Jin-Kui Tang

A pentanuclear complex derived from manganese(III) Schiff-based complex and hexacyanoferrate(III): synthesis, structure and magnetic properties

Abstract A cyano-bridged MnIII–FeIII complex, [Mn(salpn)(CH3OH)]4·[Fe(CN)6]ClO4·9(H2O), was prepared and characterized. Single crystal X-ray analysis reveals that the complex assumes a cyano-bridged Mn4Fe unit. The magnetic measurement showed this complex exhibiting ferromagnetic behavior.

Heterobinuclear copper(II)–nickel(II) complexes of macrocyclic oxamide with diamines and tetraazacyclam as blocking ligands: synthesis, crystal structure and magnetic properties

Three novel oxamido-bridged heterobinuclear copper(II)–nickel(II) complexes derived from macrocylic oxamido compound with diamines and tetraazacyclam as blocking ligands were synthesized and characterized by IR, ESR and electronic spectra. Their formula is [Cu(L)Ni(en) 2 ](ClO 4 ) 2 ·0.5C 2 H 5 OH·H 2 O ( 1 ), [Cu(L)Ni(tmd) 2 ](ClO 4 ) 2 ·4H 2 O ( 2 ) and [Cu(L)Ni( rac -cth)](ClO 4 ) 2 ·CH 3 OH ( 3 ), where L=1,4,8,11-tetraazacyclotradecanne-2,3-dione, en=1,2-diaminoethande, tmd=1,3-diaminopropane and rac -cth is rac -5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane. The crystal structures of the three complexes have been determined. The structures consist of binuclear units in which the copper(II) ion is in a square-planar environment and linked to the nickel(II) ion via the exo - cis oxygen atoms of the oxamido macrocyclic ligand, with Cu⋯Ni separations of 5.311 ( 1 ), 5.420 ( 2 ) and 5.307 A ( 3 ), respectively. The temperature dependence of the magnetic susceptibility for 1 , 2 and 3 was analyzed by means of the Hamiltonian Ĥ =−2 JŜ Ni Ŝ Cu , leading to J =−52.8, −45.7 and −56.9 cm −1 for 1 , 2 and 3 , respectively.

Synthesis, Crystal Structure and Magnetic Properties of a Terephthalato-bridged Binuclear Nickel(II) Complex

A new terephthalato-bridged binuclear nickel(II) complex with a tetraazamacrocyclic compound as the terminal ligand, [Ni 2 (cth) 2 (µ-TPHA)](ClO 4 ) 2 (1) [cth= rac -5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane] has been synthesized and characterized. According to X-ray crystallographic studies on the solvated species 1·2CH 3 OH, each Ni(II) ion lies in a distorted octahedral environment, and the terephthalato ligand bridges two Ni(II) ions in a bis bidentate fashion. Cryomagnetic measurements revealed Curie-Weiss behaviour with è = m 1.4 K. Such behaviour may be due to a very weak intramolecular superexchange interaction through the extended bridge, a weak intermolecular exchange interaction or the local zero-field splitting of Ni(II) ions.

Synthesis and structure of a supramolecular octanuclear Cu(II) complex {[Cu(sae)] 4 2CH 3 OH·H 2 O} 2 through both μ -oxo and hydrogen bonds (sae = 2-salicylideneamino-1-ethanol)

Abstract A new supramolecular octanuclear copper(II) complex, {[Cu(sae)]42CH3OH·H2O}2, has been synthesized and structurally characterized. The structure of the complex consists of two tetracopper(II) cubane units related by hydrogen bonds.

