Binuclear Orthometalated N,N-Dimethylbenzylamine Complexes of Palladium(II): Synthesis,Structures and Thermal Behavior

Abstract

Organochalcogenolate-bridged cyclometalated palladium(II) complexes of the formulae, [Pd₂(μ-Epy)₂(Me₂NCH₂C₆H₄-C,N)₂] (2) (E = S (2a), Se (2b)), [Pd₂(μ-SAr)(μ-Cl)(Me₂NCH₂C₆H₄-C,N)₂] (3) (Ar = Ph (3a), Mes (Mes = 2,4,6-Me₃C₆H₂) (3b)) and [Pd₂(μ-SeAr)₂(Me₂NCH₂C₆H₄-C,N)₂] (4) (Ar = Ph (4a), Mes (4b)), have been synthesized by the reactions of [Pd₂(μ-Cl)₂(Me₂NCH₂C₆H₄-C,N)₂] with lead or sodium salts of the chalcogenolate ligand. These complexes have been characterized by elemental analysis, mass spectral data, and NMR (¹H and ⁷⁷Se{¹H}) spectroscopy. The molecular structure of 2, determined by single crystal X-ray diffraction analysis, revealed a Epy-bridged head-to-tail arrangement in which the eight-membered “(PdECN)₂” ring adopts a distorted twist boat conformation. The Pd····Pd separation in 2a is within the van-der-Waals interaction but in 2b it is too large to support the presence of any metal–metal interaction. The thermal behavior of these complexes has been studied by thermogravimetric analysis.     

Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)4] Complexes

Compound Et₃SiOCH₂NMe₂ transfers Me₂NCH₂ to R₂NH (R₂=Et₂, PhMe, [Cr(η⁶‐C₆H₅)(CO)₃]Me, PhH) to form previously unknown diaminomethanes, Me₂NCH₂NR₂ and, in the case of R₂=PhH, the triamine Me₂NCH₂N(Ph)CH₂NMe₂. The diaminomethanes exhibit an unreported disproportionation to a mixture of (R₂N)₂CH₂, (Me₂N)₂CH₂, and Me₂NCH₂NR₂, which can be trapped as their [Mo(CO)₄(diamine)] complexes. Whereas PhMeNCH₂NMe₂ is a labile material, the metal‐substituted ([(η⁶‐C₆H₅)Cr(CO)₃]MeNCH₂NMe₂ is a stable material. The triamine Me₂NCH₂N(Ph)CH₂NMe₂ is unstable with respect to transformation to 1,3,5‐triphenyltriazine, but is readily trapped as the bidentate‐triamineMo(CO)₄. All metal complexes were characterized by single‐crystal X‐ray diffraction.     

Synthesis and conformational studies of palladium(II) complexes containing [PhP(O)NP(E)Ph]− (E=S or Se)

The ligands [Ph₂P(O)NP(E)Ph₂]⁻ (E=S I; E=Se II) can readily be complexed to a range of palladium(II) starting materials affording new six-membered Pd–O–P–N–P–E palladacycles. Hence ligand substitution reaction of the chloride complexes [PdCl₂(bipy)] (bipy=2,2′-bipyridine), [{Pd(μ-Cl)(L–L)}₂] (HL–L=C₉H₁₃N or C₁₂H₁₃N), [{Pd(μ-Cl)Cl(PMe₂Ph)}₂] or [PdCl₂(PR₃)₂] [PR₃=PPh₃; 2PR₃=Ph₂PCH₂CH₂PPh₂or cis-Ph₂PCH=CHPPh₂] with either I (or II) in thf or CH₃OH gave [Pd{Ph₂P(O)NP(E)Ph₂-O,E}(bipy)]PF₆, [Pd{Ph₂P(O)NP(E)Ph₂-O,E}(L–L)], [Pd{Ph₂P(O)NP(E)Ph₂-O,E}Cl(PMe₂Ph)] or [Pd{Ph₂P(O)NP(E)Ph₂-O,E} (PR₃)₂]PF₆ in good yields. All compounds described have been characterised by a combination of multinuclear NMR [31 P{1 H} and 1 H] and IR spectroscopy and microanalysis. The molecular structures of five complexes containing the selenium ligand II have been determined by single-crystal X-ray crystallography. Three different ring conformations were observed, a pseudo-butterfly, hinge and in the case of all three PR₃ complexes, pseudo-boat conformations. Within the Pd–O–P–N–P–Se rings there is evidence for π-electron delocalisation.     

