Pratibha Kapoor

Structural studies of diorganotin(IV) sulphonates The crystal structures of [(n-C4H9)2Sn{μ-OSO2C6H2(CH3)3}2]n and its partially hydrolyzed product [(n-C4H9)2Sn{(μ-OH)(μ-OSO2C6H2(CH3)3)}]n

The X-ray crystal structures of [( n -C 4 H 9 ) 2 Sn{μ-OSO 2 C 6 H 2 (CH 3 ) 3 } 2 ] n ( 1 ) and [( n -C 4 H 9 ) 2 Sn{(μ-OH)(μ-OSO 2 C 6 H 2 (CH 3 ) 3 )}] n ( 2 ) were determined to delineate the coordination behaviour of the sulphonate group with tin(IV) and to evaluate the metal sulphonate bonding interactions. The synthesis of 1 has been achieved by azeotropic dehydration of di- n -butyltin(IV) oxide and mesitylenesulphonic acid. 1 is polymeric containing six-coordinate tin and crystallizes from anhydrous toluene in the orthorhombic space group P 2 1 2 1 2 with unit cell dimensions a =12.555(1), b =21.238(1), c =5.415(1) A; Z =2; R , 0.0236 and wR , 0.0607 for 1281 observed reflections. The structure exhibits highly symmetrical bridging bidentate mesitylenesulphonate groups and is made up of an infinite array of ( n -C 4 H 9 ) 2 SnO 4 moieties. Compound 1 hydrolyzes very slowly to [( n -C 4 H 9 ) 2 Sn{(μ-OH)(μ-OSO 2 C 6 H 2 (CH 3 ) 3 )}] n ( 2 ), when kept in CH 3 OH–CHCl 3 mixture at room temperature for 35 days. Crystals of 2 are monoclinic with space group P 2 1 / m and unit cell dimensions a =10.040(1), b =14.500(1), c =13.978(1) A; β =91.58(1)°; Z =4; R , 0.0226; wR , 0.0592 for 2725 observed reflections. The crystal structure is built of polymeric chains in which [{( n -C 4 H 9 ) 2 Sn} 2 (OH) 2 ] units are joined by bridging bidentate meistylenesulphonate groups. The crystal lattice is stabilized by a network of hydrogen bonds running through the sheets, in which an oxygen atom of the sulphonate group and the hydroxyl group attached to tin participate in a symmetrical fashion. In DMSO solutions, chemical shift ( 119 Sn) and 1 J ( 119 Sn– 13 C) values for both 1 and 2 suggest a distorted octahedral geometry around tin in which DMSO may also be involved.

Five coordinate complexes of N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamide with copper Crystal and molecular structures of dichloro(N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamido)copper(II) and chloro(perchlorato)(N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamido)copper(II)

The title compound N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamide (DEAP) forms a 1:1 complex with anhydrous CuCl2, [Cu(DEAP)Cl2], (1) which was crystallized from EtOH solution in the monoclinic space group P21/n with cell constant, a = 10.024(1); b = 13.122(1); c = 14.404(1) Å β = 101.31(1)° V = 1857.8(3) Å3 and Z = 4. The chloro-perchlorato complex, [Cu(DEAP)Cl(ClO4)], (2) obtained in near quantitative yield by reacting (1) with an excess of NaClO4 in EtOH, crystallized in the monoclinic space group P21/n with cell constants, a = 7.965(1); b = 25.827(2); c = 10.046(1) Å β = 98.81(1)° V = 2042.2(4) Å3 and Z = 4. Both (1) and (2) contain 5-coordinated copper linked to DEAP through O∼N∼O donor set of atoms with covalently bonded chlorine atoms in (1) and chlorine and perchlorate groups in (2). The coordination geometry is intermediate between square pyramidal and trigonal bipyramidal, and is probably best described as a trigonally distorted rectangular pyramid.

