Abstract
The title compound, [Mn(C24H34O4P)(CH3OH)5](C24H34O4P)·3CH3OH, was formed in the reaction between a hydrate of a manganese(II) salt [either Mn(NO3)2(H2O)6 or MnCl2(H2O)4] with a methanol solvate of lithium bis-(2,6-diiso-propyl-phen-yl) phosphate, {Li[OOP(O-2,6- i Pr2C6H3)2]·(CH4O)3}·CH4O, in methanol. The structure has monoclinic (Cc) symmetry at 150 K. The complex consists of an [Mn{OOP(O-2,6- i Pr2C6H3)2}(CH3OH)5]+ cation, an [OOP(O-2,6- i Pr2C6H3)2]- anion and three non-coordinating methanol mol-ecules. The anion demonstrates disorder of an isopropyl group [occupancy ratio is 0.57 (4):0.43 (4)]. The di-aryl-phosphate ligand in the cation exhibits a κ1 O terminal coordination mode. The Mn atom is in a nearly unperturbed octa-hedral environment. The [Mn{OOP(O-2,6- i Pr2C6H3)2}(CH3OH)5]+ cation exhibits one intra-molecular O-H⋯O bond, and is coordinated via two inter-molecular O-H⋯O hydrogen bonds to the [OOP(O-2,6- i Pr2C6H3)2]- anion. The cations, anions and non-coordinating methanol mol-ecules are linked into infinite chains along the c-axis direction via 0-H⋯O hydrogen bonding. The complex is of inter-est as a possible inhibitor for the thermal decomposition of polydi-methyl-siloxane. The crystal studied was refined as an inversion twin with a domain ratio of 0.47 (3):0.53 (3).
Highlights
The title compound, [Mn(C24H34O4P)(CH3OH)5](C24H34O4P)Á3CH3OH, was formed in the reaction between a hydrate of a manganese(II) salt [either Mn(NO3)2(H2O)6 or MnCl2(H2O)4] with a methanol solvate of lithium bis(2,6diisopropylphenyl) phosphate, {Li[OOP(O-2,6-iPr2C6H3)2]Á(CH4O)3}ÁCH4O, in methanol
The cations, anions and non-coordinating methanol molecules are linked into infinite chains along the c-axis direction via 0—HÁ Á ÁO hydrogen bonding
The complex is of interest as a possible inhibitor for the thermal decomposition of polydimethylsiloxane
Summary
Polydimethylsiloxane (PDMS) liquids are widely applied in many devices as shock-absorbing, hydraulic and damping liquids, as bases for greases and as heat-transfer agents for many industrial processes carried out at elevated temperatures. Various lipophilic derivatives of metals with variable valency, such as Mn, Fe, Ni, Ce, etc., are used for the inhibition of thermo-oxidative decomposition of polyorganosiloxane heat carriers (Swihart & Jones, 1985; Nielsen, 1961; Halm, 1980; Kobzova et al, 1966; Kishimoto et al, 1976; Rozanova et al, 1995; Minyaev et al, 2018a) in order to increase their operating time and temperature (usually up to ca 550 K). As manganese-based inhibitors, cymantrene and its derivatives have shown promising results (Sobolevskiy et al, 1970). These Mn compounds are not available on an industrial scale. We report on the crystal structure of the Mn organophosphate complex [Mn{OOP(O-2,6-iPr2C6H3)2}(CH3OH)5]+[OOP(O-2,6-iPr2C6H3)2]ÀÁ3CH3OH, which contains a lipophilic diaryl-substituted organophosphate ligand, and on its properties regarding inhibition of the thermal oxidation of polydimethylsiloxane. Performing the reaction in a methanol medium provided the ionic complex instead of the expected neutral complex
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
