Pyrrole-2-carbaldehyde Thiosemicarbazonates of Nickel(II) and Palladium(II): Synthesis, Structure, and Spectroscopy

• Published in: Zeitschrift für anorganische und allgemeine Chemie (1950) 2012-04, Vol.638 (5), p.804-810
• Main Authors: Lobana, Tarlok S., Kumari, Poonam, Bawa, Gagandeep, Hundal, Geeta, Butcher, Ray J., Fernandez, Francisco J., Jasinski, Jerry P., Golen, James A.
• Format: Article
• Language: English
• Subjects: Bipyridine; Bis(diphenylphosphanyl)methane; Nickel; Palladium; Thiosemicarbazone
• ISSN: 0044-2313; 1521-3749
• DOI: 10.1002/zaac.201200012

Complexes of pyrrole‐2‐carbaldehyde thiosemicarbazones, [(C4H4N4)(H)C2=N3–N2(H)–C1(=S)–N1HR; R = Ph, H2L1; Me, H2L2; H, H2L3] with nickel(II) and palladium(II) are described. The reaction of nickel(II) acetate with H2L1 in methanol in 1:1 molar ratio yielded a complex of composition, [Ni(κ2‐N3,S‐HL1)2] (1). Likewise reaction of NiCl2 with H2L2 in 1:1 molar ratio in acetonitrile in the presence of triethylamine base followed by the addition of pyridine did not yield the anticipated [Ni(κ3‐N4,N3,S‐L2)(py)] complex, moreover a bis‐square‐planar complex, [Ni(κ2‐N3,S‐HL2)2] (2) was formed. However, in the presence of bipyridine (bipy), it yielded the addition product, [Ni(κ2‐N3,S‐HL2)2(κ2‐N, N‐bipy)] (3). Reaction of PdCl2(κ2‐P, P–PPh2–CH2–PPh2) with H2L3 in toluene in the presence of triethylamine has yielded a complex of stoichiometry, [Pd(κ3‐N4,N3,S–L3)(κ1‐P–PPh2–CH2–P(O)Ph2] (4). The ligands (HL1)– and (HL2)– are chelating to NiII metal atom as anions binding through N3,S‐donor atoms with pendant pyrrole groups, and (L3)2– is chelating to the PdII metal atom as dianion through N4,N3,S‐donor atoms (pyrrole is N4‐bonded). Fourth site in 4 is bonded to one P‐donor atom of PPh2–CH2–P(O)Ph2, whose pendant –PPh2 group involves auto oxidation to –P(O)PPh2 during reaction. These complexes were characterized using analytical data, IR, NMR (1H, 31P) spectroscopy and X‐ray crystallography. Complexes 1, 2, and 4 have square‐planar arrangement, whereas complex 3 is octahedral.