1,2,4-benzothiadiazine 1,1-dioxides 3. Reactions of 2-aminobenzenesulfonamide with chloroalkyl isocyanates

Reactions of 2-aminobenzenesulfonamide ( 1 ) with allyl, methyl, 2-chloroethyl aor 3-chloropropyl isocyanates gave 2-(methylureido)-, 2-(allylureido)-, 2-(2′-chloroethylureido)- and 2-(3′-chloropropylureido)-benzene sulfonamides 3a,b and 7a,b in excellent yields. Treatment of 3a,b at refluxing temperature of DMF afforded 2H-1,2,4-benzothiadiazin-3(4H)-one 1,1-dioxide ( 4 ) in good yield. However, when compounds 7a,b were refluxed in 2-propanol, 3-(2′-aminoethoxy)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 11a ) and 3-(3′-aminopropoxy)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 11b ) were obtained in a form of the hydrochloride salts 10a,b in 87% and 78% yields respectively. Heating 11b in ethanol gave a dimeric form of 2H-1,2,4-benzothiadiazin-3(4H)-one 1,1-dioxide and 3-(3′-aminopropoxy)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 12 ) in 55% yield. Treating of 7a,b or 11a,b with triethylamine at the refluxing temperature of 2-propanol afforded 3-(2′-hydroxyethylamino)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 2a ) and 3-(3′-hydroxypropylamine)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 2b ) via a Smiles rearrangement.     

One-pot synthesis of [2+2]-helicate-like macrocycle and 2+4-μ4-oxo tetranuclear open frame complexes: Chiroptical properties and asymmetric oxidative coupling of 2-naphthols

Synthesis of binuclear Cu(II) terminally closed [ 2+2 ]- double-stranded helicate-like macrocycles 1, 1′ , 1″ , 2 , 2′ , 2″ and 2+4- μ₄-oxo tetranuclear open frame complexes 3 , 3′ , 3″ , 4 , 4′ , 4″ are established. Adapting one-pot self-assembly technique from simple three components systems: 1,1′-binaphthyl-2,2′-diamine, 4-methyl-2,6-diformyl phenol and cupric salts, the helicate-like [ 2+2 ]- macrocyclic complexes 1–1″, 2–2″ and 2+4- μ₄-oxo tetranuclear complexes 3–3″ , 4–4″ were obtained by appropriately altering the reaction condition such as temperature and subcomponent ratio. Density Functional Theory (DFT) calculations were carried out for understanding the structural geometries, intermediates involved in the diverse formation of [ 2+2 ] and 2+4 frameworks. The single crystal X-ray structures obtained for 1′ , 2 and 3 confirms the self-assembly process in line with DFT. This detailed analysis tempted us to derive a plausible mechanism for this long standing challenge in the synthesis of such macrocycles using 1,1′-binaphthyl-2,2′-diamine (BNDA) and aromatic aldehyde. The chiroptical properties of enantiopure complexes and their catalytic applications in asymmetric oxidative coupling of 2-naphthol to chiral 1,1’-Bi-2-naphthol (BINOL) achieved in good yield and ee were discussed.     

Synthesis of 4-β-D-arabinofuranosyl-5,6-dihydro-2H-1,2,4-thiadiazin-3-one 1,1-dioxide and x-ray diffraction analysis of its 2′,3-anhydro precursor

Reaction of 2-amino-3′,5′-bis(O-tert-butyldimethylsilyl)-β- D -arabinofuran[1′,2′:4,5]-2-oxazoline with 2-chloroethylsulfonyl chloride in the presence of sodium bicarbonate followed by removal of the protecting groups gave 2′,3-anhydro-4-β- D -arabinofuranosyl-5,6-dihydro-2H-1,2,4-thiadiazin-3-one 1,1-dioxide ( 5 ), which by treatment with ammonia was converted to 4-β- D -arabinofuranosyl-5,6-dihydro-2H-1,2,4-thiadiazin-3-one 1,1-dioxide ( 6 ). The structure of compound 5 was unequivocally established by means of an x-ray diffraction analysis. The compound crystallized in the space group P2₁2₁2₁ with unit cell dimensions a = 5.883(3), b = 9.352(2), c = 18.769(7) Å, Z = 4. Its structure was established by direct multisolution techniques and refined by the full matrix least squares method to a final R value of 0.058 for the 1515 reflections observed.     

