A pair of diastereomeric 1:2 salts of (R)‐ and (S)‐2‐methylpiperazine with (2S,3S)‐tartaric acid

The crystal structures of a pair of diastereomeric 1:2 salts of (R)‐ and (S)‐2‐methylpiperazine with (2S,3S)‐tartaric acid, namely (R)‐2‐methylpiperazinediium bis[hydrogen (2S,3S)‐tartrate] monohydrate, (I), and (S)‐2‐methylpiperazinediium bis[hydrogen (2S,3S)‐tartrate] monohydrate, (II), both C₅H₁₄N₂²⁺·2C₄H₅O₆⁻·H₂O, each reveal the formation of well‐defined head‐to‐tail‐connected hydrogen tartrate chains; these chains are linked into a two‐dimensional sheet via intermolecular hydrogen bonds involving hydroxy groups and water molecules, resulting in a layer structure. The (R)‐2‐methylpiperazinediium ions lie between the hydrogen tartrate layers in the most stable equatorial conformation in (I), whereas in (II), these ions are in an unstable axial position inside the more interconnected layers and form a larger number of intermolecular hydrogen bonds than are observed in (I).     

Synthesis,Spectroscopy, and Structures of Mono‐ and Dinuclear Copper(I) Halide Complexes with 1,3‐Imidazolidine‐2‐thiones

Copper(I) halides with triphenyl phosphine and imidaozlidine‐2‐thiones (L ‐NMe, L ‐NEt, and L ‐NPh) in acetonitrile/methanol (or dichloromethane) yielded copper(I) mixed‐ligand complexes: mononuclear, namely, [CuCl(κ¹‐S‐L ‐NMe)(PPh₃)₂] ( 1 ), [CuBr(κ¹‐S‐L ‐NMe)(PPh₃)₂] ( 2 ), [CuBr(κ¹‐S‐L ‐NEt)(PPh₃)₂] ( 5 ), [CuI(κ¹‐S‐L ‐NEt)(PPh₃)₂] ( 6 ), [CuCl(κ¹‐S‐L ‐NPh)(PPh₃)₂] ( 7 ), and [CuBr(κ¹‐S‐L ‐NPh)(PPh₃)₂] ( 8 ), and dinuclear, [Cu₂(κ¹‐I)₂(μ‐S‐L ‐NMe)₂(PPh₃)₂] ( 3 ) and [Cu₂(μ‐Cl)₂(κ¹‐S‐L ‐NEt)₂(PPh₃)₂] ( 4 ). All complexes were characterized with analytical data, IR and NMR spectroscopy, and X‐ray crystallography. Complexes 2 – 4 , 7 , and 8 each formed crystals in the triclinic system with P$\bar{1}$ space group, whereas complexes 1 , 5 , and 6 crystallized in the monoclinic crystal system with space groups P2₁/c, C2/c, and P2₁/n, respectively. Complex 2 has shown two independent molecules, [(CuBr(κ¹‐S‐L ‐NMe)(PPh₃)₂] and [CuBr(PPh₃)₂] in the unit cell. For X = Cl, the thio‐ligand bonded to metal as terminal in complex 4 , whereas for X = I it is sulfur‐bridged in complex 3 .     

Solvent‐ and Temperature‐Controlled In Situ Ligand Reactions Mediated by CuII and 3′‐[(E)‐{[(1S,2S)‐2‐Aminocyclohexyl]imino}methyl]‐4′‐hydroxy‐4‐biphenylcarboxlic Acid

Three new compounds, CuL, CuL′, and Cu₂O₂L′′₂ (H₂L=3′‐[(E)‐{[(1S,2S)‐2‐aminocyclohexyl]imino}methyl]‐4′‐hydroxy‐4‐biphenylcarboxlic acid, H₂L′=3′‐[(E)‐{[(1S,2S)‐2‐aminocyclohexyl]imino}methyl]‐4′‐hydroxy‐5′‐nitro‐4‐biphenylcarboxlic acid, H₂L′′=3′‐(N,N‐dimethylamino methyl)‐4′‐hydroxy‐4‐biphenylcarboxlic acid), were selectively synthesized through a controlled in situ ligand reaction system mediated by copper(II) nitrate and H₂L. Selective nitration was achieved by using different solvent mixtures under relatively mild conditions, and an interesting and economical reductive amination system in DMF/EtOH/H₂O was also found. All crystal structures were determined by single‐crystal X‐ray diffraction analysis. Both CuL and CuL′ display chiral 1D chain structures, whereas Cu₂O₂L′′₂ possesses a structure with 13×16 Å channels and a free volume of 41.4 %. The possible mechanisms involved in this in situ ligand‐controlled reaction system are discussed in detail.     

