The nido–osmaboranes [2,2,2-(CO)(PPh3)2-nido-2-OsB5H9] and [6,6,6-(CO)(PPh3)2-nido-6-OsB9H13]

The structural characterization of the osmahexaborane 2-carbonyl-2,2-bis­(tri­phenyl­phosphine)-nido-2-osmahexaborane(9), [Os(B₅H₉)(C₁₈H₁₅P)₂(CO)], (I), a metallaborane analogue of B₆H₁₀, confirms the structure proposed from NMR spectroscopy. The structure of the osmadecaborane 6-carbonyl-6,6-bis­(tri­phenyl­phosphine)-nido-6-osmadecaborane(13), [Os(B₉H₁₃)(C₁₈H₁₅P)₂(CO)], (IV), is similarly confirmed. The short basal B—B distance of 1.652 (8) Å in (I), not bridged by an H atom, mirrors that in the parent hexaborane(10) [1.626 (4) Å].     

Three monoalkoxy‐substituted nido‐platinaboranes: [(PPh3)2PtB10H11‐8‐(OCH3)], [(PPh3)2PtB10H11‐8‐{OCH(CH3)2}] and [(PPh3)2PtB10H10‐9‐{OCH(CH3)2}]

Each of the title compounds, 8‐methoxy‐7,7‐bis­(tri­phenyl­phosphine‐P)‐8,9:10,11‐di‐μH‐7‐platina‐nido‐undecaborane di­chloro­methane hemisolvate, [Pt(CH₁₄B₁₀O)(C₁₈H₁₅P)₂]·0.5CH₂Cl₂, (I), 8‐isopropoxy‐7,7‐bis­(tri­phenyl­phosphine‐P)‐8,9:10,11‐di‐μH‐7‐platina‐nido‐undecaborane di­chloro­methane solvate, [Pt(C₃H₁₈B₁₀O)(C₁₈H₁₅P)₂]·CH₂Cl₂, (II), and 9‐isopropoxy‐7,7‐bis­(tri­phenyl­phosphine‐P)‐8,9:10,11‐di‐μH‐7‐platina‐nido‐undecaborane di­chloro­methane solvate, [Pt(C₃H₁₈B₁₀O)(C₁₈H₁₅P)₂]·CH₂Cl₂, (III), has an 11‐vertex nido polyhedral skeleton, with the 7‐platinum centre ligating to two exo‐polyhedral PPh₃ groups and an alkoxy‐substituted polyhedral borane ligand. Compounds (II) and (III) are isomers. The Pt—B distances are in the range 2.214 (7)–2.303 (7) Å for (I), 2.178 (16)–2.326 (16) Å for (II) and 2.205 (6)–2.327 (6) Å for (III).     

Platinum complexes of oxopurines: cis‐bis(theophyllinato‐N7)bis(triphenylphosphine)platinum(II) and cis‐chloro(theobrominato‐N1)bis(triphenylphosphine)platinum(II) ethanol hemisolvate

The syntheses and structures of two mixed‐ligand complexes of platinum(II) with deprotonated oxopurine bases and tri­phenyl­phosphine are reported, namely the theophyllinate complex cis‐bis(1,2,3,6‐tetra­hydro‐1,3‐di­methyl­purine‐2,6‐dionato‐κN⁷)­bis(tri­phenyl­phosphine‐κP)­platinum(II), [Pt(C₇H₇N₄O₂)₂(C₁₈H₁₅P)₂], (I), and the theobrominate complex cis‐chloro(1,2,3,6‐tetrahydro‐3,7‐dimethylpurine‐2,6‐dionato‐κN¹)­bis(tri­phenyl­phosphine‐κP)­platinum(II) ethanol hemisolvate, [PtCl(C₇H₇N₄O₂)(C₁₈H₁₅P)₂]·0.5C₂H₅OH, (II). In (I), the coordination geometry of Pt is square planar, formed by the two coordinating N atoms of the theophyl­linate anions in a cis arrangement and two P atoms from the tri­phenyl­phosphine groups. In (II), there are two crystallographically independent mol­ecules. They both exhibit a square‐planar coordination geometry around Pt involving one Cl atom, the coordinating N atom of the theobrominate anion and two P atoms from the tri­phenyl­phosphine groups. The two tri­phenyl­phosphine groups are arranged in a cis configuration in both structures. The heterocyclic rings are rotated with respect to the coordination plane of the metal by 82.99 (8) and 88.09 (8)° in complex (I), and by 85.91 (16) and 88.14 (18)° in complex (II). Both structures are stabilized by intramolecular stacking interactions involving the purine rings and the phenyl rings of adjacent tri­phenyl­phosphine moieties.     

