Quasi-1D chains of dinickel lantern complexes and their magnetic properties

Abstract

Four new quasi-1D Ni-lantern chain complexes of the form [Ni(SOCR)(L)] (R = Ph, L = DABCO (1); R = Ph, L = pyz (2); R = CH, L = DABCO (3); R = CH, L = pyz (4)) were prepared from the reaction of [Ni(SOCR)(EtOH)], R = CH or Ph, with the N,N'-donor bridging ligands pyrazine (pyz) or 1,4-diazabicyclo[2.2.2]octane (DABCO). Reaction of [Ni(tba)(EtOH)], (tba = thiobenzoate) with the mono-N donor ligand quinuclidine (quin) gave the discrete Ni-lantern complex [Ni(tba)(quin)] (5), whereas reaction with pyridine led to fragmentation of the lantern and formation of the known [Ni(tba)(py)] (6). Single-crystal X-ray diffraction reveals 2-4 to be 1D chain complexes comprising DABCO or pyz ligands which bridge the Ni-lantern units. Complex 5 forms dimers through two equivalent NiS interactions. The Ni-Ni distances within the Ni-lanterns are 2.5316(18)-2.595(2) Å for the 1D chain complexes 2-4, and 2.5746(4) Å in the dimeric complex 5, respectively. Comparing the solid state magnetism of 5 to precursor [Ni(tba)(EtOH)] demonstrates a change in coupling upon change of capping ligand. Meanwhile, chains 1-4 exhibit magnetic properties consistent with an S = 1 system, due to a mixed valent system where the two Ni centers differ in spin state, while 5 possesses two S = 1 Ni(ii) centers. DFT calculations confirm low-spin S = 0 {NiS} and high-spin S = 1 {NiO} centers in each lantern. Fits to the magnetic susceptibility data of the chains suggest a weak antiferromagnetic mean field interaction is present that is largely 1-D in nature, though neither pyrazine nor DABCO promote significant magnetic interaction between neighboring Ni-lanterns.

Perfect Spin Filtering in Homobimetallic Ni Complex with High Tolerance to Structural Changes

“…In the present structural model, the transition metal in each lantern unit has a different coordination environment (see Figure 1), which leads to d-oribital energy levels of Ni(II) ions in two lantern units split in different manners, as shown in Figure 3. The [NiO 4 ] and [NiS 4 ] planes of the structures A and B are twisted about the Ni−Ni axis by 15.76°and 12.77°, respectively, which is slightly smaller than the experimental values reported by Doerrer et al 37 However, the Ni−Ni distances in optimized structure A were 0.770 and 0.764 Å larger than that in the experimental products ([Ni 2 (tba) 4 (EtOH)] and [Ni 2 (SAc) 4 (EtOH)]). 37 These difference can be ascribed to two reasons: One is a slight steric effect between coordinated Ni planes arising from the absence of substituted groups in thioformic acid backbone ligands.…”

“…The [NiO 4 ] and [NiS 4 ] planes of the structures A and B are twisted about the Ni−Ni axis by 15.76°and 12.77°, respectively, which is slightly smaller than the experimental values reported by Doerrer et al 37 However, the Ni−Ni distances in optimized structure A were 0.770 and 0.764 Å larger than that in the experimental products ([Ni 2 (tba) 4 (EtOH)] and [Ni 2 (SAc) 4 (EtOH)]). 37 These difference can be ascribed to two reasons: One is a slight steric effect between coordinated Ni planes arising from the absence of substituted groups in thioformic acid backbone ligands. On the other hand, axial ligands in our model and experimental complexes have different coordination bonding characters.…”

“…Comparing the solid-state magnetism of various dinickel lantern complexes, Doerrer et al found a change in coupling upon change of axial ligand. Dinickel lantern complex belongs to a mixed valence system, which possesses two Ni centers with different spin states, S = 0 and S = 1 . In the present complex, [Ni 2 (SOCH) 4 (NCS) 2 ], the distorted octahedral environment determines the d-level splitting ways.…”

Vapochromism and Magnetochemical Switching of a Nickel(II) Paddlewheel Complex by Reversible NH3 Uptake and Release

“…[6-9, 11, 12] Theb inding of an axial ligand changes the coordination sphere at the metal site to square-pyramidal thus rendering such PW complexes paramagnetic.Asearch in the Cambridge Structural Database revealed that in O,O-, S,O-and S,S-bridged Ni 2 -PWs,the {NiO 4 }s ites are always coordinated by an axial ligand, while the {NiS 4 }a re not. [14] S,N-Bridged Ni 2 -PWs have been reported either with [11] or without [12,15] axially bound donor ligands.T ot he best of our knowledge,i nn one of those both situations have been realized within ag iven paddlewheel. However,t his would be highly interesting as it offers the possibility for molecular,m agnetic switching triggered by [*] Dr.K .M.F ürpaß, Dr.L.M.P eschel, Prof. Dr. 2021 The Authors.…”

Vapochromism and Magnetochemical Switching of a Nickel(II) Paddlewheel Complex by Reversible NH3 Uptake and Release

“…[6-9, 11, 12] Theb inding of an axial ligand changes the coordination sphere at the metal site to square-pyramidal thus rendering such PW complexes paramagnetic.Asearch in the Cambridge Structural Database revealed that in O,O-, S,O-and S,S-bridged Ni 2 -PWs,the {NiO 4 }s ites are always coordinated by an axial ligand, while the {NiS 4 }a re not. [14] S,N-Bridged Ni 2 -PWs have been reported either with [11] or without [12,15] axially bound donor ligands.T ot he best of our knowledge,i nn one of those both situations have been realized within ag iven paddlewheel. However,t his would be highly interesting as it offers the possibility for molecular,m agnetic switching triggered by ad onor ligand.…”