Three new pseudohalide bridged dinuclear Zn(II), Cd(II) complexes of pyrimidine derived Schiff base ligands: Synthesis, crystal structures and fluorescence studies

Syntheses, X-ray Crystal Structures, Photoluminescence Properties, Antimicrobial Activities and Hirshfeld Surface of Two New Cd(II) Azide/Thiocyanate Linked Coordination Polymers

“…According to such effect the red shift fluorescence is increased due to conformational rigidity of the ligand system upon compoundation with Cd(II) metal centers during coordination polymer formation, a journey experiencing structural framework variation from 1D to 2D and also intermolecular interactions. The poor overlapping extent of Cd(II) metal appropriate orbitals with ligand‐N donor orbitals during chelate ring formation causes the ligand electron pairs which are located in higher energy orbitals more readily available for quenching the fluorescence . We observed from emission spectral curve of Schiff base ligand (H 2 L 1 ) that an emission maximum is bathochromically shifted as compared to Schiff base ligand (H 2 L 2 ).…”

“…In the absence of metal ions fluorescence of the ligand is quenched by the PET process due to presence of nonbonding electron pair of electrons of the Schiff base ligand. Such PET process is prevented by the stable compoundations of Schiff base ligand (N, O) donor with Cd(II) metal ions preferably tight flexible binding. Thus the enhanced fluorescence intensity of Cd(II) compunds 1 & 2 may be due to mainly ‘chelation enhanced fluorescence’ (CHEF) .…”

Exploration of Cd(ii)/pseudohalide/di-2-pyridyl ketone chemistry – rational synthesis, structural analysis and photoluminescence

“…The structure of 2 consists of the dinuclear [Cd 2 (SCN) 4 {(py) 2 C(OCH 3 )(OH)} 2 ] units as presented in Fig. 2a 2 ], 19 5.659 Å in [Cd 2 (pydim) 2 (μ 1,3 -SCN)] 2 [BF 4 ] 2 , 20 5.791 Å in [Cd(L 1 )(NCS)(μ 1,3 -SCN)] 2 (L 1 = N-(4,6dimethyl-pyrimidin-2-yl)-N′-pyridin-2-ylmethylene-hydrazine), 21 and 5.887 Å in [Cd(L 2 )(NCS)(μ 1,3 -SCN)] 2 (L 2 = N,N-diethyl-N′-(1pyridine-2-yl-ethylidene)-ethane-1,2-diamine). 22 Each cadmiumIJII) ion is six-coordinated in a highly distorted {N 3 S 2 O} octahedral geometry defined by two nitrogen and one oxygen atoms of the tridentate chelating (2-py) 2 C(OCH 3 )(OH) molecule, sulphur and nitrogen atoms from the bridging thiocyanate ligands and a sulphur atom from the terminally bound thiocyanate ion.…”

Zinc(II) and Cadmium(II) complexes with N4-coordinate pyrazole based ligand: Syntheses, characterization and structure

“…Therefore, we can conclude that pyrazole containing tetradentate N4-coordinated ligand form mononuclear complexes with either trigonal bipyramidal (complexes) or distorted octahedral geometry and binuclear distorted octahedral geometry with Zn(II) and Cd(II) ions in the presence of pseudohalides like azide, thiocyanate or isocyanate, although zinc(II) and cadmium (II) prefer to form tetrahedral complexes [40]. Another important point is that most of the reported azide bridged binuclear cadmium(II) complexes have endon (l-1,1) coordination mode of bonding [37,41,42] but the compound [{Cd(dbdmp)} 2 (l-N 3 ) 2 ](ClO 4 ) 2 (7) synthesized by us have rare end-to-end (l-1,3) coordination mode of bonding.…”