Orthometalation of m-bis(dimethylaminomethyl)benzene: crystal structure and chemistry of trans-Rh(III)Cl2[C6H3(CH2NMe2)2-o,o'](H2O)

Abstract

From the reaction of m-(Me2NCH2)2C6H4 with aqueous rhodium trichloride in ethanol the ortho-metalated product trans-Rhn,Cl2(N-C-N)(H20) could be isolated in 45% yield (N-C-N = C6H3(CH2NMe2)2-o,oO. Its solid-state structure was determined by an X-ray diffraction study. Crystals are monoclinic, space group P7\jn, with lattice parameters a = 9.070 (1) Á, b = 17.277 (3) Á, c = 9.855 (1) Á, ß = 91.34 (1)°, V = 1543.9 (4) Á3, Z = 4, and ¿(caled) = 1.648 g cm"3. Refinement with 3710 observed reflections converged at R = 0.042. The structure of imni-RhnlCl2(N-C-N)(H20) consists of a rhodium(III) center that is octahedrally coordinated. A mer arrangement of the C and two N atoms of the monoanionic N-C-N ligand (Rh-C(aryl) = 1. 913 (3) Á) and a coordinated water molecule trans to C(aryl) form a planar arrangement. The two mutually trans Cl atoms sited above and below this plane complete the coordination sphere. In the solid state the molecules form infinite chains via intermolecular O-H-Cl hydrogen bonds. Metathesis of this new compound with either a large excess of alkali-metal salt or a slight excess of silver salt led to the formation of a range of new arylrhodium(III) compounds, rranr-RhX2(N-C-N)(H20) (X = Br, 02CH, 02CMe, N03, and CN). Halogen-bridged biand trinuclear complexes RhCl(N-C-N)^-Cl)2M(COD) (M = Rh1, Ir1; COD = 1,5cyclooctadiene) and [RhCl(N-C-N)(^-Cl)2]2M (M = Pd", Cu") were synthesized by mixing fra«y-RhCl2(N-C-N)(H20) with the appropriate metal salt: [MCl(COD)]2, CuCI2, and PdCl2(COD) or Li2PdCl4, respectively.' The same reaction with Li(acac)

Recent Findings in Cyclometallation of meta-Substituted Aryl Ligands by Platinum Group Metal Complexes by Caryl–R Bond Activation (R=H, CR3, SiR3)

“…ligand provides N,C,N'-terdentate coordination. [6] Macrocyclic aryldiamines also display this C ± H bond activation behaviour. [7] In general, other platinum group metal complexes do not undergo selective cyclometallation at C-2 of the 1,3-bis[(dimethylamino)methyl]benzene (NCN) ligand.…”

“…Aryl ligand precursors that contain two meta-positioned S-donor substituents can be cyclometallated selectively at the central C aryl ± H bond by a number of palladium(ii) complexes [Eq. (6)]. Early work by Shaw et al [15] had suggested that only arenes containing bulky groups at the S-donor atoms could be successfully activated at the central C ± H bond.…”

Sensitive analysis of anti‐HIV drugs, efavirenz, lopinavir and ritonavir, in human hair by liquid chromatography coupled with tandem mass spectrometry

“…Therefore, initial coordination of the NCN pincer ligand to the metal precursor, which is an essential prerequisite for cyclometalation, is less favored than with the corresponding PCP and SCS pincer ligands. Moreover, this situation results in kinetically rather than thermodynamically controlled reaction pathways, and consequently, ortho , para doubly metalated products rather than ortho , ortho ‐biscyclometalated species are obtained (Scheme ) 20, 21. Insertion of a Me 3 Si substituent as a directing group on the aromatic system (R 3 =Me 3 Si) successfully suppresses undesired ortho , para ‐metalation 22…”

Metallorganische Pinzetten-Komplexe von Elementen der Platingruppe: Sensoren, Schalter und Katalysatoren

“…Daher ist die für eine Cyclometallierung notwendige Wechselwirkung des NCN‐Pinzetten‐Liganden mit dem Metall‐Ausgangskomplex schwächer als bei den entsprechenden PCP‐ und SCS‐Liganden. Des Weiteren führt diese Situation zur bevorzugten Bildung des kinetisch kontrollierten doppelt metallierten ortho , para ‐Produkts anstelle des thermodynamisch kontrollierten biscyclometallierten ortho , ortho ‐Produkts (Schema ) 20, 21. Allerdings kann die unerwünschte ortho , para ‐Metallierung durch die Einführung eines Me 3 Si‐Substituenten als dirigierende Gruppe am aromatischen System (R 3 =Me 3 Si) erfolgreich unterdrückt werden 22…”