scholarly journals (N,N-Diallyldithiocarbamato-κ2 S,S′)triphenyltin(IV) and bis(N,N-diallyldithiocarbamato-κ2 S,S′)diphenyltin(IV): crystal structure, Hirshfeld surface analysis and computational study

2020 ◽  
Vol 76 (2) ◽  
pp. 167-176
Author(s):  
Farah Natasha Haezam ◽  
Normah Awang ◽  
Nurul Farahana Kamaludin ◽  
Mukesh M. Jotani ◽  
Edward R. T. Tiekink
Keyword(s):  
Significant Contribution ◽  
Computational Study ◽  
Molecular Structures ◽  
Coordination Geometry ◽  
Asymmetric Mode ◽  
Trigonal Bipyramidal ◽  
Intermolecular Contacts ◽  
Dithiocarbamate Ligand ◽  
Phenyl Rings ◽  
The Individual

The crystal and molecular structures of the title organotin dithiocarbamate compounds, [Sn(C6H5)3(C7H10NS2)] (I) and [Sn(C6H5)2(C7H10NS2)2] (II), present very distinct tin atom coordination geometries. In (I), the dithiocarbamate ligand is asymmetrically coordinating with the resulting C3S2 donor set defining a coordination geometry intermediate between square-pyramidal and trigonal–bipyramidal. In (II), two independent molecules comprise the asymmetric unit, which differ in the conformations of the allyl substituents and in the relative orientations of the tin-bound phenyl rings. The dithiocarbamate ligands in (II) coordinate in an asymmetric mode but the Sn—S bonds are more symmetric than observed in (I). The resulting C2S4 donor set approximates an octahedral coordination geometry with a cis-disposition of the ipso-carbon atoms and with the more tightly bound sulfur atoms approximately trans. The only directional intermolecular contacts in the crystals of (I) and (II) are of the type phenyl-C—H...π(phenyl) and vinylidene-C—H...π(phenyl), respectively, with each leading to a supramolecular chain propagating along the a-axis direction. The calculated Hirshfeld surfaces emphasize the importance of H...H contacts in the crystal of (I), i.e. contributing 62.2% to the overall surface. The only other two significant contacts also involve hydrogen, i.e. C...H/H...C (28.4%) and S...H/H...S (8.6%). Similar observations pertain to the individual molecules of (II), which are clearly distinguishable in their surface contacts, with H...H being clearly dominant (59.9 and 64.9%, respectively) along with C...H/H...C (24.3 and 20.1%) and S...H/H...S (14.4 and 13.6%) contacts. The calculations of energies of interaction suggest dispersive forces make a significant contribution to the stabilization of the crystals. The exception is for the C—H...π contacts in (II) where, in addition to the dispersive contribution, significant contributions are made by the electrostatic forces.

scholarly journals [N-Benzyl-N-(2-phenylethyl)dithiocarbamato-κ2S,S′]triphenyltin(IV) and [bis(2-methoxyethyl)dithiocarbamato-κ2S,S′]triphenyltin(IV): crystal structures and Hirshfeld surface analysis

2016 ◽  
Vol 72 (10) ◽  
pp. 1480-1487 ◽  
Author(s):  
Rapidah Mohamad ◽  
Normah Awang ◽  
Nurul Farahana Kamaludin ◽  
Mukesh M. Jotani ◽  
Edward R. T. Tiekink
Keyword(s):  
Molecular Structures ◽  
Coordination Geometry ◽  
Weakly Bound ◽  
Π Interactions ◽  
Trigonal Bipyramidal ◽  
Hirshfeld Surfaces ◽  
Dithiocarbamate Ligand ◽  
Distorted Trigonal Bipyramidal Coordination ◽  
Supramolecular Chains ◽  
Distorted Trigonal Bipyramidal

The crystal and molecular structures of two triphenyltin dithiocarbamates, [Sn(C6H5)3(C16H16NS2)], (I), and [Sn(C6H5)3(C7H14NO2S2)], (II), are described. In (I), the dithiocarbamate ligand coordinates the SnIVatom in an asymmetric manner, leading to a highly distorted trigonal–bipyramidal coordination geometry defined by a C3S2donor set with the weakly bound S atom approximatelytransto one of theipso-C atoms. A similar structure is found in (II), but the dithiocarbamate ligand coordinates in an even more asymmetric fashion. The packing in (I) features supramolecular chains along thecaxis sustained by C—H...π interactions; chains pack with no directional interactions between them. In (II), supramolecular layers are formed, similarly sustained by C—H...π interactions; these stack along thebaxis. An analysis of the Hirshfeld surfaces for (I) and (II) confirms the presence of the C—H...π interactions but also reveals the overall dominance of H...H contacts in the respective crystals.