A one‐dimensional zinc(II) coordination polymer incorporating [1,1′‐biphenyl]‐4,4′‐dicarboxylate and N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide ligands

In the title compound, catena‐poly[[[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]chloridozinc(II)]‐μ‐[1,1′‐biphenyl]‐4,4′‐dicarboxylato‐[[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]chloridozinc(II)]‐μ‐[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]], [Zn₂(C₁₄H₈O₄)Cl₂(C₂₆H₂₂N₄O₂)₃]_n, the Zn^II centre is four‐coordinate and approximately tetrahedral, bonding to one carboxylate O atom from a bidentate bridging dianionic [1,1′‐biphenyl]‐4,4′‐dicarboxylate ligand, to two pyridine N atoms from two N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide ligands and to one chloride ligand. The pyridyl ligands exhibit bidentate bridging and monodentate terminal coordination modes. The bidentate bridging pyridyl ligand and the bridging [1,1′‐biphenyl]‐4,4′‐dicarboxylate ligand both lie on special positions, with inversion centres at the mid‐points of their central C—C bonds. These bridging groups link the Zn^II centres into a one‐dimensional tape structure that propagates along the crystallographic b direction. The tapes are interlinked into a two‐dimensional layer in the ab plane through N—H...O hydrogen bonds between the monodentate ligands. In addition, the thermal stability and solid‐state photoluminescence properties of the title compound are reported.     

Umsetzungen von Ferrocenol und 1,1′-Ferrocendiol mit Cyclotriphosphazenen,P3N3F6 und P3N3Cl6

Reactions of Ferrocenol and 1,1′-Ferrocendiol with Cyclotriphosphazenes, P₃N₃F₆ and P₃N₃Cl₆ The hexahalogeno-cyclotriphosphazenes, P₃N₃X₆ (X ? F ( 1 a ), Cl ( 1 b )), react with ferrocenol (FcOH) in a molar ratio 1 : 1 to give the ferrocenoxy derivatives, FcO[P₃N₃X₅] (X ? F ( 3 a ), Cl ( 3 b )); in an analogous manner the tetrameric ring P₄N₄Cl₈ ( 2 b ) is converted to FcO[P₄N₄Cl₇] ( 4 b ).

1 Abkürzungen: Fc = Ferrocenyl, (C₅H₅)Fe(C₅H_4?); fc = 1,1′-ferrocendiyl, Fe(C₅H_4?)₂; rc = 1,1′-ruthenocendiyl, Ru(C₅H_4?)₂. Fluorphosphazene werden mit a , Chlorphosphazene mit b gekennzeichnet.

With 1,1′-ferrocenediol, (fc(OH) ₂ ), the cyclo triphosphazenes react in a molar ratio 1 : 1 to produce fcO ₂ [P ₃ N ₃ X ₄ ] (X ? F ( 5 a ), Cl ( 5 b )). According to the x-ray structure analysis, the 1,1′-ferrocenediolato group in 5 a , b is bound to two different phosphorus atoms. On the contrary, the 1,1′-ferrocenedithiolato- and 1,1′-ferrocenediselenolato units in fcS ₂ [P ₃ N ₃ X ₅ ] (X ? F ( 6 a ), Cl ( 6 b )) and fcSe ₂ [P ₃ N ₃ X ₅ ] (X ? F ( 7 a ), Cl ( 7 b )) are attached to only one phosphorus atom, and spirocyclic 1,3-dichalcogena-2-phospha-[3]ferrocenophanes are formed. All new products have been characterized on the basis of their ¹ H, ¹³ C and ³¹ P NMR as well as EI mass spectra. The molecular structures of 5 a , b and 6 a have been determined by x-ray structure analyses.     