cis‐Tetracarbonylbis(tricyclohexyl­phosphine)molybdenum(0) and pentacarbonyl(tricyclohexylphos­phine)molybdenum(0)

In the present redetermination of the complex cis‐tetra­carbonyl­bis­(tri­cyclo­hexyl­phosphine)molybdenum(0), (I), [Mo(C₁₈H₃₃P)₂(CO)₄] or cis‐{η¹‐[P(C₆H₁₁)₃]₂}Mo(CO)₄, the Mo atom has a distorted octahedral geometry with a large P—Mo—P angle of 104.8 (1)°. A strong trans influence on the carbonyls in (I) is seen in a shortening of the Mo—C and a lengthening of the C—O distances opposite the phosphines compared with those that are cis. This influence is greatly diminished in the complex penta­carbonyl­(tri­cyclo­hexyl­phosphine)­molyb­denum(0), (II), [Mo(C₁₈H₃₃P)(CO)₅] or {η¹‐[P(C₆H₁₁)₃]}­Mo(CO)₅, the core of which has a slightly distorted C_4v geometry.     

A monomeric three-coordinate magnesium bis(amide)

The metallation reaction between di­butyl­magnesium and 2,6-diiso­propyl-N-(tri­methyl­silyl)­aniline gives the unusual monomeric three-coordinate complex (diethyl ether-κO)­bis­[2,6-diiso­propyl-N-(tri­methyl­silyl)­anilido-κN]­magnesium(II), [Mg(C₁₅H₂₆NSi)₂(C₄H₁₀O)] or [Mg{(Me₃Si)(2,6-ⁱPr₂C₆H₃)N}₂(Et₂O)]. This low-coordinate species has a distorted trigonal-planar coordination environment, with an additional short Mg—C_ipso contact of 2.799 (2) Å.     

[μ-6,9-Cl-8-(OMe)-6,9-(η5-C5Me5)2-arachno-6,9,5-Rh2SB7H7]

The title compound, μ-6,9-chloro-8-methoxy-6,9-bis­(η⁵-penta­methyl­cyclo­penta­dienyl)-6,9-dirhoda-5-thia-arachno-decaborane(7), [Rh₂(CH₁₀B₇OS)(C₁₀H₁₅)₂Cl], has a single Cl atom bridging the two remote rhodium `prow' vertices of an arachno ten-vertex dirhoda­thia­decaborane cluster, with Rh—­Cl distances of 2.3475 (11) and 2.3536 (11) Å, and an Rh—Cl—Rh angle of 106.82 (4)°.     

New electron‐deficient chiral phosphines: (4R,5R)‐1,3‐bis(trifluoromethanesulfonyl)perhydro‐1,3,2‐benzodiazaphosphol‐2‐yl] substituted amines

Three chiral electron‐deficient phosphine ligands, [(4R,15R)‐,3‐bis­(tri­fluoro­methane­sulfonyl)­per­hydro‐1,3,2‐benzodiazaphosphol‐2‐yl]­diethyl­amine, C₁₂H₂₀F₆N₃O₄PS₂, (IIIa), [(4R,5R)‐1,3‐bis­(tri­fluoro­methane­sulfonyl)­per­hydro‐1,3,2‐benzodi­aza­phosphol‐2‐yl]­di­methyl­amine, C₁₀H₁₆F₆N₃O₄PS₂, (IIIb), and bis­[(4R,5R)‐1,3‐bis­(tri­fluoro­methane­sulfonyl)­per­hydro‐1,3,2‐benzodi­aza­phosphol‐2‐yl]­methyl­amine, (IV), as the chloroform solvate, C₁₇H₂₃F₁₂N₅O₈P₂S₄·0.98CHCl₃, have been prepared from (1R,2R)‐N,N′‐bis­(tri­fluoro­methane­sulfonyl)‐1,2‐cyclo­hexane­di­amine and diethyl phosphor­amido­us dichloride, dimethyl phosphoramidous dichloride or methyl imidodi­phosphorus tetrachloride. The π‐acceptor abilities of these new types of ligands have been evaluated by X‐ray determination of the P—N bond lengths; it has been found that the most promising ligand is the bis­(phosphine) (IV).     