Reaction of 3-dimethylamino-(1,1 -dimethyl) propyl magnesium chloride with tin (IV) and tin (II) chlorides. Stabilization of a SnCl+ cation in the new tin cluster [Me2NCH2CH2C(Me2)SnCl]3 · SnCl2

The reactions of the functional Grignard reagent Me₂ NCH₂CH₂C(Me₂)MgCl (4) with tin tetrachloride, dimethyltin dichloride, and tin (II) chloride are described. From the reactions the compounds bis(3-dimethylamino-1,1-dimethylpropyl) tin dichloride, [Me₂NCH₂CH₂C(Me₂)]₂SnCl₂ (5) , dimethyl(3-dimethylamino-1,1-dimethylpropyl) chlorostannane, Me₂ClSnC(Me₂)CH₂CH₂NMe₂ (6) , 1,1,2,2-tetramethyl-1,2-bis(3-dimethylamino-1,1-dimethylpropyl) distannane,[Me₂SnC(Me₂)CH₂CH₂NMe₂]₂ (7) , 3-dimethylamino-(1,1-dimethyl)propyl tin (II) chloride, Me₂NCH₂CH₂C(Me₂)SnCl (8) , hexakis(3-dimethylamino-1,1-dimethylpropyl) cyclotristannane, {[Me₂NCH₂CH₂C(Me₂)]₂Sn}₃ (9a) , and the tin cluster [Me₂NCH₂CH₂C(Me₂)SnCl]₃ · SnCl₂ (10) have been isolated and characterized by means of multinuclear NMR and Mössbauer spectroscopy, and X-ray diffraction. 10 crystallizes in the trigonal space group P3₁ with the unit cell dimensions a 11.938, c 21.873 Å, V 2699.6 ų Z = 3. The structure was refined to a final R value of 0.064. 10 represents a tetranuclear cluster the skeleton of which is composed out of 4 Sn and a bridging Cl. Formally, the central tin atom is a SnCl⁺ cation stabilized by three stannylene units in a Ψ-trigonal bipyramidal environment. The tin-tin bond lengths are 288.2, 287.3 and 315.6 pm. The intramolecular Sn? N interactions amount to 242.8, 247.4 and 221.0 pm.     

A convenient synthesis of methylindium(III) dithiolate complexes—precursors for indium sulfides

Methylindium(III) dithiolate complexes of the general formulae [Me₂In(S^∩S)] ( 1 ) and [MeIn(S^∩S)₂] ( 2 ) [S^∩S = (EtO)₂PS₂^?, (PrⁱO)₂PS₂^?, Et₂NCS₂^?, , O(CH₂CH₂)₂NCS₂^?, EtOCS₂^? and PrⁱOCS₂^?] have been isolated conveniently by the reaction of Me₃In·OEt₂ with In(S^∩S)₃ ( 3 ) in an appropriate stoichiometry. Both 1 and 2 have been characterized by indium analysis, IR, NMR (¹H, ¹³C{¹H} and ³¹P{H}) and mass spectral data. NMR data of 3 are also included for comparison. The Me–In and S^∩S resonances are sensitive to the number of methyl groups attached to indium metal. The mass spectral data indicate that these complexes are monomeric in nature. The thermal behavior of a few complexes has been investigated. The xanthate and dithiocarbamate complexes on pyrolysis under dynamic vacuum or flowing nitrogen atmosphere gave either In₂S₃ or a mixture of InS, In₂S₃ and In₆S₇, which were characterized using EDAX and powder XRD. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis and spectroscopy of cis-configured mononuclear palladium(II) and platinum(II) complexes of chalcogeno o-carboranes and structures of [Pt(SCboPh)2(dppm)], [Pt(SeCboPh)2(dppm)], [Pt(SCboS)(PMe2Ph)2] and [Pt(SCboS)(PMePh2)2]