Methylene‐Bridged Metallocenes with 2,2′‐Methylenebis[1H‐inden‐1‐yl] Ligands: Synthesis,Characterization, and Polymerization Catalysis of a Synthetically Simple Class of C2‐ and C2v‐Symmetric ansa‐Metallocenes

The acid‐catalyzed reaction between formaldehyde and 1H‐indene, 3‐alkyl‐ and 3‐aryl‐1H‐indenes, and six‐membered‐ring substituted 1H‐indenes, with the 1H‐indene/CH₂O ratio of 2 : 1, at temperatures above 60° in hydrocarbon solvents, yields 2,2′‐methylenebis[1H‐indenes] 1 – 8 in 50–100% yield. These 2,2′‐methylenebis[1H‐indenes] are easily deprotonated by 2 equiv. of BuLi or MeLi to yield the corresponding dilithium salts, which are efficiently converted into ansa‐metallocenes of Zr and Hf. The unsubstituted dichloro{(1,1′,2,2′,3,3′,3a,3′a,7a,7′a‐η)‐2,2′‐methylenebis[1H‐inden‐1‐yl]}zirconium ([ZrCl₂( 1′ )]) is the least soluble in organic solvents. Substitution of the 1H‐indenyl moieties by hydrocarbyl substituents increases the hydrocarbon solubility of the complexes, and the presence of a substituent larger than a Me group at the 1,1′ positions of the ligand imparts a high diastereoselectivity to the metallation step, since only the racemic isomers are obtained. Methylene‐bridged ‘ansa‐zirconocenes’ show a noticeable open arrangement of the bis[1H‐inden‐1‐yl] moiety, as measured by the angle between the planes defined by the two π‐ligands (the ‘bite angle’). In particular, of the ‘zirconocenes’ structurally characterized so far, the dichloro{(1,1′,2,2′,3,3′,3a,3′a,7a,7′a‐η)‐2,2′‐methylenebis[4,7‐dimethyl‐1H‐inden‐1‐yl]}zirconium ([ZrCl₂( 5′ )] is the most open. The mixture [ZrCl₂( 1′ )]/methylalumoxane (MAO) is inactive in the polymerization of both ethylene and propylene, while the metallocenes with substituted indenyl ligands polymerize propylene to atactic polypropylene of a molecular mass that depends on the size of the alkyl or aryl groups at the 1,1′ positions of the ligand. Ethene is polymerized by rac‐dichloro{(1,1′,2,2′,3,3′,3a,3′a,7a,7′a‐η)‐2,2′‐methylenebis[1‐methyl‐1H‐inden‐1‐yl]}zirconium ([ZrCl₂( 2′ )])/MAO to polyethylene waxes (average degree of polymerization ca. 100), which are terminated almost exclusively by ethenyl end groups. Polyethylene with a high molecular mass could be obtained by increasing the size of the 1‐alkyl substituent.     

Synthesis of diols containing 5-benzyluracil base and their polymers

Preparation of analogs of acyclic nucleoside, two diols containing 5-benzyluracil base derived from 2-(5-benzyluracil-1-yl)propanoic acid (BUPA), and the corresponding model polymers of polynucleotide with linear polyester backbone and 2-(5-benzyluracil-1-yl)propionamido-type pendant as a side chain are described. N-(1′,3′-Dihydroxy-2′-methyl-2′-propyl)-2-(5-benzyluracil-1-yl)propionamide (HEBUPA) and its isomer N(β,β′-dihydroxyethyl)-2-(5-benzyluracil-1-yl)propionamide (HEBUPA) were prepared through the selective N-acylation of primary aminodiol, 2-methyl-2-amino-1,3-propanediol and secondary aminodiol, diethanolamine with BUPA, respectively, by the active ester-N-hydroxy-5-norbornene-2,3-dicarboximide (HONB) method. The resulting diols were polycondensed with active diamide of benzotriazole (HBT) such as 1,1′-(terephthaloyl)bisbenzotriazole (PBBT), 1,1′-(isophthaloyl)bisbenzotriazole (IPBBT), 1,1′-(sebacocyl)bisbenzotriazole (SeBBT), giving semirigid and flexible polyesters containing 5-benzyluracil derivative as the side group, by the selective O-acylation of active diamide-benzotriazole technique. Diols HMBUPA and HEBUPA were found to be very potent inhibitors of uridine phosphorylase isolated from Sarcoma 180 cells, with K_i values of 0.13 and 0.11 μM, respectively.     