The synthesis and ir and NMR (1HH, 3CC AND 9Sn)Sn) spectral studies of some methyltin(IV) sulphonates

Abstract Some methyltin(IV) sulphonates, MenSn(OSO2X)4‒n (n = 1−3 and X = 4-tolyl and 2-naphthyl) have been prepared. The 1H, 3C and 9Sn NMR spectra of these compounds and the previously reported compounds, Me3Sn(OSO2X) (X = CF3, CH3 and 4-CH3 C6H4) and Me2Sn(OSO2CH3)2, in coordinating and non-coordinating solvents have been studied. From the chemical shifts δ(9Sn) and the coupling constants 1J(13C, 119Sn) and 2J(1H, 119Sn), coordination number of the tin atom and the geometry of its coordination sphere have been suggested. These observations have been complemented by IR spectroscopy. Synthesis of the ternary compounds, MeSnCl(OSO2X)2 (X = CH3 and 4-CH3C6H4), by reaction between Me3Sn(OSO2X) and Me2SnCl2 and subsequent cleavage of the tin-carbon bond is also discussed.

Syntheses and structures of cobalt(II), nickel(II), and copper(II) complexes with N,N,N′,N′-tetraalkylpyridine-2,6-dicarboxamides (O-daap) containing nitrate as the counter ion

Reactions of M(NO3)2 · xH2O [M = Co(II), Ni(II), and Cu(II)] with N,N,N′,N′-tetraalkylpyridine-2,6-dicarboxamides(O-daap) in CH3CN yield [Co(O-dmap)(NO3)2] (1), [Co(O-deap)(NO3)2] (2), [Co(O-dpap)(NO3)2] (3), [Ni(O-dmap)(H2O)3](NO3)2] (4), [Ni(O-deap)(H2O)2(NO3)](NO3)] (5), [Cu(O-deap)(NO3)2] (6), and [Cu(O-dpap)(NO3)2] (7). X-ray crystal structures of 1, 2, 4, 5, and 7 reveal that O-daap ligands coordinate tridentate to each metal, O–N–O, with nitrate playing a vital role in molecular and crystal structures of all the complexes. The coordination geometry in the two Co(II) complexes, 1 and 2, is approximately pentagonal bipyramidal with nitrate bonded in a slightly unsymmetrical bidentate chelating mode. [Ni(dmap)(H2O)3](NO3)2 (4) and [Ni(deap)(H2O)2(NO3)](NO3) (5) exhibit octahedral geometry, the former containing uncoordinated nitrate while the latter has one nitrate coordinated unidentate and the other nitrate outside the coordination sphere. The Cu(II) in [Cu(dpap)(NO3)2] (7) occupies a distorted square pyramidal geometry and is linked to two unidentate nitrates, although one nitrate is also involved in a weak interaction with the metal through its other oxygen. IR spectra and other physical studies are consistent with their crystal structural data. O-dmap = N,N,N′,N′-tetramethylpyridine-2,6-dicarboxamides; O-deap = N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamides; and O-dpap = N,N,N′,N′-tetraisopropylpyridine-2,6-dicarboxamides.

A self assembled 3-D network propagated by coordination polymerization and H-bonding: synthesis and X-ray crystal structure of [{Co(L)2(H2O)2}(ClO4)2(CH3COCH3)2(H2O)2] n , where L = N,N-diisopropylisonicotinamide

Reaction of Co(ClO4)2 · 6H2O with N,N-diisopropylisonicotinamide (L) has yielded a 1-D coordination polymer [{Co(L)2(H2O)2}(ClO4)2(CH3COCH3)2(H2O)2] n (1). Complex 1 has been characterized by infrared (IR) and UV-Vis spectroscopies, thermal analysis, and single crystal X-ray diffraction techniques. The structure has alternate arrangement of parallel 1-D cationic metal-ligand chains and H-bonded anionic chains containing perchlorate, acetone and water in the lattice. Further hydrogen bonding among both chains leads to formation of 2-D networks along almost perpendicular planes. Interpenetrations of such perpendicular 2-D sheets create a 3-D supramolecular structure.

