One-Dimensional Manganese Coordination Polymers Composed of Polynuclear Cluster Blocks and Polypyridyl Linkers: Structures and Properties

Abstract

The synthesis, crystal structures and magnetic properties of five new manganese compounds are reported. These include a linear trinuclear cluster [Mn(II)(3)(O(2)CCHMe(2))(6)(dpa)(2)].2MeCN (1) (dpa = 2,2'-dipyridylamine), a tetranuclear cluster [Mn(II)(2)Mn(III)(2)O(2)(O(2)CCMe(3))(6)(bpy)(2)] (3) (bpy = 2,2'-bipyridine), and chain coordination polymers composed of cluster blocks such as Mn(3), Mn(3)O, and Mn(4)O(2) bridged by 2,2'-bipyrimidine (bpm) or hexamethylentetramine (hmta) ligands to give ([Mn(II)(3)(O(2)CCHMe(2))(6)(bpm)].2EtOH)(n) (2), [Mn(II)(2)Mn(III)(2)O(2)(O(2)CCHMe(2))(6)(bpm)(EtOH)(4)](n) (4), and (([Mn(II)Mn(III)(2)O(O(2)CCHMe(2))(6)(hmta)(2)].EtOH)(n) (5). The magnetic analysis of the compounds was achieved using a combination of vector coupling and full-matrix diagonalization methods. Susceptibility data for compound 1 was fitted using a vector coupling model to give g = 2.02(1) and 2J/k(B) = -5.38(2) K. To model the trimer chain, we used vector coupling for initial values of J(1) and then diagonalization techniques to estimate J(2) to give g = 1.98(1), 2J(1)/k(B) = -3.3(1) K and 2J(2)/k(B) = -1.0(1) K by approximating the system to a dimer of trimers. The analysis of 3 was made difficult by the mixture of polymorphs and the difficulties of a three-J model, while for 4 an analysis was not possible because of the size of the computation and the relative magnitudes of the three couplings. Compound 5 was modeled using the same techniques as 2 to give g = 1.99(1), 2J(1)/k(B) = +32.5(2) K, 2J(2)/k(B) = -16.8(1) K, and 2J(3)/k(B) = +0.4(1) K. The combination of techniques has worked well for compounds 2 and 5 and thus opens up a method of modeling complex chains.

Iron(III)‐Pivalate‐Based Complexes with Tetranuclear {Fe4(μ3‐O)2}8+ Cores and N‐Donor Ligands: Formation of Cluster and Polymeric Architectures

“…The g value in this case was fixed to 2.00, which is reasonable in S = 5/2 ions due to the lack of appreciable spin-orbit coupling or zero-field splitting from the 6 A 1 ground state of the ion.…”

“…Recently, we have reported the synthesis and characterization of one-dimensional manganese chain coordination polymers composed of cluster blocks such as {Mn 3 }, {Mn 3 O}, and {Mn 4 O 2 } bridged by 2,2Ј-bipyrimidine (bpm) or hexamethylenetetramine (hmta) ligands to give {[Mn 3 (O 2 CCHMe 2 ) 6 6 (hmta) 2 ]· EtOH} n . [6] Thereby, using a combination of vector coupling and full-matrix diagonalization techniques, a good estimation of the intercluster coupling strength in the manganese coordination polymers between both linear {Mn 3 } cores and μ-oxo trinuclear {Mn 3 O} cores, and for which no model was previously reported, has been given.…”

“…[6] Thereby, using a combination of vector coupling and full-matrix diagonalization techniques, a good estimation of the intercluster coupling strength in the manganese coordination polymers between both linear {Mn 3 } cores and μ-oxo trinuclear {Mn 3 O} cores, and for which no model was previously reported, has been given. In continuation of this work, we extended our study on iron polynuclear carboxylate systems and present here the synthetic routes to a new butterfly-like [Fe 4 O 2 (O 2 CCMe 3 ) 8 6 ] units are linked by 1,5-dicyanamide (dca) ligands; [7] a helical polymer of Fe II centers that are linked through 6-chloro-1-pyridinol (Hchp) and acetate ligands in [Fe 9 (chp) 12.4 (O 2 CMe) 5.6 ] n ; [8] and a two-dimensional coordination polymer [Fe 10 O 4 (OMe) 14 Cl 4 (mcce)] (mcce = 2-carbamoyl-2-cyanoethanimidate) composed of antiferromagnetically coupled {Fe 10 } clusters. [9] Results and Discussion…”

Structure and magnetism of a porous three-dimensional metal-organic framework based on planar tetranuclear copper(II) cluster units

“…Recently, a breakthrough has been made by using polynuclear metal cluster units as secondary building units (SBUs) to construct highly porous metal-organic frameworks (MOFs) with good magnetic properties [7][8][9]. Polynuclear metal cluster units are promising candidates for the generation of molecular magnetic arrays [10][11][12][13][14]. Assembly of cluster units can offer a possible approach to resolve the antagonism between magnetism and porosity [15,16].…”

One-Dimensional Polymers Constructed with Paddle-Wheel Dinuclear Copper(II) Bridged by 4,4′-Bipyridine

“…Therefore, rational design and construction of new materials with specific networks has become a particularly important and topical subject. For assembly of supramolecular systems, polynuclear metal clusters have been widely used as secondary building units (SBU) [8][9][10]. Among them, polynuclear copper cluster are of especial interest due to their attracting structures as well as their potential applications in molecule-based magnet, multielectron redox processes, and catalysis [11].…”