The reactions of [MCl₂(P^∩P)] and [MCl₂(PR₃)₂)] with 1-mercapto-2-phenyl-o-carborane/NaSeCb^oPh and 1,2-dimercapto-o-carborane yield mononuclear complexes of composition, [M(SCb^oPh)₂(P^∩P)], [M(SeCb^oPh)₂(P^∩P)] (M = Pd or Pt; P^∩P = dppm (bis(diphenylphosphino)methane), dppe (1,2-bis(diphenylphosphino)ethane) or dppp (1,3-bis(diphenylphosphino)propane)) and [M(SCb^oS)(PR₃)₂] (2PR₃ = dppm, dppe, 2PEt₃, 2PMe₂Ph, 2PMePh₂ or 2PPh₃). These complexes have been characterized by elemental analysis and NMR (¹H, ³¹P, ⁷⁷Se and ¹⁹⁵Pt) spectroscopy. The ¹J(Pt–P) values and ¹⁹⁵Pt NMR chemical shifts are influenced by the nature of phosphine as well as thiolate ligand. Molecular structures of [Pt(SCb^oPh)₂(dppm)], [Pt(SeCb^oPh)₂(dppm)], [Pt(SCb^oS)(PMe₂Ph)₂] and [Pt(SCb^oS)(PMePh₂)₂] have been established by single crystal X-ray structural analyses. The platinum atom in all these complexes acquires a distorted square planar configuration defined by two cis-bound phosphine ligands and two chalcogenolate groups. The carborane rings are mutually anti in [Pt(SCb^oPh)₂(dppm)] and [Pt(SeCb^oPh)₂(dppm)].     

Synthesis and spectroscopy of cis-configured mononuclear palladium(II) and platinum(II) complexes of chalcogeno o-carboranes and structures of [Pt(SCboPh)2(dppm)], [Pt(SeCboPh)2(dppm)], [Pt(SCboS)(PMe2Ph)2] and [Pt(SCboS)(PMePh2)2]

The reactions of [MCl₂(P^∩P)] and [MCl₂(PR₃)₂)] with 1-mercapto-2-phenyl-o-carborane/NaSeCb^oPh and 1,2-dimercapto-o-carborane yield mononuclear complexes of composition, [M(SCb^oPh)₂(P^∩P)], [M(SeCb^oPh)₂(P^∩P)] (M = Pd or Pt; P^∩P = dppm (bis(diphenylphosphino)methane), dppe (1,2-bis(diphenylphosphino)ethane) or dppp (1,3-bis(diphenylphosphino)propane)) and [M(SCb^oS)(PR₃)₂] (2PR₃ = dppm, dppe, 2PEt₃, 2PMe₂Ph, 2PMePh₂ or 2PPh₃). These complexes have been characterized by elemental analysis and NMR (¹H, ³¹P, ⁷⁷Se and ¹⁹⁵Pt) spectroscopy. The ¹J(Pt–P) values and ¹⁹⁵Pt NMR chemical shifts are influenced by the nature of phosphine as well as thiolate ligand. Molecular structures of [Pt(SCb^oPh)₂(dppm)], [Pt(SeCb^oPh)₂(dppm)], [Pt(SCb^oS)(PMe₂Ph)₂] and [Pt(SCb^oS)(PMePh₂)₂] have been established by single crystal X-ray structural analyses. The platinum atom in all these complexes acquires a distorted square planar configuration defined by two cis-bound phosphine ligands and two chalcogenolate groups. The carborane rings are mutually anti in [Pt(SCb^oPh)₂(dppm)] and [Pt(SeCb^oPh)₂(dppm)].     

