Dynamic Titanium Phosphinoamides as Unique Bidentate Phosphorus Ligands for Platinum
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- 作者：Hideo Nagashima ; Takashi Sue ; Takashi Oda ; Akira Kanemitsu ; Taisuke Matsumoto ; Yukihiro Motoyama ; and Yusuke Sunada
- 刊名：Organometallics
- 出版年：2006
- 出版时间：April 10, 2006
- 年：2006
- 卷：25
- 期：8
- 页码：1987 - 1994
- 全文大小：147K
- 年卷期：v.25,no.8(April 10, 2006)
- ISSN：1520-6041
文摘
Treatment of lithium phosphinoamides, Ph2PN(Li)R [R = tBu, iPr], with TiCl4 results in formation oftitanium phosphinoamides, (Ph2PNR)2TiCl2 [R = tBu (1a), iPr (1b)]. Crystallographic studies show thatthere are covalent bonds between the titanium and two nitrogen atoms, whereas two phosphorus atomsare coordinated to the metal center intramolecularly. Variable-temperature NMR studies suggest reversibledissociation of the phosphorus moieties from the titanium in solution. The dissociated phosphorus moietiesare effectively captured by Pt(II) species; reactions of 1a with either (
4-COD)PtCl2, (4-COD)Pt(R)(Cl)(R = Me, p-Tol), or [Me2Pt(
-SMe2)]2 afford the corresponding Ti-Pt heterobimetallic complexes. Themolecular structures of these complexes reveal that they have a six-membered dimetallacycle, in whicha titanium and a platinum are connected by two bridging phosphinoamide ligands; the Pt-Ti distancesindicate the existence of a Pt
Ti dative bond. The conformation of the dimetallacycle is a boat form,with two metals at the bow and the stern in the crystal; however, dynamic conformational change involvingcleavage and re-formation of the PtTi dative bond is indicated from variable-temperature NMR studies.
4-COD)PtCl2, (4-COD)Pt(R)(Cl)(R = Me, p-Tol), or [Me2Pt(-SMe2)]2 afford the corresponding Ti-Pt heterobimetallic complexes. Themolecular structures of these complexes reveal that they have a six-membered dimetallacycle, in whicha titanium and a platinum are connected by two bridging phosphinoamide ligands; the Pt-Ti distancesindicate the existence of a PtTi dative bond. The conformation of the dimetallacycle is a boat form,with two metals at the bow and the stern in the crystal; however, dynamic conformational change involvingcleavage and re-formation of the PtTi dative bond is indicated from variable-temperature NMR studies.