Macrocyclic complexes of nickel(II) as building blocks in the construction of dynamic molecular systems

Wykorzystując makrocykliczny kompleks [Ni(cyclam)]2+ (cyclam = 1,4,8,11-tetraazacyklotetradekan) oraz policyjanometalany zsyntetyzowano dwa nowe dynamiczne materiały molekularne: dwuwymiarową sieć [NiII(cyclam)]3[WV(CN)8]2∙solv (1c) oraz łańcuch molekularny (H3O)[NiIII(cyclam)][FeII(CN)6]∙5H2O (2), których właściwości sorpcyjne, spektroskopowe i magnetyczne zostały zbadane. Układ 1c jest nową formą sieci koordynacyjnych [Ni(cyclam)]3[WV(CN)8]2 o topologii plastra miodu, charakteryzującą się najwyższą temperaturą krytyczną Tc = 12 K pośród tej grupy związków. Zaobserwowane zostały przemiany strukturalne oraz towarzyszące im zmiany właściwości magnetycznych pod wpływem sorpcji i desorpcji cząsteczek gościa. Układ 2 jest rzadkim przykładem polimeru koordynacyjnego zawierającego jony Ni(III). Dla tego układu zaobserwowano przeniesienie ładunku między centrami metalicznymi, wywołane dehydratacją/ rehydratacją, wiążące się ze znacznymi zmianami właściwości magnetycznych i spektroskopowych. Warunki odwracalności tych procesów zostały wnikliwie zbadane.On the basis of a macrocyclic complex [Ni(cyclam)]2+ (cyclam = 1,4,8,11-tetraazacyclotetradecane) and polycyanometalates, two new dynamic molecular materials were synthesised: a 2D molecular network [NiII(cyclam)]3[WV(CN)8]2∙solv (1c) and a molecular chain (H3O)[NiIII(cyclam)][FeII(CN)6]∙5H2O (2), whose sorption, magnetic and spectroscopic properties were investigated. Compound 1c is a new form of [Ni(cyclam)]3[WV(CN)8]2 coordination network with honeycomb-like topology, with the highest critical temperature Tc = 12 K observed among different solvates of this compound. Structural transitions accompanied with changes of magnetic properties upon sorption/desorption of gest molecules were observed. Compound 2 is a rare example of a coordination polymer containing Ni(III) ions. For this system, charge transfer between metal centres induced by the dehydration/rehydration process was observed, which resulted in significant changes of spectroscopic and magnetic properties of the system. The conditions of reversibility of this process were thoroughly investigated

Modification of Structure and Magnetic Properties in Coordination Assemblies Based on [Cu(cyclam)]2+ and [W(CN)8]3−

The 1D {[CuII(cyclam)]3[WV(CN)8]2.5H2O}n (1·5H2O) (cyclam = 1,4,8,11-tetraazacyclotetradecane) coordination polymer of ladder topology can be obtained in water-alcohol solution from [Cu(cyclam)]2+ and [W(CN)8]3− building blocks. Upon dehydration, 1·5H2O undergoes a single-crystal-to-single-crystal structural transformation to the anhydrous {[CuII(cyclam)]3[WV(CN)8]2}n (1) form, which retains the same topology, but is characterized by shorter Cu-W distances and significantly more bent CN-bridges. The deformation of the coordination skeleton is reflected in magnetic properties: the predominant intra-chain interactions change from ferromagnetic in 1·5H2O to antiferromagnetic in 1. The reaction between the same building blocks in water solution under slow diffusion conditions leads to the formation of a 0D {[CuII(cyclam)(H2O)]2[CuII(cyclam)][WV(CN)8]2}.3H2O pentanuclear assembly (2·3H2O)

Cyclams with varied degree of protonation in the assemblies with cyano complexes of Mo and W

