Incorporation of guanidinium ions in CuII-[MV(CN)8]3− double-layered magnetic systems

Abstract

The incorporation of guanidinium ions (Hgua+) in Cu(II)–M(V) systems results in the formation of two isostructural coordination polymers (Hgua)Cu(II)[M(V)(CN)8], M = W (1); Mo (2), which reveal a double-layered structure separated by guanidinium ions. The magnetic measurements reveal long range magnetic ordering with critical temperatures of 32.8 and 27.5 K for 1 and 2, respectively. Moreover, both assemblies exhibit hysteresis loops with coercive fields of 300 Oe for 1 and 50 Oe for 2, and a spin-flip transition around 120 Oe.

Engineering of the XY Magnetic Layered System with Adeninium Cations: Monocrystalline Angle-Resolved Studies of Nonlinear Magnetic Susceptibility

“…The topological motif of the 2D cyanido-bridged network {Cu II [W V (CN) 8 ] − } n with four equatorial and one axial cyanido-bridged linkage was reproduced (Figure a). The Cu eq ···W distances (5.23–5.26 Å) are significantly shorter compared to the Cu ax ···W distance (5.44 Å), in a good agreement with the data shown previously. − The underlying bond lengths Cu–N eq (1.92–2.04 Å), Cu–N ax (2.129 Å), W–C (2.09–2.19 Å), and C–N (1.09–1.20 Å), and the relevant angles W–C–N (172.8–176.3°), Cu–N–C eq (167.4–175.3°) and Cu–N–C ax (177.4°) are in line with the recently investigated structural models. The directions of equatorial cyanido-bridges are oriented diagonally with respect to the crystallographic directions b and c , whereas the axial bridges are parallel to the direction a *.…”

“…The double-decker topological Prussian Blue Analogue (PBA) fragment is achieved due to a stereochemical matching between the square pyramidal (SPY-5) shape of Cu II moiety or octahedral shape of Mn II moiety, and the bicapped trigonal prism (BTRP-8) [W V (μ-CN) 5 (CN) 3 ] unit (Figure ). − Such double-decker fragments were previously put together by various cationic species: tetrenH 5 5+ (CuM′), dienH 3 3+ (CuM′), Cs + (CuW, CuMo), guanidinium (guaH + ) (CuM′), single Cu 2+ (CuMo,CuW), , and Mn 2+ (MnMo) complexes or polymeric 1D {Cu­(μ-pyz)} 2+ chains (CuM′) . The average interlayer distances varied between ca.…”

“…(a) The stereochemistry of the ideal square pyramid (SPY-5) polyhedron (left) almost ideally fits to the distribution of the relevant five out of eight cyanido ligands in a biaugmented trigonal prism polyhedron (representative also for bicapped trigonal prism) (BTRP-8) (right). (b) This allows to us construct the bilayered skeleton in a reproducible manner. − Some octahedral complexes might adopt this topology with an appropriate fine distortion as well. − Color and style scheme: pink, W; brick, Cu; pale gray; N, pale blue; sticks: bridging, CN – ; wireframe, terminal CN – . The arrows show a directionality of cyanido-bridges formation.…”

Synthesis of Two-Dimensional Photomagnetic K4{[CuII(ida)]2[MIV(CN)8]}·4H2O (MIV = Mo, W) Materials

“…In addition, the mechanisms of the photomagnetic effects in these compounds are still an element of the scientific debate. In this matter, there is general agreement on the independent and simultaneous occurrence of the MMCT and LIESST effects depending on the investigated system and experimental conditions. , At this point, it should also be noted that the research for octacyanidotungstate­(IV) is much less developed than for octacyanidomolybdate­(IV) compounds, although it can be more interesting due to the formation of a stronger magnetic coupling between photoinduced metastable state and 3d metals in the analogy to previous studies on Cu II –[M V (CN) 8 ] 3– systems …”