Guest Driven Structural Correlations in DPDS [Di(4-pyridyl)disulfide]-Based Coordination Polymers

Abstract

Three novel coordination polymers have been obtained by the reaction of M(NO 3 ) 2 ·6H 2 O (M = Mn II and Co II ) or FeCl 2 ·4H 2 O with KNCS and DPDS [di(4-pyridyl)disulfi de] l igand, [Mn-(NCS) 2 (DPDS) 2 ] 2 ·DPDS·H 2 O (1), [Fe(NCS) 2 (DPDS) 2 ]·3H 2 O (2), and [Co(NCS) 2 (DPDS) 2 ]·2H 2 O (3). The three complexes exhibit infinite linear chain structures, where the metal ions are connected by double N,N′-DPDS bridges, that are further connected through hydrogen bonding to give pseudo-3D structures which contain channels where solvent and/or free DPDS molecules are located. The number and type of these guest molecules will have a determining influence in the final crystal system and space groups adopted for every compound obtained, which will be analyzed. H-bonding promotes interpenetrated 3D networks in 1− 3. Characterization by IR, UV−vis, X-ray diffraction, ESR spectroscopy, and magnetic measurements is developed. Slight antiferromagnetic interactions are observed, essentially in the Fe(II) and Co(II) compounds, that are associated with the double DPDS bridges. ■ INTRODUCTIONThe quick development in the very recent years of the research on the formerly known 4,4′-dipyridine type of ligands is related to their use in very important present fields of investigation, such as metal organic frameworks (MOFs), 1 coordination polymers (CPs), 2 spin crossover (SCO) systems, 3 and others. These ligands are well-known to be excellent different-size spacers in order to connect chains or sheets, increasing their dimensionality, increasing the structural flexibility, and generating voids of a quadrangular type. The 4,4′-relative position of the N donor atoms provides the extension of these polymers, with the rigidity being a limiting factor for a selfassembly strategy. The design and synthesis of coordination polymers are of great interest for crystal engineering. The structural motifs in the CPs range from zero to threedimensional, and their infinite network topologies are interesting for the development of host−guest functional materials such as multiferroics, 4 since many of these types of compounds present some kind of magnetic ordering. In particular, porous MOFs are increasingly being studied for potential storage of different kinds of molecules. 5 Structures and, therefore, the properties of these materials may be controlled by choosing appropriate bridging ligands and metal ions.Among this kind of ligands, one of the less studied groups is that where the extreme pyridine rings are connected through sulfur atoms. In particular, the di(4-pyridyl)disulfide (DPDS) ligand 6 has an intermediate rigidity associated with the S−S bond, allowing a characteristic twisted shape and giving rise, in combination with the geometry of the metal ion, to a structural diversity of coordination polymers. This ligand also possesses two enantiomer forms (M and P) and even has potential biological applications in their broken conformations. 7 Furthermore, the DPDS ligand is known to transform in the DPS (di(4-pyridyl)sulfide) one and ot...

Porous Metal–Organic Frameworks Containing Reversible Disulfide Linkages as Cathode Materials for Lithium‐Ion Batteries

“…The structure of 1 D‐DS‐Co‐MOF ( M w =652 g mol −1 , Figure (a)) featured a one‐dimensional chain parallel to the c ‐axis and comprising Co 2+ ions, monodentate NCS ligands in the equatorial position, and bidentate 4dpds ligands in the axial position . The chain formed a unit cell with eight H 2 O molecules per pore, attributable to hydrogen bonding between the pyridine moieties of 4dpds and NCS ligands, whereas PLATON calculations on crystal structures after solvent removal suggested that the pore size equaled 452 Å 3 per unit cell volume or 15 % of the total crystal volume.…”

“…Herein, we report the relationship between the structural characteristics and battery performance of DS‐MOFs featuring diverse structures and containing various disulfide ligands with flexible S−S bonds. In particular, we focus on the relationships between (1) porosity and battery capacity, and (2) structural dimensionality (1 D, 2 D, and 3 D) and cycling performance, by using three porous DS‐MOFs, namely 1 D‐DS‐Co‐MOF ([Co(NCS) 2 (4dpds) 2 ] ⋅ 2 H 2 O), 2 D‐DS‐Cu‐MOF ([Cu(C 2 O 4 ) 2 (4dpds)] ⋅ 6 H 2 O), 3 D‐DS‐Mn‐MOF ([Mn 2 (H 2 O) 2 (6dtna) 2 ] ⋅ 4 CH 3 OH ⋅ H 2 O), and two nonporous coordination polymers (DS‐CPs), viz. 1 D‐DS‐Cu‐CP ([Cu 4 (HCO 2 ) 6 (OH) 2 (4dpds) 2 ] ⋅ 2 CH 2 Cl 2 ) and 3 D‐DS‐Mn‐CP ([Mn 5 (OH) 2 (2 Dtba) 4 ]) …”

Cover Feature: Porous Metal–Organic Frameworks Containing Reversible Disulfide Linkages as Cathode Materials for Lithium‐Ion Batteries (ChemSusChem 9/2020)

“…The structure of 1D-DS-Co-MOF (M w = 652 gmol À1 ,F igure 1(a)) featured ao ne-dimensional chain parallel to the caxis and comprising Co 2 + ions, monodentate NCS ligands in the equatorial position, and bidentate 4dpds ligandsi nt he axial position. [29] The chain formed au nit cell with eight H 2 O molecules per pore, attributable to hydrogen bonding between the pyridine moieties of 4dpds and NCS ligands, where-as PLATON calculations [35] on crystal structures after solventr emovals uggested that the pore size equaled 452 3 per unit cell volumeo r15 %o ft he total crystal volume. To utilize these pores for electrolyte ion intercalation, we evaporated guest molecules under vacuum.T GA ( Figure S1 (a) in the Supporting Information) revealed that compared with the vacuum-dried sample, the as-prepared one showeda3.1 %w eightl oss at 40-150 8C, whereas PXRD analysisd emonstrated that the MOF structure wasretained after vacuum-drying ( Figure S1 (b) in the Supporting Information).…”

“…1D-DS-Co-MOF ([Co(NCS) 2 (4dpds) 2 ]·2 H 2 O): [29] An aqueous solution (10.0 mL) of KNCS (1.00 mmol) and Co(NO 3 ) 2 ·6H 2 O( 0.250 mmol) was added to methanolic 4dpds (0.250 mmol, 10.0 mL) to afford a pink precipitate, which was washed with deionized water (5 3mL).…”

“…Herein, we report the relationship between the structural characteristics and battery performanceo fD S-MOFs featuring diverses tructures andc ontaining various disulfide ligands with flexible SÀSb onds. In particular, we focus on the relationships between (1) porosity and battery capacity,a nd (2) structural dimensionality (1 D, 2D,a nd 3D)a nd cycling performance, by using three porous DS-MOFs, namely 1D-DS-Co-MOF ([Co(NCS) 2 (4dpds) 2 ]·2H 2 O), [29] 2D-DS-Cu-MOF ([Cu-(C 2 O 4 ) 2 (4dpds)]·6H 2 O), [30] [31] andt wo nonporous coordination polymers (DS-CPs), viz. 1D-DS-Cu-CP ([Cu 4 (HCO 2 ) 6 (OH) 2 (4dpds) 2 ]· 2CH 2 Cl 2 ) [32] and 3D-DS-Mn-CP ([Mn 5 (OH) 2 (2 Dtba) 4 ]).…”