The incorporation of two different cyanide building blocks of [(Tp)Fe(CN)] and [Au(CN)] into one molecule afforded a novel hexanuclear [FeFeAu] complex (), in which the cyanide-bridged [FeFe] square was further grafted by two [Au(CN)] fragments as long arms in orientations. Complex undergoes a gradual spin crossover (SCO) ffrom low-spin (LS) to high-spin (HS) state for the Fe(II) centers upon desolvation. Remarkably, its desolvated phase () exhibits a reversible but atypical two-step (sharp-gradual) SCO behavior with considerable hysteresis (21 K). Variable-temperature single-crystal X-ray structural studies reveal that the hysteretic spin transition takes place synchronously with the concerted displacive motions of the molecules, representing another rare example including multistep and hysteretic spin transitions due to the synergetic SCO and structural phase transition.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/acs.inorgchem.2c00192 | DOI Listing |
Chemistry
December 2024
Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, 28040-, Madrid, Spain.
The synthesis and characterization of novel compounds (5-8) as mimetics of [FeFe]-hydrogenase, combining two distinct systems capable of participating in hydrogen evolution reactions (HER): the [(μ-adt)Fe(CO)] fragment and M-salen complexes (salen=N,N'-bis(salicylidene)ethylenediamine) (M=Zn, Ni, Fe, Mn), is reported. These complexes were synthesized in high yields via a three-step procedure from N,N'-bis(4-R-salicylidene)ethanediamine) 4 [R=Fe(CO)(μ-SCH)NCOCHO]. Structural analysis through spectroscopic, spectrometric, and computational (DFT) methods confirmed distorted tetrahedral and square-planar geometries for Zn-salen and Ni-salen complexes (5 and 6) respectively, while complexes Fe-salen 7 and Mn-salen 8 exhibit square-based pyramidal structures typical of Fe(III) and Mn(III) high-spin salen-complexes.
View Article and Find Full Text PDFJ Phys Condens Matter
August 2024
Dipartimento di Fisica, Universita' di Roma 'La Sapienza' - P. Aldo Moro 2, Roma, 00185, Italy.
We have investigated the local structure of the iron-based CaKFeAssuperconductor featuring distinct aliovalent substitutions at the Ca and K sites, that is CaKFeAs, CaKSrFeAs, CaKBaFeAsand CaNaKBaFeAs. Temperature-dependent Fe K-edge extended x-ray absorption fine structure (EXAFS) measurements are used to determine the near-neighbors bondlengths and their stiffness. The EXAFS analysis reveals that the Fe-As bondlength undergoes negligible changes by substitution, however, the Fe-Fe bondlength and the As height are affected by the Sr substitution.
View Article and Find Full Text PDFInorg Chem
October 2023
Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 20126 Milan, Italy.
The salt [K(18-crown-6)][Ru(CN)(CO)] ([K(18-crown-6)][]) was generated by the reaction of Ru(CH)(CO) with [K(18-crown-6)]CN. An initial thermal reaction gives [Ru(CN)(CO)], which, upon ultraviolet (UV) irradiation, reacts with a second equiv of CN. Protonation of [] gave [HRu(CN)(CO)] ([H]), which was isolated as a single isomer with mutually trans cyanide ligands.
View Article and Find Full Text PDFReaction of the nitrosylated-iron metallodithiolate ligand, paramagnetic (NO)Fe(NS), with [M(CHCN)][BF] salts (M = Ni, Pd, and Pt; = 4 or 6) affords di-radical tri-metallic complexes in a stairstep type arrangement ([FeMFe], M = Ni, Pd, and Pt), with the central group 10 metal held in a MS square plane. These isostructural compounds have nearly identical (NO) stretching values, isomer shifts, and electrochemical properties, but vary in their magnetic properties. Despite the intramolecular Fe⋯Fe distances of 6 Å, antiferromagnetic coupling is observed between {Fe(NO)} units as established by magnetic susceptibility, EPR, and DFT studies.
View Article and Find Full Text PDFInorg Chem
July 2023
Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia & INSTM, I-41125 Modena, Italy.
Oligo-α-pyridylamides offer an appealing route to polyiron complexes with short Fe-Fe separations and large room-temperature magnetic moments. A derivative of tris(2-aminoethyl)amine (Htren) containing three oligo-α-pyridylamine branches and 13 nitrogen donors (HL) reacts with [Fe(Mes)] to yield an organic nanocage built up by two tripodal ligands with interdigitated branches (HMes = mesitylene). The nanocage has crystallographic symmetry but hosts a remarkably unsymmetric hexairon-oxo core, with a central Fe(μ-O) square pyramid, two oxygen donors bridging basal sites, and an additional Fe center residing in one of the two tren-like pockets.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!