Dihalodimethyltin(IV) complexes of 2‐(pyrazol‐1‐ylmethyl)pyridine

Reaction of dichloro‐ and dibromodimethyltin(IV) with 2‐(pyrazol‐1‐ylmethyl)pyridine (PMP) afforded [SnMe₂Cl₂(PMP)] and [SnMe₂Br₂(PMP)] respectively. The new complexes were characterized by elemental analysis and mass spectrometry and by IR, Raman and NMR (¹H, ¹³C) spectroscopies. Structural studies by X‐ray diffraction techniques show that the compounds consist of discrete units with the tin atom octahedrally coordinated to the carbon atoms of the two methyl groups in a trans disposition (Sn? C = 2.097(5), 2.120(5) Å and 2.110(6), 2.121(6) Å in the chloro and in the bromo compounds respectively), two cis halogen atoms (Sn? Cl = 2.4908(16), 2.5447(17) Å; Sn? Br = 2.6875(11), 2.7464(9) Å) and the two donor atoms of the ligand (Sn? N = 2.407(4), 2.471(4) Å and 2.360(5), 2.455(5) Å). In both cases, the Sn? N(pyridine) bond length is markedly longer than the Sn? N(pyrazole) distance. Copyright © 2003 John Wiley & Sons, Ltd.     

Vinyl polymerization of norbornene catalyzed by 2‐Py‐amidine Ni(II) complex/methylaluminoxane systems

Two 2‐Py‐amidine ligands (2‐Py―NH―C(Ph)═N―Ar, Ar = 2,6‐Me₂C₆H₃ and 2,6‐ⁱPr₂C₆H₃) and the corresponding Ni(II) complexes ( 1 and 2 ) were synthesized and characterized using elemental analysis and FT‐IR, UV–visible, ¹H NMR and ¹³C NMR spectroscopies. X‐ray crystal structures indicate that the chelate ring conformation of the less bulky complex 1 is relatively planar compared with that of the bulky complex 2 . Paramagnetic ¹H NMR and ¹³C NMR studies show that, in solution, the time‐average structures of complexes 1 and 2 have mirror symmetry. Both complexes 1 and 2 were used as catalyst precursors for norbornene polymerization with methylaluminoxane as a co‐catalyst. The effects of Al/Ni ratio, temperature and structure of precursors on the catalytic performance were investigated. Copyright © 2014 John Wiley & Sons, Ltd.     

[Hg2(μ‐bpe)(μ‐OAc)2(μ‐SCN)2]n,a New Two‐Dimensional Coordination Polymer Involving Three Simultaneously Bridging Ligands: 1,2‐Bis(4‐pyridyle)ethene,Acetate, and Thiocyanate

A new mercury(II) complex of 1,2‐bis(4‐pyridyle)ethene (bpe) with anionic acetate and thiocyanate ligands has been synthesized and characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR spectroscopy. The single crystal X‐ray analysis shows that the complex is a two‐dimensional polymer with simultaneously bridging 1,2‐bis(4‐pyridyle)ethane, acetate and thiocyanate ligands and basic repeating dimeric [Hg₂(μ‐bpe)(μ‐OAc)₂(μ‐SCN)₂] units. The two‐dimensional system forms a three‐dimensional network by packing via π‐π stacking interactions.     

Quantum‐chemical,IR, NMR,and X‐ray diffraction studies on 2‐(4‐chlorophenyl)‐1‐methyl‐ 1H‐benzo[d]imidazole

The title molecule, 2‐(4‐chlorophenyl)‐1‐methyl‐1H‐benzo[d]imidazole (C₁₄H₁₁ClN₂), was prepared and characterized by ¹H NMR, ¹³C NMR, IR, and single‐crystal X‐ray diffraction. The molecular geometry, vibrational frequencies, and gauge including atomic orbital (GIAO) ¹H and ¹³C NMR chemical shift values of the title compound in the ground state have been calculated by using the Hartree‐Fock (HF) and density functional theory (DFT/B3LYP) method with 6‐31G(d) basis sets, and compared with the experimental data. The calculated results show that the optimized geometries can well reproduce the crystal structural parameters, and the theoretical vibrational frequencies and GIAO ¹H and ¹³C NMR chemical shifts show good agreement with experimental values. The energetic behavior of the title compound in solvent media has been examined using B3LYP method with the 6‐31G(d) basis set by applying the Onsager and the polarizable continuum model (PCM). Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis, and nonlinear optical (NLO) properties of the title compound were investigated by theoretical calculations. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Three‐dimensional Hemidirected Mixed‐ligand Lead(II) Coordination Polymer, [Pb2(bpa)2(SCN)3(NO3)]n (bpa = 1,2‐di(4‐pyridyl)ethane)

