title: bis-Nitrile and bis-Dialkylcyanamide Platinum(II) Complexes as Efficient Catalysts for Hydrosilylation Cross-Linking of Siloxane Polymers.
abstract: cis- and trans-Isomers of the platinum(II) nitrile complexes [PtCl2(NCR)2] (R = NMe2, N(C₅H10), Ph, CH2Ph) were examined as catalysts for hydrosilylation cross-linking of vinyl-terminated polydimethylsiloxane and trimethylsilyl-terminated poly(dimethylsiloxane-co-ethylhydrosiloxane) producing high quality silicone rubbers. Among the tested platinum species the cis-complexes are much more active catalysts than their trans-congeners and for all studied platinum complexes cis-[PtCl2(NCCH2Ph)2] exhibits the best catalytic activity (room temperature, c = 1.0 × 10(-4) mol/L, τpot-life 60 min, τcuring 6 h). Although cis-[PtCl₂(NCCH2Ph)2] is less active than the widely used Karstedt's catalyst, its application for the cross-linking can be performed not only at room temperature (c = 1.0 × 10(-4) mol/L), but also, more efficiently, at 80 °C (c = 1.0 × 10(-4)-1.0 × 10(-5) mol/L) and it prevents adherence of the formed silicone rubbers to equipment. The usage of the cis- and trans-[PtCl2(NCR)2] complexes as the hydrosilylation catalysts do not require any inhibitors and, moreover, the complexes and their mixtures with vinyl- and trimethylsilyl terminated polysiloxanes are shelf-stable in air. Tested catalysts do not form colloid platinum particles after the cross-linking.
authors.affiliation: Institute of Chemistry, Saint Petersburg State University, 7/9 Universitetskaya Nab., 199034 Saint Petersburg, Russia. r.islamova@spbu.ru.
authors.forename: Regina M
authors.initials: RM
authors.lastname: Islamova
authors.affiliation: Institute of Chemistry, Saint Petersburg State University, 7/9 Universitetskaya Nab., 199034 Saint Petersburg, Russia. mdobrunin42@yandex.ru.
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Dobrynin
authors.affiliation: Institute of Chemistry, Saint Petersburg State University, 7/9 Universitetskaya Nab., 199034 Saint Petersburg, Russia. dan1510@rambler.ru.
authors.forename: Daniil M
authors.initials: DM
authors.lastname: Ivanov
authors.affiliation: Institute of Chemistry, Saint Petersburg State University, 7/9 Universitetskaya Nab., 199034 Saint Petersburg, Russia. andreivl25@rambler.ru.
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Vlasov
authors.affiliation: Federal State Unitary Enterprise S.V. Lebedev Research Institute for Synthetic Rubber, Gapsal'skaya, 1, 198035 Saint Petersburg, Russia. vniisk-lab7@yandex.ru.
authors.forename: Elena V
authors.initials: EV
authors.lastname: Kaganova
authors.affiliation: Federal State Unitary Enterprise S.V. Lebedev Research Institute for Synthetic Rubber, Gapsal'skaya, 1, 198035 Saint Petersburg, Russia. office@fgupniisk.ru.
authors.forename: Galina V
authors.initials: GV
authors.lastname: Grigoryan
authors.affiliation: Institute of Chemistry, Saint Petersburg State University, 7/9 Universitetskaya Nab., 199034 Saint Petersburg, Russia. v.kukushkin@spbu.ru.
authors.forename: Vadim Yu
authors.initials: VY
authors.lastname: Kukushkin
mesh_terms: D002152:Calorimetry, Differential Scanning; D002384:Catalysis; D003432:Cross-Linking Reagents / Q000737:chemistry; D003484:Cyanamide / Q000737:chemistry; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry; D009944:Organoplatinum Compounds / Q000737:chemistry*; D012833:Siloxanes / Q000138:chemical synthesis* / Q000737:chemistry; D013055:Spectrophotometry, Infrared
chemical_list: D003432:Cross-Linking Reagents; D009570:Nitriles; D009944:Organoplatinum Compounds; D012833:Siloxanes; D003484:Cyanamide
keywords: catalysis; cross-linking; hydrosilylation; platinum nitrile complexes; silicon rubber