Bernward Deubzer

Tetrakis(η1-1-phenyl-3-n-hexyltriazenido)platin(IV), der erste homoleptische Arylalkyltriazenidoplatin(IV)komplex

The first homoleptic tetrakis(arylalkyltriazenido) derivative of platinum, [C6H5NNN(CH2)5CH3]4Pt (3), has been prepared by reacting platinumtetrachloride with 1-phenyl-3-n-hexyltriazene and n-butyllithium in THF. The readily soluble, yellow complex, stable towards air and water, has been characterized by single cristal x-ray cristallography and 195Pt NMR spectroscopy. Compound 3 crystallizes in the triclinic space group P1 (a = 1090.3(3) pm, b = 1081.1(2) pm, c = 1174.4(2) pm, α = 93.86(1)°, β = 108.07(2)°, γ = 99.00(2)°, V= 1.289 (1) nm3, Z = 1 and R/Rw = 0.038/0.035). The thermo- and photochemical decomposition of the complex was investigated by DSC- and UV-measurements.

Photolysis of an arylalkyl-triazenido-platinum-IV complex

The photolytic decomposition of tetrakis(1-phenyl-3-hexyl-triazenido)-platinum(IV) is studied in a variety of media, and found to proceed according to simple first order kinetics. Two excimer laser wavelengths, an excimer-laser pumped dye laser, and a broadband mercury lamp are used for excitation. As referred to the incident power, selective irradiation near the complex-specific absorption maximum is found to be most efficient for inducing the photolytic decomposition. A different influence of degassing and oxygen saturation is observed for tetrahydrofurane and for technical siloxane solvents. To elucidate the origins of the observed behaviour, decomposition products of the complex, and products of hydrosilylation reactions catalyzed by this compound, are identified by GC/MS analysis.

Redox-initiated radical decomposition of triazenes and their platinum complexes studied by cyclic voltammetry and EPR spectroscopy

Triazenes p-R1–C6H4–NN–NR2R3(R1= H, butyl, CH3O, CN and NO2, R2= CH3, cyclohexyl, butyl or longer chains, R3= H, OH) are irreversibly cathodically reduced at –1.5 to –2.7 V (vs. saturated calomel electrode) and oxidised from 0.8 to 1.7 V. The reduction peak potentials became more negative and the first oxidation peak potentials less positive if R3 was OH. Using spin-trapping, radicals p-R1–C6H4˙ and ˙R2 were identified as fragmentation products in the electrolytic and peroxy-initiated decomposition of triazenes. Radicals p–R1C6H4–NO˙–R2, representing the oxidised cage products after N2 elimination, were observed in the oxidation of triazenes with peroxy acid. An NO2-centred radical anion was found in the cathodic reduction of a Pt complex with R1= NO2. The above specified decomposition route of triazenes is modified if these are coordinated in Pt complexes. The formation of radicals is discussed assuming two tautomeric forms of triazenes.