A new 3D hemidirected mixed‐ligand lead(II) coordination polymer with the ligand 1,2‐di(4‐pyridyl)ethane bpa) and the two metal coordinated anions nitrate and thiocyanate, [Pb₂(bpa)₂(SCN)₃(NO₃)]_n ( 1 ), has been synthesized and characterized by CHN elemental analysis, IR‐, ¹H‐ and ¹³C NMR spectroscopy. The single crystal X‐ray data of compound 1 show that the complex is a three‐dimensional coordination polymer with two different Pb atoms with stereoactive electron lone pairs and six‐ and five‐coordinate hemidirected geometries, respectively.     

DFT and experimental determination of conformations of 2‐(ethoxycarbonylmethoxy)‐5‐(arylazo)benzaldehydes and their oximes

2‐(Ethoxycarbonylmethoxy)‐5‐(arylazo)benzaldehydes 1–4 and their oximes 5–8 were synthesized and characterized by IR, ¹H and ¹³C NMR spectroscopy. The favoured conformations of aldehydes 1–4 and oximes 5–8 were predicted theoretically. Selected geometrical parameters and charges were derived from optimized structures. IR, ¹H and ¹³C NMR data were also computed using Gaussian‐03 package and compared with the observed values. ¹⁵N and ¹⁷O chemical shifts were also determined theoretically. Copyright © 2012 John Wiley & Sons, Ltd.     

Reaction of 3‐Hydroxyquinoline‐2,4‐diones with Isocyanates and Thermally Induced Transformation of the Reaction Products

3‐Hydroxyquinoline‐2,4‐diones 1 react with isocyanates to give novel 1,2,3,4‐tetrahydro‐2,4‐dioxoquinolin‐3‐yl (alkyl/aryl)carbamates 2 and/or 1,9b‐dihydro‐9b‐hydroxyoxazolo[5,4‐c]quinoline‐2,4(3aH,5H)‐diones 3 . Both of these compounds are converted, by boiling in cyclohexylbenzene solution in the presence of Ph₃P or 4‐(dimethylamino)pyridine, to give 3‐(acyloxy)‐1,3‐dihydro‐2H‐indol‐2‐ones 8 . All compounds were characterized by IR, and ¹H‐ and ¹³C‐NMR spectroscopy, as well as by EI mass spectrometry.     

New Rh(III) complexes of 5‐methyl‐5‐(pyridyl)‐2,4‐imidazolidenedione: Synthesis,X‐ray structure,electrochemical study and catalytic behaviour for hydrogenation of ketones

We describe the reaction of anion [RhCl₆]³⁻ with a series of hydantoin ligands (HL1, HL2 and HL3 = 5‐methyl‐5‐(2‐, 3‐ and 4‐pyridyl)‐2,4‐imidazolidenedione, respectively). Based on spectroscopic, cyclic voltammetric, elemental and MS analyses, the complexes have the general formula K[RhCl₂(L1)₂] ( 1 ), cis ‐ and trans ‐K[RhCl₄(HL2)₂] ( 2a and 2b ) and cis ‐ and trans ‐K[RhCl₄(HL3)₂] ( 3a and 3b ). Complexes 2a , 2b , 3a and 3b were characterized successfully using infrared, ¹H NMR and ¹³C NMR spectral analyses. Dissolution of complex 1 in dimethylsulfoxide (DMSO) led to elimination of one KL1 ligand and coordination of two DMSO molecules as ligands and transformation of this complex to cis ‐ and trans ‐[RhCl₂L1(DMSO)₂] ( 1a and 1b ). Recrystallization led to separation and isolation of crystals of 1a from the initial mixture. X‐ray analysis results showed that this complex was crystallized as solvated complex cis ‐[RhCl₂L1(DMSO)₂]DMSO. The catalytic activity of these complexes was then evaluated for the hydrogenation of various ketones.     

