Jianzhong Zou

Crystal structure of a cyanide-bridged heptanuclear manganese(III)–chromium(III) complex with a ground state S = 21/2

K3[Cr(CN)6] reacts with the mononuclear MnIII complex Mn(salen)ClO4 · 2H2O [salen: N,N′-ethylenebis(salicylideneiminato)dianion] to give a bimetallic heptanuclear complex cation salt [Cr{(CN)Mn(salen · H2O)}6][Cr(CN)6]6H2O. In the complex anion, [Cr{(CN)Mn(salen · H2O)}6]3+, six MnIII ions coordinate to a CrIII center via cyano bridges, forming a spherical species with 3 symmetry. A study of magnetic properties shows the presence of antiferromagnetic interaction through the cyanide bridge between CrIII (S = 3/2) and MnIII (S = 4/2) and results in a ground state S = 21/2.

Synthesis, crystal structure and magnetic properties of oxo-bridged binuclear iron(III) complex [Fe(phen)2PhCOO]2OCl2·7H2O

Abstract An oxo-bridged binuclear iron(III) complex, [Fe(phen) 2 PhCOO] 2 OCl 2 ·7H 2 O, was synthesized and the crystal structure indicated that two octahedrally coordinated iron(III) ions bridged with oxygen atoms formed a non-linear complex. The bond angle of FeOFe is 155.6°. The studies of magnetic properties showed that there was strong antiferromagnetic superexchange coupling ( J = −80.8 cm − ) between two S = 5 2 iron(III) ions.

Synthesis and magnetic properties of the one-dimensional linear chain structure cyano-bridged complex [Cu(teta)(H2O)2][Cu(teta) Fe(CN)6]ClO4·2H2O (teta=5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacylotetradecane)

Reaction of either K3[Fe(CN)6] or K4[Fe(CN)6] with a macrocyclic CuII complex, [Cu(teta)](ClO4)2 (teta = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacylotetradecane), in aqueous solution gave the same product as shown by spectroscopic and physicochemical characterisation. The crystal structure of the complex shows that it is a one-dimensional linear chain type heterobinuclear FeIII–CuII polymer. The unit is composed of a [Cu(teta)(H2O)2]2+ cationic complex, a FeIII–CuII alternate linear chain unit, a ClO4− ion and four water molecules. The Cu atom is coordinated in a distorted octahedral arrangement by four nitrogen atoms from one teta ligand and two nitrogen atoms of the bridging cyanide groups. The Cu—N bond distances involving the cyanide bridges, 2.522(7) and 2.608(7)Å, respectively, indicate weak antiferromagnetic interactions between the FeIII and CuII atoms.

Synthesis and X-ray crystal structure of a mixed-valent cobalt complex, Co2Cl5(py)5

Abstract A new complex, Co2Cl5(py)5 was obtained by the reaction of CoCl2·6H2O with Bun4MnO4 in pyridine in the presence of benzoic acid. The structure consists of a discrete octahedral [CoIIICl2(py)4]+ cation and a tetrahedral [CoIICl3py]− anion. The compound was also characterized by elemental analyses, IR, XPS spectra and variable-temperature magnetic susceptibility measurements. The reaction conditions indicate that when the molar ratio of benzoic acid: CoCl2·6H2O is below 0.75 the title complex cannot be obtained.

7,8,17,18-Tetrabromo-5,10,15,20-tetraphenylporphyrin, C44H26Br4N4

The molecular structure determination of the title compound shows that four Br atoms are located on antipodal pyrrole rings. The macrocyclic skeleton, including the four Br atoms, is almost planar, in spite of the presence of the bulky Br atoms on the porphyrin periphery

CRYSTAL STRUCTURE AND MAGNETIC PROPERTIES OF HETEROTRINUCLEAR COMPLEX, (CUTREN)2FE(CN)6 · 12H2O

Abstract A heterotrinuclear complex, (Cutren)2Fe(CN)6 · 12H2O, was synthesised and its crystal structure solved by direct methods. Crystal data are: C18H60N14Cu2FeO12, M = 847.7, monoclinic, space group: P21/c, a = 13.568(5), b = 10.100(3), c = 13.935(6) A, μ = 95.50(4)°, V = 1901(1) A3, Z − 2. D x = 1.48 gem−3, final R = 0.039 and Rω = 0.049. The crystal structure shows that the complex is composed of two (Cutren) and one hexacyanometallate Fe(CN)6 subunits. Bridging cyano C(l) — N(l) is 1.148(4) A, which is shorter than non-bridging (1.155(4) A and 1.164(4) A). Magnetic properties of (Cutren)2Fe(CN)6 indicate weak ferromagnetic exchange over the temperature range of 6.2–37K.

