Search

The back cover picture shows novel (1,3,5,7,9‐pentaazanona‐1,3,6,8‐tetraenato)platinum(II) [abbreviated as (PANT)PtII] complexes that were obtained by metal‐mediated organonitrile, RCN, or dialkylcyanamide, R'2NCN, double coupling with 2,3‐diphenylmaleimidine. These annulated (PANT)PtII systems demonstrate phosphorescence both in solution and in the solid state. Details are discussed in the article by P.‐T. Chou, V. Yu. Kukushkin et al. on p. 1480 ff. [ABSTRACT FROM AUTHOR]

Highlights: [•] Dibromo-bis-isocyanide Pd complexes are prepared via metathetical reaction from chlorides. [•] Geometry of complexes in solution and solid-state is established on basis of spectroscopic data. [•] trans coordination modes are preferable for dibromo species in solution and in a solid state. [ABSTRACT FROM AUTHOR]

The reaction between [Os3H2(CO)10] and 1,4-diphenylbuta-1,3-diyne yields two isomers of the triosmium cluster [Os3(μ-H)(CO)10{μ3-η1:η3:η1-Ph(C)C9H6)}] 1, 2, the structures of which involve an ‘open’ metal triangle and exhibit an unusual pseudo-allylic interaction involving a fused six- and five-membered ring system obtained from a ring-closure reaction of the diyne. Thermal decarbonylation of 1 and 2 produces [Os3(μ-H)(CO)9{μ3-η1:η3:η1-Ph(C)C9H6)}] (3) which has a ‘closed’ Os3 triangular core and the same formal μ3-η1:η3:η1-allylic coordination mode. The reaction of 1 with trimethylamine-N-oxide in the presence of acetonitrile affords [Os3(μ-H)(CO)8(MeCN){μ3-η1:η3:η1-(Ph(C)C9H6)}] (4), an acetonitrile-substituted derivative of 3. The structures of clusters 1–4 have been established by X-ray crystallography, and all the new clusters have been characterised spectroscopically. [Copyright &y& Elsevier]

Phenanthrene-9,10-dicarbonitriles show various luminescence behaviour in solution and in the solid state. Aggregation patterns of phenanthrene-9,10-dicarbonitriles govern their luminescent properties in the solid state. Single crystal structures of phenanthrene-9,10-dicarbonitriles showed head-to-tail intraplane (or quasi-intraplane) intermolecular interactions and π-stacking patterns with eclipsing of molecules when viewed orthogonal to the stacking plane. The π-stacking interactions were detected in the X-ray structures of phenanthrene-9,10-dicarbonitriles and studied by DFT calculations at the M06–2X/6–311++G(d,p) level of theory and topological analysis of the electron density distribution within the framework of QTAIM method. The estimated strength of the C⋯C contacts responsible for the π-stacking interactions is 0.6–1.1 kcal/mol. The orientation of molecules in crystals depends on the substituents in phenanthrene-9,10-dicarbonitriles. Distinct molecular orientation and packing arrangements in crystalline phenanthrene-9,10-dicarbonitriles ensured perturbed electronic communication among the nearest and non-nearest molecules through an interplay of excimer and dipole couplings. As a result, the intermolecular interactions govern the solid state luminescence of molecules. Image 1 • Crystal packing of phenanthrene-9,10-dicarbonitriles. • Fluorescence in the solid state and in solution. • Topological analysis of the electron density distribution. [ABSTRACT FROM AUTHOR]

In this data article, we present the single-crystal XRD data of phenanthrene-9,10-dicarbonitriles. Detailed structure analysis and photophysical properties were discussed in our previous study, "Intermolecular interactions-photophysical properties relationships in phenanthrene-9,10-dicarbonitrile assemblies" (Afanasenko et al., 2020). The data include the intra- and intermolecular bond lengths and angles., (© 2019 The Author(s).)