scholarly journals (N,N-Diisopropyldithiocarbamato)triphenyltin(IV): crystal structure, Hirshfeld surface analysis and computational study

2019 ◽  
Vol 75 (10) ◽  
pp. 1479-1485 ◽  
Author(s):  
Farah Natasha Haezam ◽  
Normah Awang ◽  
Nurul Farahana Kamaludin ◽  
Mukesh M. Jotani ◽  
Edward R. T. Tiekink
Keyword(s):  
Crystal Structure ◽  
Surface Analysis ◽  
Computational Study ◽  
Close Approach ◽  
Molecular Geometry ◽  
Hirshfeld Surface ◽  
Molecular Structures ◽  
Crystal And Molecular Structures ◽  
Dithiocarbamate Ligand ◽  
Dimeric Aggregates

The crystal and molecular structures of the title triorganotin dithiocarbamate, [Sn(C6H5)3(C7H14NS2)], are described. The molecular geometry about the metal atom is highly distorted being based on a C3S tetrahedron as the dithiocarbamate ligand is asymmetrically chelating to the tin centre. The close approach of the second thione-S atom [Sn...S = 2.9264 (4) Å] is largely responsible for the distortion. The molecular packing is almost devoid of directional interactions with only weak phenyl-C—H...C(phenyl) interactions, leading to centrosymmetric dimeric aggregates, being noted. An analysis of the calculated Hirshfeld surface points to the significance of H...H contacts, which contribute 66.6% of all contacts to the surface, with C...H/H...C [26.8%] and S...H/H...H [6.6%] contacts making up the balance.

scholarly journals Bis[2-(4,5-diphenyl-1H-imidazol-2-yl)-4-nitrophenolato]copper(II) dihydrate: crystal structure and Hirshfeld surface analysis

2019 ◽  
Vol 75 (11) ◽  
pp. 1664-1671 ◽  
Author(s):  
Sailesh Chettri ◽  
Dhiraj Brahman ◽  
Biswajit Sinha ◽  
Mukesh M. Jotani ◽  
Edward R. T. Tiekink
Keyword(s):  
Chelate Ring ◽  
Three Dimensional ◽  
Hirshfeld Surface ◽  
Molecular Structures ◽  
Coordination Geometry ◽  
Bidentate Ligands ◽  
Metal Centre ◽  
Hirshfeld Surfaces ◽  
Square Planar ◽  
Intermolecular Contacts

The crystal and molecular structures of the title CuII complex, isolated as a dihydrate, [Cu(C21H14N3O3)2]·2H2O, reveals a highly distorted coordination geometry intermediate between square-planar and tetrahedral defined by an N2O2 donor set derived from two mono-anionic bidentate ligands. Furthermore, each six-membered chelate ring adopts an envelope conformation with the Cu atom being the flap. In the crystal, imidazolyl-amine-N—H...O(water), water-O—H...O(coordinated, nitro and water), phenyl-C—H...O(nitro) and π(imidazolyl)–π(nitrobenzene) [inter-centroid distances = 3.7452 (14) and 3.6647 (13) Å] contacts link the components into a supramolecular layer lying parallel to (101). The connections between layers forming a three-dimensional architecture are of the types nitrobenzene-C—H...O(nitro) and phenyl-C—H...π(phenyl). The distorted coordination geometry for the CuII atom is highlighted in an analysis of the Hirshfeld surface calculated for the metal centre alone. The significance of the intermolecular contacts is also revealed in a study of the calculated Hirshfeld surfaces; the dominant contacts in the crystal are H...H (41.0%), O...H/H...O (27.1%) and C...H/H...C (19.6%).

scholarly journals Distinct coordination geometries in bis[N,N-bis(2-methoxyethyl)dithiocarbamato-κ2S,S′]diphenyltin(IV) and bis[N-(2-methoxyethyl)-N-methyldithiocarbamato-κ2S,S′]diphenyltin(IV): crystal structures and Hirshfeld surface analysis

