Bis[( 2-dimethylaminomethyl)phenyl] diselenide (RSe), was obtained by the organolithium route. It underwent facile reaction with stoichiometric amounts of bromine and iodine to give the corresponding arylselenium halides RSeBr and novel RSeI in which the selenium is covalently bonded to iodine. With an excess of bromine it gave the corresponding tribromide RSeBr, but a similar reaction with iodine gave only RSeI. With diazomethane it gave the selenoether (RSe),CH, and with HCl the known bis(hydroch1oride) (RSe),*2HCI. A catalytic conversion of alkenes into allylic acetates using (RSe), was carried out. The compounds were characterised by elemental analyses, mass, multinuclear NMR ('H, ,C, '?Se), IR, Fourier-transform-Raman spectrometry and conductance measurements. The compound RSeBr, shows evidence for the existence of
The condensation of bis(2-formylphenyl) telluride 1 with ethane-I ,2-diamine yielded the novel macrocyclic tellurium ligand 2 via metal-free dimerisation. Crystals of 2 are triclinic, space group P i with a = 7.956(3), h = 9.885(2), c = 10.068(2) A, 2 = 1. Hydrogenation of macrocycle 2 provided the corresponding saturated tetraazamacrocycle 3, protonation of which with HBr afforded 4. The co-ordination chemistry of 2 has been studied with 'soft' metal ions such as palladium(1r) and mercury(I1). N,N'-Bis[(2-chlorotelluranyl)benzylidenelethane-1,2-diamine has also been characterised by an X-ray diffraction study, with triclinic space group P i , a = 7.71(1), b = 7.90(1), c = 8.52(1) A and Z = 1.Supramolecular chemistry, which involves the design and synthesis of polytopic macrocyclic and macrobicyclic ligands containing several recognition sites, is a promising area of considerable current interest. Recently there have been extensive studies on the synthesis and ligating behaviour of macrocyclic Schiff bases containing phenol, pyridine, pyrrole, furan and thiophene units.' Very recently the first example of a Schiff-base macrocycle containing a pyridazine unit has been reported., Most of the work in this area has focussed on the design and synthesis of receptors which are selective for 'hard' metal ions. Recently Beer et al., have described the synthesis of several polyazamacrocyclic complexes which incorporate both 'hard' and 'soft' metal ions and contain multiple metallocene redoxactive groups. Interest in macrocycles which contain 'hard' and 'soft' donor atoms to complex both 'hard' and 'soft' metal cations derives from their intrinsic potential for (i) modulation of the redox properties of a complexed 'soft' transition-metal cation upon co-complexation of a 'hard' cation, (ii) allosteric effects and (iii) bimetallic activation and catalysis., Although a few examples of polyazamacrocycles containing 'soft' sulfur ' or phosphorus and 'hard' nitrogen donor atoms are known, to our knowledge neither selenium nor tellurium has been incorporated into a macrocyclic Schiff base. Some homoleptic selenoether macrocycles, however, have been reported. We report here an easy high yield synthesis, structure and co-ordination of a novel tellurium-containing azamacrocycle (see Scheme 1). Experiment a1 Materials and methodsBis(2-formylphenyl) telluride and [PdCl,(NCC,H,)] were prepared by reported procedures. Air-sensitive reactions were carried out under an inert atmosphere. Solvents were purified by standard techniques and were freshly distilled prior to use. Ethane-1,2-diamine (en) (SISCO) was reagent grade and was distilled prior to use. Melting points were recorded in capillary tubes on a Ketari melting point apparatus and are uncorrected. Proton (299.94 MHz), 13C (75.42 MHz) and 12'Te (94.75 MHz) NMR spectra were recorded on a Varian VXR 300s spectrometer. Chemical shifts are cited with respect to SiMe, as internal standard ('H and ' ,C) and Te(S,CNEt,), as external standard (' ,'Te). Elemental analyses were performed on a...
