|doi:10.5012/bkcs.2011.32.7.2249