New Silver(I) Coordination Polymer with Fe4 Single-Molecule Magnets as Long Spacer

Abstract

In continuation of our work on supramolecular architectures of single-molecule magnets (SMMs) as a promising strategy in developing their magnetic performance, in this paper we report the synthesis and single crystal X-ray structure of the centered triangular tetrairon(III) SMM, [Fe4(PhpPy)2(dpm)6], Fe4 (Hdpm = dipivaloylmethane, H3PhpPy = 2-(hydroxymethyl)-2-(4-(pyridine-4-yl)phenyl)propane-1,3-diol), and its assembly in the coordination polymer {[Fe4(PhpPy)2(dpm)6Ag](ClO4)}n, Fe4Ag, upon reaction with silver(I) perchlorate. Thanks to the presence of the pyridyl rings on the two tripodal ligands, Fe4 behaves as divergent ditopic linker, and due to the Fe4:AgClO4 1:1 ratio, Fe4Ag probably possesses a linear arrangement in which silver(I) ions are linearly coordinated by two nitrogen atoms, forming 1D chains whose positive charge is balanced by the perchlorate anions. The stabilization of such a polymeric structure can be ascribed to the long distance between the two donor nitrogen atoms (23.4 Å) and their donor power. Fe4Ag shows slow relaxation of the magnetization which follows a thermally activated process with Ueff/kB = 11.17(18) K, τ0 = 2.24(17) 10−7 s in zero field, and Ueff/kB = 14.49(5) K, τ0 = 3.88(8) 10−7 s in 1-kOe applied field, in line with what reported for tetrairon(III) SMMs acting as building blocks in polymeric structures.

Stoichiometrically Controlled Assembly of Lanthanide Molecular Complexes of the Heteroditopic Divergent Ligand 4′-(4-Pyridyl)-2,2′:6′,2″-terpyridine N-Oxide in Hypodentate or Bridging Coordination Modes. Structural, Magnetic, and Photoluminescence Studies

“…One of the most relevant contributions that ditopic organic ligands introduced into the field of molecular magnetism is the possibility of preparing the so-called single-chain magnets (SCMs), one-dimensional coordination polymers featuring significant intrachain magnetic interactions among anisotropic spin bearers but negligible interactions among the different chains, that can present an opening of the magnetic hysteresis loop at cryogenic temperatures . Moreover, the use of divergent organic ligands has been envisaged as promising for the preparation of ordered structures of SMMs with modulable magnetic properties, , and heterotopic ligands have been used to couple SMM units in one-dimensional − or three-dimensional coordination polymeric networks. Moving to discrete molecular entities, we found a coordination chemistry bottom-up approach has been used to induce a weak magnetic bias between different paramagnetic centers in SMMs, slowing their dynamics, to prepare polymetallic grids, to increase the number of addressable states in molecular candidates as qbits, or in a molecular switch, allowing movement from two to three available states within a single molecular entity …”

Nanostructures as the Substrate for Single-Molecule Magnet Deposition

“…In addition to the above-mentioned most prominent examples of varieties of iron-based molecular magnets, other mentionable examples are: [Fe 4 (acac) 6 (Br-mp) 2 ] [ 69 ], Fe 4 C 3-5 SAc [ 70 ], [Fe 4 (Ph–C (CH 2 O) 3 ) 2 (dpm) 6 ] [ 71 ], or [Fe 4 (PhpPy) 2 (dpm) 6 ] [ 72 ]. Quite a few more can be found in the literature [ 12 , 73 , 74 ].…”

Synthesis, X-ray Structures and Hirshfeld Analysis of Two Novel Thiocyanate-Bridged Ag(I) Coordination Polymers

“…Moreover, 8% of all the CPs (1D-3D) in the MOF subset are Ag-CPs [37]. These materials were found to exhibit fascinating structural motifs [21,[38][39][40] and intriguing properties, including electrical conductivity [41,42], photoluminescence [27,43], guest exchange and sorption [44,45], magnetism [46,47], catalysis [48,49], antitumor [50] as well as antibacterial activities [51]. More recently, Ag(I) compounds with N-heterocyclic ligands have been reported to show more cytotoxic action than cis-platin against tested cancer cell lines [52].…”