The oxidative coupling of indole with some phenolic compounds,naphthols and catechols

The oxidative coupling of indole with three naphthols, 2-naphthol, 2,3-dihydroxynaphthalene and 2,7-dihydroxynaphthalene gave 1,1-bis(3′-indolyl)-2(1H)naphthalenone, 1,1-bis(3′-indolyl)-3-hydroxy-2(1H)naphthalenone and 1,1-bis(3′-indolyl)-7-hydroxy-2(1H)naphthalenone, respectively. The coupling of indole with protocatechuic aldehyde gave bis-(3-indolyl)-(3′,4′-di-hydroxyphenyl)methane and that of indole with homocatechol gave 3-(2′-methyl-3′,4′-di-hydroxyphenyl)indole.     

Simultaneous Determination of Concentration and Enantiomeric Composition of Amino Acids in Aqueous Solution by Using a Tetrabromobinaphthyl Dialdehyde Probe

3,3′-Diformyl-1,1′-bi-2-naphthol or its methoxymethyl-protected derivative is found to undergo a highly selective reaction with excess bromine in CH₂Cl₂ at reflux to give the novel 5,5′,6,6′-tetrabrominated product (S)- or (R)- 2 . The observed electrophilic substitution at the 5,5′-positons of an optically active binaphthyl compound is unprecedented. Unlike unbrominated 3,3′-diformyl-1,1′-bi-2-naphthol, which is not suitable for fluorescent recognition in water, compound (S)- 2 , in combination with Zn²⁺, exhibits a highly enantioselective fluorescent response toward amino acids in aqueous solution (HEPES buffer, pH 7.4). It is further found that the condensation product of (R)- 2 with tryptophan, (R)- 3 , shows dual-responsive emissions toward amino acids; the short wavelength (λ₁=350 nm) emission is sensitive to the concentration of the substrate regardless of the chiral configuration and the long wavelength (λ₂>500 nm) emission is highly enantioselective. Thus, the use of (R)- 3 allows the simultaneous determination of the concentration and enantiomeric composition of an amino acid sample from one fluorescence measurement.     

Helical Poly(α,β‐unsaturated ketone) with Bulky Pendant of Binaphthyl from Anionic Polymerization of ((−)‐Menthyl (S)‐6′‐Acrylyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate

((?)‐Menthyl (S)‐6′‐acrylyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate ( 3 ) was synthesized and anionically polymerized using n‐BuLi as an initiator in toluene. The monomer 3 was levorotatory and had an [α]_D²⁵ value of ?72.4, but its corresponding polymer poly‐ 3 was dextrorotatory and showed an [α]_D²⁵ value of +162.0. Poly‐ 3 was confirmed to exist in the form of one‐handed helical structure in solution by means of comparing the specific optical rotation and the CD spectra with that of 3 and the model compounds such as (?)‐menthyl (S)‐6′‐propionyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate 2b and (?)‐menthyl (S)‐6′‐heptanoyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate 2c . This conclusion was also confirmed by the fact that the g‐value of poly‐ 3 is about 11 times of that of monomer 3 .     

