Playing with different metalloligands [NiL] and Hg to [NiL] ratios to tune the nuclearity of Ni(II)–Hg(II) complexes: Formation of di-, tri-, hexa- and nona-nuclear Ni–Hg clusters.

Five new hetero-metallic nickel(II)–mercury(II) complexes, [(NiL 1 )HgCl 2 ] ( 1 ), [(NiL 1 ) 2 HgCl 2 ] ( 3 ), [(NiL 1 ) 2 Hg(N 3 ) 2 ] ( 4 ), [{(NiL 2 ) 2 Hg(N 3 )(μ 1,1 -N 3 )} 2 ] ( 5 ) and [{(NiL 2 ) 2 Hg(N 3 )(μ 1,1 -N 3 )HgCl 2 } 2 {Hg(N 3 )(μ 1,1 -N 3 )}] ( 6 ) have been synthesized by reacting metalloligands [NiL 1 ] or [NiL 2 ] (where H 2 L 1 is N,N′-bis(salicylidene)-1,2-ethylenediamine and H 2 L 2 is N,N′-bis(salicylidene)-1,3-propanediamine) with HgX 2 (X − = Cl − or N 3 − ) at different molar ratios. All five complexes have been characterised by X-ray single-crystal structural, elemental and spectroscopic analyses. In complex 1 , the Hg(II) ion is coordinated to two phenoxido oxygen atoms of one [NiL 1 ] moiety and two terminal chloride ions to form a NiHg dinuclear complex. In the trinuclear complexes 3 and 4 , the central Hg(II) ion is coordinated by two terminal [NiL 1 ] units through two phenoxido oxygens from each and two terminal chloride (in 3 ) or azide (in 4 ) ions. The centrosymmetric hexanuclear complex 5 consists of two trinuclear [(NiL 2 ) 2 Hg(N 3 )(μ 1,1 -N 3 )] units, where the phenoxido bridges connect two terminal Ni(II) atoms of the trinuclear units. In these trinuclear units, one azido ligand adopts a μ l,1 -briding mode between Hg and Ni whereas the other one is terminal. In the nonanuclear complex 6 , two tetranuclear [{(NiL 2 ) 2 Hg(N 3 )(μ 1,1 -N 3 )}HgCl 2 ] units are linked to a central Hg(II) positioned on a two fold axis, via chlorido, azido, and phenoxido bridges. The tetranuclear unit is formed by the addition of a HgCl 2 molecule to a trinuclear [(NiL 2 ) 2 Hg(N 3 )(μ 1,1 -N 3 )] unit, similar to that present in 5 . Complex 5 shows weak ferromagnetic interactions ( J = +2.1 cm −1 ) between the two octahedral Ni(II) ions through double phenoxido bridges with a Ni–O–Ni bond angle of 95.87(11)°. [ABSTRACT FROM AUTHOR]