2016 ◽  
Vol 72 (8) ◽  
pp. 1130-1137 ◽  
Author(s):  
Rapidah Mohamad ◽  
Normah Awang ◽  
Mukesh M. Jotani ◽  
Edward R. T. Tiekink
Keyword(s):  
Surface Analysis ◽  
Rotation Axis ◽  
Hirshfeld Surface ◽  
Molecular Structures ◽  
Hirshfeld Surface Analysis ◽  
Coordination Geometry ◽  
Axis Direction ◽  
Bond Lengths ◽  
Dithiocarbamate Ligand ◽  
Supramolecular Chains

The crystal and molecular structures of two diphenyltin bis(dithiocarbamate)s, [Sn(C6H5)2(C5H10NOS2)2], (I), and [Sn(C6H5)2(C7H14NO2S2)2], (II), are described. In (I), in which the metal atom lies on a twofold rotation axis, the dithiocarbamate ligand coordinates with approximately equal Sn—S bond lengths and theipso-C atoms of the Sn-bound phenyl groups occupycis-positions in the resulting octahedral C2S4donor set. A quite distinct coordination geometry is noted in (II), arising as a result of quite disparate Sn—S bond lengths. Here, the four S-donors define a trapezoidal plane with theipso-C atoms lying over the weaker of the Sn—S bonds so that the C2S4donor set defines a skewed trapezoidal bipyramid. The packing of (I) features supramolecular layers in theabplane sustained by methylene-C—H...π(Sn–aryl) interactions; these stack along thec-axis direction with no specific interactions between them. In (II), supramolecular chains along theb-axis direction are formed by methylene-C—O(ether) interactions; these pack with no directional interactions between them. A Hirshfeld surface analysis was conducted on both (I) and (II) and revealed the dominance of H...H interactions contributing to the respective surfaces,i.e. >60% in each case, and other features consistent with the description of the molecular packing above.

scholarly journals Resolving Entangled JH-H-Coupling Patterns for Steroidal Structure Determinations by NMR Spectroscopy

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2643
Author(s):  
Danni Wu ◽  
Kathleen Joyce Carillo ◽  
Jiun-Jie Shie ◽  
Steve S.-F. Yu ◽  
Der-Lii M. Tzou
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr Spectroscopy ◽  
Chemical Shifts ◽  
Atomic Level ◽  
Molecular Structures ◽  
Naturally Occurring ◽  
Structure Determinations ◽  
Ligand Interactions ◽  
Synthetic Steroids ◽  
The Individual

For decades, high-resolution 1H NMR spectroscopy has been routinely utilized to analyze both naturally occurring steroid hormones and synthetic steroids, which play important roles in regulating physiological functions in humans. Because the 1H signals are inevitably superimposed and entangled with various JH–H splitting patterns, such that the individual 1H chemical shift and associated JH–H coupling identities are hardly resolved. Given this, applications of thess information for elucidating steroidal molecular structures and steroid/ligand interactions at the atomic level were largely restricted. To overcome, we devoted to unraveling the entangled JH–H splitting patterns of two similar steroidal compounds having fully unsaturated protons, i.e., androstanolone and epiandrosterone (denoted as 1 and 2, respectively), in which only hydroxyl and ketone substituents attached to C3 and C17 were interchanged. Here we demonstrated that the JH–H values deduced from 1 and 2 are universal and applicable to other steroids, such as testosterone, 3β, 21-dihydroxygregna-5-en-20-one, prednisolone, and estradiol. On the other hand, the 1H chemical shifts may deviate substantially from sample to sample. In this communication, we propose a simple but novel scheme for resolving the complicate JH–H splitting patterns and 1H chemical shifts, aiming for steroidal structure determinations.

scholarly journals Photoprotective Properties of Eumelanin: Computational Insights into the Photophysics of a Catechol:Quinone Heterodimer Model System

Photochem ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 26-37
Author(s):  
Victoria C. Frederick ◽  
Thomas A. Ashy ◽  
Barbara Marchetti ◽  
Michael N. R. Ashfold ◽  
Tolga N. V. Karsili
Keyword(s):  
Ground State ◽  
Sandwich Structure ◽  
Computational Study ◽  
Minimum Energy ◽  
Carbonyl Oxygen ◽  
Model System ◽  
Molecular Structures ◽  
Uv Damage ◽  
Chromosomal Dna ◽  
Relevant Model

