Platinum(II) complexes of the tridentate thioether ligands RS(CH2)3S(CH2)3SR (R = Et, iPr, Ph). Structures of [PtCl (iPrS(CH2)3S(CH2)3SiPr)][BF4], [PtI(PhS(CH2)3S(CH2)2SPh)][BF4], and [Pt(PPh3)(iPrS(CH2)3S(CH2)3SiPr)][BF4]2•CH2Cl2

1996 ◽  
Vol 74 (7) ◽  
pp. 1377-1390 ◽  
Author(s):  
Stephen J. Loeb ◽  
James R. Mansfield

The tridentate thioether ligands RS(CH2)3S(CH2)3SR (L1, R = Et; L2, R = iPr, L3, R = Ph) were synthesized by nucleophilic addition of thiolate, SR−, to the ditosylate TsO(CH2)3S(CH2)3OTs. The complexes [PtX(Ln)][BF4] were prepared by displacement of 1,5-COD from [PtX2(1,5-COD)] (X = Cl, I) in the presence of one equivalent of AgBF4 and one equivalent of thioether ligand. [PtCl(L2)][BF4] crystallized in the monoclinic space group P21/c with a = 10.409(6), b = 14.180(4), c = 13.726(8) Å, β = 104.49(4)°, V = 1961(2) Å3 and Z = 4. The structure refined toR = 5.62% and Rw = 6.86% for 2121 reflections with F02 > 3σ(Fo2). [PtI(L3)][BF4] crystallized in the monoclinic space group P21/n with a = 13.415(4), b = 12.350(5), c = 14.316(5) Å, β = 107.48(3)°, V = 2262(1) Å3 and Z = 4. The structure refined to R = 4.85% and Rw = 6.33% for 2168 reflections with Fo2 > 3σ(Fo2). In both compounds, the thioether ligand acts as a tridentate chelator occupying three of the four sites of the square-planar Pt(II) complex. Variable temperature 13C{1H} NMR verified that there are three possible stereoisomers for these complexes resulting from inversion at sulphur: meso-A, meso-B, and racemic. Thermodynamic parameters were calculated for the interconversion among isomers of [PtCl(L2)][BF4] by a full line-shape analysis. Removal of chloride ligand from [PtCl(L2)][BF4] with Ag+ in the presence of PPh3 yielded the phosphine adduct [Pt(PPh3)(L2)][BF4]2, which crystallized in the triclinic space group [Formula: see text] with a = 13.266(3), b = 11.315(2), c = 13.970(2) Å, α = 106.04(2)°, β = 84.95(2)°, γ = 86.56(2)°, V = 1999.7(7) Å3 and Z = 2. The structure refined to R = 4.22% and Rw = 5.38% for 4493 reflections with Fo2 > 3σ(Fo2). Unlike the two halide complex structures, which crystallized in the meso-B form, [Pt(PPh3)(L2][BF4]2 crystallized in the racemic form. Key words: tridentate thioether ligand, crystal structure, platinum(II) halide, dynamic NMR spectroscopy.

1995 ◽  
Vol 50 (7) ◽  
pp. 1018-1024 ◽  
Author(s):  
Axel Michalides ◽  
Dagmar Henschel ◽  
Armand Blaschette ◽  
Peter G. Jones

In a systematic search for supramolecular complexes involving all combinations of the cyclic polyethers 12-crown-4 (12C4), 15-crown-5 (15C 5), 18-crown-6 (18C 6) and dibenzo- 18-crown-6 (DB -18C6), and the geminal di- or trisulfones H2C(SO 2Me)2, H2C (SO2Et)2 and HC (SO2Me)3-n (SO2Et)n (n = 0 -3 ) , only the following four complexes could be isolated and unequivocally characterized by elemental analysis and 1H NMR spectroscopy: [(12C4){H2C (SO2Et)2}2] (3), [(18C6){H2C (S O2Me)2}] (4), [(DB -18C 6){H2C (SO2Et)2}] (5) and [(D B -18C 6)2{HC (SO2Me )(SO2Et)2}3] (6). The structure of 3 (triclinic, space group P1̄) consists of crystallographically centrosymmetric formula units, in which the disulfone molecules are bonded on each side of the ring by two C -H ··· O(crown) interactions originating from the central methylene group (H···O 213 pm) and from the methylene group of one EtSO2 moiety ( H ··· O 237 pm). Formula units related by translation are connected into parallel strands by a third type of reciprocal C -H ···O bond (H ···O 232 pm) between the second H atom of the central methylene group and a sulfonyl oxygen atom of the adjacent unit. The structure of 4 (monoclinic, space group C2/c) showed severe disorder of the crown ether and could not be refined satisfactorily. Compounds 5 and 6 crystallized as long and extremely thin fibres, indicative of linear-polymeric supramolecular structures; single crystals for X-ray crystallography were not available.