(2S,3S)‐2,6‐Dimethylheptane‐1,3‐diol,the oxygenated side chain of 22(S)‐hydroxycholestrol,and its synthetic precursor (R)‐4‐benzyl‐3‐[(2R,3S)‐3‐hydroxy‐2,6‐dimethylheptanoyl]‐1,3‐oxazolidin‐2‐one

(2S,3S)‐2,6‐Dimethylheptane‐1,3‐diol, C₉H₂₀O₂, (I), was synthesized from the ketone (R)‐4‐benzyl‐3‐[(2R,3S)‐3‐hydroxy‐2,6‐dimethylheptanoyl]‐1,3‐oxazolidin‐2‐one, C₁₉H₂₇NO₄, (II), containing C atoms of known chirality. In both structures, strong hydrogen bonds between the hydroxy groups form tape motifs. The contribution from weaker C—H...O hydrogen bonds is much more evident in the structure of (II), which furthermore contains an example of a direct short Osp³...Csp² contact that represents a usually unrecognized type of intermolecular interaction.     

Sulfur‐assisted Chloride and Triphenylphosphine Dissociation of Palladium(II) Complex with Phenyloxythiocarbonyl,PhOC(S), Containing Ligand: X‐Ray Structure of [Pd(PPh3)2{η1‐C(S)OPh}(Cl)]

Treatment of Pd(PPh₃)₄ with phenylchlorothionoformate, PhOC(S)Cl, in dichloromethane at ?20 °C produces the phenyloxythiocarbonyl complex [Pd(PPh₃)₂{η¹‐C(S)OPh}(Cl)], 1 . The ³¹P{¹H} NMR spectrum of 1 shows the dissociation of either the chloride or the triphenylphosphine ligand to form complex [Pd(PPh₃)₂(η²‐SCOPh)][Cl], 2 or the dipalladium complex [Pd(PPh₃)Cl]₂(μ,η²‐SCOPh)₂, 3 . Continuous stirring of the dichloromethane solution of 1 at room temperature for 4 h forms the dipalladinum complex [Pd(PPh₃)Cl]₂(μ,η²‐SCOPh)₂, 3 as the final product. Respective reactions of 1 and Et₂NCS₂Na or dppa {bis(diphenylphosphino)amine} gives complex [Pd(PPh₃){η¹‐C(S)OPh}(η²‐S₂CNEt₂)], 4 or [Pd(PPh₃){η¹‐C(S)OPh}(η²‐dppa)][Cl], 5 . Complex 1 is determined by single‐crystal X‐ray diffraction and crystallized in the monoclinic space group P2₁ with Z = 4. The cell dimensions of 1 are as follows: a = 9.5613(1) Å, b = 33.6732(3) Å, c = 12.2979(1) Å.     

Complexes of N‐Thiophosphorylthiourea tBuNHC(S)NHP(S)(OiPr)2 with Zinc(II), Cadmium(II), Nickel(II), and Cobalt(II) Cations

Reaction of the potassium salt of N‐thiophosphorylthiourea tBuNHC(S)NHP(S)(OiPr)₂ ( HL ) with Zn^II, Cd^II, Ni^II and Co^II in aqueous EtOH leads to complexes of common formula M(L‐S,S′)₂ ( ML₂ ). Complexes were investigated by IR, UV‐Vis, ¹H and ³¹P{¹H} NMR spectroscopy and microanalysis The structure of complex NiL₂ was investigated by single crystal X‐ray diffraction analysis. The nickel(II) ion has a squre‐planar environment, S₄, with two anionic ligands involving 1,5‐S,S′‐coordination mode. The ligands are bound in a trans configuration.     