Melanins are skin-centered molecular structures that block harmful UV radiation from the sun and help protect chromosomal DNA from UV damage. Understanding the photodynamics of the chromophores that make up eumelanin is therefore paramount. This manuscript presents a multi-reference computational study of the mechanisms responsible for the experimentally observed photostability of a melanin-relevant model heterodimer comprising a catechol (C)–benzoquinone (Q) pair. The present results validate a recently proposed photoinduced intermolecular transfer of an H atom from an OH moiety of C to a carbonyl-oxygen atom of the Q. Photoexcitation of the ground state C:Q heterodimer (which has a π-stacked “sandwich” structure) results in population of a locally excited ππ* state (on Q), which develops increasing charge-transfer (biradical) character as it evolves to a “hinged” minimum energy geometry and drives proton transfer (i.e., net H atom transfer) from C to Q. The study provides further insights into excited state decay mechanisms that could contribute to the photostability afforded by the bulk polymeric structure of eumelanin.

scholarly journals Discoloration of Historical Plastic Objects: New Insight into the Degradation of β-Naphthol Pigment Lakes

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2278
Author(s):  
Anna Micheluz ◽  
Eva Mariasole Angelin ◽  
João Almeida Lopes ◽  
Maria João Melo ◽  
Marisa Pamplona
Keyword(s):  
Light Exposure ◽  
Molecular Structures ◽  
Conservation Science ◽  
Organic Pigment ◽  
Organic Pigments ◽  
Before And After ◽  
The Individual ◽  
Determining Factor ◽  
Insight Into ◽  
Historical Samples

Light is a determining factor in the discoloration of plastics, and photodegradation processes can affect the molecular structures of both the polymer and colorants. Limited studies focused on the discoloration of heritage plastics in conservation science. This work investigated the discoloration of red historical polyethylene (PE) objects colored with PR 48:2 and PR 53:1. High-density and low-density PE reference polymers, neat pigment powders, and historical samples were assessed before and after accelerated photoaging. The applied methodology provided insight into the individual light-susceptibility of polyethylenes, organic pigment lakes, and their combined effect in the photoaging of historical plastic formulations. After light exposure, both PE references and historical samples yellowed, PR53:1 faded, and PR 48:2 darkened; however, both organic pigments faded severely in the historical samples. This highlights the role played by the plastic binder likely facilitating the pigment photofading. Fourier transform infrared spectroscopy and mass spectrometry techniques—EGA-MS, PY-GC/MS, and TD-GC/MS—were successfully employed for characterizing the plastic formulations and degradation. The identification of phthalic compounds in both aged β-naphthol powders opens new venues for studies on their degradation. This work’s approach and analytical methods in studying the discoloration of historical plastics are novel, proving their efficacy, reliability, and potentiality.

Chloridobis(1,10-phenanthroline-κ2 N,N′)copper(I) hexahydrate

2007 ◽  
Vol 63 (3) ◽  
pp. m826-m828 ◽  
Author(s):  
H. Zhong ◽  
X.-R. Zeng ◽  
X.-M. Yang ◽  
Q.-Y. Luo ◽  
S.-Z. Xiao
Keyword(s):  
Three Dimensional ◽  
Water Molecules ◽  
Stacking Interactions ◽  
Coordination Geometry ◽  
Rotation Axes ◽  
Trigonal Bipyramidal ◽  
Distorted Trigonal Bipyramidal Coordination ◽  
Cl Atom ◽  
Phenanthroline Ligands ◽  
Distorted Trigonal Bipyramidal

The CuI atom in the title complex, [CuCl(C12H8N2)2]·6H2O, exists in a distorted trigonal-bipyramidal coordination geometry defined by one Cl atom and four N atoms of two 1,10-phenanthroline ligands. In the crystal structure, molecules are linked into a three-dimensional framework by O—H...O hydrogen bonds and π–π stacking interactions. Four water molecules lie on crystallographic twofold rotation axes.

scholarly journals Steric control of supramolecular association in structures of Zn(S2COR)2 with N,N′-bis(pyridin-4-ylmethyl)oxalamide

2019 ◽  
Vol 234 (3) ◽  
pp. 165-175 ◽  
Author(s):  
Yee Seng Tan ◽  
Hao Zhe Chun ◽  
Mukesh M. Jotani ◽  
Edward R.T. Tiekink
Keyword(s):  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Molecular Structures ◽  
Coordination Geometry ◽  
Hirshfeld Surfaces ◽  
Binuclear Molecule ◽  
Supramolecular Chain ◽  
The One ◽  
Distorted Tetrahedral Coordination ◽  
Cyclohexyl Group

