Bridge-disubstituted calix[4]arenes obtained via a new preparative route. Synthesis and structural study

A series of calix[4]arenes bearing various substituents including alkyl, p-bromobenzyl, carboxy and allyl at opposite methylene bridges has been synthesized via successive metallation followed by nucleophilic substitution. In a first step, mono-lithiated calix[4]arenes react with terminal bromoalkanes to give 2-alkylated calix[4]arenes or with CO₂ the respective calixarene-2-carboxylic acid in good yields. A second lithiation step of the monosubstituted products with subsequent attachment of both polar and non-polar substituents yields several new diametrally bridge-disubstituted calix[4]arenes. 2D-NMR measurements establish the disubstituted calixarenes to predominantly adopt the 1,2-alternate conformation in solution. First examples of X-ray crystal structures of the new type of disubstituted calix[4]arenes are described featuring the calix[4]arene also in the rare 1,2-alternate conformation.     

[Me4N]2[(WOS3Ag)2]: a novel quasi-one-dimensional compound

Orange–yellow plate-like crystals of a new polymeric complex [Me₄N]₂[(WOS₃Ag)₂] were obtained at room temperature from the reaction of a suspension of [Me₄N]₂[WOS₃] in MeCN with solid AgCN. The new compound is obviously formed by cyanide elimination of primary [WOS₃(AgCN)]²⁻. It is monoclinic space group P2₁/c with unit cell parameters a=20.44(2) Å, b=9.655(6) Å, c=11.913(5) Å, β=99.06(2)°, Z=4. The crystal structure was determined from single crystal diffractometer data (Mo-Kα radiation) and refined to R=0.070 (2979 reflections, 199 variables). The structure is characterized by infinite anionic chains, ${}_{\mathrm{\infty }}{}^{\mathrm{<mspace\; xmlns="true"\; sp="0.3"\; width="2px"\; linebreak="nobreak"\; is="true"></mspace><mtext>1</mtext>}}$[(WOS₃Ag)₂]²⁻. The infrared spectrum of the complex (KBr powder) shows the terminal ν(WO) as strong absorption bands found at 913 and 905 cm⁻¹. The bridging ν(WS) shows bands at 438 (vs) and 434 (sh) cm⁻¹. The anionic mass spectrum shows a peak at m/z 404 for [WOS₃Ag]⁻. In addition, the primary formation of the potential monomeric precursor [WOS₃(AgCN)]²⁻ could be established in the filtrate by mass spectroscopy.     

铁铂硫原子簇化合物的合成与结构研究 V: [MoFe3S4]类立方烷簇合物的转化反应和[Et4N]3[Mo2Fe6S8(SC6H4CH3-m)3Cl6]的晶体结构

具[MoFe2S4]类立方烷结构单元的双类立方烷化合物[Et4N]4[Mo2Fe7S8(SR)12](1a,R=Ph; 1b, R=tolyl-m)或单类立方烷化合物[MoFe3S4(dteR2)5](2a, R=Me; 2b, R=Et)与酰氯在乙腈中反应, 分别得到不含Fe桥的双类立方烷化合物(Et4N)3[Mo2Fe6S8(SR)3Cl6](3a, R=Ph; 3b, R=toly-m)与[MoFe3S4]骨架支解后的Fe(dteR2)2Cl(4a, R=Me; 4b, R=Et)。说明在相同反应条件下, [MoFe3S4]单元在1中比在2中稳定, 本文首次将1型与3型结构通过一步化学反应连系起来。3型化合物的产生得到X射线衍射测定及^1H NMR谱的证实。本文报道3b的单晶结构及3的^!H NMR数据, 3b属六方晶系, P63/m, a=1.6827(3), c=1.5951(16)nm; V=3.91158nm^3; Dc=1.491g/cm^3;Z=2; F(000)=1780; 偏离因子R=0.048, 化合物2与酰氯反应产生4, 由红外及紫外可见光谱证实。     

Synthesis, structure, and properties of [RuNO(NH3)4OH][PtCl4] and [RuNO(NH3)4OH][PdCl4]

Double complex [RuNO(NH₃)₄OH][PtCl₄] (I) and [RuNO(NH₃)₄OH][PdCl₄] (II) salts have been prepared and explored with TGA, IR spectroscopy, powder and single crystals X-ray diffraction. Crystal phases of I and II are isostructural (space group Cmc2₁) and have the following crystal chemical characteristics: a = 8.106 Å, b = 18.190(3) Å, c = 8.097 Å, V = 1194.0 ų, Z = 4, ρ_calc = 3.077 g/cm³ (I), and a = 8.116 Å, b = 18.135 Å, c = 8.062 Å, V = 1186.5 ų, Z = 4, ρ_calc = 2.600 g/cm³ (II). The product of thermal decomposition of I in inert and hydrogen atmospheres is a substitution solid solution Pt_0.5Ru_0.5 with the parameter of the FCC unit cell a = 3.856(3) Å. Thermolysis of II affords two-phase mixtures of limited solid solutions of the metals featuring Ru-based HCP and Pd-based FCC cells. __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 48, No.1, pp.114–121, January–February, 2007.     