1, 9‐Dihydro‐purine‐6‐thione Derivatives of the d8–d10 Metal Ions (PdII,PtII, and CuI): Synthesis,Spectroscopy, and Structures

Reaction of 1, 9‐dihydro‐purine‐6‐thione (puSH₂) in presence of aqueous sodium hydroxide with PdCl₂(PPh₃)₂ suspended in ethanol formed [Pd(κ²‐N⁷,S‐puS)(PPh₃)₂] ( 1 ). Similarly, complexes [Pd(κ²‐N⁷,S‐puS)(κ²‐P, P‐L‐L)] ( 2 – 4 ) {L‐L = dppm (m = 1) ( 2 ), dppp (m = 3) ( 3 ), dppb (m = 4) ( 4 )} were prepared using precursors the [PdCl₂(L‐L)] {L‐L = Ph₂P–(CH₂)_m–PPh₂}. Reaction of puSH₂ suspended in benzene with platinic acid, H₂PtCl₆, in ethanol in the presence of triethylamine followed by the addition of PPh₃ yielded the complex [Pt(κ²‐N⁷,S‐puS)(PPh₃)₂] ( 5 ). Complexes [Pt(κ²‐N⁷,S‐puS)(κ²‐P, P‐L‐L)] ( 6 – 8 ) {L‐L = dppm ( 6 ), dppp ( 7 ), dppb ( 8 )} were prepared similarly. The 1, 9‐dihydro‐purine‐6‐thione acts as N⁷,S‐chelating dianion in compounds 1 – 8 . The reaction of copper(I) chloride [or copper(I) bromide] in acetonitrile with puSH₂ and the addition of PPh₃ in methanol yielded the same product, [Cu(κ²‐N⁷,S‐puSH)(PPh₃)₂] ( 9 ), in which the halogen atoms are removed by uninegative N, S‐chelating puSH^– anion. However, copper(I) iodide did not lose iodide and formed the tetrahedral complex, [CuI(κ¹‐S‐puSH₂)(PPh₃)₂] ( 10 ), in which the thio ligand is neutral. These complexes were characterized with the help of elemental analysis, NMR spectroscopy (¹H, ³¹P), and single‐crystal X‐ray crystallography ( 3 , 7 , 8 , 9 , and 10 ).     

Two mononuclear Tc complexes: [2,2′‐(3‐phenylpropylimino)‐ and [2,2′‐(propylimino)bis(ethanethiolato)](4‐methoxybenzenethiolato)oxidotechnate(V)

The molecular structures of the two mononuclear title complexes, namely (4‐methoxybenzenethiolato‐κS)oxido[2,2′‐(3‐phenylpropylimino)bis(ethanethiolato)‐κ³S,N,S′]technetium(V), [Tc(C₁₄H₂₁NS₂)(C₇H₇OS)O], (I), and (4‐methoxybenzenethiolato‐κS)oxido[2,2′‐(propylimino)bis(ethanethiolato)‐κ³S,N,S′]technetium(V), [Tc(C₇H₁₅NS₂)(C₇H₇OS)O], (II), exhibit the same coordination environment for the central Tc atoms. The atoms are five‐coordinated (TcNOS₃) with a square‐pyramidal geometry comprising a tridentate 2,2′‐(3‐phenylpropylimino)bis(ethanethiolate) or 2,2′‐(propylimino)bis(ethanethiolate) ligand, a 4‐methoxybenzenethiolate ligand and an additional oxide O atom. Intermolecular C—H...O and C—H...S hydrogen bonds between the monomeric units result in two‐dimensional layers with a parallel arrangement.     

Synthesis and Characterization of New Copper(I) Complexes Containing Thione Derivatives of 1, 2, 4‐Triazine. Crystal Structure of [Cu(PPh3)2(ATTO)]NO3 (ATTO = 4‐amino‐1, 2, 4‐triazin‐3(2H)‐thione‐5‐one)

The reaction of 4‐amino‐1, 2, 4‐triazin‐3(2H)‐thione‐5‐one (ATTO, 1 ) with [Cu(PPh₃)₂]NO₃ in ethanol led to the complex [Cu(PPh₃)₂(ATTO)]NO₃ ( 2 ). 2 was characterized by elemental analyses, IR, ¹H NMR and Raman spectroscopy. A single‐crystal X‐ray diffraction of compound 2 revealed that ATTO acts as a bidentate ligand via its nitrogen and sulfur atoms. Crystal data for 2 at 20 °C: space group P2₁/n with a = 975.7(1), b = 1533.5(2), c = 2504.2(3) pm, β = 92.25(1)°, Z = 4, R₁ = 0.0632.     