1994 ◽  
Vol 49 (12) ◽  
pp. 1763-1773 ◽  
Author(s):  
Jochen Ellermann ◽  
Jörg Sutter ◽  
Falk A. Knoch ◽  
Matthias Moll ◽  
Walter Bauer

Reaction of (1) in CH2Cl2 with benzimidazole yields . The salt [4]+BPh4- has been prepared in THF by metathesis of [4]+Cl- with NaBPh4. Deprotonation of the cationic ring in [4]+BPh4- was accomplished using 1,8-diazabicyclo[5.4.01,7]undec-7-ene and resulted in the six-membered carbacyclophosphazene (6). Treating 1 with 8 -hydroxyquinoline in CH2Cl2 yields the octahedral cis-complex = 8-oxyquinolinate group). The com pounds [4]+BPh4-, 6 and 7 are characterized by their IR, Raman, 31P{1H} NMR, 13C{1H} NMR, 1H NMR and mass spectra. Crystals suitable for X-ray structure analyses have been obtained for [4]+BPh4- and 7×0.5 CH2Cl2. The colourless plates of [4]+BPh4- crystallize in the triclinic space group P1̄, with the lattice constants a = 1172.7(3), b = 1326.2(3), c = 1806.1(6) pm; α = 100.79(2), β = 103.71(3), γ = 108.18(2)°. The black blocks of 7×0.5 CH2Cl2 crystallize in the monoclinic space group P 21/c with the lattice constants a = 1159.0(10), b = 2008.9(10), c = 2034.6(12) pm; β = 105.86(5)°.


1986 ◽  
Vol 64 (9) ◽  
pp. 1829-1835 ◽  
Author(s):  
Carmen Esteban-Calderon ◽  
Martín Martinez-Ripoll ◽  
Severino García-Blanco ◽  
Fernando Temprano ◽  
José Gonzalo Rodriguez

The structures of cyclohexan[b]indole N-β-propionic acid (1) and cyclooctan[b]indole N-β-propionic acid (2) have been determined by X-ray methods. The conformational populations of their N-β-propionic chains have been determined in solution by 1H nmr analyses. Crystals of 1 are triclinic, space group [Formula: see text] with a = 12.3562(4), b = 11.0727(3), c = 10.2050(4) Å, α = 108.519(3), β = 83.941(3), γ = 104.826(3)°, and Z = 4. Crystals of 2 are monoclinic, space group P21/c, with a = 5.636(1), b = 18.937(3), c = 13.976(4) Å, β = 98.84(3)°, and Z = 4. In both structures, the molecules are linked forming dimers through centrosymmetric H bonds. In solution the trans conformation of the chain is the preferred one in both compounds and increases with dilution until a constant value is reached.


1991 ◽  
Vol 69 (2) ◽  
pp. 357-362 ◽  
Author(s):  
David G. Dick ◽  
Roger Rousseau ◽  
Douglas W. Stephan

Reaction of simple amides with TiCl4 affords mixed amido-chloride species Ti(NR2)4−nCln. The trisamide-chloride species Ti(NR2)3Cl can be prepared directly employing three equivalents of amide or by reaction Ti(NR2)4 with TiCl4. The compound Ti(NMe2)3Cl, 1, crystallizes in the trigonal space group [Formula: see text] with a = 11.525(5), c = 14.939(3) Å, Z = 6, and V = 1718(1) Å3. The compound Ti(NEt2)3Cl, 2, crystallizes in the monoclinic space group P21/c, with a = 8.385(2) Å, b = 15.958(2) Å, c = 14.230(4) Å, β = 107.79(1)°, Z = 4, and V = 1813(1) Å3. The geometry of the Ti coordination sphere in these complexes is best described as pseudo-tetrahedral. The structural data are consistent with Ti—N multiple bonding. Preliminary results of EHMO calculations are consistent with dπ—pπ Ti—N bonding. Attempts to replace the halides with phosphides (LiPR2, R = Me, Et, Ph) led not to the Ti(IV) phosphido species, but rather to redox chemistry yielding Ti(III) amides and P2R4. The barrier to rotation about the Ti—N bonds has been considered. Variable temperature 1H NMR studies reveal that the barrier is small. Extended Hückel total energy minimization calculations have been performed. In addition, MMX calculations of the barrier to Ti—N rotation are reported. The results of these calculations imply that the rotational barrier is dominated by steric effects. Key words: titanium amides, structures, Ti—N bonding