Syntheses and X-ray crystal structures of five- and six-coordinate copper(II) complexes of N,N,N′,N′-tetraalkylpyridine-2,6-dicarboxamides containing–OClO3 and–OSO2CF3 counter ions

Reactions of anhydrous copper(II) chloride with NaX (1 : 1 or 1 : 2) and AgX (1 : 2) containing appropriate N,N,N′,N′-tetraalkylpyridine-2,6-dicarboxamides(O-daap) in CH3CN yield monosubstituted five-coordinate [Cu(L1)Cl(CF3SO3)] (1), [Cu(L2)Cl(ClO4)] (2), [Cu(L3)Cl(ClO4)] (3), and six-coordinate [Cu(L2)(CF3SO3)2] · H2O (4) (X = −OClO3 and–OSO2CF3; L1 = N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamides; L2 = N,N,N′,N′-tetraisopropylpyridine-2,6-dicarboxamides; L3 = N,N,N′,N′-tetraisobutylpyridine-2,6-dicarboxamides). The structures of these complexes have been determined by X-ray crystallography. The Cu2+ in 1–3 adopts distorted square-pyramidal geometry, while 4 exhibits octahedral structure. Steric factors in conjunction with lattice effects and the nature of the anions are responsible for the variety in coordination spheres. These compounds undergo extensive intermolecular H-bonding to give to 2-D sheets extending along various planes.

Trimethyltin(IV) naphthoates: X-ray structure of the 2-isomer

Abstract The isomeric trimethyltin(IV) 1- and 2- naphthoates have been prepared in high yield from trimethyltin chloride and the appropriate sodium naphthoate in THF solution. Spectroscopic data for the compounds point to the presence of monomers, probably with a tetrahedral structure in CDCl3 solution, but five-coordinate trigonal bipyramidal units in the donor solvent DMSO. An X-ray structure of the 2-isomer shows an infinite zig-zag chain structure in which the carboxylate group bridges asymmetrically between pairs of tin atoms, which have distorted trigonal bipyramidal geometry. Much of the distortion can be traced to a weak residual chelating effect from the carboxylate group.

Chemistry of imidobis(sulphuryl chloride)—III solvolytic reactions and the nature of the solvolysed products

Abstract Solvolytic reactions in imidobis(sulphuryl chloride) have been carried out to prepare the ammonium and substituted ammonium salts; Me x NH 4− x Y, where x varies from 0–4 and Y = N(SO 2 Cl) 2 , Et 4 NY and Et 3 NHY. Other solvolysed products prepared are; AlY 3 , R 3 SnY [where R = Me and Ph], TiX 3 Y [where X = Cl and Br], ZrCl 3 Y, SbCl 3 Y 2 , TeBr 3 Y, S 4 N 3 Y and S 3 N 2 ClY. All these compounds have been characterized by elemental analyses, IR spectral studies and molar conductance measurements.

Chemistry of imidobis(sulphuryl chloride)—IV measurements of physical properties of imidobis(sulphuryl chloride)

Abstract Density, viscosity and specific conductance have been measured at 5° interval between 25 to 50° for imidobis(sulphuryl chloride). The surface tension, freezing point and cryoscopic constant have also been determined. Its IR and proton NMR spectra have been recorded. Relative acidity strength measurements in acetic acid suggest that imidobis(sulphuryl chloride) is a stronger protonic acid than HBr, HSO3Cl and (CF3)2POOH.

Chemistry of imidobis(sulphuryl chloride)-II: some novel derivatives of imidobis(sulphuryl chloride)

Abstract Silver imidobis(sulphuryl chloride), AgN(SO 2 Cl) 2 ; nitrosyl imidobis(sulphuryl chloride), NON(SO 2 Cl) 2 ; nitryl imidobis(sulphuryl chloride), NO 2 N(SO 2 Cl) 2 ; alkali metal imidobis(sulphuryl chloride), MN(SO 2 Cl) 2 (where M is Li, Na, K) and N-chloroimidobis(sulphuryl chloride), CIN(SO 2 Cl) 2 have been prepared. The compounds have been characterized by analytical and spectral techniques.