scholarly journals Comparison of molecular structures of cis-bis[8-(dimethylphosphanyl)quinoline]nickel(II) and -platinum(II) complex cations

2020 ◽  
Vol 76 (12) ◽  
pp. 1813-1817
Author(s):  
Masatoshi Mori ◽  
Takayoshi Suzuki

The crystal structures of the complexes (SP-4-2)-cis-bis[8-(dimethylphosphanyl)quinoline-κ2 N,P]nickel(II) bis(perchlorate) nitromethane monosolvate, [Ni(C11H12NP)2](ClO4)2·CH3NO2 (1), and (SP-4-2)-cis-bis[8-(dimethylphosphanyl)quinoline-κ2 N,P]platinum(II) bis(tetrafluoroborate) acetonitrile monosolvate, [Pt(C11H12NP)2](BF4)2·C2H3N (2), are reported. In both complex cations, two phosphanylquinolines act as bidentate P,N-donating chelate ligands and form the mutually cis configuration in the square-planar coordination geometry. The strong trans influence of the dimethylphosphanyl donor group is confirmed by the Ni—N bond lengths in 1, 1.970 (2) and 1.982 (2) Å and, the Pt—N bond lengths of 2, 2.123 (4) and 2.132 (4) Å, which are relatively long as compared to those in the analogous 8-(diphenylphosphanyl)quinoline complexes. Mutually cis-positioned quinoline donor groups would give a severe steric hindrance between their ortho-H atoms. In order to reduce such a steric congestion, the NiII complex in 1 shows a tetrahedral distortion of the coordination geometry, as parameterized by τ4 = 0.199 (1)°, while the PtII complex in 2 exhibits a typical square-planar coordination geometry [τ4 = 0.014 (1)°] with a large bending deformation of the ideally planar Me2Pqn chelate planes. In the crystal structure of 2, three F atoms of one of the BF4 − anions are disordered over two sets of positions with refined occupancies of 0.573 (10) and 0.427 (10).

1983 ◽  
Vol 61 (6) ◽  
pp. 1132-1141 ◽  
Author(s):  
Gordon William Bushnell ◽  
Roderick James Densmore ◽  
Keith Roger Dixon ◽  
Arthur Charles Ralfs

Synthesis and 31P nmr spectra of the complex cations, cis-[PtCl(L)(PEt3)2]+, L= theophylline, caffeine, or isocaffeine, and cis[Pt(isocaff)2(PEt3)2]2+ are reported. The crystal structure of cis-[PtCl(caffeine)(PEt3)2][BF4] is determined, space group [Formula: see text], a = 1.1766(6), b = 1.4428(5), c = 0.9002(4) nm, α = 97.28(4)°, β = 97.69(4)°, γ = 100.96(5)°, Dm = 1.649 g cm−1, the bond lengths are Pt—Cl= 233.4(4) pm, Pt—N = 215(1) pm, Pt—P = 225.4(5) pm (mean), and the residual R = 0.071. The crystal structure of cis-[Pt(isocaffeine)2(PEt3)2][BF4]2 is orthorhombic, space group Pbca, a = 2.317(3), b = 1.717(3), c = 2.130(3) nm, Dm = 1.574 g cm−3, with an opposing isocaffeine conformation, bond lengths Pt—N = 211(2) pm, Pt—P = 227.6(9) pm (mean), and R = 0.073. Both crystal structures contain approximately square planar Pt(II) coordination with the purine coordinated via an imidazole nitrogen. The structures are discussed as models for the possible involvement of [Formula: see text] chelation of guanine to platinum when platinum drugs act as antitumour agents, but there is no evidence that isocaffeine acts as an [Formula: see text] chelate.


2017 ◽  
Vol 232 (5) ◽  
pp. 339-347 ◽  
Author(s):  
Zoran Mazej ◽  
Evgeny Goreshnik

AbstractThe [Ag(H2O)2]SbF6, is triclinic, P1̅ (No. 2), with a=6.6419(3) Å, b=7.6327(3) Å, c=11.1338(3) Å, α=95.492(3)°, β=96.994(3)°, γ=113.535(4)°, V=507.13(4) Å3 at 150 K, and Z=3. There are two crystallographically non-equivalent Ag+ cations. The Ag1 is coordinated by two water molecules with Ag–OH2 distances equal to 2.271(2) Å forming in that way a discrete linear [Ag(H2O)2]+ cation. Additionaly, it forms two short Ag···F contacts (2.630(2) Å), resulting in AgO2F2 plaquette, and four long ones (2×3.001(2) Å and 2×3.095(2) Å) with fluorine atoms located below and above the AgO2F2 plaquette. The H2O molecules bridge Ag2 atoms into {–[Ag(μ-OH2)2]–}n infinite chains, with Ag–O distances of 2.367(2)–2.466(2) Å. The [Pd(H2O)4](SbF6)2·4H2O is monoclinic, P21/a (No.14), with a=8.172(2) Å, b=13.202(3) Å, c=8.188(3) Å, β=115.10(1)o, V=799.9(4) Å3 at 200 K, and Z=2. Its crystal structure can be described as an alternation of layers of [Pd(H2O)4]2+ cations (interconnected by H2O molecules) and [SbF6]− anions. It represents the first example where [Pd(H2O)4]2+ has been structurally determined in the solid state. Four oxygen atoms provided by H2O molecules are in almost ideal square-planar arrangement with Pd–O bond lengths 2×2.004(5) Å and 2×2.022(6) Å. The [Cd(H2O)6](SbF6)2, is orthorhombic, Pnnm (No.58), with a=5.5331(2) Å, b=14.5206(4) Å, c=8.9051(3) Å, V=715.47(4) Å3 at 200 K, and Z=2. It consists of [Cd(H2O)6]2+ cations and [SbF6]− anions.