Synthesis and complexation of a new facultative tridentate S2Te donor ligand MeS(CH2)3Te(CH2)3SMe: crystal structures of [Rh(Cp*)(S2Te)][PF6]2 and [PtCl(S2Te)]PF6

The syntheses and spectroscopic characterisation of the new facultative tridentate tellurium containing ligands MeS(CH₂)₃Te(CH₂)₃SMe (S₂Te) and H₂N(CH₂)₃Te(CH₂)₃NH₂ are described. The complexes of the former, fac-[Mn(CO)₃(S₂Te)]CF₃SO₃, [Rh(Cp*)(S₂Te)][PF₆]₂, [MCl(S₂Te)]PF₆ (M=Pd or Pt), [Cu(S₂Te)]BF₄ and [Ag(S₂Te)]CF₃SO₃ have been prepared and characterised by analysis, IR, ¹H-, ¹³C{¹H}-, ¹²⁵Te- and ¹⁹⁵Pt-NMR spectroscopy and mass spectrometry. The X-ray crystal structures of [Rh(Cp*)(S₂Te)][PF₆]₂ and [PtCl(S₂Te)]PF₆ are described. The results are compared with those obtained from complexes of the related tridentates Te{(CH₂)₃TeR}₂, Se{(CH₂)₃SeMe}₂ and S{(CH₂)₃SR}₂.     

Hypervalent selenium compounds containing N → Se intramolecular interactions: synthesis,characterization and X‐ray structures of [2‐(Me2NCH2)C6H4]SeS(S)PR2 (R = Ph,OiPr)

[2‐(Me₂NCH₂)C₆H₄]Se? S(S)PR₂ [R = Ph (1), OⁱPr (2)] were prepared by reacting [2‐(Me₂NCH₂)C₆H₄]₂Se₂ with the appropriate disulfanes, [R₂P(S)S]₂. The compounds were characterized by multinuclear magnetic resonance (¹H, ¹³C, ³¹P). The molecular structures of 1 and 2 were determined by single‐crystal X‐ray diffraction. Both compounds are monomeric and the nitrogen atom of the pendent CH₂NMe₂ arm is strongly coordinated to the selenium atom. The organophosphorus ligands are monodentate, thus resulting in a T‐shaped coordination geometry around selenium. Copyright © 2002 John Wiley & Sons, Ltd.     

Syntheses of phenoxo-bridged Zn(II) and metallamacrocyclic Hg(II) complexes of organochalcogen (Se,Te) substituted Schiff-bases: structure and DNA-binding studies of Zn(II) complexes

The coordination of organochalcogen (especially Se and Te) substituted Schiff-bases L¹H, L²H, L³H, and L⁴H toward Zn(II) and Hg(II) has been studied. Reactions of these ligands with ZnCl₂ in 1?:?1 molar ratio gave binuclear complexes [{2-[PhX(CH₂) _n N?=?C(Ph)]-6-[PhCO]-4-MeC₆H₂O}₂Zn₂Cl₂] (where X?=?Se, n?=?2 (1); X?=?Se, n?=?3 (2); X?=?Te, n?=?2 (3); and X?=?Te, n?=?3 (4)) with partial hydrolytic cleavage of proligands. In these complexes, two partially hydrolyzed ligand fragments coordinate tridentate (NOO) with two Zn's. Reaction of HgBr₂ with L¹H and L²H in 1?:?1 molar ratio gave monometallic complexes [C₆H₂(4-Me)(OH)[2,6-{C(Ph)?=?N(CH₂) _n Se(Ph)}₂HgBr₂]] (n?=?2 (5) or 3 (6)) and under similar conditions with L³H and L⁴H gave bimetallic complexes [C₆H₂(4-Me)(OH)[2,6-{C(Ph)?=?N(CH₂) _n Te(Ph)}₂Hg₂Br₄]] (n?=?2?(7) or 3 (8)) in which the ligands coordinate with metal through selenium or tellurium, leaving the imino nitrogen and phenolic oxygen uncoordinated. The proligands L¹H, L²H give 14- or 16-membered metallamacrocycles through Se–Hg–Se linkages and L³H, L⁴H give 16- or 18-membered metallamacrocycles through Te–Hg–Br–Hg–Te linkages. All the complexes were characterized by elemental analyses, ESIMS, FTIR, multinuclear NMR, UV-Vis, and conductance measurements. The redox properties of the complexes were investigated by cyclic voltammetry (CV). Complexes 1–4 exhibited ligand-centered irreversible oxidation processes. Complexes 5 and 6 showed metal-centered quasi-reversible single electron transfer, whereas dinuclear complexes 7 and 8 displayed two quasi-reversible, one-electron transfer steps. A single-crystal X-ray structure determination of 1 showed that the coordination unit is centrosymmetric with Zn(II) in square-pyramidal coordination geometry and the two square pyramids sharing an edge. The Zn?···?Zn separation is 3.232?Å. The DNA-binding properties of 1 and 3 with calf thymus DNA were explored by a spectrophotometric method and CV.     

