353263-67-9Relevant academic research and scientific papers
Homo and heterometallic rhomb-like Ni4 and Mn2Ni 2 complexes
Modak, Ritwik,Sikdar, Yeasin,Mandal, Senjuti,Gómez-García, Carlos J.,Benmansour, Samia,Chatterjee, Sudipta,Goswami, Sanchita
, p. 155 - 163 (2014)
Two new polynuclear complexes with hydroxyl-rich Schiff base ligand 3-[(2-Hydroxy-benzylidene)-amino]-propane-1,2-diol (H3L), namely [NiII2(HL)(H2L)(SCN)]2·DMF (1) and [MnIII2NiII2(HL) 2(L)2] (2) have been synthesized and characterized by single crystal X-ray diffraction, elemental analyses, FTIR, UV-Vis spectroscopy and variable temperature magnetic susceptibility measurements. The X-ray refinements reveal that both compounds present defective rhomb-like dicubane central cores (Ni4 in 1 and Mn2Ni2 in 2). Magnetic susceptibility measurements indicate the presence of overall antiferromagnetic exchange interactions in 1 along the side connected by a N and O atoms (J1 = -43.6 cm-1) and along the short diagonal of the rhomb (J3 = -3.9 cm-1) and a weak ferromagnetic coupling (J2 = +5.8 cm-1) along the side of the rhomb connected by a double O-bridge. In 2 the three exchange interactions are negative (J1 = J2 = -0.3 cm-1 and J3 = -0.7 cm-1). A magneto-structural correlation with the ratio between the Ni-O-Mn bond angle and the Mn-O bond length is also discussed for double O-bridged Mn-Ni pairs.
Co-existence of ferro- and antiferromagnetic interactions in a hexanuclear mixed-valence Co III 2 Mn II 2 Mn IV 2 cluster sustained by a multidentate Schiff base ligand
Stetsiuk, Oleh,Synytsia, Valentyn,Petrusenko, Svitlana R.,Kokozay, Vladimir N.,El-Ghayoury, Abdelkrim,Cano, Joan,Lloret, Francesc,Julve, Miguel,Fleury, Benoit,Avarvari, Narcis
, p. 11862 - 11871 (2019)
The successful utilization of the direct synthesis approach yielded the unprecedented hexanuclear complex of formula [Co2MnII2MnIV2(L1)4Cl2(μ3-O)2(dmf)4]·2dmf (1) (H3L is the Schiff base derived from the condensation of salicylaldehyde and 3-aminopropane-1,2-diol). Single crystal X-ray analysis revealed that 1 crystallizes in the monoclinic system P21/c and it contains a rare mixed-valence {CoIII2MnII2MnIV2(μ2-O)8(μ3-O)2} core where all metal ions are linked through the phenolato and alkoxo groups of the L3- ligand. Besides the charge balance resulting from the X-ray structure, the oxidation state of the metal ions has been confirmed by XPS spectroscopy. Cryomagnetic studies indicate the coexistence of ferro- (MnIV-MnII, J2 = +1.10(3) cm-1, J3 = +2.19(3) cm-1; MnII-MnII, j = +0.283(3) cm-1) and antiferromagnetic interactions (MnIV-MnIV, J1 = -17.31(4) cm-1), with the six-coordinate CoIII ions being diamagnetic. DFT type calculations were carried out to substantiate these values. The energy diagram for the different spin states using the best-fit parameters shows the occurrence of six low-lying spin states (S = 0-5) which are close in energy but clearly separated from the remaining ones, with the ground spin state being S = 5. Complex 1 is found to be the first example where weak ferromagnetic exchange between MnII ions through the long -O-MnIV-O- pathway takes place.