2018 ◽  
Vol 74 (12) ◽  
pp. 1705-1709
Author(s):  
Anthony Linden ◽  
Grzegorz Mlostoń ◽  
Paulina Grzelak ◽  
Heinz Heimgartner

The title compounds, C19H21F3O2S and C24H19F3OS, were prepared via chemo- and regioselective [3 + 2]-cycloadditions of the respective thiocarbonyl ylides (thiocarbonyl S-methanides), generated in situ, with (E)-4,4,4-trifluoro-1-phenylbut-2-en-1-one. The thiophene ring in the crystal structure of each compound has an envelope conformation. The largest differences between the two molecular structures is in the bond lengths about the quaternary C atom of the thiophene ring; in the spirocyclic structure, the C—C bonds to the spiro C atom in the cyclobutane ring are around 1.60 Å, although this is also observed in related structures. In the same structure, weak intermolecular C—H...X (X = S, O) interactions link the molecules into extended ribbons running parallel to the [001] direction. In the other structure, weak C—H...π interactions link the molecules into sheets parallel to the (010) plane.


Author(s):  
Patrick O'Brien ◽  
Matthias Zeller ◽  
Wei-Tsung Lee

The title compound, [NiBr(C25H29N2O)], contains an NiII atom with a slightly distorted square-planar coordination environment defined by one O and two N atoms from the 2-{[(8-aminonaphthalen-1-yl)imino]methyl}-4,6-di-tert-butylphenolate ligand and a bromide anion. The Ni—O and Ni—N bond lengths are slightly longer than those observed in the phenyl backbone counterpart, which can be attributed to the larger steric hindrance of the naphthyl group in the structure of the title compound. The molecule as a whole is substantially distorted, with both the planar naphthalene-1,8-diamine and imino–methyl–phenolate substitutents rotated against the NiN2OBr plane by 38.92 (7) and 37.22 (8)°, respectively, giving the molecule a twisted appearance. N—H...Br hydrogen bonds and N—H...C(π) contacts connect the molecules into dimers, and additional C—H...Br contacts, C—H...π interactions, and an offset stacking interaction between naphthyl units interconnect these dimers into a three-dimensional network.


2019 ◽  
Vol 74 (2) ◽  
pp. 233-240 ◽  
Author(s):  
Ralf Albrecht ◽  
Phil Liebing ◽  
Uwe Morgenstern ◽  
Christoph Wagner ◽  
Kurt Merzweiler

AbstractThioether-functionalized aminosilanes R2Si(NH-C6H4-2-SR′)2 with R=Me, Ph and R′=t-Bu, Me, Ph were synthesized from the corresponding dichlorosilanes R2SiCl2 and lithiated aniline derivatives LiNH-C6H4-2-SR′. Treatment of the functionalized aminosilanes R2Si(NH-C6H4-2-SR′)2 with two eq. of n-BuLi and subsequent reaction with nickel(II) halides NiX2 (X=Cl, Br) or [Ni(acac)2(TMEDA)] led to the formation of the Ni(II) complexes [Ni{R2Si(N-C6H4-2-SR′)2}]. The X-ray single-crystal structure determinations of the nickel complexes revealed that the thioether-functionalized silylamides R2Si(NC6H4-2-SR′)22− act as tetradentate ligands. The nickel atoms exhibit a distorted square-planar coordination with Ni–N and Ni–S bond lengths in the range of 186.4(3)–186.9(2) pm and 217.5(1)–221.5(1) pm, respectively.


