The volatile trimethylplatinum(IV) complexes: Effect of β-diketonate substituents on thermal properties

The series of trimethylplatinum(IV) complexes with a general formula (CH3)(3)Pt(L)Py: [L = beta-diketonate ligand: (1) (BuC)-Bu-t(O)CHC(O)C(OCH3)(CH3)(2)) - L-1, (2) CF3C(O)CHC(O)CC(CH3)(2) (OCH3)) - L-2, (3) CF3C(O)CHC (O)C4H3S - ttfa, (4) CF3C(O)CHC(O)Bu-t - ptac, Py -pyridine] were synthesized with high yields using novel synthesis technique based on the interaction of (CH3)(3) PtI with an appropriate PbL2. A number of methods including elemental analysis, IR and NMR spectroscopy, were used to identify the purity of complexes. Both 1 and 3 crystals are monoclinic, P2(1)/n, Z = 4. The crystallographic parameters are: a = 9.3199 (11)angstrom, b = 16.1798(19)angstrom, c = 14.1544(13)angstrom, beta = 90.090(4)degrees, V = 2134.4(4)angstrom(3) for 1; a = 10.5676(3)angstrom, b = 17.1804(5)angstrom, c = 12.0353(4)angstrom, beta = 90.7430(10)degrees, V = 2184.89(11)angstrom(3) for 3, respectively. The temperature dependences of saturated vapor pressure of the complexes were measured using Knudsen method giving logP = 17.3-6908/T, Delta T = 326-353 K and logP = 17.7-6793/T, Delta T = 303-333 K, for 1 and 4, respectively. The effect of substituents combination in L on thermal stability of (CH3)(3)Pt(L)Py vapors was studied using mass spectrometry. The energies of Pt-N(Py) bonds of (CH3)(3)Pt(L)Py calculated using DFT approach were in the ranges of 78.97-92.73 and 73.32-83.09 kJ/mol depending on Py rings orientation. (C) 2020 Elsevier Ltd. All rights reserved.