The synthesis and characterization of homoleptic zinc(II), cadmium(II), and mercury(II) selenolates incorporating the intramolecularly chelating oxazoline ligand are described. The derivatives, M[Se(Ox)](2) [M = Zn (1), Cd (2), Hg (3); Ox = 2-(4,4-dimethyl-2-oxazolinyl)benzene], were prepared in good yield via the metathesis reactions of MCl(2) with a lithium areneselenolate, OxSe(-)Li(+). The mercury complex 3 was also synthesized by treating the corresponding diselenide with elemental mercury. The complexes are quite stable and highly soluble in common nonpolar organic solvents. X-ray diffraction results show that the complexes are monomeric in the solid state. The geometry around the metal ion in all complexes is found to be distorted tetrahedral. The crystal structure of Zn[Se(Ox)](2) (1) shows that the complex is "helically" chiral and enantiomerically pure. The spontaneous splitting of the racemates indicates the solubility differences between the racemates and pure enantiomers. (1)H, (13)C, and (77)Se NMR measurements indicate that complex 1 retains its "helical" structure in solution. Crystal data (Mo Kalpha; 293(2) K) are as follows: 1, monoclinic space group P2(1), a = 9.3900(12) Å, b = 11.618(2) Å, c = 10.8822(14) Å, beta = 98.245(8) degrees, Z = 2; 2, orthorhombic space group Pbca, a = 12.777(6) Å, b = 17.841(10) Å, c = 21.010(8) Å, Z = 8; 3, monoclinic space group P2(1)/c, a = 9.087(2) Å, b = 11.889(2) Å, c = 22.456(4) Å, beta = 98.780(13) degrees, Z = 4.
The synthesis and characterization of chiral hybrid ligand R 2 *Se 2 (R* ) 2-Me 2 NCH(Me)C 6 H 4 ) (9) and some of its derivatives is described. The reaction of 9 with a Pd(II) chloride complex leads to cleavage of the Se-Se bond and formation of the corresponding areneselenenyl chloride, R*SeCl (18). However, reactions of [RS; RS] and [SR; SR] bis[2-{1-(dimethylamine)ethyl}ferrocenyl] diselenides (7 and 8) with a Pd(II) chloride complex under identical conditions afford dinuclear complexes [PdCl{(SeC 5 H 3 CH(Me)NMe 2 -2)Fe(C 5 H 5 )}] 2 (19 and 20). Reaction of achiral ditelluride, R 2 Te 2 (R ) 2-Me 2 NCH 2 C 6 H 4 ) (10), with a Pd(II) chloride complex gives a novel dinuclear complex, [PdCl(TeC 6 H 4 CH 2 NMe 2 -2)] 2 (21), and the dimeric tellurium complex (RTeCl) 2 ( 22), whereas the reaction of chiral Schiff base tridentate tellurium ligand R′ 2 Te (R′ ) 2-C 6 H 4 CHd NCH(Me)C 6 H 5 ) (11) with a Pd(II) chloride complex produces cleaved products (R′PdCl) 2 ( 23) and (R′TeCl) 2 (24). Similarly, the reaction between the tridentate ligand R 2 Te (12) and Pd(COD)Cl 2 gives 22 and the dimeric palladium complex (RPdCl) 2 ( 25). The treatment of bidentate ligand RTeMe ( 13) results in decomposition of the ligand and precipitation of Te. All the compounds are characterized by detailed IR and NMR ( 1 H, 13 C, 77 Se, and 125 Te) spectroscopic techniques, MS, and optical rotation measurements. The structures of R*SeBr (17), 21, 24, and 25 were determined by single-crystal X-ray crystallography. In 17 the coordination geometry around selenium is essentially T-shaped with a short Se • • • N distance (2.132(6) Å). The palladium tellurolato complex 21 crystallizes as a centrosymmetric dimer. Compound 23 crystallizes as a dimer in which each tellurium atom coordinates to two bridging chlorines, one nitrogen, and one carbon. Compound 25 crystallizes as a chloro-bridged centrosymmetric dimer.
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