Abstract
The dimeric compound [Pd(bzan)(μ-OOCCH3)]2 (1) (bzan=N-benzylideneaniline) reacts with KX, in methanol/acetone (2:1), affording the analogous dimeric pseudohalogen-bridged species [Pd(bzan)(μ-X)]2 [X=NCO(2),SCN(3), CN(4)]. The compounds were characterized by elemental analysis, infrared spectroscopy, NMR and thermogravimetric analysis. IR data for 2–4 showed bands typical of coordinated pseudohalogen ligands clearly indicating the occurrence of the exchange reaction. Their thermal behaviour was investigated and suggested that their stability is influenced by the bridging ligand. The thermal stability decreased in the order[Pd(bzan)(μ-CN)]2>[Pd(bzan)(μ-SCN)]2>[Pd(bzan)(μ-OOCCH3)]2>[Pd(bzan)(μ-NCO)]2. X-ray results showed the formation of Pd as final decomposition product.
Nickel(II) complexes prepared from NNN type ligands and pseudohalogens
Synthesis, structure and thermal decomposition
Abstract
Six nickel(II) complexes, using azide and thiocyanate ions, have been synthesized from bis-2,6(pyrazol-1-yl)pyridine (pp) and some methyl derivatives, 2-(3,5-dimethyl(pyrazol-1-yl)-6-(pyrazol-1-yl)pyridine (app) and bis-2,6(3,5-dimethyl(pyrazol-1-yl) pyridine (dmpp) in non-aqueous media. The complex structures were analyzed using elemental analysis, IR spectroscopy and thermogravimetry. Appropriate crystals of complex, containing azide [Nipp(N3)2]·MeOH (I) and thiocyanate [Nidmpp(SCN)2·MeOH] (VI) were prepared and the molecular structures determined using X-ray diffraction. Complex I was seen to be dinuclear as stated in literature, space group P21/n, monoclinic, a=10.503, b=10.681, c=13.291 Å, β=106.56° and Z=2 whereas complex VI was found to be mononuclear, space group P21/n, monoclinic, a=8.646, b=12.614, c=20.697 Å, β=97.18° and Z=2. The Ni(II) coordination in both complexes were octahedral. Thermogravimetric studies showed azide containing structures to resemble the characteristics of explosive materials. Coordinative MeOH were seen to leave the structure in thiocyanate containing complexes, followed by irregular degradation above 300°C.
Abstract
Reactions of At/
/+, 
Ato.H2O
, AtCl
2
–
and AtBr2 with the pseudohalogenides tricyanomethanide and azide are described. Information on the compound formation of astatine with C/CN/
3
–
and N
3
–
could be obtained on the basis of electromigration investigations under variation of the conditions /composition of the electrolyte, pH, exchange reactions of ligands/. For the reaction: [At/H2O/C/CN/3]+C/CN/
3
–
[At/C/CN/3/2]+H2O at 301 K and u=0.075 mol.l–1 K2=/675±25/ [1.mol–1] and uo=–/3.50±0.10/×10–4 [cm2.s–1.V–1]. According to this astatine/I/-tricyanomethanide is classified between AtI
2
–
and At/SCN/
2
–
. First investigations in azid-containing systems confirm the formation of astatine/I/-azide-compounds. Their composition is probably At/N3/
2
–
. There is no dependence of the ion mobility of astatine/I/-azide in the investigated range on azide concentration which is due to its high stability.
