Dimensionality controlled by light exposure: 1D versus 3D oxalate-bridged [CuFe] coordination polymers based on an [Fe(C₂O₄)₃]³⁻ metallotecton

Abstract

The studied heterometallic [CuFe] compounds, based on an [Fe(C2O4)3]3− building block and containing a 3D network or 1D ladder-like chains, were synthesized depending on whether the test tube with the same reaction layers was exposed to daylight or not.

Magnetic and Electrical Behaviors of the Homo- and Heterometallic 1D and 3D Coordination Polymers Based on the Partial Decomposition of the [Cr(C2O4)3]3− Building Block

“…The partial decomposition of the [Cr(C 2 O 4 ) 3 ] 3− anion enabled the release of the oxalate ligand from the coordination sphere of chromium(III), which was consequently coordinated to manganese(II) ions in the reaction mixture during the crystallization process, forming a 1D homometallic oxalate-bridged coordination polymer {[Mn(bpy)(C 2 O 4 )]·1.5H 2 O} n ( 1 ). This appearance in which the building block serves as a suitable, additional oxalate source has been recently observed for the tris(oxalato)metalate(III) precursors [ 26 , 27 ], bis(oxalato)chromate(III) [ 5 , 39 ] and oxotris(oxalato)niobate(V) [ 40 , 41 ].…”

“…This homodinuclear cation can be regarded as magnetically independent from the other magnetic centres, since a terminal oxalate oxygen atom from the Cr1–Cu3 chain coordinated to copper(II) ion of this dinuclear unit, does not provide the exchange bridging path. Such dimers usually have a strong antiferromagnetic interaction [ 26 , 27 , 56 , 57 ], so that the spin of a dimer is 0. Assuming that is the case here, the increase of as the temperature rises can be understood as the start of the decoupling of a dimer with very strong antiferromagnetic exchange intradimer interaction (few hundreds of Kelvins).…”

“…In this work, as a continuation of our magneto-structural studies about the oxalate-bridged polymers prepared by a building block approach [ 23 , 24 , 25 , 26 , 27 ], we report crystal structures, electrical and magnetic properties of novel oxalate-bridged coordination compounds: one-dimensional (1D) homometallic {[Mn(bpy)(C 2 O 4 )]·1.5H 2 O} n ( 1 ) and heterodimetallic {[CrCu 3 (bpy) 3 (CH 3 OH)(H 2 O)(C 2 O 4 ) 4 ][Cu(bpy)Cr(C 2 O 4 ) 3 ]·CH 2 Cl 2 ·CH 3 OH·H 2 O} n ( 2 ) polymers, and a three-dimensional (3D) heterotrimetallic {[CaCr 2 Cu 2 (phen) 4 (C 2 O 4 ) 6 ]·4CH 3 CN·2H 2 O} n ( 3 ) (1,10-phenanthroline) network. Structural diversity reflected on magnetic and electrical properties of these polymers, containing bpy or phen as an additional ligand, all prepared using same precursor [Cr(C 2 O 4 ) 3 ] 3− , has been investigated by single-crystal X-ray diffraction, infrared (IR) and impedance spectroscopies and magnetization measurements.…”

Sorption and Magnetic Properties of Oxalato-Based Trimetallic Open Framework Stabilized by Charge-Assisted Hydrogen Bonds

“…To limit dimensions of the formed compounds, additional auxiliary capping ligands are used [30,31] as well as crown ethers [10]. Ladder chain was detected in [Cu 2 (bpy) 2 (ox)Cr/Fe(ox) 3 ] − 1D compounds [4,32] and the interactions were described using 0D model and a single exchange parameter because of the dominating antiferromagnetic interactions in the copper dimer over other couplings. For the description of the magnetic properties of homo-and heterometallic oxalato-based chains, the Heisenberg model was often used with a single exchange parameter [30,33].…”

“…Parallel to the above mentioned works of Kanizaj et al [4,32] we aimed to prepare a trimetallic (Co-Fe-Cu) compound with oxalate anions acting as bridges starting with tris(oxalato)ferrate unit and bpy as a capping ligand. Oxalate anions also offer an opportunity to create a robust hydrogen bond network.…”