Molybdenum and tungsten

A review of recent advances in non-enzymatic electrochemical creatinine biosensing.

Coordination properties of the bioligands creatinine and creatine in various reaction media

Assay of creatinine using the peroxidase activity of copper-creatinine complexes.

Spectroscopic and structural study of the newly synthesized heteroligand complex of copper with creatinine and urea.

Cobalt(II) complexes of creatinine [Co(creat)2X2] (X = Cl, Br, I or NCS) and [Co(creat)2X2(H2O)2] (X = HCO2, HOCH2CO2 or CNCH2CO2) have been prepared. Their i.r. spectra show an increase in ν(NH) of the cyclic secondary amine group, compared to free ligand (3300 cm−1), indicating that cyclic nitrogen is involved in coordination. The thiocyanate group coordinates through nitrogen and carboxylates coordinate as univalent unidentate ligands. The electronic spectra and magnetic moments suggest a d7 configuration for cobalt: a tetrahedral geometry (4.4 B.M.) for halide and thiocyanate complexes, and an octahedral geometry (5.0 B.M.) for the carboxylate complexes. On heating, the ligand moiety is lost and the respective cobalt halide or cobalt carboxylate is formed, which is converted finally into Co3O4. There is a correlation between the high intensity electronic transitions and the polarographic half-wave potentials.

Cobalt(II) Complexes of Creatinine

The interaction of hard base chelating agents (LH) such as 8-quinolinol (oxH), salicylaldehyde (salH) andN-nitrosophenylhydroxylamine (NphaH) with ammonium tetrathiomolybdate(VI), (1), in aqueous solution yields disulphidomolybdenum(VI) complexes, [MoS2L2] The ir absorptions at 540 and 510 cm−1 are assigned tov(Mo-S), which indicate that the two sulphido-groups arecis to each other, The interaction of (1) with soft base chelating agents (SS), such as dithiocarbamates (dtc), dithiophosphate (dtp) and xanthates (xan) yields dimeric sulphido-bridged sulphidomolybdenum(V) complexes, [Mo2S4(SS)2] and with potassium ethylthioxanthate (KEttxan) yields a molybdenum(IV) complex, [Mo(Ettxan)4] The [Mo2S4(R2dtc)2] complexes were also obtained by the interaction of [MoO2(R2dtc)2] with phosphorus pentasulphide in xylene It was concluded that tetrathiomolybdate(VI) undergoes facile reduction when compared with tetraoxomolybdate(VI)

Reactivity of the tetrathiomolybdate(VI) anion towards hard and soft base chelating agents

Selenidomolybdenum(V) dithiocarbamate complexes

Isothiocyanatooxomolybdenum(V) complexes, [MoO-(NCS)(R2dtc)2] (R=ethyl or dibenzyl; R2=piperidinyl or 4-morpholinyl) have been prepared and characterized. The i.r. spectral bands at 2020 cm−1 are assigned tov(CN) which suggest that thiocyanate coordinates through nitrogen. The bands at 930, 1500 and 960 cm−1 are attributed tov(MoO),v(CN) andv(CS), respectively, and indicate the presence of the MoO3+ moiety and a bidentate dithiocarbamate group. The e.p.r. and electronic spectral data together with magnetic moment values (1.69 B.M.) suggest the presence of one unpaired electron. The complexes are monomeric. The thermal decomposition behaviour of the complexes is reported.

K. Seetharamiah Nagaraja

Papers

Cobalt(II) Complexes of Creatinine

Reactivity of the tetrathiomolybdate(VI) anion towards hard and soft base chelating agents

Selenidomolybdenum(V) dithiocarbamate complexes

Isothiocyanatooxomolybdenum(V) dithiocarbamates