2021 ◽  
Vol 76 (3-4) ◽  
pp. 193-199
Author(s):  
Muhammad Said ◽  
Sadia Rehman ◽  
Muhammad Ikram ◽  
Hizbullah Khan ◽  
Carola Schulzke

Abstract Three guanidine-derived tri-substituted ligands viz. N-pivaloyl-N′,N″-bis-(2-methoxyphenyl)guanidine (L1), N-pivaloyl-N′-(2-methoxyphenyl)-N″-phenylguanidine (L2) and N-pivaloyl-N′-(2-methoxyphenyl)-N″-(2-tolyl)guanidine (L3) were reacted with Cu(II) acetate to produce the corresponding complexes. The significance of the substituent on N″ for the resulting molecular structures and their packing in the solid state has been studied with respect to the structural specifics of the corresponding Cu(II) complexes. The key characteristic of the guanidine-based metal complexation with Cu(II) is the formation of an essentially square planar core with an N2O2 donor set. As an exception, in the complex of L1, the substituent’s methoxy moiety also interacts with the Cu(II) center to generate a square-pyramidal geometry. The hydroxyl groups of the imidic acid tautomeric forms of L1–L3, in addition to N″, are also bonded to Cu(II) in all three complexes rather than the nitrogen donor of the guanidine motif.


Author(s):  
Amalina Mohd Tajuddin ◽  
Hadariah Bahron ◽  
Hamizah Mohd Zaki ◽  
Karimah Kassim ◽  
Suchada Chantrapromma

The asymmetric unit of the title complex, [Pd(C15H13FNO)2], contains one half of the molecule with the PdIIcation lying on an inversion centre and is coordinated by the bidentate Schiff base anion. The geometry around the cationic PdIIcentre is distorted square planar, chelated by the imine N- and phenolate O-donor atoms of the two Schiff base ligands. The N- and O-donor atoms of the two ligands are mutuallytrans, with Pd—N and Pd—O bond lengths of 2.028 (2) and 1.9770 (18) Å, respectively. The fluorophenyl ring is tilted away from the coordination plane and makes a dihedral angle of 66.2 (2)° with the phenolate ring. In the crystal, molecules are linked into chains along the [101] direction by weak C—H...O hydrogen bonds. Weak π–π interactions with centroid–centroid distances of 4.079 (2) Å stack the molecules alongc.


1992 ◽  
Vol 47 (2) ◽  
pp. 197-200 ◽  
Author(s):  
Kurt O. Klepp

K2Sn2S5 and K2Sn2Se5 were prepared by reacting stoichiometric powdered mixtures of the binary compounds K2S or K2Se with Sn and the corresponding chalcogen at 1070 K, followed by slow cooling of the melt. The two compounds are isostructural and crystallize with the Tl2Sn2S5 structure type, s.g. C 2/c, Z = 4 with a = 11.072(5) Å, b = 7.806(3)Å, c = 11.517(5)Å, β = 108.43(2)° for K2Sn2S5 and a = 11.613(5)Å, b = 8.189(3) Å, c = 11,897(6) Å, β = 108.28(2)° for K2Sn2Se5. The crystal structures were refined to conventional R-factors of 0.032 and 0.031, respectively. Sn-atoms are in a distorted trigonal-bipyramidal chalcogen coordination. The average equatorial bond lengths are Sn -S: 2.427 Å and Sn -Se: 2.552 Å , the axial ones are Sn -S: 2.600 Å and Sn -Se: 2.774 Å.


2007 ◽  
Vol 63 (11) ◽  
pp. m2802-m2802 ◽  
Author(s):  
Yong Hou ◽  
Hongrong Zuo ◽  
Qian Huang ◽  
Chunlin Ni

The title compound, (C5H12N)2[Ni(C4N2S2)2], is a new [Ni(mnt)2]2− salt (mnt2− is 1,2-dicyanoethene-1,2-dithiolate) with piperidinium [(PIH)+] cations. The NiII ion lies on an inversion centre and the asymmetric unit contains a (PIH)+ cation and one half of the [Ni(mnt)2]2− anion. The NiII ion exhibits a square-planar coordination geometry. In the crystal structure, weak C—H...N, C—H...S and C—H...Ni hydrogen bonds are observed between the anions and the cations.


1985 ◽  
Vol 40 (2) ◽  
pp. 251-257 ◽  
Author(s):  
Siegfried Pohl ◽  
Wolfgang Saak ◽  
Bernt Krebs

Abstract The compounds [(C6H5)4As]2 TeCl4 (1), [(C2H5)4 N]2 TeBr4 · CH3CN (2), and [(C2H5)4N]2TeI4 (3) were prepared by the reaction of Te, X2 , and excess (C2H5)4NX (X = Br, I) in acetonitrile solution or by heating of [(C6H5)4 As]2TeCl6 , Te, and (C6H5)4 ASCl for several hours in the same solvent.The structures of 1-3 were determined from single crystal X-ray data.1 crystallizes in the monoclinic space group P21/n with a = 1061.8(2), b = 1614.2(3), c = 1341.7(3) pm, β = 94.21° and Z = 2; 2: tetragonal, P4/mmm, a = 1039.7(2), c = 690.5(1), Z = 1; 3: tetragonal, I4/mmm, a = 1061.7(2), c = 1342.8(4), Z = 2. In 1-3 Te(II) exhibits a square planar coordination. The Te -CI, Te -Br, and Te-I bond lengths were found to be 260.7 (mean), 275.3, and 298.5 pm, respectively.


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