One‐ and two‐dimensional NMR characterization of N‐vinyl‐2‐pyrrolidone/methyl acrylate copolymers

N‐vinyl‐2‐pyrrolidone/methyl acrylate (V/M) copolymers were prepared by free‐radical bulk polymerization using benzoyl peroxide as an initiator. The copolymer composition of these copolymers was calculated from ¹H NMR spectra. The radical reactivity ratios for N‐vinyl‐2‐pyrrolidone (V) and methyl acrylate (M) were r_V = 0.09, r_M = 0.44. These reactivity ratios for the copolymerization of V and M were determined using the Kelen–Tudos and nonlinear least‐squares error‐in‐variable methods. The ¹³C{¹H} and ¹H NMR spectra of these copolymers overlapped and were complex. The complete spectral assignment of the ¹³C and ¹H NMR spectra were done with distortionless enhancement by polarization transfer and two dimensional ¹³C‐¹H heteronuclear single quantum correlation spectroscopic experiments. The two‐dimensional ¹H‐¹H homonuclear total correlation spectroscopic NMR spectrum showed the various bond interactions, thus inferring the possible structure of the copolymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2225–2236, 2002     

One‐ and two‐dimensional NMR characterization of N‐vinyl‐2‐pyrrolidone/methyl acrylate copolymers

N‐vinyl‐2‐pyrrolidone/methyl acrylate (V/M) copolymers were prepared by free‐radical bulk polymerization using benzoyl peroxide as an initiator. The copolymer composition of these copolymers was calculated from ¹H NMR spectra. The radical reactivity ratios for N‐vinyl‐2‐pyrrolidone (V) and methyl acrylate (M) were r_V = 0.09, r_M = 0.44. These reactivity ratios for the copolymerization of V and M were determined using the Kelen–Tudos and nonlinear least‐squares error‐in‐variable methods. The ¹³C{¹H} and ¹H NMR spectra of these copolymers overlapped and were complex. The complete spectral assignment of the ¹³C and ¹H NMR spectra were done with distortionless enhancement by polarization transfer and two dimensional ¹³C‐¹H heteronuclear single quantum correlation spectroscopic experiments. The two‐dimensional ¹H‐¹H homonuclear total correlation spectroscopic NMR spectrum showed the various bond interactions, thus inferring the possible structure of the copolymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2225–2236, 2002     

Syntheses and Crystal Structures of Copper(II) and Silver Complexes with 5‐Methyl‐1‐(4‐Methylphenyl)‐1,2,3‐Triazol‐4‐Carboxylic Acid

Two novel complexes [Cu L ₂(MeOH)] ( 1 )and [Ag₂ L (H L )₂(MeOH)] ( 2 ) ( L = 5‐methyl‐1‐(4‐methylphenyl)‐1,2,3‐triazol‐4‐carboxylic acid) were synthesized and characterized by elemental analysis, IR and X‐ray diffraction. Complex 1 is a mononuclear structure; the molecules were assembled into an infinite 2–D supramolecular by the C–H···O weak interactions. Complex 2 is a centrosymmetric dinuclear structure with bis(unidentate) carboxylato co‐ordination mode, and the molecules were assembled into 2–D layers by C–H···O and O–H···O weak interactions.     

Synthesis,characterization and antibacterial activity of 3‐(2‐methoxyphenyl)‐2‐sulfanylpropenoic acid and di‐isopropylammonium [3‐(2‐methoxyphenyl)‐2‐sulfanylpropenoato] triphenylstannate(IV). The crystal structure of [HQ][SnPh3(o‐mpspa)]

Reaction of 3‐(2‐methoxyphenyl)‐2‐sulfanylpropenoic acid [H₂(o‐mpspa)] with SnPh₃OH in the presence of di‐isopropylamine resulted in the formation of the complex [HQ][SnPh₃(o‐mpspa)] (where HQ = di‐isopropylammonium cation and o‐mpspa = 3‐(2‐methoxyphenyl)‐2‐sulfanylpropenoato), which was characterized by mass spectrometry and vibrational spectroscopy, as well as by ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy. The single‐crystal X‐ray structural analysis of the new complex shows a trigonal‐bipyramidal coordination geometry around the Sn atom where o‐mpspa behaves as a bidentate chelating ligand. Dimeric units arise from the existence of N? H…O hydrogen bonds between the NH₂ group of the di‐isopropylammonium cation and the oxygen atoms of the two neighbouring carboxylato groups. The bacteriostatic activity of the complex is also reported. Copyright © 2007 John Wiley & Sons, Ltd.     