A domino synthesis of dispiro-fused N-vinyl β-lactams from diazo-Meldrum's acid and 2H-azirines or 5-alkoxyisoxazoles via the "2-azabuta-1,3-diene formation/Staudinger ketene-imine cycloaddition" sequence is described. The Rh2(Piv)4-catalyzed formation of the 2-azabuta-1,3-diene intermediates in the first stage of the reaction sequence proceeds via addition of the rhodium carbenoid to the azirines/isoxazoles and provides the first example of the generation of iminium-type ylides from diazo-Meldrum's acid. This methodology was extended to monospiro-β-lactams, which were synthesized in two steps using acyclic α-diazocarbonyl compounds in the stage of the formation of 2-azabuta-1,3-dienes. The method allows for the rapid assemblage of the carbon part of the azetidin-2-one system from diazo compounds only and affords spiro- and dispiro-β-lactams in moderate yields. A bromine atom in the 2-bromoalkenyl moiety of the synthesized β-lactams can be easily substituted by hydrogen under catalytic hydrogenation conditions or by 2-pyridyl-substituent via the Stille cross-coupling reaction.

3'-Azidothymidine (AZT) reacts with 1-propargyl-5-R-1 H - and 2-propargyl-5-R-2 H -tetrazoles (R = H, Me, CH 2 COOEt, CH 2 CON(CH 3 ) 2 , Ph, 2-CH 3 -C 6 H 4 , or 4-NO 2 -C 6 H 4 ) via the Cu(I)-catalyzed asymmetric [3 + 2] cycloaddition to give 3'-modified thymidine analogs incorporating 1 H -1,2,3-triazolyl, 1 H -, and 2 H -tetrazolyl fragments in 41-76% yield. The structures of the obtained compounds have been elucidated by means of HRESI + -MS, 1 H and 13 C{ 1 H} NMR, and single crystal X-ray diffraction {for 3'-[4-(1 H -5- N , N -dimethylaminocarbonylmethyltetrazol-1-yl)-1 H -1,2,3-triazol-1-yl]thymidine 10d }. In vitro biological evaluation of the prepared compounds has been performed; they have exhibited low activity against phenotypic HIV-1 899A . Moderate anti-influenza activity against influenza virus A/Puerto Rico/8/34 (H1N1) strain has been observed in the cases of 3'-(4-(1 H -tetrazol-1-ylmethyl)-1 H -1,2,3-triazol-1-yl)thymidine 10a (IC 50 39.6 μg/mL), 3'-(4-(2 H -5-ethoxycarbonyltetrazol-2-ylmethyl)-1 H -1,2,3-triazol-1-yl)thymidine 11c (IC 50 31.6 μg/mL), and 3'-(4-(2 H -5-(4-nitrophenyl)-tetrazol-2-ylmethyl)-1 H -1,2,3-triazol-1-yl)thymidine 11g (IC 50 46.4 μg/mL). The tested compounds possess very low cytotoxicity towards MDCK and MT4 cells as well as tumor human cervical carcinoma HeLa and promyelocytic leukemia HL-60 cells.

An effective and operationally simple method for the preparation of methyl 2-(di/tri/tetraazol-1-yl)-2 H-azirine-2-carboxylates from accessible methyl 2-halo-2 H-azirine-2-carboxylates and NH-azoles has been developed. The azoles having enhanced NH acidity, react with 2-halo-2 H-azirines in the presence of Et 3 N in a deprotonated form, while the azoles having highly nucleophilic sp 2 nitrogen react in neutral form. According to the DFT calculations, the substitution of the halogen by the azole proceeds via an S N 2'-S N 2' cascade, with the initial conjugate substitution of the halogen being the rate-determining step. The formation of 2,3-dipyrazolylaziridines in the reaction of pyrazole provides experimental evidence for the cascade mechanism of the reaction.