Five ionic assemblies of octacoordinated cyano complexes of molybdenum and tungsten with protonated cyclam (1,4,8,11-tetraazacyclotetradecane) and tmc (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetra- decane) have been obtained: (cyclamH 4 )[Mo IV (CN) 8 ] 1.5H 2 O( 1 ), (cyclamH 2 )(cyclamH 4 )[W V (CN) 8 ] 2 4H 2 O ( 2 ), (cyclamH 4 )[W V (CN) 8 ]Cl 4H 2 O( 3 ), (tmcH 4 )(tmcH 2 )[W V (CN) 8 ] 2 4H 2 O( 4 ) and (cyclamH 4 )[W IV (CN) 6 - (bpy)] 2 12H 2 O( 5 ) (bpy = 2,2 0 -bipyridine). The presence of 3d metal cations as a template led to partly protonated cyclams in 2 and 4 , where for the first time cyclam and tmc cations of different degree of pro- tonation are encountered within one structure. Compounds 2 , 3 and 5 crystallise in triclinic system space group P 1, while 4 crystallises in monoclinic system space group P 21/ c . Compound 1 shows the highest symmetry of the lattice: orthorombic system space group I 41/ a . Thermogravimetric analyses of 1 , 3 and 4 show the presence of stable anhydrous phase below 140° C

Connecting visible photoluminescence and slow magnetic relaxation in dysprosium(III) octacyanidorhenate(V) helices

Functional crystalline materials based on bimetallic cyanido-bridged {[DyIII(4-Mephen)­(dmf)4]­[MV(CN)8]}·0.5H2O (M = Re, 1; Mo, 2; W, 3; 4-Mephen = 4-methyl-1,10-phenanthroline) helices have been prepared. 1 is the first heterometallic coordination polymer incorporating an unexplored [ReV(CN)8]3– ion. Implementation of the ReV-based diamagnetic analogue of broadly investigated paramagnetic [MoV(CN)8]3– and [WV(CN)8]3– ions into the d–f coordination framework results in yellow photoluminescence originating from 4F9/2 → 6HJ f–f electronic transitions of DyIII sensitized by 4-Mephen, and field-induced slow magnetic relaxation related to the single-ion anisotropy of the dysprosium­(III) complexes. We prove that [ReV(CN)8]3– can work as a noninnocent metalloligand in the preparation of emissive 4f-metal-based single-molecule magnets

A photomagnetic sponge : high-temperature light-induced ferrimagnet controlled by water sorption

“Converting” light energy to magnetization is the attribute of molecule-based compounds called photomagnets and is inaccessible for conventional magnetic solids. The design and synthesis of such compounds, however, is a formidable challenge, and only a few examples are known, all with rather low magnetic ordering temperatures well below the boiling point of liquid nitrogen. Herein, a cyanide-bridged coordination polymer, {[MnII(imidazole)]2[WIV(CN)8]}n, exhibiting the highest light-induced magnetic ordering temperature ever observed and a magnetic hysteresis loop up to 90 K is reported. The photomagnetic effect results from the blue light excitation (450 nm) of the constituent octacyanotungstate­(IV) moiety, which then couples magnetically with manganese­(II), resulting in light-induced ferrimagnetic ordering. The reported coordination framework shows also outstanding water sorption properties that are strongly correlated with the photomagnetic functionality. The photoswitching observed in the anhydrous state is completely quenched by the reversible capture of water, with the fully hydrated phase becoming practically non-photomagnetic

New topology of CN-bridged clusters : dodecanuclear face-sharing defective cubes based on octacyanometallates(IV) and nickel(II) with diimine ligands

New dodecanuclear bimetallic Ni8M4 clusters were obtained in the reaction between octacyanometallates(IV), nickel(II) cations and diimine ligands. {[Ni(LL)(H2O)]2[Ni(LL)(H2O)2]6[M(CN)8]4} assemblies, where LL = 1,10-phenanthroline M = Mo, (1) or LL = 2,2′-bipyridine M = W (2) or Mo (3), are among the largest octacyanometallate-based clusters. They show the same compact topology of the cluster core, which can be described as defective face-sharing cubes with corners defined by alternating metal centres. The structures are stabilised by π–π interactions between aromatic rings of diimine ligands and hydrogen bonds connecting terminal CN groups and coordinated H2O molecules through a crystallisation solvent. Different decorating ligands cause different arrangements of clusters in the crystal structure. 1 crystallises in the triclinic system space group P[1 with combining macron], while 2 and 3 crystallise in the monoclinic system space group P21/n. The clusters show paramagnetic behaviour with weak antiferromagnetic interactions between the NiII centres through diamagnetic NC–MIV–CN linkages