Structure of [Rh2(CO)2(.mu.-CO)(.mu.-Cl)((C6H5)2PCH2P(C6H5)2)2][B(C6H5)4]: an "A-frame" complex having a carbonyl ligand coordinated in the proposed active site

Abstract

Martin CowieBoth compounds show deviation from tetrahedral angles about the amine nitrogens (N(3) and N(4)) with the external C-N-C angles opening to nearly 120°to facilitate the tetradentate coordination. In both cases the M-N-0 angles are slightly larger («122°) than the "ideal" 120°s p2 angle which tends to slightly lengthen the hydrogen bond. Other bond angles in the two cases are also very similar. The bond distances in the two compounds are generally in agreement except for the oxime N-0 distances (average 1.383 Á in this complex and average 1.356 Á in the Ni complex) and the adjacent N(oxime)-C distances (average 1.271 Á in this complex and average 1.288 A in the nickel complex). The apparent shift in the multiple bonding from the N-0 toward C-N bond in this complex may be a result of the longer hydrogen bond (O-O, 2.698 Á) in this complex compared with the case of the nickel complex (2.474 A). The longer N-0 distance (1.398 A) involves the oxygen to which the hydrogen atom is bonded in a nearly covalent fashion (O-H, 0.75 A from difference Fourier position). The other O-H distance is 1.95 A. The hydrogen bond in this complex is much longer than that in any other -amine oxime complex we have studied. This may be partially due to the steric requirements of the ligand with the larger Cu(II) metal but is probably also partially a result of the dimerization which involves coordination of one of the hydrogen bond oxime oxygens with the copper. Attempts are under way to obtain single crystals with some other better coordinating anion replacing the perchlorate ion in hopes of obtaining a monomer.Acknowledgment. Financial support of the National Science Foundation (Grant CHE77-08325) is gratefully acknowledged.Registry No. [Cu(EnAO-H)]2(C104)2, 68492-44-4. Supplementary Material Available: Hydrogen atom positional parameters and a listing of structure factor amplitudes (14 pages). Ordering information is given on any current masthead page.

Molecular Structures and Photophysical Properties of Dirhodium Fluorophosphine Complexes

“…Table displays selected bond distances and angles for the two classes of compounds; the appropriate data for the Rh 0 2 complex are also included. The dirhodium complexes display bond lengths characteristic of Rh−Rh single bonds, which arise from the pairing of an odd electron residing in the d z 2 orbital of a d 9 Rh 0 P 4 fragment or d 7 Rh II P 3 X 2 fragment to yield species with d-electron configurations of (d 8 )d 1 −d 1 (d 8 ), (d 8 )d 1 −d 1 (d 6 ), and (d 6 )d 1 −d 1 (d 6 ) (for the Rh 0 2 , Rh 0 Rh II X 2 , and Rh II 2 X 4 cores, respectively) . The increase in Rh−Rh bond length along the chloride and bromide series Rh II 2 < Rh 0 Rh II < Rh 0 2 is expected in view of the larger atomic radius of Rh(0) as compared to Rh(II).…”

Redox-active binuclear complexes. Preparation, oxidation, and structure of Rh2(Ph2PCH2PPh2)2(1,2-O2C6Cl4)(CO)

“…-268 ( 6) 5897 ( 4) 24 (2) C( 16) 6818 ( 6) 3063 ( 6) 8307 (3) 11 (2) C( 52) 630 ( 6) 4209 ( 6) 7616 (4) 16 (2) C( 17) 7701 ( 6) 3021 ( 6) 8906 ( 4) 20 (2) C(53)…”

Structure of [RhCl(H)((C6H5)2PCH2P(C6H5)2)2][B(C6H5)4]: a rhodium(III) hydrido complex containing chelating bis(diphenylphosphino)methane ligands

“…The Rh-P-C(methylene) and P-C-P angles (average 94.3 (2) and 96.6 (3)°, respectively) are significantly distorted from their expected tetrahedral values owing to the strain imposed by the four-membered ring. In contrast, values near 109°are observed when DPM ligands bridge two metals.1,2,16™19…”