Influence of the Homopolar Dihydrogen Bonding CH⋅⋅⋅HC on Coordination Geometry: Experimental and Theoretical Studies

The reaction of the N‐thiophosphorylated thiourea (HOCH₂)(Me)₂CNHC(S)NHP(S)(OiPr)₂ (HL), deprotonated by the thiophosphorylamide group, with NiCl₂ leads to green needles of the pseudotetrahedral complex [Ni(L‐1,5‐S,S′)₂] ? 0.5 (n‐C₆H₁₄) or pale green blocks of the trans square‐planar complex trans‐[Ni(L‐1,5‐S,S′)₂]. The former complex is stabilized by homopolar dihydrogen C?H???H?C interactions formed by n‐hexane solvent molecules with the [Ni(L‐1,5‐S,S′)₂] unit. Furthermore, the dispersion‐dominated C?H??? H?C interactions are, together with other noncovalent interactions (C?H???N, C?H???Ni, C?H???S), responsible for pseudotetrahedral coordination around the Ni^II center in [Ni(L ‐1,5‐S,S′)₂] ? 0.5 (n‐C₆H₁₄).     

Flip‐type disorder in 3‐substituted 2,2′:5′,2′′‐terthiophenes

In the crystal structures of four thiophene derivatives, (E)‐3′‐[2‐(anthracen‐9‐yl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₂₈H₁₈S₃, (E)‐3′‐[2‐(1‐pyrenyl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₃₀H₁₈S₃, (E)‐3′‐[2‐(3,4‐dimethoxyphenyl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₂₂H₁₈O₂S₃, and (E,E)‐1,4‐bis[2‐(2,2′:5′,2′′‐terthiophen‐3′‐yl)ethenyl]‐2,5‐dimethoxybenzene, C₃₆H₂₆O₂S₆, at least one of the terminal thiophene rings is disordered and the disorder is of the flip type. The terthiophene fragments are far from being coplanar, contrary to terthiophene itself. The central C—C=C—C fragments are almost planar but the bond lengths suggest slight delocalization within this fragment. The crystal packing is determined by van der Waals interactions and some weak, relatively short, C—H...S and C—H...π directional contacts.     

Bis(2,4,7‐tri­methyl­indenyl)­cobalt(II) and rac‐2,2′,4,4′,7,7′‐hexamethyl‐1,1′‐biindene

The crystal and molecular structures of bis(η⁵‐2,4,7‐tri­methyl­indenyl)­cobalt(II), [Co(C₁₂H₁₃)₂], (I), and rac‐2,2′,4,4′,7,7′‐hexamethyl‐1,1′‐biindene, C₂₄H₂₆, (II), are reported. In the crystal structure of (I), the Co atom lies on an inversion centre and the structure represents the first example of a bis(indenyl)cobalt complex exhibiting an eclipsed indenyl conformation. The (1R,1′R) and (1S,1′S) enantiomers of the three possible stereoisomers of (II), which form as by‐products in the synthesis of (I), cocrystallize in the monoclinic space group P2₁/c. In the unit cell of (II), alternating (1R,1′R) and (1S,1′S) enantiomers pack in non‐bonded rows along the a axis, with the planes of the indenyl groups parallel to each other and separated by 3.62 and 3.69 Å.     

