Differences in nuclearity, molecular shapes and coordination modes of azide in the complexes of Cd (II) and Hg (II) with a “Metalloligand” [CuL] (H 2 L = N,N′-Bis(salicylidene)-1,3-propanediamine): characterization in solid and in solutions and theoretical calculations
American Chemical Society, 2012
academicJournal
Zugriff:
Two new heterometallic copper (II)–mercury (II) complexes [(CuL)Hg(N 3 ) 2 ] n (1) and [(CuL) 2 Hg(N 3 ) 2 ] (2) and one copper (II)–cadmium (II) complex [(CuL) 2 Cd(N 3 ) 2 ] (3) have been synthesized using “metalloligand” [CuL] (where H 2 L = N,N′-bis(salicylidene)-1,3-propanediamine) and structurally characterized. Complex 1 is a one-dimensional (1D) helical coordination polymer constructed by the joining of the dinuclear [(CuL)Hg(N 3 ) 2 ] units through a single μ -l,l azido bridge. In the dinuclear unit the Hg (II) is bonded with two phenoxido oxygen atoms of “metalloligand” [CuL] and two nitrogen atoms of azido ligands. Complex 2 is a linear trinuclear entity, in which two terminal “metalloligands” [CuL] are coordinated to central Hg (II) through double phenoxido bridges. The azido ligands link the central mercury atom with the terminal copper atoms via μ -l,3 bridges. In contrast, the trinuclear complex 3 is bent. Here, in addition to two double phenoxido bridges, central Cd (II) is bonded to two mutually cis nitrogen atoms of two terminal azido ligands. The variation in the coordination modes of the azido ligand seems to be responsible for the different molecular shapes of 2 and 3. Interestingly, bond distances between the Hg atoms and the central nitrogen atom of the azido ligands are 2.790(4) and 2.816(5) Å in 1 and 2.823(4) Å in 2. These bond distances are significantly less than the sum of van der Waals radii of mercury (2.04 Å) and nitrogen (1.55 Å) and considerably longer than the sum of their covalent radii (2.03 Å). However the distances are similar to reported Hg–N bond distances of some Hg (II) complexes. Therefore, we have performed a theoretical density functional theory study to know whether there is any interaction between the central nitrogen atom of the azido ligand and the mercury atoms. We have used the Bader’s “atoms-in-molecules”, energetic and orbital analyses to conclude that such interaction does not exist. The probable reason for different molecular shapes observed in trinuclear ...
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Differences in nuclearity, molecular shapes and coordination modes of azide in the complexes of Cd (II) and Hg (II) with a “Metalloligand” [CuL] (H 2 L = N,N′-Bis(salicylidene)-1,3-propanediamine): characterization in solid and in solutions and theoretical calculations
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Autor/in / Beteiligte Person: | Das, Lakshmi Kanta ; Kadam, Ramakant M. ; Bauza, Antonio ; Frontera, Antonio ; Ghosh, Ashutosh |
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Veröffentlichung: | American Chemical Society, 2012 |
Medientyp: | academicJournal |
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