New ligands with enhanced hemilabile character compared to iminophosphoranes known in the literature are presented. When diphenyl-2-picolylphosphane was oxidized with elemental sulfur or gray selenium, the new ligands Ph 2 P(S)(CH 2 Py) (1) and Ph 2 P(Se)(CH 2 Py) (2) were obtained. In addition, the calcium complex [(thf) 2 Ca{(PyCH)(Se)PPh 2 } 2 ] (3), based on 2, is presented. This is only the second example of a molecular structure displaying a direct calcium-selenium contact. A structural comparison of the parent ligands and the related motifs in the organometallic complex reveals the bonding to the central phosphorus atom to be mostly strengthened by electrostatic means rather than by any double bonding. The spectroscopic data of 3 show features similar to those of iminophosphoranes, despite small differences in electronegativity. All of the compounds presented are accessible in good yields and high purity. The DTA analysis of 3 points to possible CVD applications to form CaSe from the gas phase.

Organometallics COMMUNICATION' ASSOCIATED CONTENT b S Supporting Information. Text giving experimental details and a table and CIF files giving crystal data for 1 and 2. This material is available free of charge via the Internet at http://pubs. acs.org. Experimental crystallographic data, including the coordinates of both complexes, are also available from the CCDC: 802685 (1) and 802686 (2).

1946James Bachteller Sumner "for his discovery that enzymes can be crystallized" 1963 Karl Ziegler, Giulio Natta "for their discoveries in the field of the chemistry and technology of high polymers" 1975 John W. Cornforth "for his work on the stereochemistry of enzyme-catalyzed reactions" 2001 William S. Knowles, Ryoji Noyori Barry Sharpless "for their work on chirally catalysed hydrogenation reactions" "for his work on chirally catalysed oxidation reactions" 2005 Yves Chauvin, Robert Grubbs, Richard R. Schrock "for the development of the metathesis method in organic synthesis" 2007 Gerhard Ertl "for his studies of chemical processes on solid surfaces"