Complexes of mixed silicon halides with 4‐picoline

The reaction products of an addition reaction of five different silicon tetrahalides with the aromatic nitro­gen base 4‐methyl­pyridine are presented. The following five structures are isomorphous: (I) tetra­chloro­bis(4‐methyl­pyridine)­silicon, C₁₂H₁₄­Cl₄­N₂Si, (II) bromo­tri­chloro­bis(4‐methyl­pyridine)­silicon, C₁₂H₁₄­Br­Cl₃N₂Si, (III) di­bromo­di­chloro­bis(4‐methyl­pyridine)­silicon, C₁₂H₁₄­Br₂­Cl₂N₂Si, (IV) tri­bromo­chloro­bis(4‐methyl­pyridine)­silicon, C₁₂H₁₄Br₃­Cl­N₂Si, and (V) tetra­bromo­bis(4‐methyl­pyridine)­silicon, C₁₂H₁₄Br₄N₂Si. The mol­ecules of (I) and (V), with D_2h symmetry, have crystallographic C_2h symmetry, while the molecules of (II), (III) and (IV) have a lower molecular symmetry, but as a result of the disorder of the halogen ligands, they appear to be of the same crystallographic symmetry. The environment around the Si atom can be described as a slightly distorted octahedron with the methyl­pyridine ligands occupying axial positions and the four halogen ligands in the equatorial plane. In spite of the different substitution pattern of the silicon centre, there are only insignificant differences between these five structures.     

Bis­[1,3‐bis­(tri­methyl­silyl)­allyl]­cobalt(II), a stable electron‐deficient allyl complex

The title compound, bis­[(1,2,3‐η)‐(2E)‐1,3‐bis­(tri­methyl­silyl)­prop‐2‐enyl]­cobalt(II), [Co(C₉H₂₁Si₂)₂], is a homoleptic allyl complex with η³‐bound ligands. The Co—C distances range from 1.996 (3) to 2.096 (3) Å and the allyl ligands adopt staggered, nearly parallel, arrangements around the Co atom. The tri­methyl­silyl groups are in syn–anti conformations; the steric shielding they provide to the metal is probably responsible for the thermal stability of the compound.     

Three sulfur‐containing diborane(4) compounds

The preparation and structures of three diborane(4) compounds are described. The compound B₂(3,4‐S₂C₄H₂‐1‐S)₂ [2,2′‐bi(1,3,5,2‐tri­thia­borapentalene), C₈H₄B₂S₆] is planar and lies at a crystallographic inversion centre. The amine adducts [B₂(C₃S₅)₂(NHMe₂)₂] [2,2′‐bis­(di­methyl­amino)‐2,2′‐bi(1,3,4,6,2‐tetra­thia­borapentalene‐5‐thione), C₁₀H₁₄B₂N₂S₁₀] and [B₂(1,2‐S₂C₂H₄)₂(NHMe₂)₂]·0.33CH₂Cl₂ [1,2‐bis­(di‐methylamino)‐1,1:2,2‐bis(dimethylenedithioxy)diborane(4) di­chloro­methane solvate, C₈H₂₂B₂N₂S₄·0.33CH₂Cl₂] contain di­methyl­amine ligands bound to each boron in an anti conformation about the B—B bond, with tetrahedral geometry at the B atoms. The crystal structures display a number of S?S interactions, which appear to dictate the packing arrangements.     

A ferrocenyl‐substituted pseudo­titanocene complex

The title compound, (η⁵‐cyclo­penta­dienyl)[(1,2,3,4,5‐η)‐4‐ferro­cenyl‐1,2,5,6‐tetrakis­(tri­methyl­silyl)­cyclo­hexa‐2,4‐dien‐1‐yl]­titanium(II), [TiFe(C₅H₅)₂(C₂₃H₄₂Si₄)] or [Ti{η⁵‐C₆H₂{Fe­(η⁵‐C₅H₄)(η⁵‐C₅H₅)}{Si(CH₃)₃}₄}(η⁵‐C₅H₅)], possesses two directly linked metallocene units that subtend an angle of 52.9 (1)° (defined by the least‐squares planes of the directly connected π‐ligands) associated with the steric requirements of the bulky tri­methyl­silyl substituents. The cyclo­hexa­dienyl ligand adopts an envelope conformation; the perpendicular distance of its η⁵‐plane to the Ti atom is 1.512 (1) Å.     

