Abstract
The octaphosphine {cyclo-(P4tBu3)}2 (1) possesses a multifaceted coordination chemistry. The predominant binding mode is a P,P-chelate, e.g., in the monometallic chelate complex [MLL'(1-κ2P2,P4')] in which the ligand 1 adopts a gauche conformation. Examples include square-planar (M = RhI, L = CO, L' = Cl (2), M = PdII, L = L' = Cl (3), M = PtII, L = L' = Cl (9)), tetrahedral (M = Co-I, L = NO, L' = CO (4)), and trigonal-planar complexes [ML(1-κ2P2,P4')] (M = Pd0, L = PPh3, (5), M = CuI, L = Br (6)). With 2 equiv of [CuBr(SMe2)], a dinuclear complex [(CuBr)2(1-κ2P2,P2',κ2P4,P4')] (7) was obtained which features a synperiplanar conformation of the octaphosphine. A second coordination mode was also observed in [PtCl2(1-κ2P1,P2')] (10) in which the bridge phosphorus atom in octaphosphine 1 is involved in the chelation, with the ligand in an antiperiplanar conformation. Thermolysis of selected complexes showed them to be suitable candidates for the generation of phosphorus-rich metal phosphides MPx (x > 1).
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