Influence of the Substituted Ethylenediamine Ligand on the Structure and Properties of [Cu(diamine)2Zn(NCS)4]∙Solv. Compounds

Abstract

In this paper, three new heterometallic compounds were described and compared with the molecular formula [Cu(pn)2Zn(NCS)4] (1), [Cu(N,N-Me2-en)2Zn(NCS)4] (2), [Cu(N-Me-en)2Zn(NCS)4]∙½H2O (3) where pn = 1,2−diaminopropane, N,N-Me2-en = N,N‒dimethylethylenediamine and N-Me-en = N-methylethylenediamine, respectively. The compounds mentioned above were characterized by elemental analysis, infrared (IR), electronic, electron paramagnetic resonance (EPR) spectra, and magnetic studies. Crystal structures for 1 and 2 were determined by X-ray analysis. Copper(II) in these complexes adopts 4 + 2 coordination with two elongated (in 2 very long and considered as semi-coordination) Cu-S bonds. The Cu-N and Cu-S bond lengths depend on substituent position affecting steric hindrance and hence a topology of the chain. Both chains form different zigzag patterns characterized by one or two Cu-Zn distance values. Weak magnetic interaction is observed, ferromagnetic in the case of 1 and antiferromagnetic in the case of 2, due to diversity of the above structural features.

Structural Diversity, XAS and Magnetism of Copper(II)-Nickel(II) Heterometallic Complexes Based on the [Ni(NCS)6]4− Unit

“…Copper(II) ions adopt 4+2 coordination with four short Cu-N and two much longer Cu-S bonds. The Cu-N bonds are found in the range 2.003(3)–2.028(3) Å and are similar to the values found in other complexes [ 27 , 31 , 76 , 77 , 78 ]. The axial bonds are distinctly longer than equatorial bonds and are equal to 2.9883(11) and 3.0224(10) Å for Cu-S5 and Cu-S6, respectively.…”

“…The one-dimensional [Cu(en)(µ 1,3 -NCS) 4 Hg] n compound consists of ladder-like zigzag ribbons with three different, {Cu(en)(µ 1,3 -NCS) 2 Hg}, ({Cu(en)(µ 1,3 -NCS) 2 Hg}) 2 and ({Cu(en)(µ 1,3 -NCS) 3 Hg}) 2 , macrocycles [ 24 ]. Three different types of 1D chain crystal structures in the [Cu(diamine) 2 Zn(NCS) 4 ] n ·n(solv) (diamine = en, pn) systems have been described, namely zigzag, helical or quasi-linear [ 25 , 26 , 27 ]. Additionally, two modes of thiocyanate bridges, µ 1,3 -NCS (more common) and µ 1,1 -SCN, have been found among these compounds.…”

“…With the above in mind, we extended our previous research interest to heterometallic compounds containing anionic blocks with N -coordinated thiocyanate ions, e.g., [Cr(NCS) 6 ] 3− [ 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ], [Cr(NCS) 4 (NH 3 ) 2 ] − [ 65 ] and [Zn(NCS) 4 ] 2− [ 26 , 27 ], and involve rarely used [Ni(NCS) 6 ] 4− building block. We present synthesis, SC-XRD crystal structure, X-ray absorption spectra and magnetic properties of three new [Ni(NCS) 6 ] 4− based compounds, with different dimensionality and variety of Cu oxidation states and polyhedral coordination geometries: [{Cu(pn) 2 } 2 Ni(NCS) 6 ] n ·2nH 2 O ( 1 ), [{Cu II (trien)} 2 Ni(NCS) 6 Cu I (NCS)] n ( 2 ) and [Cu(tren)(NCS)] 4 [Ni(NCS) 6 ] ( 3 ).…”