Four tri­fluoro­methyl­nitro­benzene analogues

The crystal structures of four tri­fluoro­methyl­nitro­benzene analogues (CF₃)C₆H₃(NO₂)[C₄H₈N₂]R (where C₄H₈N₂ is piperazinyl and R is ethyl carboxyl­ate, CO₂C₂H₅, or phenyl, C₆H₅), have been determined, and their conformations and packing arrangements are compared. The four compounds are ethyl 4‐[4‐nitro‐2‐(tri­fluoro­methyl)­phenyl]­piperazine‐1‐car­boxyl­ate, (I), and ethyl 4‐[2‐nitro‐4‐(tri­fluoro­methyl)­phen­yl]piper­azine‐1‐carboxyl­ate, (II), both C₁₄H₁₆F₃N₃O₄, and 1‐­[4‐nitro‐2‐(tri­fluoro­methyl)­phenyl]‐4‐phenyl­piperazine, (III), and 1‐[2‐nitro‐4‐(tri­fluoro­methyl)­phenyl]‐4‐phenyl­piperazine, (IV), both C₁₇H₁₆F₃N₃O₂. All mol­ecules adopt a rod‐like conformation, while the asymmetric units of (II) and (IV) contain two unique mol­ecules that pack as monodirectional pairs. All mol­ecules pack with C—H⋯O/F close contacts to all but one of the O atoms and to five of the 18 F atoms.     

Complex of cobalt(II) bromide with hexa­methyl­phospho­ric tri­amide

The title compound, di­bromo­bis­[tris­(di­methyl­amino)­phos­phine oxide]­cobalt(II), [CoBr₂(C₆H₁₈N₃OP)₂], displays tetrahedral coordination about cobalt. The mol­ecule has twofold crystallographic site symmetry. The short P—N bonds and the planarity of the di­methyl­amino groups indicate the importance of dπ–pπ interactions. One of the NMe₂ groups has an irregular conformation about the P—N bond and deviates from planarity. It is ascribed to the steric hindrance induced by coordination at the O atom of hexa­methyl­phospho­ric tri­amide.     

(Z)‐2‐Methylbuten‐1‐yl(aryl)iodonium trifluoromethanesulfonates containing electron‐withdrawing groups on the aryl moiety

The crystal structures of [(Z)‐2‐methyl­but‐1‐en‐1‐yl]­[4‐(tri­fluoro­methyl)­phenyl]­iodo­nium tri­fluoro­methane­sulfonate, C₁₂H₁₃F₃I⁺·CF₃O₃S^?, (I), (3,5‐di­chloro­phenyl)­[(Z)‐2‐methyl­but‐1‐en‐1‐yl]­iodo­nium tri­fluoro­methane­sulfonate, C₁₁H₁₂­Cl₂I⁺·CF₃O₃S^?, (II), and bis{[3,5‐bis­(tri­fluoro­methyl)­phenyl][(Z)‐2‐methyl­but‐1‐en‐1‐yl]­iodo­nium} bis­(tri­fluoro­methane­sulfonate) di­chloro­methane solvate, 2C₁₃H₁₂F₆I⁺·­2CF₃­O₃S^?·CH₂Cl₂, (III), are described. Neither simple acyclic β,β‐di­alkyl‐substituted alkenyl­(aryl)­idonium salts nor a series containing electron‐deficient aryl rings have been described prior to this work. Compounds (I)–(III) were found to have distorted square‐planar geometries, with each I atom interacting with two tri­fluoro­methane­sulfonate counter‐ions.     

The polysulfonylamines bis(methylsulfonamido) sulfone and bis(trifluoromethylsulfonamido) sulfone

Bis­(methyl­sulfon­amido) sulfone, C₂H₈N₂O₆S₃ or SO₂(NHSO₂CH₃)₂, was synthesized from imidobis­(sulfonyl ­chloride), HN(SO₂Cl)₂, and bis­(tri­methyl­silyl)­methane, CH₂[Si(CH₃)₃]₂, in ­chlorotri­methyl­silane solution. In the solid state, there are two independent mol­ecules linked by two N—H⋯O hydrogen bridges into infinite chains parallel to the b axis. The central S atoms of the independent molecules each lie on a twofold axis. Bis­(tri­fluoro­methyl­sulf­onamido) sulfone, C₂H₂F₆N₂O₆S₃ or SO₂(NHSO₂CF₃)₂, was formed by the reaction of tri­chloro­phosphazosulfuryl tri­fluoro­methane, Cl₃PNSO₂CF₃, with fluoro­sulfonic acid, FSO₃H. The mol­ecules are connected by bifurcated N—H⋯O bridges into infinite layers parallel to the [001] plane. The central S atom lies on a twofold axis.     

