We present a comprehensive study of the synthesis, heat capacity, crystal structures, UV-vis-NIR and mid-IR spectra, DFT calculations, and magnetic and electrical properties of a one-dimensional (1D) rhodium(I)-semiquinonato complex, [Rh(3,6-DBSQ-4,5-(MeO)2)(CO)2]∞ (3), where 3,6-DBSQ-4,5-(MeO)2(•-) represents 3,6-di-tert-butyl-4,5-dimethoxy-1,2-benzosemiquinonato radical anion. The compound 3 comprises neutral 1D chains of complex molecules stacked in a staggered arrangement with short Rh-Rh distances of 3.0796(4) and 3.1045(4) Å at 226 K and exhibits unprecedented bistable multifunctionality with respect to its magnetic and conductive properties in the temperature range of 228-207 K. The observed bistability results from the thermal hysteresis across a first-order phase transition, and the transition accompanies the exchange of the interchain C-H···O hydrogen-bond partners between the semiquinonato ligands. The strong overlaps of the complex molecules lead to unusually strong ferromagnetic interactions in the low-temperature (LT) phase. Furthermore, the magnetic interactions in the 1D chain drastically change from strongly ferromagnetic in the LT phase to antiferromagnetic in the room-temperature (RT) phase with hysteresis. In addition, the compound 3 exhibits long-range antiferromagnetic ordering between the ferromagnetic chains and spontaneous magnetization because of spin canting (canted antiferromagnetism) at a transition temperature T(N) of 14.2 K. The electrical conductivity of 3 at 300 K is 4.8 × 10(-4) S cm(-1), which is relatively high despite Rh not being in a mixed-valence state. The temperature dependence of electrical resistivity also exhibits a clear hysteresis across the first-order phase transition. Furthermore, the ferromagnetic LT phase can be easily stabilized up to RT by the application of a relatively weak applied pressure of 1.4 kbar, which reflects the bistable characteristics and demonstrates the simultaneous control of multifunctionality through external perturbation.

The metalloporphyrins serves as models for the active sites and formed of a heme (protoporphyrinIX of iron(II)). The porphyrin complex of iron(III) present an anionic ligand, this new complex is not known in the literature.The preparation and characterization of the (oxalato) complex is described. The synthesis procedure utilizes the crown(18-C-6) to solubilize potassium oxalate. This compound has been characterized by UV-vis, IR and 1 H NMR spectroscopies. In electronic spectroscopie, our derivative presents a strip of Soret to 415 nm and a strip to 509 nm. These values are very near of those of the porphyrins iron(III) complex to high-spin (S = 5/2). The IR data show the existence of two epaulements 1672 cm -1 and 1664 cm -1 that one can assign to the ν1(C=O) and a second 1385 cm -1 assigned to the ν2(C-O) vibration of the ligand oxalate [1]. Many works of the 1 H NMR on porphyrins iron(III) complex show that in the case of the méso-porphyrins, the protons β-pyrrolic is very sensitive to the state of spin of the iron(III) [2]. The 1 H NMR is a spectroscopic method of choice to determine the state of spin of the complex of iron(III) [2]. The derivatives of iron(III) high-spin (S = 5/2) with the méso-porphyrins present in 1 H NMR spectroscopie of the proton of the resonance peaks β-pyrrolic a lot of deblind ([70,100]ppm). Proton NMR data for the isolated product is in accordance with high-spin (S = 5/2) ferric porphyrin species. The X-ray molecular structure of this species has been also determined. The iron atom is hexa-coordinated by the four nitrogen atoms of the pyrrol rings and the two oxygen atoms of the ligand group. 1 these isomers possess very d i ff e r e n t C u -C u a n d O -O distances. Whereas resonance Raman spectra indicate that both are present in solution, the X-Ray data describe an average of both forms that exist as a solid solution. EXAFS data in support of this conclusion and the ability of single-crystal diffraction studies to adequately differentiate the side-on peroxo from the bis-μ-oxo species are discussed. Additionally, the techniques used to prepare the sample at low-temperatures for the diffraction experiment are described. A new complex CH3NH3[(C6H6O7)2B] (I) has been synthesized and its X-ray investigation has been carried out in order to extend the investigations of bis(citrato)borate structures containing alkylammonium cations LH + [(C6H6O7)2B] nH2O, L = (CH3)2NH (II), L = (C2H5)2NH (III), L = (C2H5)3N, n = 1 (IV). In the crystals I the spiran-type complex anion are formed by two citric acid molecule residues coordinated to the BO4 tetrahedron. The bonds B O(carb.) (av. 1.492(2) Å) are longer than bonds B O(hydr.) (av.