Mononuclear and Heterodinuclear Metal Complexes of Nonsymmetric Ditertiary Phosphanes Derived from R2PCH2OH

Abstract

AbstractThe new nonsymmetric ditertiary phosphanes, Ph2PCH2N(R)CH2PAd [3a: R = C6H5, 3b: R = C6H4(4‐CH3)] were prepared using a three‐step sequence of condensation reactions. Hence treatment of AdP‐H (AdP‐H = 1,3,5,7‐tetramethyl‐2,4,8‐trioxa‐6‐phosphaadamantane) with (CH2O)n at 110 °C gave the adamantane‐derived hydroxymethylphosphane 1, which upon condensation with C6H5NH2 or C6H4(4‐CH3)NH2 gave the secondary aminophosphanes HN(R)CH2PAd [2a: R = C6H5, 2b: R = C6H4(4‐CH3)]. Further condensation of 2a or 2b with Ph2PCH2OH gave 3a or 3b in high yields (ca. 85 %) containing the sterically encumbered adamantane cage. The coordination capabilities of 2a, 3a and 3b have been explored with various PdII, PtII, RuII, IrIII and AuI metal centres. Bridge cleavage of {Pd(κ2‐C,N‐C16H16N)Br}2 with 2 equiv. of 2a gave the neutral, mononuclear complex Pd(κ2‐C,N‐C16H16N)Br(2a) (4). Reaction of 3a/3b with MCl2(cod) (M = Pt, Pd) gave the corresponding κ2‐P,P′‐chelate complexes cis‐MCl2(3) [5a: M = Pt, R = C6H5, 5b: Pt, R = C6H4(4‐CH3), 5c: Pd, R = C6H5, 5d: Pd, R = C6H4(4‐CH3)]. In contrast, bridge cleavage of the dimers {RuCl2(η6‐p‐cym)}2 or {IrCl2(η5‐Cp*)}2 with 3a gave the κ1‐P‐monodentate complexes RuCl2(η6‐p‐cym)(3a) (6) and IrCl2(η5‐Cp*)(3a) (7), respectively, in which the –PAd group is noncoordinating. Reaction of 6 or 7 with AuCl(tht) (tht = tetrahydrothiophene) gave the mixed‐metal complexes κ2‐P,P′‐μ‐RuCl2(η6‐p‐cym){Ph2PCH2N(Ph)CH2PAd(AuCl)} (8) and κ2‐P,P′‐μ‐IrCl2(η5‐Cp*){Ph2PCH2N(Ph)CH2PAd(AuCl)} (9). All new compounds have been fully characterised by spectroscopic and analytical methods. Furthermore, the structures of 2a, 4, 5a, 5b and 6–9 have been elucidated by single‐crystal X‐ray crystallography. The X‐ray structures of 5a, 5b and 6–9 represent the first examples of crystallographically characterised nonsymmetric ditertiary phosphane complexes bearing one adamantane moiety. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)