An effective method for the synthesis of fully substituted 5-sulfonamidoimidazoles by Rh(II)-catalyzed transannulation of 1,2,4-oxadiazole derivatives with N-sulfonyl-1,2,3-triazoles is reported. The reaction works well with both aromatic 1,2,4-oxadiazoles and 1,2,4-oxadiazol-5-ones providing a flexible approach to N-(alkoxy/amino)carbonyl- and N-alkyl-substituted imidazoles. Both the disclosed reactions are completely regioselective and provide the first examples of a carbenoid-mediated transformation of N,N,O-heterocycles.

A series of novel diimine (N ∧ N) ligands containing developed aromatic [2,1- a]pyrrolo[3,2- c]isoquinoline system have been prepared and used in the synthesis of Ir(III) luminescent complexes. In organic solvents, the ligands display fluorescence which depends strongly on the nature of solvents to give moderate to strong orange emission in aprotic solvents and shows a considerable blue shift and substantial increase in emission intensity in methanol. Insertion of electron-withdrawing and -donating substituents into peripheral phenyl fragment has nearly no effect onto emission parameters. The ligands were successfully used to prepare the metalated [Ir(N ∧ C) 2 (N ∧ N)] + complexes (where N ∧ C = phenylpyridine (N ∧ C-1), p-tolylpyridine (N ∧ C-2), 2-(benzo[ b]thiophen-2-yl)pyridine (N ∧ C-3), 2-benzo[ b]thiophen-3-yl)pyridine (N ∧ C-4), and methyl 2-phenylquinoline-4-carboxylate (N ∧ C-5)) using standard synthetic procedures. The complexes obtained display moderate to strong phosphorescence in organic solvents; the emission characteristics is determined by the nature of emissive triplet state, which varies substantially with the variations in the structure and donor properties of the C- and N-coordinating functions in metalating ligands. TD-DFT calculations show that for complexes 1, 2, and 4 the emission originates from the mixed 3 MLCT/ 3 LLCT excited states with the major contribution from the aromatic moiety of the diimine ligand, whereas in 3 the emissive triplet manifold is mainly located at the N ∧ C ligand to give structured emission band typical for the ligand centered (LC) excited state. In the case of 5, the phosphorescence may be also assigned to the mixed 3 MLCT/ 3 LLCT excited state; however, the major contribution is attributed to the aromatic moiety of the metalating N ∧ C ligand.

The reaction of cis-[PdCl 2 (CNCy) 2 ] (1) with thiazol-2-amines (2-10) leads to the C,N-chelated diaminocarbene-like complexes [PdCl{ C(N(H)4,5-R 2 -thiazol-2-yl)NHCy}(CNCy)] (11-14; 82-91%) in the case of 4,5-R 2 -thiazol-2-amines (R, R = H, H (2), Me, Me (3), -(CH 2 ) 4 - (4)) and benzothiazol-2-amine (5) or gives the diaminocarbene species cis-[PdCl 2 {C(N(H)Cy)N(H)4-R-thiazol-2-yl}(CNCy)] (15-19; 73-93%) for the reaction with 4-aryl-substituted thiazol-2-amines (R = Ph (6), 4-MeC 6 H 4 (7), 4-FC 6 H 4 (8), 4-ClC 6 H 4 (9), 3,4-F 2 C 6 H 3 (10)). Inspection of the single-crystal X-ray diffraction data for 15-17 and 19 suggests that the structures of all these species exhibit previously unrecognized bifurcated chalcogen-hydrogen bonding μ (S,N-H) Cl and also Pd II ···Pd II metallophilic interactions. These noncovalent interactions collectively connect two symmetrically located molecules of 15-17 and 19, resulting in their solid-state dimerization. The existence of the μ (S,N-H) Cl system and its strength (6-9 kcal/mol) were additionally verified/estimated by a Hirshfeld surface analysis and DFT calculations combined with a topological analysis of the electron density distribution within the formalism of Bader's theory (AIM method) and NBO analysis. The observed noncovalent interactions are jointly responsible for the dimerization of 15-19 not only in the solid phase but also in CHCl 3 solutions, as predicted theoretically by DFT calculations and confirmed experimentally by FTIR, HRESI-MS, 1 H NMR, and diffusion coefficient NMR measurements. Available CCDC data were processed under the new moiety angle, and the observed μ (S,E-H) Cl systems were classified accordingly to E (E = N, O, C) type atoms.