Chiral and Nonchiral [OsX2(diphosphane)(diamine)] (X: Cl,OCH2CF3) Complexes for Fast Hydrogenation of Carbonyl Compounds

The osmium complexes trans‐[OsCl₂(dppf)(diamine)] (dppf: 1,1′‐bis(diphenylphosphino)ferrocene; diamine: ethylenediamine in 3 , propylenediamine in 4 ) were prepared by the reaction of [OsCl₂(PPh₃)₃] ( 1 ) with the ferrocenyl diphosphane, dppf and the corresponding diamine in dichloromethane. The reaction of derivative 3 with NaOCH₂CF₃ in toluene afforded the alkoxide cis‐[Os(OCH₂CF₃)₂(dppf)(ethylenediamine)] ( 5 ). The novel precursor [Os₂Cl₄(P(m‐tolyl)₃)₅] ( 2 ) allows the synthesis of the chiral complexes trans‐[OsCl₂(diphosphane)(1,2‐diamine)] ( 6 – 9 ; diphosphane: (R)‐[6,6′‐dimethoxy(1,1′‐biphenyl)‐2,2′‐diyl]bis[1,1‐bis(3,5‐dimethylphenyl)phosphane] (xylMeObiphep) or (R)‐(1,1′‐binaphthalene)‐2,2′‐diylbis[1,1‐bis(3,5‐dimethylphenyl)phosphane] (xylbinap); diamine=(R,R)‐1,2‐diphenylethylenediamine (dpen) or (R,R)‐1,2‐diaminocyclohexane (dach)), obtained by the treatment of 2 with the diphosphane and the 1,2‐diamine in toluene at reflux temperature. Compounds 3 – 5 in ethanol and in the presence of NaOEt catalyze the reduction of methyl aryl, dialkyl, and diaryl ketones and aldehydes with H₂ at low pressure (5 atm), with substrate/catalyst (S/C) ratios of 10 000–200 000 and achieving turnover frequencies (TOFs) of up to 3.0×10⁵ h^?1 at 70 °C. By employment of the chiral compounds 6 – 9 , different ketones, including alkyl aryl, bulky tert‐butyl, and cyclic ketones, have successfully been hydrogenated with enantioselectivities up to 99 % and with S/C ratios of 5000–100 000 and TOFs of up to 4.1×10⁴ h^?1 at 60 °C.     

Multiple-State Emissions from Neat,Single-Component Molecular Solids: Suppression of Kasha's Rule

Three rigid and structurally simple heterocyclic stilbene derivatives, (E)-3H,3′H-[1,1′-biisobenzofuranylidene]-3,3′-dione, (E)-3-(3-oxobenzo[c] thiophen-1(3H)-ylidene)isobenzofuran-1(3H)-one, and (E)-3H,3′H-[1,1′-bibenzo[c] thiophenylidene]-3,3′-dione, are found to fluoresce in their neat solid phases, from upper (S₂) and lowest (S₁) singlet excited states, even at room temperature in air. Photophysical studies, single-crystal structures, and theoretical calculations indicate that large energy gaps between S₂ and S₁ states (T₂ and T₁ states) as well as an abundance of intra and intermolecular hydrogen bonds suppress internal conversions of the upper excited states in the solids and make possible the fluorescence from S₂ excited states (phosphorescence from T₂ excited states). These results, including unprecedented fluorescence quantum yields (2.3–9.6 %) from the S₂ states in the neat solids, establish a unique molecular skeleton for achieving multi-colored emissions from upper excited states by “suppressing” Kasha's rule.     

Enantiomerically Pure Cyclic trans-1,2-Diols,Diamines, and Amino Alcohols by Intramolecular Pinacol Coupling of Planar Chiral Mono-Cr(CO)3 Complexes of Biaryls

Without any formation of stereoisomers , the intramolecular pinacol cyclization of 1 —planar chiral mono-Cr(CO)₃ complexes of 1,1′-biphenyls with carbonyl functionalities at the 2- and 2′-positions—with samarium diiodide gives cyclic trans-1,2-diols 2 . Upon exposure to sunlight, the chromium-complexed diols 2 produce optically pure chromium-free trans-diols 3 . Similarly, the corresponding enantiomerically pure trans-1,2-diamines and amino alcohols are obtained from the planar chiral chromium complexes of biphenyls with diimino or keto-imino functionalities. R¹=H, OMe; R²=H, Me; R³=H, Me.     

