Ylide Ligands as Building Blocks for Bioactive Group 11 Metal Complexes

Abstract

The reactivity of the phosphonium salt (cyanomethyl)triphenylphosphonium chloride and the ylide (triphenylphosphonio)cyanomethanide towards Group 11 metal complexes is described. Mononuclear neutral gold(I) and gold(III) complexes of the type [AuX{CH(CN)PPh }] or [AuX {CH(CN)PPh }] and cationic derivatives such as [AuL{CH(CN)PPh }]X have been prepared. Surprisingly, the cationic gold species could only be prepared with ligands with a large steric hindrance, such as bulky NHCs or the JohnPhos phosphine, in contrast to silver and copper derivatives, which have dimeric structures through the coordination of the metal to the cyano group of the ylide of a second complex. Bis(ylide) metal complexes have also been synthesised in which a different structure is observed for the gold complexes compared with the copper and silver complexes. Although gold forms mononuclear species, the silver complex presents a two-dimensional polymeric structure as a result of further coordination of the silver centre to the nitrogen atoms of cyano groups of further silver complexes. These complexes possess two chiral centres; the gold compound was obtained as a mixture of diastereoisomers, whereas the copper and silver derivatives afford only one diastereoisomer. These compounds were screened for their in vitro cytotoxic activity against the human lung carcinoma cell line (A549). The IC values reveal an excellent cytotoxic activity for these metal complexes compared with cisplatin.

Isolation of the Metalated Ylides [Ph3P−C−CN]M (M=Li, Na, K): Influence of the Metal Ion on the Structure and Bonding Situation

“…Comparable to CDPs, the electronic structure in yldiides can be described by different bonding situations.I nt he past, the ylidic form 1A (Figure 2) was used to account for the two lone pairs at the central carbon atom and the high nucleophilicity, which have both been experimentally provenb yt he use in double-functionalization and cascadereactions or in the formation of digold complexes. [13,14] However,t he dative fragmentation pattern 1B has also been proposed in analogy to transition-metal complexes. [15] Previous DFT studies have already revealed that often different (also unsymmetrical) structures must be considered to fully describe the electronic distribution in metalated ylides.…”

Yldiide Ligands as Building Blocks for Polynuclear Coinage Metal Complexes: Metal Squares, Triangles and Chains

“…[41] Here the NBu 4 (acac) deprotonates the ylide to form the yldiide which will readily displace the labile tht from the gold precursor.I nt he absence of the gold precursor this deprotonation does not occur,c onfirmed by NMR studies (see Supporting Information), suggesting coordination to the first gold centre musto ccur before the deprotonation step. Anionic trinucleard erivatives 3 and 4 were synthesised by initial preparation of the previously reported bis-ylide complex [39] II ands ubsequentd eprotonation with two equivalents of NBu 4 (acac) in the presence of two equivalents of [AuX(tht)] (X = Cl, C 6 F 5 ).…”

“…The neutral tetrameric gold complex 5 could also be prepared by reaction of the previously reported chlorido gold ylide complex, [39] III,w ith av ariety of differentb ases including nBuLi, NBu 4 (acac) and Cs 2 CO 3 (Scheme 2). In each case, the chloridol igand was removed as the corresponding chloride salt LiCl, NBu 4 Cl or CsCl.…”

“…These studies led to the first structural characterisation of astable dinuclear yldiide derivative with gold triphenylphosphine groups, highlighting the potential for this ligand in the synthesis of stable yldiide digold complexes. [39] In this ligand first studied by Bestmann et al, [40] the nitrile group not only increasest he acidity of the CÀHi nt he parenty lide, aiding the synthesis of the yldiide, but also results in ar ich coordination chemistry due to the possibility for the delocalisationo fe lectron density or additional coordination through the Na tom ( Figure 2).…”

Preise der Spanischen Chemischen Gesellschaft 2018

“…Gimeno und ihre Gruppe entwerfen und synthetisieren Koordinationsverbindungen (hauptsächlich von Gruppe‐11‐Metallen) mit besonderen Eigenschaften für verschiedene Anwendungen in Lumineszenz, Medizin oder Katalyse. Sie hatte einen Beitrag in Chemistry—A European Journal über Ylid‐Liganden für biologisch aktive Metallkomplexe . Gimeno gehört dem internationalen Beirat von European Journal of Inorganic Chemistry an.…”