Darstellung und Eigenschaften von 3-(N,N-Dimethylamino)propyl-Verbindungen des Thalliums

Preparation and Properties of 3-(N,N-Dimethylamino)propyl Thallium Compounds TlCl₃ reacts with Me₂NCH₂CH₂CH₂Li in molar ratio 1:2 with formation of (Me₂NCH₂CH₂CH₂)₂TlCl ( 1 ) which can be transfered with MeLi into (Me₂NCH₂CH₂CH₂)₂TlMe ( 2 ) and with excess of Me₂NCH₂CH₂CH₂Li into (Me₂NCH₂CH₂CH₂)₃Tl ( 3 ) respectively. Comproportionation of 1 with TlCl₃ yields rather instable Me₂NCH₂CH₂CH₂TlCl₂ ( 4 ) from which Me₂NCH₂CH₂CH₂TlMe₂ ( 5 ) can be obtained by alkylation with MeLi. 1–3 and 5 were characterized by elemental analysis, mass spectra, ¹H- and ¹³C-n.m.r. spectra.     

Palladium(II) and platinum(II) 2-(methoxycarbonyl)ethylselenolates: Synthesis, spectroscopy, structures and their conversion into metal selenide

A diselenide, (MeOOCCH₂CH₂Se)₂ (1) has been prepared by esterification of (HOOCCH₂CH₂Se)₂ in methanol. The reductive cleavage of Se-Se bond in 1 by NaBH₄ in methanol generates MeOOCCH₂CH₂SeNa. The latter in different stoichiometries reacts with [M₂Cl₂(μ-Cl)₂(PR₃)₂] to give a variety of products of compositions [M₂Cl₂(μ-SeCH₂CH₂COOMe)₂(PR₃)₂] (2); [M₂Cl₂(μ-Cl)(μ-SeCH₂CH₂COOMe)(PR₃)₂] (3); [Pd₂(SeCH₂CH₂COOMe)₂(μ-SeCH₂CH₂COOMe)₂(PR₃)₂] (4);[Pd₃Cl₂(μ-SeCH₂CH₂COOMe)₄(PR₃)₂] (5). Treatment of complexes 2 with [M₂Cl₂(μ-Cl)₂(PR₃)₂] affords complexes 3 in nearly quantitative yield. The formation of various products in these reactions is sensitive to stoichiometric ratio of reactants employed. This enables interconversion of various complexes by manipulating mole ratios of appropriate starting materials. A homoleptic palladium complex, [Pd(SeCH₂CH₂COOMe)₂]₆ (6) was isolated from a reaction between Na₂PdCl₄ and MeOOCCH₂CH₂SeNa. All these complexes have been characterized by elemental analysis, IR, UV-Vis and NMR (¹H, ¹³C, ³¹P, ⁷⁷Se, ¹⁹⁵Pt) spectroscopy. Structures of trans-[Pd₂Cl₂(μ-SeCH₂CH₂COOMe)₂(PPh₃)₂] (2d), [Pt₂Cl₂(μ-Cl)(μ-SeCH₂CH₂COOMe)(PⁿPr₃)₂] (3e), [Pd₃Cl₂(μ-SeCH₂CH₂COOMe)₄(PⁿPr₃)₂] (5) and [Pd(SeCH₂CH₂COOMe)₂]₆ (6) have been established unambiguously by X-ray crystallography. In these complexes, there are bridging selenolate ligands with their uncoordinated ester groups. Compound 6 has a centrosymmetric Pd₆Se₁₂ hexagon in which every two palladium atoms are bridged by selenolate ligands. Thermal behaviour of some complexes has been investigated. Pyrolysis of compound 2b in tributylphosphate at 195 °C gave Pd₁₇Se₁₅ nanoparticles which were characterized by XRD and EDAX.     