Preparation,characterization and cytotoxic activity of new compounds trans-[PtCl2NH3(3-(hydroxymethyl)-pyridine)] and trans-[PtCl2NH3(4-(hydroxymethyl)-pyridine)]

We report the synthesis, characterization and cytotoxic assays of new trans-platinum compounds, trans-[PtCl₂NH₃(3-(hydroxymethyl)-pyridine)] and trans-[PtCl₂NH₃(4-(hydroxymethyl)-pyridine)]. In the present work, we found that the replacement of the ammine ligand in “classical” transplatinum with the two new ligands does not increase the cytotoxic activity, maybe because these complexes do not produce a stability of the intrastrand cross-links in DNA.     

Platinum(IV) analogues of AMD473 (cis-[PtCl2(NH3)(2-picoline)]): preparative, structural, and electrochemical studies

The preparation and oxidation of the anticancer drug AMD473, cis-[PtCl2(NH3)(2-pic)] (2-pic = 2-methylpyridine), has been investigated. cis-[PtCl2(NH3)(2-pic)] is readily oxidized with peroxide to give the trans-dihydroxoplatinum(IV) complex cis,trans,cis-[PtCl2(OH)2(NH3)(2-pic)]. The crystal structure of this complex reveals that it is highly strained as a result of a steric clash between the methyl group of the 2-picoline ligand and an axial hydroxo ligand, with the Pt-N-C angle adjacent to this clash opened up to an unprecedented 138.6(6) degrees . Attempts at converting the dihydroxoplatinum(IV) complex to dichloro and diacetato analogues were unsuccessful with reaction with HCl leading to loss and protonation of the 2-picoline ligand to form the salt (2-picH)[PtCl5(NH3)] and the platinum(II) complex cis-[PtCl2(NH3)(2-pic)], both confirmed by crystallography. Electrochemical studies revealed that cis,trans,cis-[PtCl2(OH)2(NH3)(2-pic)] is reduced more readily (-714 mV vs Ag/AgCl) than its pyridine analogue cis,trans,cis-[PtCl2(OH)2(NH3)(pyridine)] (-770 mV vs Ag/AgCl) consistent with the steric clash in the former complex destabilizing the platinum(IV) oxidation state.     

Synergism in molybdenum iron sulphur cluster compounds. Synthetic,structural, magnetic,cyclic voltammetric evidence and the reaction of dicubane clusters containing [MoFe3S4] unit

Summary Dicubane cluster compounds (Et₄N)₄[Mo₂Fe₇S₈(SR)₁₂] (2A) (R=Ph,a;o-tolyl,b;m-tolyl,c;p-tolyl,d) were made by reaction of (Et₄N)₂[Fe₄(SR)₁₀] (1) with (Et₄N)₂MoS₄ in MeCN at room temperature. The structure,¹Hn.m.r.,⁵⁷Fe Mössbauer spectrum, magnetic susceptibility and cyclic voltammogram are described. (Et₄N)₃[Mo₂Fe₆S₈Cl₆(SR)₃] (3) (R=Ph,a;m-tolyl,b) was obtained from the reaction of (2Aa) or (2Ac) with acetyl chloride in MeCN. This is the first time that compound of structural type (2) is transformed into that of structural type (3) by chemical conversion. Compound (2Aa) crystallizes in the triclinic space group P with Z=1 and unit cell dimensionsa=12.775(4),b=13.076(3), andc=20.576(4) Å; the structure was refined to R=7.7% using 4031 unique data with I>3(I_o). Compound (2Ac) 2THF crystallizes in the monoclinic space group P2₁/n with Z=2 and unit cell dimensionsa=18.022(2),b=18.375(2) andc=22.254(3) Å; the structure was refined to R=6.4% using 5173 unique data with I>3(I_o). Compound (3b) crystallizes in the hexagonal space groupP6₃/m with Z=2 and unit cell dimensionsa=b=16.827(3) andc=15.951(16) Å; the structure was refined to R=4.9% using 1296 unique data with I>3(I_o). Its characteristics are discussed and compared with those of known compounds. The ratios of core volumes S₄/M₄ are within the 2.34–2.40 range for core oxidation level [MoFe₃S₄]³⁺ indicating that distortion of the cubane core is a general phenomenon. Different thiolato ligands induce significant changes of structural parameters only at the Fe(SR)₆ region for compound (2A) while terminal chlorides induce changes over the whole molecule of (3b) with the latter structure more comparable to [Mo₂Fe₆S₈(SPh)₉]^5– (3f) with [MoFe₃S₄]²⁺ core than to [Mo₂Fe₆S₈(SPh)₉]^3– (3d). The isotropic shifts of (2A) originate mainly from -contact interaction. Both¹H n.m.r. spectra and magnetic susceptibility measurements indicate practically no magnetic interaction among the three magnetic centres,i.e. a Fe(SR)₆ bridge and two [MoFe₃S₄(SR)₃] units. CV studies showed that the reduction of cubane unit having aromatic thiolates is easier than that having aliphatic thiolates as the aliphatic group is electron-donating. In addition, the very similar differences of E_p,c for first and second cubane units in compounds (2A) and in (3d) and (3e) imply that the effect of the first reduced unit [MoFe₃S₄]²⁺ upon the second unit [MoFe₃S₄]³⁺ is very similar in the two types of dicubane cluster compounds. Synergism in Mo–Fe–S cluster compounds is thus proposed to play an important role in their structural correlation with reactivities and must function in nitrogenase.     