A Tetracarboxylatobenzene-Bridged Binuclear Copper(II) Complex

The tetracarboxylatobenzene tetraanion in μ-(1,2,4,5-benzenetetracarboxylato-O1:O4)bis[aqua(4-azaheptane-1,7-diamine-N, N′, N′′) copper(II)] octahydrate, [{Cu(C6H17N3)(H2O)}2(μ-C10H2O8].8H2O, bridges two N′N′′N′′′-chelated aquacopper entities in a monodentate manner to give rise to square-pyramidal coordination at the metal centres. Hydrogen bonding involving the three nitrogen atoms, the four carboxyl O atoms and the five water molecules gives rise to a three-dimensional network structure.

Synthesis, molecular structure and magnetic properties of [Mn11CrO12(CH3CO2)16(H2O)4] · 4H2O with A S = 8 ground state

Abstract The title compound [Mn11CrO12(CH3CO2)16(H2O)4] ·4H2O was obtained by reaction of K2Cr2O7 and Mn(OAc)2 in CH3CO2H/H2O mixed solvent and its crystal structure was determined. The crystal data show that there are three crystallographical independent metal atoms Mn(1), Mn(2) and Mn(3). Mn(3) ions comprise four Mn4+, which with four oxygen atoms form the centre cube of the title compound. The Mn(2) ions comprise four Mn3+ ions, Mn(1) ions represent three Mn3+ ions and one Cr3+ ion. The Cr3+ ion occupied each site of Mn(1), Mn(1a), Mn(1b) and Mn(1c), statistically, so, Mn(1) = 1/4Cr+3/4Mn. Variable temperature magnetic susceptibilities of the title complex were determined. The effective magnetic moment (μeff) per molecule shows that there is intramolecular ferromagnetic exchange interaction with the ground state S = 8.

A New Azide-Bridged Three-Dimensional Supramolecular Manganese(II) Compound: Synthesis, Crystal Structure and Magnetic Properties

A three-dimensional supramolecular compound [Mn(N3)2(H2O)3(hmt)] 2 , where hmt stands for hexamethylenetetramine, was synthesized and characterized by IR, crystal structure and magnetic susceptibility. The compound [Mn(N3)2(H2O)3(hmt)] n , crystallizes in the orthorhombic system, space group Pn 21 a, with a = 6.5201(9), b = 9.322(2), c = 22.192(3) Å, β = 90° and Z = 2. The Mn atom is coordinated in an octahedral arrangement by three nitrogen atoms from three azido ions, and three oxygen atoms from three water molecules, respectively. The azide ligand bridges Mn atoms in μ-1,3 fashion, forming a zigzag chain. Hmt connected with the zigzag chain by hydrogen bonds, to form a three-dimensional supramolecular structure. The magnetic susceptibility data show that there is an antiferromagnetic exchange interaction in the title compound. The data were modeled using an infinite chain model leading to J = -4.8 cm−1.

Crystal structure and magnetic properties of a new polymer [Cu(PzdcH)2·2H2O]n

Two different products are obtained when 2,3-pyrazinedicarboxylic acid (PzdcH2) reacts separately with two copper(II) salts: Cu(OAc)2 and CuCl2. One product is a mononuclear CuII complex Cu(PzdcH)2·2H2O, the other is a linear polymeric copper(II) complex [Cu(PzdcH)2·2H2O]n, whose structure has been determined by X-ray diffraction at room temperature. The polymeric complex is composed of copper(II) ions, PzdcH- anions and crystal water molecules. The Cu(1) atom is located in elongated octahedral coordination environment with six donor atoms: O(1), N(1), O(1a), N(1a), O(3b) and O(3c) from four different PzdcH- anions. The two oxygen atoms O(3b) and O(3c) come from the carboxylic acid group of the PzdcH- anion of the upper and lower layers, so that an infinite chain constitutes the crystal lattice. There are very strong hydrogen bond interactions between chains which lead to a three-dimensional structure. The magnetic susceptibility of the polymeric complex [Cu(PzdcH)2·2H2O]n has been determined in the 1.5–300K range. A study of magnetic properties shows that a weak antiferromagnetic interaction exists between two copper(II) ions.