Thiocyanate-Ligated Heterobimetallic {PtM} Lantern Complexes Including a Ferromagnetically Coupled 1D Coordination Polymer

Abstract

A series of heterobimetallic lantern complexes with the central unit {PtM(SAc)4(NCS)} have been prepared and thoroughly characterized. The {Na(15C5)}[PtM(SAc)4(NCS)] series, 1 (Co), 2 (Ni), 3 (Zn), are discrete compounds in the solid state, whereas the {Na(12C4)2)}[PtM(SAc)4(NCS)] series, 4 (Co), 5 (Ni), 6 (Zn), and 7 (Mn), are ion-separated species. Compound 7 is the first {PtMn} lantern of any bridging ligand (carboxylate, amide, etc.). Monomeric 1-7 have M(2+), necessitating counter cations that have been prepared as {(15C5)Na}(+) and {(12C4)2Na}(+) variants, none of which form extended structures. In contrast, neutral [PtCr(tba)4(NCS)]∞ 8 forms a coordination polymer of {PtCr}(+) units linked by (NCS)(-) in a zigzag chain. All eight compounds have been thoroughly characterized and analyzed in comparison to a previously reported family of compounds. Crystal structures are presented for compounds 1-6 and 8, and solution magnetic susceptibility measurements are presented for compounds 1, 2, 4, 5, and 7. Further structural analysis of dimerized {PtM} units reinforces the empirical observation that greater charge density along the Pt-M vector leads to more Pt···Pt interactions in the solid state. Four structural classes, one new, of {MPt}···{PtM} units are presented. Solid state magnetic characterization of 8 reveals a ferromagnetic interaction in the {PtCr(NCS)} chain between the Cr centers of J/kB = 1.7(4) K.

Structural diversity in Cd(NCS)2-3-cyanopyridine coordination compounds: synthesis, crystal structures and thermal properties

“…In compound 3 one of the thiocyanate anions is disordered leading to a centrosymmetric Cd-(NCS) 2 -Cd pair, in which each Cd cation is coordinated by the S or N atom of this ligand. For this structure super structure reflections are observed that lead to a 4-fold larger triclinic unit cell with a = 13.8420 (8), b = 22.1948(15), c = 23.5542 (14) Å, α = 112.178(5), β = 93.435(5), γ = 97.248(5)° and V = 6601.7(8) Å 3 with Z = 16 and 9 crystallographically independent Cd cations. In this unit cell the disorder is reduced but still one Cd-(NCS) 2 -Cd pair is disordered.…”

“…several of them show spin crossover [1][2][3][4]. On the other hand, compounds with bridging thiocyanate anions are of importance because they can form dimers as well as 1D and 2D networks, in which significant magnetic exchange can be observed [5][6][7][8][9][10][11][12][13][14]. For the metal cations mentioned above the coordination to the sulfur atom of the anionic ligand is energetically unfavorable and therefore, such compounds are frequently difficult to synthesize from solution [15].…”

Thermodynamically stable and metastable coordination polymers synthesized from solution and the solid state

“…[29][30][31][32][33][34][35] This is a pity, especially because the bridging coordination is of interest, as it will lead to coordination polymers of different dimensionality, which is of special importance, e.g., for the synthesis of magnetic materials. [36][37][38][39][40][41][42][43] This is completely different for coordination polymers based on chalcophilic cations like CdIJII), which easily forms compounds with bridging thiocyanate anions. 44,45 However, if such compounds with terminally anionic ligands are heated, the coligands are often emitted in discrete steps, which enforces the formation of intermediates with condensed thiocyanate networks.…”

Crystal structure of octakis(4-methoxypyridinium) bis(4-methoxypyridine-κN)tetrakis(thiocyanato-κN)ferrate(III) bis[(4-methoxypyridine-κN)pentakis(thiocyanato-κN)ferrate(III)] hexakis(thiocyanato-κN)ferrate(III) with iron in three different octahedral coordination environments

“…In particular, compounds in which the paramagnetic metal cations are linked by small-sized anionic ligands that can mediate magnetic exchange are of special importance. For example, this can be achieved by thio-or selenocyanate anions that are able to coordinate to a central metal cation in different ways (Palion-Gazda et al, 2015;Guillet et al, 2016;Prananto et al, 2017). Most of the reported compounds contain terminally N-bonded thiocyanate ligands, whereas compounds with these ligands in a bridging mode are relatively rare.…”