Author(s):  
Abhinav Raghuvanshi ◽  
Anna Krupp ◽  
Lydie Viau ◽  
Michael Knorr ◽  
Carsten Strohmann

The first title compound, C29H24S2, L1, represents an example of an anthracene-based functionalized dithioether, which may be useful as a potential chelating or terminal ligand for coordination chemistry. This dithioacetal L1 crystallizes in the monoclinic space group P21/c. The phenyl rings of the benzyl groups and that of the anthracene unit form dihedral angles of 49.21 (4) and 58.79 (5)° and the crystal structure displays short C–H...π contacts. Surprisingly, when attempting to coordinate L1 to [PdCl2(PhCN)2], instead of the targeted chelate complex [PdCl2(κ2-L1)], a cleavage reaction leads to the formation of the centrosymmetric hexanuclear cyclic cluster of composition [Pd6(μ2-SCH2Ph)12] Pd6, or [Pd6(C7H7S)12]·C14H8O2. This tiara-shaped hexamer crystallizing in the triclinic space group P\overline{1} consists of six approximately square planar Pd(II)S4 centers, which are interconnected through twelve μ2-bridging benzyl thiolate groups. The Pd...Pd contacts range from 3.0892 (2) to 3.1609 (2) Å and can be considered as weakly bonding. The unit cell of Pd6 contains also a co-crystallized anthracene-9,10-dione molecule.


2006 ◽  
Vol 84 (7) ◽  
pp. 971-978 ◽  
Author(s):  
Soria Meghdadi ◽  
Mehdi Amirnasr ◽  
Vratislav Langer ◽  
Alison Zamanpoor

Cobalt(II), nickel(II), copper(II), and two cobalt(III) complexes of a new dianionic ligand, bqb, [H2bqb = N,N'-bis(2-quinolinecarboxamide)-1,2-benzene] have been synthesized and characterized by elemental analyses, IR, and 1H NMR spectroscopy. The crystal and molecular structures of the [Ni(bqb)] (2) and [N(n-Bu)4][CoIII(bqb)(N3)2] (5) complexes were determined by X-ray crystallography. Complex 2 crystallizes in the monoclinic space group C2/c with a distorted square-planar structure including two short Ni–N (1.848 Å) and two long Ni–N (1.958 Å) bonds. The structure consists of sheets formed in the plane parallel to the b axis and diagonal to vectors a and c by intermolecular hydrogen bonds. Complex 5 crystallizes in the monoclinic space group C2 with a distorted octahedral structure. The [N(n-Bu)4]+ ion is disordered at the C3A and C4A atoms of one Bu. The IR and 1H NMR spectra of the complexes are also discussed.Key words: N4-dianionic amido ligand (bqb), (bqb) complexes of Co(II), Ni(II), Cu(II), and Co(III), azide, cyanide, X-ray crystal structures.


1997 ◽  
Vol 75 (6) ◽  
pp. 702-711 ◽  
Author(s):  
James Blackwell ◽  
Corinne Lehr ◽  
Yimin Sun ◽  
Warren E. Piers ◽  
Susan D. Pearce-Batchilder ◽  
...  

Reaction between the potassium salts of the hydro-tris-pyrazolylborate ligands TpMe'Me and TptBu'Me and the tris THF adduct of scandium trichloride lead to isolation of the scandium complexes (TpMe,Me)ScCl2(THF), 1a, and (TptBu,Me)ScCl2, 1b, in 65 and 49% yield, respectively. Subsequent reactions between 1a and 1b and alkyl lithium reagents RLi (R = Me, CH2SiMe3, and CH(SiMe3)2) gave the lithium salts of the Tp ligands as the major isolated products in all cases but one. The complex (TpMe,Me)Sc(CH2SiMe3)2(THF), 2a, could be obtained contaminated with at least 10% TpMe,MeLi via this methodology. A salt-free alkane elimination route to bis-trimethylsilylmethyl complexes 2a and the THF-free (TptBu,Me)Sc(CH2SiMe3)2, 2b, involving reaction between in situ generated Sc(CH2SiMe3)3(THF)2 and the protonated ligands, TpR,MeH, gave samples of the desired bis-alkyl derivatives in 67 and 87% yield, respectively. In solution, complexes 2a and 2b are both fluxional at room temperature. These dynamic processes were frozen out on the NMR time scale at lower temperatures and interpreted on the basis of the 1H NMR spectra obtained as well as information obtained from the solid state structures of both compounds, 2a: monoclinic, space group P21/c, a = 11.765(4) Ǻ, b = 14.8311(20) Ǻ, c = 20.891(5) Ǻ, β = 105.69(3)°, V = 3509.4(15) Ǻ3, Z = 4, R = 0.088, Rw = 0.082. 2b: triclinic, space group [Formula: see text], a = 11.9427(2) Ǻ, b = 20.3641(3) Ǻ, c = 26.5602(2) Ǻ, α = 112.192(1)°, β = 100.569(1)°, γ = 92.928(1)°, V = 5830.38(14) Ǻ3, Z = 6, R = 0.0500, Rw = 0.1137. Keywords: organoscandium complexes, hydro-tris-pyrazolylborate ligands, alkane elimination.