Condensed benzopyrans III. 3H,4H[1] benzopyrano [3,4-b] pyrrol-4-ones

The diazotization of 3-aminocoumarin followed by its reduction gave the cournarin-3-yl-hydrazine which, without isolation, reacted with various carbonyl compounds in a Fisher's indohzation reaction to give derivatives (Ib-Ih) of the yet unreported system 3H,4H[1]benzopyrano[3,4-b]pyrrol-4-one.     

Selenium heterocycles. XXXIX. Synthesis of thieno[3, 4-d]thiazole,thieno[3, 4-d]selenazole,selenolo[3, 4-d]thiazole and selenolo[3, 4-d]selenazole

Starting from readily available methyl 2-substituted4-methyl-5-thiazolyl ketone and methyl 4-methyl-2-phenyl-5-selenazolyl ketone, thieno[3, 4-d]thiazole, thieno[3, 4-d]selenazole, selenolo[3, 4-d]thiazole and selenolo[3, 4-d]selenazole were prepared. The structures of all compounds were confirmed by analytical and spectroscopic methods.     

Crystallographic report: Hydroxytrimethylarsonium iodide, [Me3AsOH]I

Hydroxytrimethylarsonium iodide, [Me₃AsOH]I, was obtained from the reaction of Me₂AsI and MeI in strong basic aqueous solution. The arsenic atom, lying on a mirror plane, is surrounded by one OH and three Me groups, forming a tetrahedral centre. Copyright © 2005 John Wiley & Sons, Ltd.     

Solid state synthesis of copper(I) thiotungstate cluster compounds at low heating temperatures. Crystal structures of [(n-Bu)4N]3-[WS4Cu3Cl3Br] and [Et4N]4[WS4Cu4I6]

Summary Reaction of [NH₄]₂[WS₄] with CuX (X = Cl or I) and R₄NX (R = Et or n-Bu) in the solid state gave two new bimetallic compounds with W:Cu compositions from 1:3 to 1:4. Compound (1), [(n-Bu)₄N]₃[WS₄Cu₃Cl₃Br], crystallizes in the hexagonal space group R3c with a = 17.051(5), c = 38.372(5) Å, V = 9661.8 ų, Z = 6. The cluster anion of (1) comprises a cubane-like cluster core [WS₃Cu₃Br] of C₃ symmetry with a Cl atom attached to each of the three Cu atoms and one terminal sulphido ligand attached to the W atom. Compound (2), [Et₄N]₄[WS₄Cu₄I₆], crystallizes in the monoclinic space group C2/m with a = 29.702(6), b = 12.7887(5), c = 15.327(3)Å, = 99.69(2), V = 5738.1 ų, Z = 4. In the cluster anion of (2), four edges of the WS₄ core are coordinated by four Cu atoms, giving a WS₄Cu₄ aggregate of approximate C_2V symmetry.     

Syntheses of [BpBut,Me]AlMe2 and [BpBut,Me]GaMe2: structural comparison of a pair of bis(pyrazolyl)hydroborato aluminum and gallium methyl complexes

The aluminum and gallium dimethyl complexes, [Bp^But,Me]AlMe₂ and [Bp^But,Me]GaMe₂, are readily obtained by the reactions of [Bp^But,Me]Tl with Me₃Al and Me₃Ga, respectively. [Bp^But,Me]AlMe₂ and [Bp^But,Me]GaMe₂ have been structurally characterized by X-ray diffraction, which indicates that the most noticeable difference in these otherwise very similar structures is the C–M–C bond angle, which increases from 118.9(3)° for [Bp^But,Me]AlMe₂ to 124.0(2)° for [Bp^But,Me]GaMe₂.     