Tellurium(IV) Fluorides and Azides containing the Nitrogen Donor Substituent R = 2‐Me2NCH2C6H4; Crystal Structure of RTeF3 and of an Unusual Tellurium(VI) Fluoride Salt

The tellurenyl fluoride, 2‐Me₂NCH₂C₆H₄TeF, was obtained from reaction of the tellurenyl iodide RTeI with AgF. The compound was unambiguously identified by ¹⁹F and ¹²⁵Te NMR spectroscopy. The decomposition under disproportionation leads to the tellurium(IV) trifluoride, 2‐Me₂NCH₂C₆H₄TeF₃ and the ditelluride RTeTeR. The fluorination of the ditelluride, (2‐Me₂NCH₂C₆H₄Te)₂, with XeF₂ results in pure RTeF₃. The molecular structure of 2‐Me₂NCH₂C₆H₄TeF₃, the second structural characterized tellurium(IV) trifluoride, has been determined. Furthermore the syntheses of the new tellurium(IV) difluoride, (2‐Me₂NCH₂C₆H₄)₂TeF₂, and corresponding tellurium(IV) diazide, (2‐Me₂NCH₂C₆H₄)₂Te(N₃)₂ as well as the tellurium(IV) triazide, 2‐Me₂NCH₂C₆H₄Te(N₃)₃, and their characterization by spectroscopic methods were reported. During these investigations a rather interesting tellurium(VI) species was formed and the molecular structure of a subsequent product, [(2‐Me₂NHCH₂C₆H₄)₂TeF₃O]₂(SiF₆), was elucidated. Theoretical investigations for the compounds containing the stabilizing 2‐dimethylaminomethylphenyl substituent are illustrated.     

Structural and spectroscopic trends in mononuclear arylchalcogenolato-palladium(II) and -platinum(II) complexes: Crystal structures of [M(TeAr)2(dppe)] {M = palladium, platinum; Ar = phenyl, 2-thienyl; dppe = 1,2-bis(diphenylphosphino)ethane}

A series of mononuclear [M(EAr)₂(dppe)] [M = Pd, Pt; E = Se, Te; Ar = phenyl, 2-thienyl; dppe = 1,2-bis(diphenylphosphino)ethane] complexes has been prepared in good yields by the reactions of [MCl₂(dppe)] and corresponding ArE⁻ with a special emphasis on the aryltellurolato palladium and -platinum complexes for which the existing structural information is virtually non-existent. The complexes have crystallized in five isomorphic groups: (1) [Pd(SePh)₂(dppe)] and [Pt(SePh)₂(dppe)], (2) [Pd(TePh)₂(dppe)] and [Pt(TePh)₂(dppe)], (3) [Pd(SeTh)₂(dppe)], (4) [Pt(SeTh)₂(dppe)] and [Pd(TeTh)₂(dppe)], and (5) [Pt(TePh)₂(dppe)]. In addition, solvated [Pd(TePh)₂(dppe)] · CH₃OH and [Pd(TeTh)₂(dppe)] · 1/2CH₂Cl₂ could be isolated and structurally characterized. The metal atom in each complex exhibits an approximate square-planar coordination. The Pd-Se, Pt-Se, Pd-Te, and Pt-Te bonds span a range of 2.4350(7)-2.4828(7) Å, 2.442(1)-2.511(1) Å, 2.5871(7)-2.6704(8) Å, and 2.6053(6)-2.6594(9) Å, respectively, and the respective Pd-P and Pt-P bond distances are 2.265(2)-2.295(2) Å and 2.247(2)-2.270(2) Å. The orientation of the arylchalcogenolato ligands with respect to the M(E₂)(P₂) plane has been found to depend on the E-M-E bond angle. The NMR spectroscopic information indicates the formation of only cis-[M(EAr)₂(dppe)] complexes in solution. The trends in the ³¹P, ⁷⁷Se, ¹²⁵Te, and ¹⁹⁵Pt chemical shifts expectedly depend on the nature of metal, chalcogen, and aryl group. Each trend can be considered independently of other factors. The ⁷⁷Se or ¹²⁵Te resonances appear as second-order multiplets in case of palladium and platinum complexes, respectively. Spectral simulation has yielded all relevant coupling constants.     

