Melissa L. Matthews

Synthesis and complexation of the mixed tellurium–oxygen macrocycles 1-tellura-4,7-dioxacyclononane, [9]aneO2Te, and 1,10-ditellura-4,7,13,16-tetraoxacyclooctadecane, [18]aneO4Te2 and their selenium analogues

1,10-Ditellura-4,7,13,16-tetraoxacyclooctadecane ([18]aneO4Te2) has been synthesised in good yield (50–55%) from Na2Te and ClCH2CH2OCH2CH2OCH2CH2Cl in liquid ammonia, and fully characterised by NMR spectroscopy (1H, 13C{1H} and 125Te{1H}) and mass spectrometry, and by the preparation of the Te(IV) derivatives [18]aneO4Te2Me2I2 and [18]aneO4Te2Cl4. A minor by-product (ca. 4%) of the preparation is 1-tellura-4,7-dioxacyclononane ([9]aneO2Te) which has been isolated and similarly characterised. The corresponding reaction of Na2Se with ClCH2CH2OCH2CH2OCH2CH2Cl in liquid ammonia is less satisfactory and gives variable yields of 1,10-diselena-4,7,13,16-tetraoxacyclooctadecane ([18]aneO4Se2), which is better obtained from the same reagents in ethanol solution under high dilution conditions. [18]aneO4Se2 has also been thoroughly characterised spectroscopically. In these reactions the nine-membered ring 1-selena-4,7-dioxacyclononane is generally produced only in trace amounts. A range of complexes of [18]aneO4Te2 (L) in which the ligand behaves only as a Te2 donor has been synthesised, including cis-[MX2L] (M = Pd or Pt, X = Cl or Br), [RhCl2L2]Y (Y = Cl or PF6), [CuL2]BF4, [AgL2]BF4 and [Cu2L][BF4]2. The complexes have been characterised by microanalysis, multinuclear NMR spectroscopy (1H, 125Te{1H}, 195Pt, 63Cu), ES+ mass spectrometry, UV/visible and IR spectroscopy as appropriate. Two complexes of [9]aneO2Te, cis-[MCl2{[9]aneO2Te}2] (M = Pd or Pt) are also reported, together with the selenoether complex [PtCl2{[18]aneO4Se2}]. The X-ray structures of [MCl2{[18]aneO4Te2}] (M = Pt or Pd) and [PtCl2{[18]aneO4Se2}] all reveal cis square planar coordination with no interaction between the metal and the ether oxygens.

Unusual structural variations within a family of thioether macrocyclic complexes. Tin(IV) halide adducts of [12]-, [14]- and [16]-aneS4

The hydrolytically sensitive compounds [(SnCl4)2([n]aneS4)] (n = 12, 14, 16) and [SnBr4([n]aneS4)] are obtained in good yield upon reaction of 2 mol. equiv. of the parent tin tetrahalide with 1 mol. equiv. of macrocycle in rigorously anhydrous CH2Cl2 solution. Reactions of [16]aneSe4 with SnX4 (X = Cl or Br) affords [SnX4([16]aneSe4)], while reaction of [8]aneSe2 gives [SnCl4([8]aneSe2)]. The crystal structures of the three closely related complexes [SnBr4([12]aneS4)], [SnBr4([14]aneS4)]·2/3CH2Cl2 and [SnBr4([16]aneS4)] have been determined. These species represent the first examples of Sn(IV) halide adducts with neutral Group 16 ligands which adopt polymeric structures. The complexes are all chain polymers, although there is unexpected structural dependence upon the macrocycle ring-size, giving each a distinct structural form. Unusually, the coordinated S atoms in both [SnBr4([14]aneS4)]·2/3CH2Cl2 and [SnBr4([16]aneS4)] adopt a mutually trans arrangement. Far-IR spectra indicate that the chloro complexes all exist as cis octahedral tin(IV) species. Solution NMR spectroscopy shows that the tetrathia and tetraselena macrocyclic complexes are extensively dissociated at 295 K.