2-(1 H-Pyrazol-1-ylcarbonyl)-2 H-azirines were synthesized by in situ trapping of 2 H-azirine-2-carbonyl chlorides, generated by Fe(II)-catalyzed isomerization of 5-chloroisoxazoles, with pyrazoles. According to DFT calculations, the selectivity of nucleophilic substitution at the carbonyl group of 2 H-azirine-2-carbonyl chloride by a pyrazole nucleophile, which is a mixture of two tautomers, is controlled by thermodynamic factors. 2-(1 H-Pyrazol-1-ylcarbonyl)-2 H-azirines are excellent precursors for the preparation of two other pyrazole-nitrogen heterocycle dyads: 5-(1 H-pyrazol-1-yl)oxazoles by photolysis and 1-(1 H-pyrrol-2-ylcarbonyl)-1 H-pyrazoles by a Ni(II)-catalyzed reaction with 1,3-dicarbonyl compounds. 5-(1 H-Pyrazol-1-yl)oxazoles show strong emission in acetonitrile at 360-410 nm with high quantum yields.

Trimethylsilyl ethers of 1,5-diaryl-3-(trifluoromethyl)pent-1-en-4-yn-3-oles in superacid CF 3 SO 3 H (TfOH) give rise to the corresponding intermediate CF 3 -pentenynyl cations. These species react with benzene to afford conjugated CF 3 -pentenynes, which undergo subsequent cyclization, first, into CF 3 -cycloheptadienes and, finally, into unusual CF 3 -"helicopter"-like bicyclic structures.

A rational approach to the synthesis of cage-like compounds has been realized to build a new family of sulfido-phosphane Au(i) polynuclear complexes. Ditopic phosphane ligands with an extended aromatic system were used to obtain cage compounds with a clearly determined geometry. Au(i) complexes have been fully characterised in solution using spectroscopy methods, and DFT optimisation of the molecular structure gives additional arguments in favour of the suggested structural patterns. All complexes obtained are luminescent in solution and in the solid state, and display multiple emissions with an unusual combination of two phosphorescence bands and one fluorescence band. DFT calculations show that multiple emissions were mainly determined by 1 IL and metal perturbed 3 IL transitions. The ratio of singlet and triplet emission components depends on the distance between the ligand chromophoric centre and Au(i).

The reaction of cis-[PdCl 2 (CNXyl) 2 ] (Xyl = 2,6-Me 2 C 6 H 3 ) with various 1,3-thiazol- and 1,3,4-thiadiazol-2-amines in chloroform gives a mixture of two regioisomeric binuclear diaminocarbene complexes. For 1,3-thiazol-2-amines the isomeric ratio depends on the reaction conditions and kinetically (KRs) or thermodynamically (TRs) controlled regioisomers were obtained at room temperature and on heating, respectively. In CHCl 3 solutions, the isomers are subject to reversible isomerization accompanied by the cleavage of Pd-N and C-N bonds in the carbene fragment XylNCN(R)Xyl. Results of DFT calculations followed by the topological analysis of the electron density distribution within the formalism of Bader's theory (AIM method) reveal that in CHCl 3 solution the relative stability of the regioisomers (ΔG exp = 1.2 kcal/mol; ΔG calcd = 3.2 kcal/mol) is determined by the energy difference between two types of the intramolecular chalcogen bonds, viz. S···Cl in KRs (2.8-3.0 kcal/mol) and S···N in TRs (4.6-5.3 kcal/mol). In the case of the 1,3,4-thiadiazol-2-amines, the regioisomers are formed in approximately equal amounts and, accordingly, the energy difference between these species is only 0.1 kcal/mol in terms of ΔG exp (ΔG calcd = 2.1 kcal/mol). The regioisomers were characterized by elemental analyses (C, H, N), HRESI + -MS and FTIR, 1D ( 1 H, 13 C{ 1 H}) and 2D ( 1 H, 1 H-COSY, 1 H, 1 H-NOESY, 1 H, 13 C-HSQC, 1 H, 13 C-HMBC) NMR spectroscopies, and structures of six complexes (three KRs and three TRs) were elucidated by single-crystal X-ray diffraction.

