Complexes of platinum metals with crown ethers containing tertiary phosphine-substituted benzo groups

Abstract

Some benzo-crown ethers substituted in the arene ring are described, e.g. some 15-X-substituted benzo-[15-crown-5] ethers [1; X = I, CHO, CH₂OH, CH₂CI, CH₂Ph₂(Q), or CH₂PBu^t₂(Q′)] : 18-iodobenzo-[18-crown-6](2; X = I) and 15-iodo-16-methylbenzo-[15-crown-51](3; X = I) are also described. We have failed, however, to lithiate or to prepare a Grignard derivative of a benzo-crown ether. The model phosphines PR₂[C₆H₃(OMe)₂-3.4][4; R = Ph(L) or Bu^t(L′)] have also been synthesized. Reduction of (1; X = CHO) by Li[AlH₄] gives, in addition to (1; X = CH₂OH), a dicrown ether dibenzyl ether derivative (5; X = H). Similar reduction of 15-formyl-16-methylbenzo-[15-crown-5](3; X = CHO) gives only a dicrown diphenylmethane derivative (6). The chloromethyl derivatives react with Li[PPh₂] to give the corresponding phosphines (4; R = Ph) and (1; X = CH₂PPh₂). and with PBu^t₂H + I^– followed by base (Na[OH]) their Bu^t analogues. Adducts of the sub-stituted crown ethers (1; X = CHO, Me, or I) with Na[SCN] have been prepared and some conductimetric studiesmade of complex formation with Nal. Complexes of the phosphines L, L′, Q, or Q′ of the types trans-[MCl(CO)-(phosphine)₂](M = Rh or Ir), trans-[IrCl₂H(CO)Q₂], and trans-[IrMe(Cl)I(CO)Q₂](also with L) have been prepared. The complex [PdCl₂(NCPh)₂] reacts with ether Q or L to give [PdCl₂Q₂] or [PdCl₂L₂](cis+trans isomers). When treated with Na[O₂CMe] in 2-methoxyethanol, [PdCl₂L₂] undergoes cyclometallation to give [[graphic omitted]Ph₂-2)(OMe)₂-4,5}₂Cl₂](8; R = Ph, M = Pd). The complex [PdCl₂(NCPh)₂] with the bulky crown phosphine Q′ gives a mixture of trans-[PdCl₂Q′₂] and the corresponding cyclometallated complex; the complex (8; R = Bu^t, M = Pd) has also been prepared. A similar but more extensive series of platinum complexes has been made including mononuclear species formed by splitting the chloride-bridged systems with PPh₃. Infrared, ¹H and ³¹P n.m.r., and mass spectral data are given.