PdCl2(Ph3P)2/Salicylaldimine Catalyzed Diarylation of Anilines with Unactivated Aryl Chlorides

Triphenylphosphine and salicylaldimine could be used as a mixed ligand system to obtain a high catalytic activity for palladium catalyzed diarylation of primary anilines with unactivated aryl chlorides by the synergistic effect of ligands. The activity and selectivity of the catalytic system could be improved by modifying the structure of salicylaldimine. In refluxing o ‐xylene, PdCl₂(Ph₃P)₂ with 2,5‐ditrifluoromethyl N ‐phenylsalicylaldimine as a coligand shows high efficiency for the diarylation of various anilines. The catalytic system shows good toleration for the steric hindrance of the substrates. The facile catalytic system works as well on the multiple arylation of 1,1′‐biphenyl‐ 4,4′‐diamine with aryl chlorides to afford N ,N ,N′ ,N′ ‐tetraaryl‐1,1′‐biphenyl‐4,4′‐diamines which are important intermediates of organic light emitting diode (OLED) hole transport materials.     

Ring transformations of heterocyclic compounds. XVI. Spiro[cyclohexadiene-dihydroacridines]. A novel class of spirodihydroacridines by ring transformation of pyrylium salts with 9-methylacridine and its quaternary salts

2,4,6-Triarylpyrylium salts 1 react with the in situ generated anhydrobase of 9,10-dimethylacridinium methosulfate ( 2a ) in the presence of anhydrous sodium acetate in ethanol by a 2,5-[C₄+C₂] pyrylium ring transformation to give the hitherto unknown 6-aroyl-3,5-diaryl-10′-methylspiro[cyclohexa-2,4-diene-1,9′-9′,10′-dihydro-acridines] 3 . When the pyrylium perchlorate 1a is treated under the same conditions with the N-ethyl, N-allyl or N-benzyl substituted acridinium salts 2b-d a dealkylation of these salts occurs and the N-unsubstituted spiro[cyclohexadiene-dihydroacridine] 4a is formed. The same compounds 4 can also be obtained by transformation of the pyrylium salts 1 with 9-methylacridine ( 7 ) and triefhylamine/acetic acid in ethanol. Structure elucidation is performed by an X-ray crystal structure determination of the spiro[cyclohexadiene-dihydroacridine] 3a . Spectroscopic data of the transformation products and their mode of formation are discussed.     

Metallocene monomers and polymers. Ferrocenyl and ferrocenylene derivatives

The synthesis and study of some polyenes, polýiminoimides and Schiff polybases with ferrocene obtained by either polymerization or polycondensation are reported.The following monomers were used: ethynylferrocene, 1-chloro-1′-ethynyl-ferrocene, α-chloro-β-formyl-p-ferrocenylstyrene, p-ferrocenylphenylacetylene, p-ferrocenylacetophenone, 1,1′-diacetylferrocene and 1,1′-bis[β-(2-furyl)acryloyl]ferrocene which were characterized by spectral and thermodifferential analyses and Hückel MO calculations. The polymerization was performed in the presence of benzoyl and lauroyl peroxides, triisopropylboron and complex catalysts of [P(C₆H₅)₃]₂ NiX₂ type. The ferrocene derivatives were polycondensed with biuret, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl thioether, 4,4′-diamino-2,2′-dinitrodiphenyl disulphide in the presence of metallic salts and p-toluene sulphonic acid as catalysts.Polymers with either linear or tridimensional structure showing good thermal stability and semiconducting properties have been obtained. Some polymers show catalytical activity in the polymerization of chloroformylated vinylic derivatives.     