Binuclear complexes of macrocyclic oxamide M(II)-Cu(II) (M = Cu, Ni, Mn): synthesis, crystal structure and magnetic properties

Three oxamido-bridged binuclear M(II)Cu(II) complexes of formulas [Cu(L)Cu(phen)(H 2 O)](ClO 4 ) 2 ( 1 ), [Cu(L)Ni(phen) 2 ](ClO 4 ) 2 ·2H 2 O ( 2 ), and [Cu(L)Mn(bpy) 2 ](ClO 4 ) 2 ( 3 ) have been synthesized, and structurally and magnetically characterized, where L=1,4,8,11-tetraazacyclotradecanne-2,3-dione, phen=1,10-phenanthroline and bpy=2,2′-bipyridine. In the three complexes, the copper atom from the macrocyclic oxamido–copper(II) precursor in a square-planar or axially elongated octahedral environment and the nickel and manganese atoms from 2 and 3 in a distorted octahedral environment are bridged by the oxamidate groups, with Cu⋯Ni and Cu⋯Mn separations of 5.281 and 5.418 A, respectively, while the other copper atom from 1 in square pyramidal coordination geometry, with Cu⋯Cu separation of 5.152 A. The metal–metal separations are consistent with the sequence of decrease of the ion radius of the metal ion. The magnetic properties of all three complexes have been investigated. The χ M T versus T plots for 1 – 3 are typical of antiferromagnetically coupled M(II)Cu(II) pairs (M=Cu, Ni and Mn). The magnitude of spin-exchange interactions in different metal pairs containing the same oxamido bridging ligand is preliminarily discussed.

Synthesis and crystal structure of oxo-bridged dimanganese(III) complex [MnIII(salpn)OH]2(CH3OH)(CH3CN)2

Abstract A dimanganese(III) complex [Mn(salpn)OH]2(CH3OH)(CH3CN)2 (1) has been synthesized and characterized structurally(salpn=N,N′-propanolbis(salcylideneiminato)dianion). The structure consists of centrosymmetric [Mn2(salpn)2(OH)2] molecules with each MnIII ion in a distorted octahedral environment: two nitrogen atoms and two oxygen atoms from the basal plane of Schiff-based ligand and two oxygen atoms from two hydroxides.

Heterobinuclear copper(II)–manganese(II) complexes behaving as three-dimensional supramolecular networks via both macrocyclic oxamido-bridges and hydrogen bonds

Two novel oxamido-bridged heterobinuclear copper(II)–manganese(II) complexes derived from macrocylic oxamido compounds incorporating different blocking ligands were synthesized and characterized by IR and electronic spectroscopy. They are of formula [Cu(L)Mn(phen)2](ClO4)2·1.5H2O (1) and [Cu(L)Mn(ntb)](ClO4)2·H2O (2), where L = 1,4,8,11-tetraazacyclotetradecane-2,3-dione, phen = 1,10-phenanthroline and ntb = tris(2-benzimidazolylmethyl)amine. The crystal structures of the two complexes have been determined and they consist of binuclear units in which the copper(II) ion is in a square-planar environment and linked to the manganese(II) ion via the exo–cis oxygen atoms of the oxamido macrocyclic ligand, with Cu⋯Mn separations of 5.421 (1) and 5.486 A (2), respectively. The packing of the molecules along the a orientation in 2 results in open channels, which were extended into a three-dimensional hydrogen-bonded supramolecular network. The temperature dependence of the magnetic susceptibility for 1 and 2 were analyzed by means of the Hamiltonian, Ĥ = −2JŜMnŜCu, leading to J = −14.2 and −14.7 cm−1 for 1 and 2, respectively.

Crystal structure of the addition compound of [Ni(meso-cth)][Cr(ox)2(bpy)](H2O)(ClO4) with weak coordination bonds and hydrogen bonds

A new ionic complex [Ni(meso-cth)][Cr(ox)2(bpy)](H2O)(ClO4) [meso-cth = meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, ox = oxalato ainon, bpy = 2,2′-bipyridine] was prepared and its structure was determined. The complex was found to crystallized in monoclinic space group P2(1)/n, with a = 13.6000(4) Å, b = 18.763(5) Å, c = 14.995(4) Å, β =106.958(5)°, V = 3659.9(17) Å3, and Z = 4. The structure consisted of cationic [Ni(meso-cth)]2+, anionic [Cr(ox)2(bpy)]−, and perchlorate anions; the cationic [Ni(meso-cth)]2+ and anionic [Cr(ox)2(bpy)]− units were related by weak coordination bonds and hydrogen bonds.