A pair of diastereomeric 1:1 salts of (S)‐ and (R)‐2‐methylpiperazine with (2S,3S)‐tartaric acid

The structures of diastereomeric pairs consisting of (S)‐ and (R)‐2‐methylpiperazine with (2S,3S)‐tartaric acid are both 1:1 salts, namely (S)‐2‐methylpiperazinium (2S,3S)‐tartrate dihydrate, C₅H₁₄N₂²⁺·C₄H₄O₆²⁻·2H₂O, (I), and (R)‐2‐methylpiperazinium (2S,3S)‐tartrate dihydrate, C₅H₁₄N₂²⁺·C₄H₄O₆²⁻·2H₂O, (II), which reveal the formation of well defined ammonium carboxylate salts linked via strong intermolecular hydrogen bonds. Unlike the situation in the more soluble salt (II), the alternating columns of tartrate and ammonium ions of the less soluble salt (I) are packed neatly in a grid around the a axis, which incorporates water molecules at regular intervals. The increased efficiency of packing for (I) is evident in its lower `packing coefficient', and the hydrogen‐bond contribution is stronger in the more soluble salt (II).     

Aktivierung von Schwefelkohlenstoff an Trirutheniumclustern: Synthese und Kristallstruktur von [Ru3(CO)4(μ‐PCy2)2(μ‐Ph2PCH2PPh2)(μ3‐S){μ3‐η2‐CSC(S)S}]

Activation of Carbon Disulfide on Triruthenium Clusters: Synthesis and X‐Ray Crystal Structure Analysis of [Ru₃(CO)₄(μ‐PCy₂)₂(μ‐Ph₂PCH₂PPh₂)(μ₃‐S){μ₃‐η²‐CSC(S)S}] [Ru₃(CO)₄(μ‐H)₃(μ‐PCy₂)₃(μ‐dppm)] ( 2 ) (dppm = Ph₂PCH₂PPh₂) reacts with CS₂ at room temperature and yields the open 50 valence electron cluster [Ru₃(CO)₄(μ‐PCy₂)₂(μ‐dppm)(μ₃‐S){μ₃‐η²‐CSC(S)S}] ( 3 ) containing the unusual μ₃‐η²‐C₂S₃ mercaptocarbyne ligand. Compound 3 was characterized by single crystal X‐ray structure analysis.     

The Influence of Substituents at C2 Carbon Atom of Thiosemicarbazones {R(H)C2=N3‐N2(H)‐C1(=S)‐N1H2} on their Dentacy in PtII/PdII Complexes: Synthesis,Spectroscopy, and Crystal Structures

The coordination chemistry of platinum(II) with a series of thiosemicarbazones {R(H)C²=N³‐N²(H)‐C¹(=S)‐N¹H₂, R = 2‐hydroxyphenyl, H₂stsc; pyrrole, H₂ptsc; phenyl, Hbtsc} is described. Reactions of trans‐PtCl₂(PPh₃)₂ precursor with H₂stsc (or H₂ptsc) in 1 : 1 molar ratio in the presence of Et₃N base yielded complexes, [Pt(η³‐ O, N³, S‐stsc)(PPh₃)] ( 1 ) and [Pt(η³‐ N⁴, N³, S‐ptsc)(PPh₃)] ( 2 ), respectively. Further, trans‐PtCl₂(PPh₃)₂ and Hbtsc in 1 : 2 (M : L) molar ratio yielded a different compound, [Pt(η²‐ N³, S‐btsc)(η¹‐S‐btsc)(PPh₃)] ( 3 ). Complex 1 involved deprotonation of hydrazinic (‐N²H‐) and hydroxyl (‐OH) groups, and stsc^2? is coordinating via O, N³, S donor atoms, while complex 2 involved deprotonation of hydrazinic (‐N²H‐) and ‐N⁴H groups and ptsc^2? is probably coordinating via N⁴, N³, S donor atoms. Reaction of PdCl₂(PPh₃)₂ with Hbtsc‐Me {C₆H₅(CH₃)C²=N³‐N²(H)‐C¹(=S)‐N¹H₂} yielded a cyclometallated complex [Pd(η³‐C, N³, S‐btsc‐Me)(PPh₃)] ( 4 ). These complexes have been characterized with the help of analytical data, spectroscopic techniques {IR, NMR (¹H, ³¹P), U.V} and single crystal X‐ray crystallography ( 1 , 3 and 4 ). The effects of substituents at C² carbon of thiosemicarbazones on their dentacy and cyclometallation are emphasized.     

