An Exotic Layered Compound Consisting of Interconnected Arsenato‐Polyoxovanadate Clusters: Thermal and Magnetic Properties and Liquid Phase Exfoliation

Abstract

The compound {[Mn(teta)]4V16As4O42(H2O)}n ⋅ 10 H2O (teta=triethylenetetraamine) was synthesized under solvothermal conditions. The crystal structure consists of layers composed of {V16As4O42} moieties joined by O−Mn−O bridges. The crystal water molecules can be thermally removed and they are reintegrated in humid atmosphere. The water sorption occurs in two steps indicating differing strengths of hydrogen bonding interactions. Investigations of the magnetic properties present evidence that the antiferromagnetic exchange interactions between the spins of the Mn2+ and of the V4+ cations are relatively strong. The magnetocaloric effect could be observed but is relatively small due to the antiferromagnetic exchange. Using liquid phase exfoliation, small crystallites with thicknesses as low as 10 nm could be obtained, while larger crystallites exhibit thicknesses of 20–40 nm.

The Coordination Polymer Cr(en)2As2VO7 Consisting of Alternating VO4 Tetrahedra and As2O5 Handles Decorated by Cr3+ Centered Complexes

“…New cluster types like in e. g. [H 3 KV 12 As 3 O 39 (AsO 4 )] 6− , [3] [V 12 As 8 O 40 (HCO 2 )] 3− , [4] [V 16 As 4 O 42 ] 8− , [5] [V 14 As 8 O 42 (SO 3 )] 6− , [6] or [As 8 V 6 O 26 ] 4−[7] increased the structural and chemical variety of As‐POVs. The chemistry could be further enhanced by e. g. decoration of the cluster anions by transition metal complexes [8–16] or by integration of transition metal cations into the cluster shell [17,18] . The latter cluster modification was also reported for a variety of POVs [19] .…”

Mn2+ substitution within the {V14As8} polyoxovanadate archetype results in {Mn2V12As8} shells with trans‐positioned heterometal positions

“…[13] In the crystal structures of these compounds the cluster anions and cations are either isolated, or cluster shells are joined (or expanded) by transition metal cation-centered complexes. [14][15][16][17][18][19][20][21][22] Additional structural mod-ification is achieved by integration of transition metal cations like Zn 2+ or Cd 2 + into the As-POV cluster shell. [23][24][25][26][27] In the structure of these compounds one or two V centers of the {V 14 As 8 O 42 } moiety are substituted by either Zn 2 + or Cd 2+ .…”

“…[28] Most As-POVs containing transition metal cations were synthesized with Co 2 + , Ni 2 + , Zn 2 + or Cd 2+ while only one As-POV with incorporated Mn 2 + was reported until now. [22] Hence, we systematically investigated the MnÀ AsÀ V-dien reaction system and isolated the new cluster-based coordination network compound [Mn 4 V 12 As 8 O 40 (dien) 4 H 2 O] • 3.5H 2 O under solvothermal conditions, featuring the first As-POV with Mn 2 + as an integral constituent of the cluster shell. Moreover, the central cluster moiety {Mn 2 V 12 As 8 } is further expanded by Mn 2 + complexes, leading finally to a layered crystal structure.…”

“…[29] Two of the four unique Mn S2), and are in the range reported for [Mn(dien) 2 ] 2 + containing compounds. [22,[30][31][32][33][34][35][36][37][38][39] The NÀ MnÀ N, NÀ MnÀ O and OÀ MnÀ O angles (Table S2) indicate significant distortions compared to regular polyhedra with coordination number six. Forced by the integration of Mn1 and Mn2 into the structure of the As-POV cluster shell, the polyhedra around both cations contain four O atoms forming a distorted rectangular plane, and one N and one O atom located above the plane leads to formation of an oblique triangular prism with one triangle comprising three O 2À ligands and the other consisting of two O and one N atom.…”

“…In the following years the chemistry of high‐nuclearity As‐POVs was systematically developed by isolation and characterization of cluster anions with different compositions like [V 14 AsO 40 ] 7− , [2] [V 10 AsO 26 (H 2 O)] ⋅ 8H 2 O, [3] [V 5 As 2 O 19 ] 4− , [4] [V 12 As 3 O 42 ] 15− , [5] [V 16 As 4 O 42 (H 2 O)] 8− , [6] [H 3 V 12 As 4 O 43 ] 8− , [7] [V 15 As 6 O 51 ] ∞ 9− , [8] [V 12 As 8 O 40 (HCO 2 )] 3− , [9] [V 12 As 8 O 40 (H 2 O)] 4− , [10] [V 14 As 8 O 42 (H 2 O) 0.5 ] 4− , [11,12] [V 6 As 8 O 26 ] 4− [13] . In the crystal structures of these compounds the cluster anions and cations are either isolated, or cluster shells are joined (or expanded) by transition metal cation‐centered complexes [14–22] . Additional structural modification is achieved by integration of transition metal cations like Zn 2+ or Cd 2+ into the As‐POV cluster shell [23–27] .…”