Synthesis, crystal structures and catalytic properties of three-dimensional nickel(II) and manganese(II) coordination polymers with dicarboxylate and semi-rigid bis(imidazole) ligands

Recent advances in structures and applications of coordination polymers based on cyclohexanepolycarboxylate ligands

Coordination polymers (CPs) are emerging crystalline materials constructed by metal entities and organic ligands through coordination bonds, containing infinite coordination units in one, two, or three dimensions. Here an overview...

Synthesis, Structure, and Characterization of Tris(1-ethyl-4-isopropyl-imidazolyl-κN)phosphine Nickel(II) Complexes

In this work we report the synthesis of five new nickel(II) complexes all coordinated to the tripodal ligand tris(1-ethyl-4- i Pr-imidazolyl)phosphine (TlEt4iPrIP). They are [Ni(T1Et4iPrIP)(CH3CN)2(OTf)](OTf) (1), [Ni(T1Et4iPrIP)(OTf)2] (2), [Ni(T1Et4iPrIP)(H2O)(OTf)](OTf) (3), [Ni(T1Et4iPrIP)Cl](OTf) (4), and [Ni(T1Et4iPrIP)Cl2] (5). The complexes serve as bioinorganic structural model complexes for histidine-coordinated nickel proteins. The X-ray structures have been determine for all complexes which feature coordination numbers 4-6. We investigated the spectroscopic interconversions for these compound in dichloromethane solution and demonstrate interconversion between 1-3 and conversion of 2 to 4. Complex 5 can be spectroscopically converted to the cation of 4 by dissolving it in dichloromethane. Fits of variable temperature magnetic susceptibility data yielded the following parameters: g = 1.944, D = -0.327 cm-1, E/D = 3.706 for 1; g = 2.280, D = -0.365 cm-1, E/D = 22.178 for 2; g = 2.000, D = -7.402 cm-1, E/D = -0.272 for 3; g = 2.176, D = -0.128 cm-1, E/D = -0.783 for 4; g = 2.258, D = 14.288 cm-1, E/D = 0.095 for 5. DFT structure optimizations afforded HOMO and LUMO energies indicating that complex 1 is the most stable.

Co-ligand tuned pyrimidine-2-carboxylate Mn(ii) complexes from a 2D 63 layer to an interpenetrated srs-net

A 6³ 2D layer complex [Mn₃Cl₃(L₃)]_n·H₂O (1) (L = pyrimidine-2-carboxylate) was obtained by assembling 2-cyanopyrimidine and manganese chloride, in which the L ligands were generated in situ. In 1 six-membered Mn rings were constructed from Mn^II ions and L ligands, which were connected to each other by double chloride anions affording a 2D layer. When the chloride anions in 1 were substituted partly by formate, [Mn₄Cl₃L₄(HCO₂)]_n (2) was obtained. In 2, the L ligands bridge Mn^II to give a 1D chain, which was further connected by the double chloride anions and Cl/formate bridges to form a two-fold interpenetrated srs-net. Interestingly, 2 exhibits an obvious SHG response of approximately 0.8 times that of KDP. Furthermore, 2 is an antiferromagnet with a field induced spin flop transition.