Reactivity of cyclometallated compounds of N-benzylideneamines. Synthesis and X-ray crystal structure of [P [formula omitted]-C 6H 5)-3,5-(CH 3) 2C 6H 2} (2,4-Me 2C 5H 3N)]ClO 4

Abstract

The action of Ph 2PCH 2CH 2PPh 2 (dpe) on the cyclometallated compounds [{Pd( CN )Br} 2] ( CN = 2-(HCNC 6H 5)-5-ClC 6H 3 1a, 2-(CH 2NCH-2′,6′-Cl 2C 6H 3)C 6H 4 1b, or 1-CH 2-2-(CHN-C 6H 5)-3,5-(CH 3) 2C 6H 2 1c) in a 2:1 molar ratio, gives the novel neutral species [Pd( CN )Br(dpe)] ( 2a,b) or the ionic compound [ ▪(dpe)]Br ( 3c). The action of dpe on compound 1 in a 1:1 molar ratio gives the dinuclear cyclometallated compound 4, in which two palladium atoms are bridged by the diphosphine. The ionic compounds[ ▪(lut)(PPh 3)]ClO 4 6 (lut = 2,4-lutidine) were obtained by reaction between AgClO 4 and acetone solutions of the cyclometallated compounds ▪, and subsequent addition of 2,4-lutidine. [P d{1-CH 2-2-(CHN -C 6H 5)-3,5-(CH 3) 2C 6H 2}(2,4-lut)]ClO 4 crystallizes in the orthorhombic space group Pcab with a = 16.331(3) Å; b = 18.885(3) Å; c = 24.702(4) Å, and Z = 8. The endo six-membered ring displays a half-skew-chair conformation, with the palladium atom out of the plane (1.086 Å) defined by the other atoms.