The nitrile complexes trans-[PtCl 2 (RCN) 2 ] (R=Et (NC1), tBu (NC2), Ph (NC3), p-BrC 6 H 4 (NC4)) and cis-[PtCl 2 (RCN) 2 ] (R=Et (NC5), tBu (NC6), Ph (NC7)) react with 1 equiv of the hydroxyguanidine OC 4 H 8 NC(=NOH)NH 2 (HG) furnishing the mono-addition products trans- and cis-[PtCl 2 (RCN){NH=C(R)ON=C(NH 2 )NC 4 H 8 O}] (1-4 and 9-11; 7 examples; 54-74 % yield). Treatment of any of the nitrile complexes NC1-NC7 with HG in a 1:2 molar ratio generated the bis-addition products trans- and cis-[PtCl 2 {NH=C(R)ON=C(NH 2 )NC 4 H 8 O} 2 ] (5-8 and 12-14; 7 examples; 69-89 % yield). The Pt II -mediated coupling between nitrile ligands and HG proceeds substantially faster than the corresponding reactions involving amid- and ketoximes and gives redox stable products under normal conditions. Complexes 1, 6⋅4 CH 2 Cl 2 , 7⋅4 CH 2 Cl 2 , 8⋅2 CH 2 Cl 2 , and NC4 were studied by X-ray crystallography. Platinum(II) species 1-3, 10, 11, and especially 9, efficiently catalyze the hydrosilylation cross-linking of vinyl-terminated poly(dimethylsiloxane) and trimethylsilyl-terminated poly(dimethylsiloxane-co-ethylhydrosiloxane) giving high-quality thermally stable silicon resins with no structural defects. The usage of these platinum species as the catalysts does not require any inhibitors and, moreover, the complexes and their mixtures with vinyl- and trimethylsilyl-terminated polysiloxanes are shelf-stable in air., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The cyanamides NCNR2 (R2 = Me2, Ph2, C5H10) react with ZnX2 (X = Cl, Br, I) in a 2 : 1 molar ratio at RT, giving a family of zinc(ii) complexes [ZnX2(NCNR2)2] (R2 = Me2, X = Cl , X = Br , X = I ; R2 = C5H10, X = Cl , X = Br ; X = I ; R2 = Ph2, X = Cl , X = Br , X = I ; 75-92% yields). Complexes and undergo ligand redistribution in wet CH2Cl2 solutions giving the [Zn(NCNPh2)4(H2O)2][Zn2(μ-X)2X4] (X = Cl , Br ) species that were characterized by (1)H NMR, HRESI-MS, and X-ray diffraction. Halide abstraction from by the action of AgCF3SO3 or treatment of Zn(CF3SO3)2 with NCNR2 (R2 = Me2, C5H10) leads to labile complexes [Zn(CF3SO3)2(NCNR2)3] (R2 = Me2, ; C5H10, ). Crystallization of from wet CH2Cl2 or from the reaction mixture gave [Zn(NCNMe2)3(H2O)2](SO3CF3)2 () or [Zn(CF3SO3)2(NCNMe2)2]∞ (), whose structures were determined by X-ray diffraction. The Zn(II)-mediated hydration was observed for the systems comprising ZnX2 (X = Cl, Br, I), 2 equiv. NCNR2 (R2 = Me2, C5H10, Ph2) and ca. 40-fold excess of water and conducted in acetone at 60 °C (R2 = Me2, C5H10) or 80 °C (R2 = Ph2) in closed vials, and it gives the urea complexes [ZnX2{OC(NR2)NH2}] (R2 = Me2, X = Cl , X = Br , X = I ; R = C5H10, X = Cl , X = Br ; X = I ; R2 = Ph2, X = Cl , X = Br , X = I ; 57-81%). In contrast to the Zn(II)-mediated hydration of conventional nitriles, which proceeds only in the presence of co-catalyzing oximes or carboxamides, the reaction with cyanamides does not require any co-catalyst. Complexes , were characterized by (1)H, (13)C{(1)H} NMR, IR, HRESI-MS, and X-ray crystallography (for , , , , and ), whereas and were characterized by HRESI(+)-MS and (1)H and (13)C{(1)H} NMR (for ). The structural features of the cyanamide complexes , , , and were interpreted by theoretical calculations at the DFT level.