A comparison of the ligating properties of the mixed P/O- and P/S-donor ligands Ph2P(CH2)2O(CH2)2O(CH2)2PPh2 and Ph2P(CH2)2S(CH2)2S(CH2)2PPh2 with group 6 and 7 carbonyls

[M(CO)(4)(nbd)] (M = Cr or Mo) react with L-1 (Ph2P(CH2)(2)O(CH2)(2)O(CH2)(2)PPh2) to give the trans-[Cr(CO)(4)(L-1)] and cis-[Mo(CO)(4)(L-1)] respectively, both of which show coordination of L-1 through the P atoms only, giving 11-membered ring metallocyclic complexes. The crystal structure of [MO(CO)(4)(L-1)] confirms the cis-geometry of the product. The cis-[W(CO)(4)(L-1)] is obtained similarly from [W(CO)(4)(TMPA)]. Prolonged reaction of [MnCl(CO)(5)] with L-1 affords mer-trans-[MnCl(CO)(3)(L-1)], with L-1 functioning as a trans chelate via the phosphine functions. The kinetic product fac-[MnCl(CO)(3)(L-1)] is obtained when short reaction times are used. In contrast, [ReBr(CO)(5)] reacts with L-1 to give [ReBr(CO)(3)(L-1)] as a mixture of geometric isomers. Both 1:1 and 2:1 M:L-2 (L-2 = Ph2P(CH2)(2)S(CH2)(2)S(CH2)(2)PPh2) may be obtained for M = Mn(I) or Mn(0). The [MnCl(CO)(3)(L-2)] exists in solution as the fac isomer with L-2 functioning as a bidentate P,S-donor ligand giving a five-membered chelate ring and with the remaining thioether and phosphine functions uncoordinated. Addition of a further equivalent of [MnCl(CO)(5)] affords the binuclear fac-[{MnCl(CO)(3)}(mu(2)-L-2)], with symmetrical P,S-chelation to each metal centre. Similar behaviour is seen for Mo, thus cis-[{Mo(CO)(4)}(2)(mu(2)-L-2)] involves P,S-chelation to each Mo(0) ion. The related 1:1 species cis-[Mo(CO)(4)(L-2)] exists as a mixture of two compounds each with bidentate L-2 coordination, the P-2-chelate (11-membered ring metallocycle) and P,S-coordinated (five-membered chelate ring) species. The new compounds are characterised by microanalyses, IR, H-1-, C-13{H-1}-, P-31{H-1}-,Mn-55-NMR spectroscopy and mass spectrometry as appropriate. The different ligating properties of the related compounds L-1 and L-2 are discussed.

Silver(I) complexes with the mixed P/O donor ligand Ph2P(CH2)2O(CH2)2O(CH2)2PPh2 (L1) and the crystal structures of [Ag(L1)](CF3SO3), [Ag2(L1)3](CF3SO3)2 and [Ag(L1)(NO3)]

Abstract The Ag(I) salts AgY (Y=ClO4, CF3SO3, NO3, Cl or I) react with one molar equivalent of the diphosphinodiether ligand Ph2P(CH2)2O(CH2)2O(CH2)2PPh2 (L1) to give 1:1 species of stoichiometry Ag(L1)Y. The structures of these species have been investigated in solution by 31P NMR spectroscopy and for [Ag(L1)](ClO4), [Ag(L1)](CF3SO3) and [Ag(L1)(NO3)] in the solid state by single crystal X-ray diffraction. In particular, the 107Ag–P and 109Ag–P coupling constants provide a convenient method for identifying the solution speciation, especially for the occurrence of anion coordination in the nitrate and halide complexes. The conclusions from the NMR spectroscopic studies are also consistent with the solid state structures. Addition of a further equivalent of L1 to [Ag(L1)](CF3SO3) results in a very significant drop in the Ag–P coupling constants, indicative of higher P-coordination at Ag(I), now involving three P-donor atoms. This conclusion is also borne out by a crystallographic study on [Ag2(L1)3](CF3SO3)2 which shows a dinuclear cation with one chelating L1 and one bridging L1 ligand coordinated to each metal centre, giving a distorted trigonal planar geometry.