Copper(II) and cadmium(II) isothiocyanate coordination polymers with 4,4′‐bi‐1,2,4‐triazole

The coordination polymers catena‐poly[[[(4,4′‐bi‐1,2,4‐triazole‐κN¹)bis(thiocyanato‐κN)copper(II)]‐μ‐4,4′‐bi‐1,2,4‐triazole‐κ²N¹:N^1′] dihydrate], {[Cu(NCS)₂(C₄H₄N₆)₂]·2H₂O}_n, (I), and poly[tetrakis(μ‐4,4′‐bi‐1,2,4‐triazole‐κ²N¹:N^1′)bis(μ‐thiocyanato‐κ²N:S)tetrakis(thiocyanato‐κN)tricadmium(II)], [Cd₃(NCS)₆(C₄H₄N₆)₄]_n, (II), exhibit chain and two‐dimensional layer structures, respectively. The differentiation of the Lewis acidic nature of Cu^II and Cd^II has an influence on the coordination modes of the triazole and thiocyanate ligands, leading to topologically different polymeric motifs. In (I), copper ions are linked by bitriazole N:N′‐bridges into zigzag chains and the tetragonal–pyramidal CuN₅ environment is composed of two thiocyanate N atoms and three triazole N atoms [basal Cu—N = 1.9530 (18)–2.0390 (14) Å and apical Cu—N = 2.2637 (15) Å]. The structure of (II) contains two types of crystallographically unique Cd^II atoms. One type lies on an inversion center in a distorted CdN₆ octahedral environment, with bitriazole ligands in the equatorial plane and terminal isothiocyanate N atoms in the axial positions. The other type lies on a general position and forms centrosymmetric binuclear [Cd₂(μ‐NCS‐κ²N:S)₂(NCS)₂] units (tetragonal–pyramidal CdN₄S coordination). N:N′‐Bridging bitriazole ligands link the Cd centers into a flat (4,4)‐network.     

Tris(2,2′‐bioxazoline‐κ2N,N′)copper(II) diperchlorate and tris(2,2′‐bioxazoline‐κ2N,N′)­nickel(II) diperchlorate

In the two isomorphous title compounds, viz. tris­[2,2′‐bi(4,5‐di­hydro‐1,3‐oxazole)‐κ²N,N′]copper(II) diperchlorate, [Cu(C₆H₈N₂O₂)₃](ClO₄)₂, (I), and tris­[2,2′‐bi(4,5‐di­hydro‐1,3‐oxazole)‐κ²N,N′]­nickel(II) diperchlorate, [Ni(C₆H₈N₂O₂)₃](ClO₄)₂, (II), the M^II ions each have a distorted octahedral coordination geometry formed via six N atoms from three 2,2′‐bioxazoline ligands. For each ligand, the two five‐membered rings are nearly coplanar. It is noteworthy that the Jahn–Teller effect is stronger in (I) than in (II). The three‐dimensional supramolecular structures of (I) and (II) are formed via weak hydrogen‐bonding interactions between O atoms from per­chlorate anions and H atoms from 2,2′‐bioxazoline ligands.     

On the reactivity of platina‐β‐diketones: a straightforward synthesis of trans‐acetylchlorobis(phosphine)platinum(II) complexes and their reactivity

