Neutron diffraction studies on a system with a 4-coordinate hydrogen atom in an yttrium cluster

Abstract

A 4-coordinate H atom has been unambiguously located, by single-crystal neutron diffraction for the first time, in the center of the tetrahedral metal complex Y 4H 8(Cp″) 4(THF) [Cp″=C 5Me 4(SiMe 3)]. The core of the molecule consists of a tetranuclear cluster with one interstitial, one face-bridging and six edge-bridging hydride ligands. The four individual Y–H distances to the unique interstitial hydride ligand are 2.184(16), 2.189(16), 2.221(13) and 2.168(12) Å. Neutron data were collected on a 4-mm 3 crystal at the Quasi–Laue diffractometer VIVALDI at ILL (Grenoble), and the present agreement factor is R=12.2% for 3566 reflections.