1'-(Diphenylphosphino)-1-cyanoferrocene: A Simple Ligand with Complicated Coordination Behavior toward Copper(I)
Abstrakt
1'-(Diphenylphosphino)-1-cyanoferrocene (3), a new donor-asymmetric ferrocene ligand obtained in two steps from 1'-(diphenylphosphino)ferrocene-1-carboxaldehyde, reacts with CuCl at a Cu/3 molar ratio of 1:1 to give the heterocubane complex [Cu(mu(3)-Cl)(3-kappa P)](4) (4). When the Cu/3 ratio is changed to 1:2 or 1:3, the reaction takes a different course, producing the P,N-bridged dimer [CuCl(3-kappa P)(mu(P,N)-3)](2) (5) after crystallization.
Notably, CuBr and CuI behave differently, affording the corresponding 2D coordination polymers [CuX(mu(P,N)-3)](n) [X = I (7), and Br (8)], regardless of the Cu/3 ratio. Reaction of 3 with sources of naked Cu+, such as [Cu(MeCN)(4)](+) salts or their synthetic equivalents, provides the 1D coordination polymer [Cu(MeCN-kappa N)(mu(P,N)-3)][BF4] (9) or salts of a quadruply bridged dicopper(I) cation, [Cu-2(mu(P,N)-3)(4)]X-2 ([10]X-2), depending on the Cu/3 molar ratio (1:1 vs 1:2 and 1:3).
Except for 4, in which 3 binds as a simple P-monodentate ligand, the complexes reported here represent the first structurally characterized compounds in which a phosphinonitrile ligand coordinates through both of its soft donor moieties, thereby extending the coordination chemistry of these ligands.