The platina‐β‐diketone [Pt₂{(COMe)₂H}₂(µ‐Cl)₂] ( 1 ) was found to react with monodentate phosphines to yield acetyl(chloro)platinum(II) complexes trans‐[Pt(COMe)Cl(PR₃)₂] (PR₃ = PPh₃, 2a ; P(4‐FC₆H₄)₃, 2b ; PMePh₂, 2c ; PMe₂Ph, 2d ; P(n‐Bu)₃, 2e ; P(o‐tol)₃, 2f ; P(m‐tol)₃, 2g ; P(p‐tol)₃, 2h ). In the reaction with P(o‐tol)₃ the methyl(carbonyl)platinum(II) complex [Pt(Me)Cl(CO){P(o‐tol)₃}] ( 3a ) was found to be an intermediate. On the other hand, treating 1 with P(C₆F₅)₃ led to the formation of [Pt(Me)Cl(CO){P(C₆F₅)₃}] ( 3b ), even in excess of the phosphine. Phosphine ligands with a lower donor capability in complexes 2 and the arsine ligand in trans‐[Pt(COMe)Cl(AsPh₃)₂] ( 2i ) proved to be subject to substitution by stronger donating phosphine ligands, thus forming complexes trans‐[Pt(COMe)Cl(L)L′] (L/L′ = AsPh₃/PPh₃, 4a ; PPh₃/P(n‐Bu)₃, 4b ) and cis‐[Pt(COMe)Cl(dppe)] ( 4c ). Furthermore, in boiling benzene, complexes 2a – 2c and 2i underwent decarbonylation yielding quantitatively methyl(chloro)platinum(II) complexes trans‐[Pt(Me)Cl(L)₂] (L = PPh₃, 5a ; P(4‐FC₆H₄)₃, 5b ; PMePh₂, 5c ; AsPh₃, 5d ). The identities of all complexes were confirmed by ¹H, ¹³C and ³¹P NMR spectroscopy. Single‐crystal X‐ray diffraction analyses of 2a ·2CHCl₃, 2f and 5b showed that the platinum atom is square‐planar coordinated by two phosphine ligands (PPh₃, 2a ; P(o‐tol)₃, 2f ; P(4F‐C₆H₄)₃, 5b ) in mutual trans position as well as by an acetyl ligand ( 2a, 2f ) and a methyl ligand ( 5b ), respectively, trans to a chloro ligand. Single‐crystal X‐ray diffraction analysis of 3b exhibited a square‐planar platinum complex with the two π‐acceptor ligands CO and P(C₆F₅)₃ in mutual cis position (configuration index: SP‐4‐3). Copyright © 2005 John Wiley & Sons, Ltd.     

Concomitant polymorphism in the stereoselective synthesis of a β‐benzyl‐β‐hydroxyaspartate analogue

Two concomitant polymorphs, (I) and (II), of a β‐benzyl‐β‐hydroxyaspartate analogue [systematic name: dibenzyl 2‐benzyl‐2‐hydroxy‐3‐(4‐methylphenylsulfonamido)succinate], C₃₂H₃₁NO₇S, crystallize from a mixture of ethyl acetate and cyclohexane at ambient temperature. The structure of (I) has triclinic (P) symmetry and that of (II) monoclinic (P2₁/c) symmetry. Both crystal structures are made up of a stacking of homochiral racemic dimers (2S,3S and 2R,3R) which are internally connected by a similar R₂²(9) hydrogen‐bonding pattern consisting of intermolecular N—H...O and O—H...O hydrogen bonds. The centroid of the racemic dimer lies on an inversion centre. The main structural difference between the two polymorphs is the conformational orientation of two of the four aromatic rings present in the molecule. Polymorph (II) is found to be twinned by reticular merohedry with twin index 3 and twin fractions 0.854 (1) and 0.146 (1).     

Mixed‐Ligand Complexes of Copper(II) with α‐Hydroxycarboxylic Acids and 1,10‐Phenanthroline

Eight new two‐ligand complexes of copper(II) with 1,10‐phenanthroline and one of four different α‐hydroxy‐carboxylic acids (glycolic, lactic, mandelic and benzylic) were prepared. The complexes of general formula [Cu(HL)₂(phen)] · nH₂O (HL = monodeprotonated acid) ( 1 – 4 ) were characterized by elemental analysis, IR, electronic and EPR spectroscopy, magnetic measurements and thermo‐gravimetric analysis. The complexes of general formulae [Cu(HL)(phen)₂](HL) · H₂L · nSolv [ 1 a (HL = HGLYO^–, n = 1, Solv = MeCN) and 3 a (HL = HMANO^–, n = 0)] and [Cu(L)(phen)(OH₂)] · nH₂O [ 2 a (L = LACO^2–, n = 4) and 4 a (L = BENO^2–, n = 2)] were characterized by X‐ray diffractometry. In all these latter a pentacoordinated copper atom has a basically square pyramidal coordination polyhedron, the distortion of which towards a trigonal bipyramidal configuration has been evaluated in terms of the parameter τ. In 1 a and 3 a there are three forms of α‐hydroxycarboxylic acid: a monodentate monoanion, a monoanionic counterion, and a neutral molecule lying in the outer coordination sphere; in 2 a and 4 a the α‐hydroxycarboxylic acid is a bidentate dianion coordinating through carboxyl and hydroxyl oxygens.