20‐Di­cyano­methyl­ene‐5,8,11,14‐tetraoxa‐2,17‐di­thia­bi­cyclo­[16.4.1]­tricosa‐1(23),18,21‐triene and its mercury(II) dichloride complex

The structures of the title compound, C₂₀H₂₄N₂O₄S₂, and its mercury(II) dichloride complex, dichloro{20‐di­cyano­methyl­ene‐5,8,11,14‐tetraoxa‐2,17‐di­thia­bi­cyclo­[16.4.1]­tricosa‐1(23),18,­21‐tri­ene‐κ⁴O,κS¹⁷}mercury(II), [HgCl₂(C₂₀­H₂₄­N₂­O₄­S₂)], have been determined by X‐ray crystallographic analyses. The mercury(II) dichloride complex has two independent mol­ecules of [HgCl₂(C₂₀H₂₄N₂O₄S₂)] in the lattice. The mercury(II) ion has pentagonal bipyramidal coordination which involves one S atom, four O atoms and two Cl^? ions.     

The 1:1 adduct of Kemp's triacid with 2‐aminopyridine

The crystal structure determination of the molecular proton‐transfer adduct of Kemp's triacid (cis‐cis‐1,3,5‐tri­methyl­cyclo­hexane‐1,3,5‐tri­carboxylic acid, KTA) with 2‐amino­pyridine (2‐APY), namely 2‐amino­pyridinium 3,5‐di­carboxy‐1,3,5‐tri­methyl­cyclo­hexane­carboxyl­ate, 2‐APY⁺·KTA^? or C₅H₇N₂⁺·C₁₂H₁₇O₆^?, has revealed a centrosymmetric hydrogen‐bonded cyclic KTA homodimer repeating unit [O?O 2.524 (4) Å] linked into a polymer structure through the pyridinium and amino groups of the 2‐APY mol­ecule [O?N 2.736 (4), 2.989 (4) and 2.999 (4) Å].     

A series of three bis­[2‐(methyl/tri­fluoro­methyl)‐4H‐3,1‐benzoxazin‐4‐one] compounds

Each of the three title compounds, namely 6,6′‐methyl­ene­bis­(2‐methyl‐4H‐3,1‐benz­oxazin‐4‐one), C₁₉H₁₄N₂O₄, 6,6′‐methyl­ene­bis­(2‐tri­fluoro­methyl‐4H‐3,1‐benz­oxazin‐4‐one), C₁₉H₈F₃N₂O₄, and 6,6′‐bi­(2‐tri­fluoro­methyl‐4H‐3,1‐benz­oxazin‐4‐one), C₁₈H₆F₆N₂O₄, contains two planar benz­ox­azin­one fragments. In the first two compounds, these planes are virtually perpendicular to each other, while the third compound is planar overall. The electronic effects of the substituent groups on the oxazine moiety result in distortion of the bond angles at the C atoms of the C=O and C=N bonds, and in redistribution of electronic density in the oxazine rings. The latter leads to different bond lengths within this ring in the three mol­ecules. All the mol­ecules form stacks in their crystals with distances of 3.2–3.6 Å between adjacent mol­ecules in a stack.     

meso-1,2-Bis­(methyl­azo)-1,2-di­phenyl­ethane

The title compound, meso-1,2-bis­(methyl­diazenyl)-1,2-di­phenyl­ethane, C₁₆H₁₈N₄, is arranged in a disordered manner around an inversion point. The N—N atom distances in the azo group of 1.192 (8) and 1.195 (8) Å, and the C—C atom distances in the ethyl­ene moiety at 1.512 (8) and 1.503 (8) Å in the two models [refined to 51.7 (6) and 48.3 (6)% occupancies] were not significantly different.     

Bis(2,5‐dimethoxy‐4‐methylphenyl)methane and bis(2,5‐dimethoxy‐3,4,6‐trimethylphenyl)methane

Bis(2,5‐di­methoxy‐4‐methyl­phenyl)­methane, C₁₉H₂₄O₄, (IIa), was obtained and characterized as a minor product from the reaction of tolu­hydro­quinone di­methyl ether (1,4‐dimethoxy‐2‐methylbenzene) with N‐(hydroxy­methyl)­tri­fluoro­acet­amide. Similarly, bis(2,5‐di­methoxy‐3,4,6‐tri­methyl­phenyl)­methane, C₂₃H₃₂O₄, (IIb), was prepared from the corresponding reaction of tri­methyl­hydro­quinone di­methyl ether (2,5‐dimethoxy‐1,3,4‐trimethylbenzene). The mol­ecules of (IIa) and (IIb) each lie on a twofold axis passing through the methyl­ene group. The dihedral angle between the planar phenyl rings is 73.4 (1)° in (IIa) and 77.9 (1)° in (IIb). The external bond angles around the bridging methyl­ene group are 116.6 (2) and 117.3 (2)° for (IIa) and (IIb), respectively. In (IIa), the methoxy substituents lie in the plane of the ring and are conjugated with the aromatic system, whereas in (IIb), they are almost perpendicular to the phenyl ring and are positioned on opposite sides.