Synthesis,crystal structure,and electrochemistry of [Co{(Me-sal)2dien}(N3)] and [Co{(Me-sal)2dpt}(N3)]

The structure, spectroscopic, and electrochemical properties of [Co{(Me-sal)₂dien}(N₃)] and [Co{(Me-sal)₂dpt}(N₃)], where (Me-sal)₂dien = 2,2′-[1,1′-(3-azapentane-1,5-diyldinitrilo)diethylidyne] diphenolate and (Me-sal)₂dpt = 2,2′-[1,1′-(4-azapentane-1,7-diyldinitrilo)diethylidyne] diphenolate, have been investigated. These complexes have been characterized by elemental analyses, IR, UV–Vis, and ¹H-NMR spectroscopy. The crystal structures of these complexes have been determined by X-ray diffraction. Complex 1 crystallizes in the triclinic space group P 1, with a = 7.8443(4) Å, b = 11.0660(5) Å, c = 11.6216(6) Å, α = 73.360(1)°, β = 76.965(1)°, γ = 84.436(1)° and Z = 2. Complex 2 crystallizes in the monoclinic space group P2₁/n, with a = 12.1985(13) Å, b = 10.9332(12) Å, c = 15.2808(16) Å, β = 76.965(1)° and Z = 4. The coordination geometry around cobalt(III) in both complexes is a distorted octahedron. The electrochemical reduction of these complexes at a glassy carbon electrode in acetonitrile indicates that the first reduction corresponding to Co^III–Co^II is electrochemically irreversible, accompanied by dissociation of the axial Co–N(N₃) bond. The second reduction step of Co(II/I) leads to decomposition of the complex. These observations are rationalized based on the structure-function relations.     

A ter­phenyl halide series: 2,6‐Trip2­H3C6X (Trip = 2,4,6‐triiso­propyl­phenyl; X = Cl,Br, I)

The sterically encumbered ter­phenyl halides 2′‐chloro‐2,2′′,4,4′′,6,6′′‐hexaisopropyl‐1,1′:3′,1′′‐terphenyl, C₃₆H₄₉Cl, (I), 2′‐bromo‐2,2′′,4,4′′,6,6′′‐hexaisopropyl‐1,1′:3′,1′′‐terphenyl, C₃₆H₄₉Br, (II), and 2′‐iodo‐2,2′′,4,4′′,6,6′′‐hexaisopropyl‐1,1′:3′,1′′‐terphenyl, C₃₆H₄₉I, (III), crystallize in space group Pnma. They are isomorphous and isostructural with a plane of symmetry through the centre of the mol­ecule. The C–halide bond distances are 1.745 (3), 1.910 (4) and 2.102 (6) Å for (I)–(III), respectively.     

Charge-Transfer Salts of Ferrocene Derivatives with Bis(maleonitriledithiolato)metallate(III) Complexes ([M(mnt)2]−, M=Ni,Pt): A Ground-State High-Spin [(Ni(mnt)2)2]2− Dimer