The search for 3d-4f single-molecule magnets: synthesis, structure and magnetic properties of a [Mn(III)2Dy(III)2] cluster

Tetranuclear [Mn(III)2Ln(III)2] complexes formed using tripodal ligands display frequency dependent out-of-phase ac susceptibility signals and temperature and sweep rate dependent hysteresis loops.     

Synthesis and structural evolution of rusb3, a new metastable skutterudite compound

A thin-layer synthesis technique was used to synthesize bulk amounts of the metastable phase, RuSb(3), a novel compound with the skutterudite structure. The compound crystallized at 350 degrees C and was stable to 525 degrees C. When annealed above 550 degrees C, it decomposed into RuSb(2) and Sb. Rietveld refinement of X-ray diffraction data showed the presence of excess Sb residing in the interstitial site in the skutterudite structure. X-ray diffraction and thermal analysis experiments allowed us to examine the evolution of the sample as a function of annealing and determine the reaction pathway. The activation energy for the crystallization of the compound was determined to be 3 eV/nucleation event, while the activation energy for decomposition was approximately 8 eV.     

Synthesis, characterization, and reactivity of trans-[PtCl(R'R'SO)(A)2]NO3 (R'R'SO = Me2SO, MeBzSO, MePhSO; A= NH3, py, pic). Crystal structure of trans-[PtCl(Me2SO)(py)2]+

Trans complexes such as trans-[PtCl(2)(NH(3))(2)] have historically been considered therapeutically inactive. The use of planar ligands such as pyridine greatly enhances the cytotoxicity of the trans geometry. The complexes trans-[PtCl(R'R'SO)(A)(2)]NO(3) (R'R'SO = substituted sulfoxides such as dimethyl (Me(2)SO), methyl benzyl (MeBzSO), and methyl phenyl sulfoxide (MePhSO) and A = NH(3), pyridine (py) and 4-methylpyridine or picoline (pic)) were prepared for comparison of the chemical reactivity between ammine and pyridine ligands. The X-ray crystal structure determination for trans-[PtCl(Me(2)SO)(py)(2)]NO(3) confirmed the geometry with S-bound Me(2)SO. The crystals are orthorhombic, space group P2(1)2(1)2(1), with cell dimensions a = 7.888(2) A, b = 14.740(3) A, c =15.626(5) A, and Z = 4. The geometry around the platinum atom is square planar with l(Pt-Cl) = 2.304(4) A, l(Pt-S) = 2.218(5) A, and l(Pt-N) = 2.03(1) and 2.02(1) A. Bond angles are normal with Cl-Pt-S = 177.9(2) degrees, Cl-Pt-N(1) = 88.0(4) degrees, Cl-Pt-N(2) = 89.3(5) degrees, S-Pt-N(1) = 93.8(4) degrees, S-Pt-N(2) = 88.9(4) degrees, and N(1)-Pt-N(2) = 177.2(6) degrees. The intensity data were collected with Mo Kalpha radiation with lambda = 0.710 69 A. Refinement was by full-matrix least-squares methods to a final R value of 3.80%. Unlike trans-[PtCl(2)(NH(3))(2)], trans-[PtCl(2)(A)(2)] (A = py or pic) complexes do not react with Me(2)SO. The solvolytic products of cis-[PtCl(2)(A)(2)] (A = py or pic) were characterized. Studies of displacement of the sulfoxide by chloride were performed using HPLC. The sulfoxide was displaced faster for the pyridine complex relative to the ammine complex. Chemical studies comparing the reactivity of trans-[PtCl(R'R'SO)(amine)(2)]NO(3) with a model nucleotide, guanosine 5'-monophosphate (GMP), showed that the reaction gave two principal products: the species [Pt(R'R'SO)(amine)(2)(N7-GMP)], which reacts with a second equivalent of GMP, forming [Pt(amine)(2)(N7-GMP)(2)]. The reaction pathways were different, however, for the pyridine complexes in comparison to the NH(3) species, with sulfoxide displacement again being significantly faster for the pyridine case.     

Synthesis and characterization of a new Mo-Fe-S cluster compound containing MoO_3S_3 unit and mixed-valent Mo atoms [Et_4N]_2[Mo_2Fe(CO)_4(S,O-C_6H_4-1,2)_3Cl_2]

Reaction of [Mo3(CO)7(S,O-C6H4-1,2)3]2- with FeCl2 in MeCN at 60℃ affords a new Mo-Fe-S cluster complex containing MoO3S3 unit and mixed-valeut Mo atoms, [Et4N]2[Mo2Fe-(CO)4(O,S-C6H4-1,2)aCl2] (1). 1 is characterized by elemental analysis, IR, Mossbauer spectra, X-ray photoelectron spectra and mass spectra. And the structure of 1 is suggested as the structure which contains a [Mo(S,O-C6H4-1,2)3] unit of which the two of three sulfur atoms link to a Mo(CO)4-moiety and the three oxygen atoms are coordinated to a FeCl2 ligand.