Darstellung,Eigenschaften und Konstitution von Bis(dimethylaminopropyl)cadmium und -quecksilber

Synthesis, Properties, and Constitution of Bis(dimethylaminopropyl) Cadmium and Mercury It is reported about synthesis and properties of the bis[3-(N,N-dimethylamino)propyl] compounds of cadmium and mercury. The ¹³C-NMR spectrum of the cadmium compound indicates a spiranoid chelate structure. The concentration dependence of the coupling constants ¹³C? ¹⁹⁹Hg in case of (Me₂NCH₂CH₂CH₂)₂Hg and Me₂NCH₂CH₂CH₂Hg? i-C₄H₉indicates a partial Hg? N interaction.     

Organoselenium(II) and selenium(IV) compounds containing 2-(Me2NCH2)C6H4 moieties: solution behavior and solid state structure

The cleavage of the Se-Se bond in [2-(Me₂NCH₂)C₆H₄]₂Se₂ (1) was achieved by treatment with SO₂Cl₂ (1:1 molar ratio) or elemental halogens to yield [2-(Me₂NCH₂)C₆H₄]SeX [X = Cl (2), Br (3), I (4)]. Oxidation of 1 with SO₂Cl₂ (1:3 molar ratio) gave [2-(Me₂NCH₂)C₆H₄]SeCl₃ (5). [2-(Me₂NCH₂)C₆H₄]SeS(S)CNR₂ [R = Me (6), Et (7)] were prepared by reacting [2-(Me₂NCH₂)C₆H₄]SeBr with Na[S₂CNR₂] · nH₂O (R = Me, n = 2; R = Et, n = 3). The reaction of 3 with K[(SPMe₂)(SPPh₂)N] resulted in isolation of [2-(Me₂NCH₂)C₆H₄]Se-S-PMe₂N-PPh₂S (8). The compounds were characterized by solution NMR spectroscopy (¹H, ¹³C, ³¹P, ⁷⁷Se, 2D experiments). The solid-state molecular structures of 2, 4-8 were established by single crystal X-ray diffraction. All compounds are monomeric, with the N atom of the pendant CH₂NMe₂ arm involved in a three-center-four-electron N?Se-X (X = halogen, S) bond. This results in a T-shaped coordination geometry for the Se(II) atom in 2, 4, 6-8. In 5, the Se(IV) atom achieves a square pyramidal coordination in the mononuclear unit. Loosely connected dimers are formed through intermolecular Se?Cl interactions (3.40 Å); the overall coordination geometry being distorted octahedral. In all compounds hydrogen bonds involving halide or sulfur atoms generate supramolecular associations in crystals.     

Crystal and Molecular Structure of [2,6‐(Me2NCH2)2C6H3]2SnF2, an Intramolecularly Coordinated Diorganotin Difluoride

Single‐crystal X‐ray diffraction analysis of [2,6‐(Me₂NCH₂)₂C₆H₃]₂SnF₂ reveals that only one of the two dimethylaminomethyl groups of each pincer‐type ligands [2,6‐(CH₂NMe₂)₂C₆H₃]^? is coordinated to the tin atom at Sn‐N distances of 2.576(2) and 2.470(2) Å, inducing chirality of the latter. The tin atom exhibits a distorted octahedral trans(C,C)cis(N,N)cis(F,F) configuration. Extensive intra‐ and intermolecular C‐H···F hydrogen bonding is observed with the latter giving rise to formation of polymeric chains.     

