Excess MeI Research Articles

Co-ordination chemistry of a P,O-donor ligand: synthesis of new complexes of Ru, Rh and Ir containing Ph2PNHP(O)Ph2 or [Ph2PNP(O)Ph2

Methylation of the monooxide Ph2PNHP(O)Ph2(HL) with MeI in tetrahydrofuran afforded [{Ph2P(Me)NP(O)Ph2}2H]I which contains a symmetrical hydrogen bond, whereas benzylation with PhCH2Br gave [Ph2P(CH2Ph)NP(OH)Ph2]Br. The compound HL can be complexed, as a monodentate P-bound ligand, to various, metal centres (RuII, RuIV, RhIII and IrIII). These compounds are excellent precursors for the construction of new five-membered metallacycles containing either M–P–N(H)–P–O or M–P–N–P–O rings. Treatment of [Ir{Ph2PNHP(O)Ph2-P,O}(cod)][BF4](cod = cycloocta-1,5-diene) with an excess of MeI gave the oxidative addition compound [IrI(Me){Ph2PNHP(O)Ph2-P,O}(cod)][BF4] in which a cis configuration of the iodide and methyl ligands is tentatively assigned. Deprotonation of it with NEt3 gave the known neutral iridium(III) complex [IrI(Me){Ph2PNP(O)Ph2-P,O}(cod)]. All compounds were characterised by a combination of 31P-{1H} and 1H NMR spectroscopy, IR spectroscopy and microanalysis. The solid-state structures of [{Ph2P(Me)NP(O)Ph2}2H]I, [Ph2P(CH2Ph)NP(OH)Ph2]Br, [Rh{Ph2PNHP(O)Ph2-P,O}(cod)]-[BF4]·0.33CHCl3 and [RuCl{Ph2PNP(O)Ph2-P,O}(η6-p-MeC6H4Pri)] have been elucidated by X-ray crystallography. The two complexes contain the P,O-chelating ligand Ph2PNHP(O)Ph2 and [Ph2PNP(O)Ph2]– respectively. With the exception of the rhodium complex the P–N–P–O fragments all show π-electron delocalisation.

ChemInform Abstract: Synthesis, Structure, and Some Reactions of Tris‐ and Tetrakis(diphenylphosphino)allenes.

AbstractThe title compounds (III) and (VII) react with excess of MeI (V) to afford the salt (VIII) (in part no yields given).

Spaltung von tetramethyldistiban mit brom, iod und methyliodid. Bildung des addukts MeSbI 2·2 Me 4SbI

Very pure halides Me 2SbX (X = Br, I) are obtained by a cleavage reactions of Me 2SbSbMe 2 with equimolar amounts of Br 2 or I 2. Me 3Sb and Me 2SbI are formed in the reaction of Me 2SbSbMe 2 and MeI in a 1/1 molar ratio. With excess MeI the products are: Me 4SbI, Me 3SbI 2 and an adduct of composition MeSbI 2 · 2Me 4SbI, which can also be formed by the reaction of its components.

Purines. XXII. Methylation of 1-,3-,7-,9-, and N6-methyladenines bearing a methoxyl group at the N6-position: A synthesis of 7,9-dimethyladenine.

In order to investigate the effect of the N6-methoxy group on the site of methylation, N6-methyl-(27), 1-methyl-(17), 3-methyl-(11), 7-methyl-(7), and 9-methyl-N6-methoxyadenine (2) were methylated with an excess of MeI in AcNMe2. The products isolated were the 3-methylated product 12·HClO4 (67%yield) and 9-methylated product 3 (18%) from 27 ; 3-methylated product 15 (X=I) (44%) and 9-methylated product 18·HClO4 (38%) from 17 ; 15 (X=I) (40%) and 12·HClO4 (36%) from 11 ; 9-methylated product 5 (X=I) (36%) and 3-methylated product 8 (44%) from 7 ; 5 (X=I) (59%) and 3·HI (24%) from 2. Further methylation of 18 in a similar manner was found to give N6-methoxy-1, 7, 9-trimethyladeninium iodide (33 : X=I) in 92% yield. A similar methylation of the betaine 32, generated from 5 (X=I) by treatment with 1, 8-diazabicyclo [5. 4. 0] undec-7-ene (DBU), also produced 33 (X=I) in fair yield. The 7, 9-dimethyl derivative 5 (X=I) thus obtained was converted into the perchlorate 5 (X=ClO4), and hydrogenolysis of 5 (X=ClO4) using Pd-C and hydrogen furnished hitherto unknown 7, 9-dimethyladeninium perchlorate (6 : X=ClO4) in good yield. The substrates 11 and 27 used for the methylation study were prepared in 87 and 86% yields from 3-methyl-6-methylthiopurine (10) and 6-chloropurine (26) by amination with methoxyamine and N, O-dimethylhydroxylamine, respectively. For the synthesis of the substrate 17, 1-methoxyadenosine (25) was methylated to give the N6-methyl derivative 23. Treatment of 23 with hot water and hydrolysis of the resulting isomer 21 with 98% formic acid afforded the desired compound 17.

Basic Metals : XXXIII. Synthesis and reactivity of pentamethylcyclopentadienylrhodium(I) complexes: metal basicity versus phosphorus basicity in C 5Me 5Rh(CO)P 2Me 4

C 5Me 5Rh(CO) 2 (I) reacts with PMe 3 and P 2Me 4 to give C 5Me 5Rh(CO)PMe 3 (II) and C 5Me 5Rh(CO)P 2Me 4 (VIII), respectively, in high yields. Reactions of II with acids HX yields stable salts IIIa–IIIc of the hydridorhodium cation [C 5Me 5RhH(CO)PMe 3] +, whereas methyl and ethyl iodide give the acyl complexes C 5Me 5RhI(COR)PMe 3 (IV,V); the latter react with AgPF 6 to form [C 5Me 5RhR(CO)PMe 3]PF 6 (VI, VII). Treatment of the tetramethyldiphosphine complex VIII with MeI in 1 : 1 molar ratio yields C 5Me 5RhI(COMe)P 2Me 4 (X), which with excess MeI forms [C 5Me 5RhI(COMe)P 2Me 5]I (XI). The syntheses of [C 5Me 5RhMe(CO)P 2Me 4]X (XIIa: X = BF 4; XIIb: X = PF 6), [C 5Me 5RhMe(CO)P 2Me 5](PF 6) 2 (XIII) and the dinuclear rhodium(I) complex [C 5Me 5Rh(CO)]-(μ-P 2Me 4) (IX) are also described.