Binuclear dichlorido(η6‐p‐cymene)ruthenium(II) complexes with bis(nicotinate)‐ and bis(isonicotinate)‐polyethylene glycol ester ligands

Neutral binuclear ruthenium complexes 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 of the general formula [{RuCl₂(η⁶‐p‐cym)}₂ μ‐(N^∩N)] (N^∩N = bis(nicotinate)‐ and bis(isonicotinate)‐polyethylene glycol esters: (3‐py)COO(CH₂CH₂O)_nCO(3‐py) and (4‐py)COO(CH₂CH₂O)_nCO(4‐py), n =1–4), as well as mononuclear [RuCl₂(η⁶‐p‐cym)((3‐py)COO(CH₂CH₂OCH₃)‐κN)], complex 9 , were synthesized and characterized using elemental analysis and electrospray ionization high‐resolution mass spectrometry, infrared, ¹H NMR and ¹³C NMR spectroscopies. Stability of the binuclear complexes in the presence of dimethylsulfoxide was studied. Furthermore, formation of a cationic complex containing bridging pyridine‐based bidentate ligand was monitored using ¹H NMR spectroscopy. Ligand precursors, polyethylene glycol esters of nicotinic ( L1 · 2HCl– L4 · 2HCl and L9 · HCl) and isonicotinic acid dihydrochlorides ( L5 · 2HCl– L8 · 2HCl), binuclear ruthenium(II) complexes 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 and mononuclear complex 9 were tested for in vitro cytotoxicity against 518A2 (melanoma), 8505C (anaplastic thyroid cancer), A253 (head and neck tumour), MCF‐7 (breast tumour) and SW480 (colon carcinoma) cell lines. Copyright © 2014 John Wiley & Sons, Ltd.     

Synthesis,spectra, crystal structures and anticancer studies of 26‐membered macrocyclic dibutyltin(IV) dithiocarbamate complexes: Single‐source precursors for tin sulfide nanoparticles

Four new macrocyclic dinuclear dibutyltin(IV) dithiocarbamate complexes of the type [Bu₂Sn(dtc)]₂, where dtc = hexane‐1,6‐diylbis(4‐fluorobenzyldithiocarbamate) anion ( 1 ), hexane‐1,6‐diylbis(4‐chlorobenzyldithiocarbamate) anion ( 2 ), hexane‐1,6‐diylbis(furfuryldithiocarbamate) anion ( 3 ) and hexane‐1,6‐diylbis(pyrrole‐2‐ylmethyldithiocarbamate) anion ( 4 ), have been prepared. The dithiocarbamate ligands efficiently self‐assemble with Bu₂Sn(IV) to form bimetallic 26‐membered macrocycles. All the complexes have been characterized using elemental analysis, infrared and NMR (¹H and ¹³C) spectroscopies and X‐ray crystallography. Single‐crystal X‐ray diffraction analysis of all the complexes confirms the formation of the dinuclear metallomacrocycles in which dithiocarbamate ligands are asymmetrically bound to the tin atoms. The coordination sphere around the tin atom in 1 – 4 can be described as a skew trapezoidal bipyramid. The dimensions of the cavity of the macrocycles of 1 – 4 are ca 8.0 × 9.0 Å². Complexes 1 – 4 were evaluated for their in vitro anticancer activity against MCF‐7 and HL‐60 cells. Complexes 1 and 2 are more active against MCF‐7 and HL‐60. Thermal decomposition of 1 and 4 yielded tin sulfides. They were characterized using powder X‐ray diffraction (PXRD), high‐resolution transmission electron microscopy and UV diffuse reflectance and energy‐dispersive X‐ray spectroscopies. PXRD studies reveal that the as‐prepared tin sulfides are composed of orthorhombic phase of SnS.     

Ultrasound‐Assisted Synthesis of 6‐Methyl‐1,2,3,4‐tetrahydro‐N‐aryl‐2‐oxo/thio‐4‐arylpyrimidine‐5‐carboxamides Catalyzed by Uranyl Nitrate Hexahydrate

An efficient and simple method developed for the synthesis of 6‐methyl‐1,2,3,4‐tetrahydro‐N‐aryl‐2‐oxo/thio‐4‐arylpyrimidine‐5‐carboxamide derivatives ( 4a‐o ) using UO₂(NO₃)₂.6H₂O catalyst under conventional and ultrasonic conditions. The ultrasound irradiation synthesis had shown several advantages such as milder conditions, shorter reaction times and higher yields. The structures of all the newly synthesized compounds have been confirmed by FT‐IR, ¹H NMR, ¹³C NMR and mass spectra.     

KAl(SO4)2·12H2O (Alum) Catalyzed One‐Pot Three‐Component Synthesis of 2‐Alkyl and 2‐Aryl‐4(3H)‐quinazolinone under Microwave Irradiation and Solvent Free Conditions

Twenty 2,3‐disubstituted‐4(3H)‐quinazolinones were synthesed by one‐pot three‐component method with isatoic anhydride, orthoesters and amines as raw materials in the presence of KAl(SO₄)₂·12H₂O (Alum) under microwave irradiation and solvent‐free conditions. 6‐Bromo‐2‐propyl‐3‐p‐tolylquinazolin‐4(3H)‐one ( 4m ), 6‐bromo‐2‐methyl‐3‐phenethylquinazolin‐4(3H)‐one ( 4n ) and 6‐bromo‐2‐ethyl‐3‐phenethylquinazolin‐4(3H)‐one ( 4o ) were characterized by IR, ¹H NMR, ¹³C NMR and elemental analysis.     