Five- and six-membered platinacycles derived from phenantryl and anthracenyl imines

The reaction of [Pt₂Me₄(μ-SMe₂)₂] with ligands Me₂NCH₂CH₂NCHAr (2a, Ar=9-phenantryl; 2b, Ar=9-anthracenyl) carried out in acetone at room temperature produced the corresponding compounds [PtMe₂{9-(Me₂NCH₂CH₂NCH)C₁₄H₉}] (3) in which the imines act as bidentate [N,N^′] ligands. Refluxing toluene solutions of compounds 3 gave cyclometallated [C,N,N^′] compounds [PtMe{9-(Me₂NCH₂CH₂NCH)C₁₄H₈}] (4) as a mixture of two isomers containing either a five- or a six-membered metallacycles for 3a and as a single isomer containing a six-membered metallacycle for 3b. The reactions of compounds 4 with acetyl chloride and with methyl iodide produced, respectively, compounds [PtCl{9-(Me₂NCH₂CH₂NCH)C₁₄H₈}] (5) and [PtMe₂I{9-(Me₂NCH₂CH₂NCH)C₁₄H₈}] (6). All compounds were characterised by NMR spectroscopies and analytical data.     

The trans-Influence in Platinum (II) Complexes. 1H- and 13C-NMR. and X-ray structural studies of tridentate Schiff's base complexes of platinum (II)

¹H- and ¹³C-NMR. data are reported for the complexes [Pt (1) L] and [Pt (2) L]; 1 = OC₆H₄CH ? NCH₂CH₂O, 2 = OC₆H₄CH ? NC₆H₄O; L = PR₃, AsR₃, C ? N (cyclohexyl), DMSO, pyridine, secondary amine. The molecular structures of [Pt (2) (NHEt₂)] (I) and [Pt (2) (PPh₃)] (II) have been determined by X-ray analysis. Relevant bond distances for I: Pt-N (amine) = 2.076 Å, Pt-N (imine) = 2.017 Å, Pt-O = 1.992 Å and 2.002 Å; for II: Pt-P = 2.248 Å, Pt-N = 2.064 Å, Pt-O = 1.964 and 2.005 Å. Both the solid and solution state data are interpreted in terms of differences in the trans influence of the ligand L. The question of metal-ligand d-p π back bonding to the imine is discussed.     

Tellurium(II) and tellurium(IV) complexes of phosphine chalcogenide ligands,synthesis and X-ray structures

Reaction of TeX₄ (X = Cl or Br) with 2 mol. equiv. of OPR₃ (R = Me, Et or Ph) gives the distorted octahedral cis-[TeX₄(OPR₃)₂], while the bidentates Ph₂P(E)(CH₂)_nP(E)Ph₂ (E = O, n = 1 or 2; E = S, n = 1) give the six-coordinate [TeX₄{Ph₂P(E)(CH₂)_nP(E)Ph₂}]. These species have been characterised spectroscopically (via ¹H and ³¹P{¹H} NMR and IR) and by crystallographic analyses on cis-[TeBr₄(OPPh₃)₂], [TeCl₄{Ph₂P(O)CH₂P(O)Ph₂}] and [TeBr₄{Ph₂P(S)CH₂P(S)Ph₂}]. The TeX₄ (X = Cl or Br) are reduced by Ph₂P(S)(CH₂)₂P(S)Ph₂ and Ph₂P(Se)CH₂P(Se)Ph₂, giving the planar, four-coordinate Te(II) species [Te{Ph₂P(S)(CH₂)₂P(S)Ph₂}₂]²⁺ (isolated as [(TeCl₅)₂{μ-Ph₂P(S)(CH₂)₂P(S)Ph₂}]^2? and [TeBr₆]^2? salts) and [TeBr₂{Ph₂P(Se)CH₂P(Se)Ph₂}], all of which have also been identified crystallographically. On the basis of the structural data the Te-based lone pair associated with the Te(IV) species is assumed to occupy the 5s orbital, whereas in the Te(II) complexes the planar coordination is consistent with the two stereochemically active lone pairs occupying the axial sites.