Versatility in the Coordination Modes of n‐Chlorobenzoato Ligands: Synthesis, Structure and Magnetic Properties of Three Types of Polynuclear Mn^II Compounds

Abstract

Three different types of polynuclear manganese(II) compounds with chlorobenzoato bridges were obtained from the reaction of Mn(n-ClC 6 H 4 COO) 2 with 1,10-phenanthroline (phen): three trinuclear compounds [Mn 3 (µ-n-ClC 6 H 4 COO) 6 -(phen) 2 ] with n = 2, 3, 4 (1-3), one one-dimensional system [Mn(µ-3-ClC 6 H 4 COO) 2 (phen)] n (4) and one neutral dinuclear compound [{Mn(4-ClC 6 H 4 COO)(phen)} 2 (µ-4-ClC 6 H 4 COO) 2 -(µ-H 2 O)] (5). Compounds 1, 3, 4 and 5 were characterized by X-ray diffraction and show four different coordination modes for the carboxylate ligand: as a bidentate bridge in a syn-syn mode or syn-anti mode, as a monodentate bridge and as a terminal monodentate ligand. The five compounds show weak antiferromagnetic coupling; the J values are -2

Two new carboxylate–oxygen bridged trinuclear M(II) (MMn and Co) compounds with zwitterionic dicarboxylate ligands: crystal structures and magnetism

“…In the previous related reports, we note that although a dozen of compounds with similar bridges were characterized structurally and magnetically, no unambiguous correlations were found between the structural parameters (such as Mn-O bridge -Mn angles and the bond parameters of the syn-syn carboxyalte bridges) and the J values due to the complexity arising from the coexistence of mixed oxygen and carboxylate bridges, the presence of unpaired five electrons per Mn(II) and the effects of the terminal ligands. Compound 1 shows a relatively weaker interaction than the previous compounds which may be accounted for the longer Mn-O bridge distance (2.37 Å, 2.49 Å) and the Mn⋯Mn distance (3.69 Å, 3.76 Å) spanned by the mixed bridges than those (2.18-2.33 Å for Mn-O bridge and 3.43-3.69 Å for Mn⋯Mn distance) for the previous reported compounds [23][24][25][26][36][37][38][39].…”

Determination of ZFS parameters from the EPR spectra of mono-, di- and trinuclear MnIIcomplexes: impact of magnetic coupling

“…25 The reaction between Mn II carboxylate and bidentate ligands (NN), such as 2,2′-bipyridine (bpy) and 1,10-phenanthroline ( phen), leads to the formation of Mn II compounds with different nuclearity: mononuclear, dinuclear, trinuclear, or 1D systems. 26,27 The carboxylate groups display a wide variety of coordination modes, such as monodentate terminal, chelating, bidentate bridging, and monodentate bridging modes. Particularly in these compounds, the carboxylate ligands could bridge the Mn II ions in µ 1,1 or µ 1,3 coordination modes, and in the latter case in either a syn-syn or syn-anti conformation.…”

Synthesis and Characterization of a Linear [Mn3(O2CMe)4(py)8]2+ Complex

“…The obtained J value is smaller than values reported in the literature for other linear Mn II 3 clusters with three bridging ligands per manganese pair which in most cases range from ~−2.5 to ~−7 K [18]. This behaviour could be rationalized on the basis of the existence of only two bridging ligands per manganese pair and larger Mn⋯Mn separations in 1 as was discussed in detail above (description of the structures).…”