One‐step synthesis of 6‐acetamido‐3‐(N‐(2‐(dimethylamino) ethyl) sulfamoyl) naphthalene‐1‐yl 7‐acetamido‐4‐hydroxynaphthalene‐2‐sulfonate and its characterization with 1D and 2D NMR techniques

A one‐step method was reported for the synthesis of 6‐acetamido‐3‐(N‐(2‐(dimethylamino) ethyl) sulfamoyl) naphthalene‐1‐yl 7‐acetamido‐4‐hydroxynaphthalene‐2‐sulfonate by treating 7‐acetamido‐4‐hydroxy‐2‐naphthalenesulfonyl chloride with equal moles of N, N‐dimethylethylenediamine in acetonitrile in the presence of K₂CO₃. The chemical structure of the obtained compounds was characterized by MS, FTIR, ¹H NMR, ¹³C NMR, gCOSY, TOCSY, gHSQC, and gHMBC. The chemical shift differences of ¹H and ¹³C being δ 0.04 and 0.2, respectively, were unambiguously differentiated. Copyright © 2013 John Wiley & Sons, Ltd.     

Preparation and structures of [2‐(dimethylamino)phenyl]diorganotin(IV) acetates substituted with organophosphorus groups in the α‐position of the acetate ligand

Organotin(IV) carboxylates R₂L^NCSnOC(O)CH₂P(E)Ph₂, where L^NC is an N‐chelating 2‐(dimethylamino)phenyl group, and R/E = Ph/void (1a), Ph/O (1b), Ph/S (1c), Me/void (2a), Me/O (2b) and Me/S (2c), were synthesized, characterized by ¹H, ¹³C, ³¹P and ¹¹⁹Sn NMR, IR and MS spectra, and the solid‐state structures of 1b, 1c, 2b and 2c were determined by single‐crystal X‐ray diffraction. Spectral and structural data showed that the compounds are monomeric in CDCl₃ solution and the solid state, with the organophosphorus groups in the α‐position of the monodentate carboxylate ligands not interacting with the tin atom. Copyright © 2005 John Wiley & Sons, Ltd.     

Water Soluble Gold(I)‐diacetyl‐1,3,5‐triaza‐7‐phosphaadamantane‐arylazoimidazole Complexes: Synthesis and Spectroscopic Study

Reaction of [Au(DAPTA)(Cl)] with RaaiR’ in CH2Cl2 medium following ligand addition leads to [Au(DAPTA)(RaaiR’)](Cl) [DAPTA＝diacetyl-1,3,5-triaza-7-phosphaadamantane, RaaiR’＝p-R-C6H4-N＝N- C3H2-NN-1-R’, (1—3), abbreviated as N,N’-chelator, where N(imidazole) and N(azo) represent N and N’, respectively; R＝H (a), Me (b), Cl (c) and R’＝Me (1), CH2CH3 (2), CH2Ph (3)]. The 1H NMR spectral measurements in D2O suggest methylene, CH2, in RaaiEt gives a complex AB type multiplet while in RaaiCH2Ph it shows AB type quartets. 13C NMR spectrum in D2O suggest the molecular skeleton. The 1H-1H COSY spectrum in D2O as well as contour peaks in the 1H-13C HMQC spectrum in D2O assign the solution structure.     

C—H···X (X = N,O, S) intramolecular interaction in 1‐vinyl‐2‐(2′‐heteroaryl)pyrroles as monitored by 1H and 13C NMR spectroscopy

¹H and ¹³C NMR spectroscopy of a series of 1‐vinyl‐2‐(2′‐heteroaryl)‐pyrroles were employed for the analysis of their electronic and spatial structure. The C—H···N intramolecular interaction between the α‐hydrogen of the vinyl group and the pyridine nitrogen, a kind of hydrogen bonding, was detected in 1‐vinyl‐2‐(2′‐pyridyl)pyrrole, which disappeared in its iodide methyl derivative. It was shown that this interaction is stronger than the C—H···O and C—H···S interactions in 1‐vinyl‐2‐(2′‐furyl)‐ and ‐2‐(2′‐thienyl)‐pyrroles. Copyright © 2001 John Wiley & Sons, Ltd.