The Phosphinate Group in the Formation of 2D Coordination Polymer with Sm(III) Nodes: X-ray Structural, Electrochemical and Mössbauer Study

Abstract

A coordination polymer has been synthesized using ferrocene-based ligand-bearing phosphinic groups of 1,1′-ferrocene-diyl-bis(H-phosphinic acid)), and samarium (III). The coordination polymer’s structure was studied by both single-crystal and powder XRD, TG, IR, and Raman analyses. For the first time, the Mössbauer effect studies were performed on ferrocenyl phosphinate and the polymer based on it. Additionally, the obtained polymer was studied by the method of cyclic and differential pulse voltammetry. It is shown that it has the most positive potential known among ferrocenyl phosphinate-based coordination polymers and metal–organic frameworks. Using the values of the oxidation potential, the polymer was oxidized and the ESR method verified the oxidized Fe(III) form in the solid state. Additionally, the effect of the size of the phosphorus atom substituent of the phosphinate group on the dimension of the resulting coordination compounds is shown.

Influence of the Substituent’s Size in the Phosphinate Group on the Conformational Possibilities of Ferrocenylbisphosphinic Acids in the Design of Coordination Polymers and Metal–Organic Frameworks

“…However, in the case of lanthanides, a crystalline structure of a 2D polymer was obtained. It has been established that heating a mixture of acid 1 and Sm(III) chloride in water up to 100 °C leads to the formation of a layered two-dimensional coordination polymer 8a ( Scheme S1 ) [ 60 ].…”

“…However, in the case of lanthanides, a crystalline structure of a 2D polymer was obtained. It has been established that heating a mixture of acid 1 and Sm(III) chloride in water up to 100 • C leads to the formation of a layered two-dimensional coordination polymer 8a (Scheme S1)[60].According to the data of X-ray structural analysis, compound 8a contains two different types of ligands in eclipsed conformations characterized by torsion angles of 71 • and 75.4 • , respectively. One type of ligand binds two samarium ions, forming an eight-membered cycle, while the other participates in stitching such cycles together through a bridging OPO bond, forming a two-dimensional structure (Figure8).…”

Effect of Phosphorus Substitution in the Cyclopentadienyl Ring of Ferrocene: Combined Mössbauer Spectroscopy and DFT Studies

“…Based on the polarized Mössbauer absorption studies, features in the low-temperature λ point were examined . Moreover, the effect of substitution in the cyclopentadienyl rings of both CH-groups by nitrogen, phosphorus, and hydrogen atoms by various radicals was studied using Mössbauer spectroscopy. − Currently, this method is still actively used to characterize ferrocene-related compounds. − …”

Evidence of extremely short hydrogen bond in the homoconjugated ferrocene-1,1′-diyl-bisphosphinic acid anion: sign change of the H/D isotope effect on the 31P NMR chemical shift

“…[17][18][19] Besides, the conformational manifold of intra-and intermolecular hydrogen bonding patterns of Fc(P(R)OOH) 2 in conjunction with the substituent size in the phosphinate group have proven to be paramount for the coordination properties of Fc(P(R)OOH) 2 in novel coordination polymers and metal-organic frameworks with tunable optical, magnetic and redox properties. [20][21][22][23][24] Separate interest is drawn toward H-bonded complexes formed solely by Fc(P(R)OOH) 2 . Along with other phosphorus-containing acids (phosphinic, phosphonic and phosphoric), Fc(P(R)OOH) 2 species possess both proton-donating POH and proton-accepting PQO moieties and are therefore inherently capable of forming H-bonded complexes of two types: electroneutral self-associates [25][26][27] and homoconjugated anions, [28][29][30] i.e.…”