In title compound, [PtCl2(C15H21N3O2)2], the Pt(II) cation, located on an inversion center, is coordinated by two Cl(-) anions and two 3-(4-meth-oxy-phen-yl)-2-methyl-5-(piperidin-1-yl)-2,3-di-hydro-1,2,4-oxa-diazole ligands in a distorted Cl2N2 square-planar geometry. The di-hydro-oxa-diazole and piperidine rings display envelope (with the non-coordinating N atom as the flap atom) and chair conformations, respectively. In the crystal, weak C-H⋯Cl hydrogen bonds link the mol-ecules into supra-molecular chains running along the b axis. The piperidine ring is disordered over two positions with the occupancy ratio of 0.528 (4):0.472 (4).

The title ionic compound, C16H36N(+)·C10H20B10N3O3(-), consists of a tetra-butyl-ammonium cation and a closo-deca-borate cluster anion, which is bound to the substituted 2,3-dihydro-1,2,4-oxadiazole ring through a B-N bond [1.540 (2) Å]. The distances between connected B atoms in the deca-borate cluster range from 1.689 (2) to 1.844 (2) Å. The 2,3-dihydro-1,2,4-oxadiazole ring adopts an envelope conformation with the N atom as the flap atom.

The previously predicted ability of the methyl group of nitromethane to form hydrogen bonding with halides is now confirmed experimentally based on X-ray data of novel nitromethane solvates followed by theoretical ab initio calculations at the MP2 level of theory. The cationic (1,3,5-triazapentadiene)Pt(II) complexes [Pt{HN=C(NC(5)H(10))N(Ph)C(NH(2))=NPh}(2)](Cl)(2), [1](Hal)(2) (Hal = Cl, Br, I), and [Pt{HN=C(NC(4)H(8)O)N(Ph)C(NH(2))=NPh}(2)](Cl)(2), [2](Cl)(2), were crystallized from MeNO(2)-containing systems providing nitromethane solvates studied by X-ray diffraction. In the crystal structure of [1][(Hal)(2)(MeNO(2))(2)] (Hal = Cl, Br, I) and [2][(Cl)(2)(MeNO(2))(2)], the solvated MeNO(2) molecules occupy vacant spaces between lasagna-type layers and connect to the Hal(-) ion through a weak hydrogen bridge via the H atom of the methyl thus forming, by means of the Hal(-)···HCH(2)NO(2) contact, the halide-nitromethane cluster "filling". The quantum-chemical calculations demonstrated that the short distance between the Hal(-) anion and the hydrogen atom of nitromethane in clusters [1][(Hal)(2)(MeNO(2))(2)] and [2][(Cl)(2)(MeNO(2))(2)] is not just a consequence of the packing effect but a result of the moderately strong hydrogen bonding.