Synthesis, crystal structure and magnetic behavior of a linear trinuclear and an infinite chain mixed valence manganese(II,III) complex

• Published in: Inorganica Chimica Acta Vol. 257; no. 2; pp. 203 - 210
• Main Authors: Tan, Xiang Shi, Sun, Jie, Hu, Chun Hua, Fu, De Gang, Xiang, Dao Feng, Zheng, Pei Ju, Tang, Wen Xia
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.04.1997
• Subjects: Crystal structures; Magnetism; Manganese complexes; Mixed-valence complexes; Mixed-valence complexes; Crystal structures; Magnetism; Manganese complexes
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/S0020-1693(96)05476-X

Two mixed valence manganese(II,III) salicylate complexes [Mn 3(sal) 2(salH) 2(H 2O) 4(4-Me-py) 3][Mn(sal) 2(4-Me-py) 2]·2 (4-Mepy) ( 1) and [{Mn 2 (sal) 2(im) 2(CH 3OH) 4} n][Mn(sal) 2(py 2)] n ( 2), where H 2sal=salicylic acid, im=imidazole and py-pyridine, have been prepared and characterized by means of X-ray crystallography and magnetic measurements. Complex 1 crystallizes in the monoclinic system, space group C2/ c, with a = 36.737(4), b = 10.595(4), c = 28.041(5) A ̊ , β = 111.337(9)°, V = 10166(3) A ̊ 3 and Z=4, while 2 crystallizes in the triclinic system, space group P1, with a = 9.060(1), b = 10.238(2), c = 15.693(5) A ̊ , α = 103.07(2), β = 100.50(2), γ = 109.47(1)°, V = 1283.1(2) A ̊ 3 and Z = 1. The structures were solved by direct methods and refined by least-squares methods to R ( Rw) values of 0.046 (0.046) and 0.040 (0.042) for 1 and 2, respectively. The structure of 1 is composed of a linear trinuclear mixed valence manganese(II,III,II) cationic unit [Mn 3(sal) 2(sal H) 2(H 2O) 4(4-Me-py) 6] + with two bridging sal 2− ligands, a monomeric manganese(III) anionic unit [Mn(sal) 2(4-Me-py) 2] − and two 4-Me-py molecules. The structure of 2 consists of two distinct ionic units. One of them is a polymeric chain formed by the cationic unit [Mn 2(sal) 2(im) 2(CH 3OH) 4] +, and in the chain Mn(II) and Mn(III) ions are arranged alternately and bridged with sal 2− ligands. The other is a monomeric anionic unit [Mn(sal) 2(py 2)] −. All Mn ions of the structures are six-coordinate and each sal 2− group has a μ− η 3-sal bridging mode. The magnetic behavior of the two complexes shows that the salicylate carboxylate bridge mediates a weakly antiferromagnetic exchange interaction.