Synthesis, characterisation and coordinating properties of the small ring S2Te-donor macrocycles [9]aneS2Te, [11]aneS2Te and [12]aneS2Te

The reaction of Na2Te with various α,ω-dichlorodithioether reagents in thf–NH3(l) at ca. −78 °C produces moderate yields of the [1+1] cyclisation products, [9]aneS2Te (1,4-dithia-7-telluracyclononane), [11]aneS2Te (1,4-dithia-8-telluracycloundecane) and [12]aneS2Te (1,5-dithia-9-telluracyclododecane), together with polymer. These new small ring macrocycles may be purified by flash column chromatography on silica (11-and 12-membered rings) or by recrystallisation from MeOH–thf (9-membered ring), affording yellow waxy solids. The products have been characterised by NMR (1H, 13C{1H} and 125Te{1H}) and IR spectroscopy, mass spectrometry and the crystal structures of [11]aneS2Te and [12]aneS2Te have been obtained. The more stable organo-Te(IV) derivatives [n]aneS2TeI2 (n = 11 or 12) and [n]aneS2TeMeI (n = 9, 11 or 12) are obtained in high yield as powdered solids by reaction with I2 or MeI and these have been characterised similarly. A crystal structure of [12]aneS2TeI2 has also been determined and is compared with the parent macrocycle. The synthesis of [9]aneS2Te is more sensitive to the precise reaction conditions than the others, and is accompanied by the formation of the ring-contraction products 1-thia-4-telluracyclohexane and 1,4-dithiane. These too have been characterised by NMR and IR spectroscopy and by mass spectrometry. The former has been unambiguously identified by X-ray crystallography and its Te(IV) methiodide derivative has been prepared for comparison. The ligating properties of the new dithiatellura-macrocycles have been investigated with a variety of transition metal species giving fac-[Mn(CO)3(L)]CF3SO3, cis-[MCl2(L)] (M = Pd or Pt), [Rh(Cp*)(L)](PF6)2, [Cu(L)]BF4 and [Ag(L)]CF3SO3. Where possible, the mode of coordination has been established by spectroscopic methods, ring-size effects established and the data compared with other complexes incorporating related cyclic and acyclic ligands.

Tris­(nitrato-κ2O,O′)­tris­(tri­phenyl­phosphine oxide-κO)­terbium(III) acetone sesquisolvate

The title compound, [Tb(NO3)(3)(C18H15OP)(3)] . 1.5(CH3)(2)CO, contains discrete molecules with nine-coordinate Tb atoms, all nitrate groups being bonded as symmetrical bidentate ligands; Tb - O(P) = 2.307 (4), 2.309 (4) and 2.295 (4) Angstrom, and Tb-O( N) = 2.467 (4)- 2.539 (4) Angstrom).

Synthesis, properties and structures of eight-coordinate zirconium(IV) and hafnium(IV) halide complexes with phosphorus and arsenic ligands

Eight-coordinate [MX(4)(L-L)(2)] (M = Zr or Hf; X = Cl or Br; L-L = o-C(6)H(4)(PMe(2))(2) or o-C(6)H(4)(AsMe(2))(2)) were made by displacement of Me(2)S from [MX(4)(Me(2)S)(2)] by three equivalents of L-L in CH(2)Cl(2) solution, or from MX(4) and L-L in anhydrous thf solution. The [MI(4)(L-L)(2)] were made directly from reaction of MI(4) with the ligand in CH(2)Cl(2) solution. The very moisture-sensitive complexes were characterised by IR, UV/Vis, and (1)H and (31)P NMR spectroscopy and microanalysis. Crystal structures of [ZrCl(4)[o-C(6)H(4)(AsMe(2))(2)](2)], [ZrBr(4)[-C(6)H(4)(PMe(2))(2)](2)], [ZrI(4)[o-C(6)H(4)(AsMe(2))(2)](2)] and [HfI(4)[o-C(6)H(4)(AsMe(2))(2)](2)] all show distorted dodecahedral structures. Surprisingly, unlike the corresponding Ti(iv) systems, only the eight-coordinate complex was found in each system. In contrast, the ligand o-C(6)H(4)(PPh(2))(2) forms only six-coordinate complexes [MX(4)[-C(6)H(4)(PPh(2))(2)]] which were fully characterised spectroscopically and analytically. Surprisingly the tripodal triarsine, MeC(CH(2)AsMe(2))(3), also produces eight-coordinate [MX(4)[MeC(CH(2)AsMe(2))(3)](2)] in which the triarsines bind as bidentates in a distorted dodecahedral structure. There is no evidence for seven-coordination as found in some thioether systems.