New hexamethylated ferrocene derivatives containing thioether moieties (1,1′-bis[(tert-butyl)thio]-2,2′,3,3′,4,4′-hexamethylferrocene ( 3a , b )) or fused S-heteropolycyclic substituents (rac-1-[(1,3-benzodithiol- 2-yliden)methyl]-2,2′,3,3′,4,4′-hexamethylferrocene ( 5 ) and rac-1-[1,2-bis(1,3-benzodithiol-2-yliden)ethyl]-2,2′,3,3′,4,4′-hexamethylferrocene ( 14 )), as well as a series of ferrocene-substituted vinylogous tetrathiafulvalenes (1,1′-bis[1,2-bis(1,3-benzodithiol-2-yliden)ethyl]ferrocene ( 6a ), 1,1′-bis[1-(1,3-benzodithiol-2-yliden)-2-(5,6-dihydro-1,3-dithiolo[4,5-b] [1,4]dithiin-2-yliden)ethyl]ferrocene ( 6b ), [1,2-bis(1,3-benzodithiol-2-yliden)ethyl]ferrocene ( 21a ), [1-(1,3-benzodithiol-2-yliden)-2-(5,6-dihydro-1,3-dithiolo[4,5-b] [1,4]dithiin-2-yliden)ethyl]ferrocene ( 21b ), [1,2-bis(5,6-dihydro-1,3-dithiolo[4,5-b] [1,4]dithiin-2-yliden)ethyl]ferrocene ( 21c ), [1-(5,6-dihydro-1,3-dithiolo[4,5-b] [1,4]dithiin-2-yliden)-2-(1,3-benzodithiol-2-yliden)ethyl]ferrocene ( 21d )) were prepared and fully characterized. Their redox properties show that some of them are easily oxidized and undergo transformation to paramagnetic salts containing bis(maleonitriledithiolato)-metallate(III) anions [M(mnt)₂]⁻ (M=Ni, Pt; bis[2,3-dimercapto-κS)but-2-enedinitrilato(2⁻)]nickelate (1⁻) or -platinate (1⁻). The derivatives [ 3a ] [Ni(mnt)₂] ( 26 ), [ 3a ] [Pt(mnt)₂] ( 27 ), [Fe{(η⁵-C₅Me₄S)₂S}] [Ni(Mnt)₂] ( 28 ), [Fe{(η⁵-C₅Me₄S)₂S}] [Pt(mnt)₂] ( 29 ), [ 5 ] [Ni(mnt)₂]⋅ClCH₂CH₂Cl ( 30 ), [ 6a ] [Ni(mnt)₂] ( 31 ), [ 6a ] [Ni(mnt)₂]⋅ClCH₂CH₂Cl ( 31a ), [ 6a ] [Pt(mnt)₂] [ 32 ), and [ 6b ] [Ni(mnt)₂] ( 33 ) were prepared and fully characterized, including by SQUID (superconducting quantum interference device) susceptibility measurements. X-Ray crystal-structural studies of the neutral ferrocene derivatives 6a , b , 21c , d , and 1,1′-bis[1-(1,3-benzodithiol-2-yliden)-2-oxoethyl]ferrocene ( 23 ), as well as of the charge-transfer salts 26 – 28 , 30 , and 31a , are reported. The salts 28 and 30 display both a D⁺A⁻A⁻D⁺ structural motif, however, with a different relative arrangement of the [{Ni(mnt)₂}₂]²⁻ dimers, thus giving rise to different but strong antiferromagnetic couplings. Salt 26 exhibits isolated ferromagnetically coupled [{Ni(mnt)₂}₂]²⁻ dimers. Salt 27 displays a D⁺A⁻D⁺A⁻ structural motif in all three space dimensions, and a week ferromagnetic ordering at low temperature. Salt 31a , on the contrary, shows segregated stacks of cations and anions. The cations are connected with each other in two dimensions, and the anions are separated by a 1,2-dichloroethane molecule.     

Synthesis of 1,2,5-Thiadiazolidin-3-one 1,1-Dioxide Derivatives and Evaluation of Their Affinity for MHC Class-II Proteins

1,2,5-Thiadiazolidin-3-one 1,1-dioxide derivatives (±)- 1a – d and (±)- 2 were designed by molecular modeling as MHC (major histocompatibility complex) class-II inhibitors. They were prepared from the unsymmetrically N,N′-disubstituted acyclic sulfamides (±)- 4a – d (Scheme 1) and (±)- 11 (Scheme 2). These N-alkyl-N′-arylsulfamide precursors were synthesized by nucleophilic substitution of either a sulfamoyl-chloride or a N-sulfamoyloxazolidinone. Extension of base-induced cyclization methods from aliphatic to aromatic sulfamides gave access to the desired target molecules. The N-alkyl-1,2,5-thiadiazolidin-3-one 1,1-dioxide derivatives (±)- 3a – c were also prepared by the oxazolidinone route (Scheme 4) for coupling to a tetrapeptide fragment. The X-ray crystal structure of 1,2,5-thiadiazolidin-3-one 1,1-dioxide (±)- 21a was solved, and the directionality of the H-bond donor (N−H) and acceptor (SO₂) groups of the cyclic scaffold determined (Figs. 1 and 2). The pK_a value of the N−H group in (±)- 21a was determined by ¹H-NMR titration as 11.9 (Fig. 3). Compounds (±)- 1a – d were shown to inhibit competition peptide binding to HLA-DR4 molecules in the single-digit millimolar concentration range.