1993 ◽  
Vol 71 (3) ◽  
pp. 358-363 ◽  
Author(s):  
Juan N. Fernández-G. ◽  
Raúl G. Enríquez ◽  
Amalia Tobón-Cervantes ◽  
Margarita I. Bernal-Uruchurtu ◽  
René Villena-I ◽  
...  

The crystal structures of N,N′-di(2-acetylcyclohexenyl)ethylenediamine (L1) and its copper(II) complex, which crystallizes with one solvent molecule of chloroform (Cu(L1-2H)•CHCl3), were determined. Crystallographic details are as follows: L1 is monoclinic, space group P21/c, with a = 8.280(2), b = 11.692(2), and c = 9.355(2) Å, β = 114.10(2)°, V = 826.7(3) Å3, Z = 2; ρc = 1.22 g cm−3, μ(Cu Kα) = 5.93 cm−1, with the final residual indices of R = 0.046 and Rw = 0.070 for 991 unique reflections. Cu(L1-2H)•CHCl3 is triclinic, space group[Formula: see text] with a = 11.121(3), b = 11.713(3), and c = 8.974(2) Å, α = 99.35(2)°, β = 110.83(2)°, γ = 82.33(2)°, V = 1074(1) Å3, Z = 2; ρc = 1.50 g cm−3, μ(Cu Kα) = 50.74 cm−1, with the final residual indices of R = 0.048 and Rw = 0.077 for 2369 unique reflections. The X-ray diffraction study shows that in the crystal state the ligand L1 is in the methylketonecyclohexanonenamine isomeric form. For the copper complex Cu(L1 2H)•CHC13, the geometry around the metal atom is distorted square planar, and the angle between the chelate ring planes in the complex is 15.1°. An NMR study shows that L1 in solution has the same structure as that observed in the solid state by X-ray diffraction.


2013 ◽  
Vol 69 (11) ◽  
pp. 1234-1237 ◽  
Author(s):  
Heidi Lopez de Diego ◽  
Vishal Koradia ◽  
Andrew D. Bond

Gaboxadol hydrochloride, also known as THIP hydrochloride (systematic name: 3-hydroxy-4,5,6,7-tetrahydro-1,2-oxazolo[5,4-c]pyridin-6-ium chloride), C6H9N2O2+·Cl−, exists as two enantiotropically related polymorphs. Transformation between the polymorphs occurs in a single-crystal-to-single-crystal manner at 221 K, and the enthalpy of transformation from the high-temperature form to the low-temperature form is −0.7 kJ mol−1. Single-crystal structures have been determined at 298 and 220 K. At 298 K, the structure is triclinic (space groupP\overline{1}), with two formula units in the crystallographic asymmetric unit. At 220 K, the structure is monoclinic (space groupI2/a), with one formula unit in the asymmetric unit. The structures contain identical hydrogen-bonded layers and the transformation between the polymorphs corresponds to a shift of adjacent layers relative to each other. The transformation is shown to be reversible by differential scanning calorimetry and variable-temperature powder X-ray diffraction.


1984 ◽  
Vol 39 (10) ◽  
pp. 1344-1349 ◽  
Author(s):  
Gerhard Thiele ◽  
Heinz W. Rotter ◽  
Martin Lietz ◽  
Jochen Ellermann

The molecular and crystal structures of the nor-heteroadam antanes CH3C(CH2As)3[C(COOCH2CH3)2]2 (1) and CH3C(CH2As)3Se2 (2) have been investigated in order to obtain confirmation of the rare structures deduced earlier from mass, 1H NMR and vibrational spectroscopy. Crystals of 1 are triclinic, space group P1̄-C1i with a - 769.27(30), b = 1036.09(14), c = 1599.18(17) pm, α = 98.236(10)°, β = 97.987(18)°, γ = 103.633(20)° and Z = 2. On the basis of 1821 unique reflections the structure was refined to a weighted R value of 5.28%. The crystals of 2 are monoclinic, space group P 21/c-C52h with a = 1102.73(23), b - 727.49(14), c = 1281.27(42) pm. β = 98.803(21)° and Z = 4. On the basis of 1065 unique reflections the structure was refined to a weighted R value of 5.93%.Several attempts to synthesize CH3C(CH2As)3Te2 failed.


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