Abstract The crystal and molecular structures of the one-dimensional coordination polymer [Zn(S2COEt)2(4LH2)]n (1) and binuclear [Zn(S2COCy)2]2(4LH2) (2) are described, where 4LH2 is N,N′-bis(pyridin-4-ylmethyl)ethanediamide. In 1, the Zn(S2COEt)2 entities are linked by bidentate bridging 4LH2 ligands through the pyridyl-N atoms to generate a twisted supramolecular chain. As a result of monodentate xanthate ligands, the N2S4 donor set defines a distorted tetrahedral coordination geometry and, crucially, allows the participation of the non-coordinating sulfur atoms in supramolecular association. Thus, in the crystal amide-N–H···O(amide) and amide-N–H···S(thione) hydrogen bonds link chains into a three-dimensional architecture. The substitution of the ethyl group in the xanthate ligand with a cyclohexyl group results in very different structural outcomes. In 2, a binuclear molecule is observed with the coordination geometry for zinc being defined by chelating xanthate ligands and a pyridyl-N atom with the NS4 donor set defining a highly distorted geometry. In the molecular packing, amide-N–H···S(thione) hydrogen bonds stabilise a supramolecular chain along the a-axis and these are connected into a three-dimensional arrangement by methylene-C–H···O and methylene-C–H···π(pyridyl) interactions. The relative importance of the specified intermolecular interactions and weaker, contributing contacts has been revealed by an analysis of the calculated Hirshfeld surfaces of 1 and 2.

scholarly journals Some chalcones derived from thiophene-3-carbaldehyde: synthesis and crystal structures

2019 ◽  
Vol 75 (7) ◽  
pp. 957-963 ◽  
Author(s):  
Trung Vu Quoc ◽  
Duong Tran Thi Thuy ◽  
Thuan Dang Thanh ◽  
Thanh Phung Ngoc ◽  
Vuong Nguyen Thien ◽  
...  
Keyword(s):  
Potassium Hydroxide ◽  
Thiophene Ring ◽  
Three Dimensional ◽  
Ethanol Solution ◽  
Molecular Structures ◽  
Chain Formation ◽  
Axis Direction ◽  
Crystal And Molecular Structures ◽  
Phenyl Rings ◽  
Thiophene Derivatives

The synthesis, spectroscopic data and crystal and molecular structures of four 3-(3-phenylprop-1-ene-3-one-1-yl)thiophene derivatives, namely 1-(4-hydroxyphenyl)-3-(thiophen-3-yl)prop-1-en-3-one, C13H10O2S, (1), 1-(4-methoxyphenyl)-3-(thiophen-3-yl)prop-1-en-3-one, C14H12O2S, (2), 1-(4-ethoxyphenyl)-3-(thiophen-3-yl)prop-1-en-3-one, C15H14O2S, (3), and 1-(4-bromophenyl)-3-(thiophen-3-yl)prop-1-en-3-one, C13H9BrOS, (4), are described. The four chalcones have been synthesized by reaction of thiophene-3-carbaldehyde with an acetophenone derivative in an absolute ethanol solution containing potassium hydroxide, and differ in the substituent at the para position of the phenyl ring: –OH for 1, –OCH3 for 2, –OCH2CH3 for 3 and –Br for 4. The thiophene ring in 4 was found to be disordered over two orientations with occupancies 0.702 (4) and 0.298 (4). The configuration about the C=C bond is E. The thiophene and phenyl rings are inclined by 4.73 (12) for 1, 12.36 (11) for 2, 17.44 (11) for 3 and 46.1 (6) and 48.6 (6)° for 4, indicating that the –OH derivative is almost planar and the –Br derivative deviates the most from planarity. However, the substituent has no real influence on the bond distances in the α,β-unsaturated carbonyl moiety. The molecular packing of 1 features chain formation in the a-axis direction by O—H...O contacts. In the case of 2 and 3, the packing is characterized by dimer formation through C—H...O interactions. In addition, C—H...π(thiophene) interactions in 2 and C—H...S(thiophene) interactions in 3 contribute to the three-dimensional architecture. The presence of C—H...π(thiophene) contacts in the crystal of 4 results in chain formation in the c-axis direction. The Hirshfeld surface analysis shows that for all four derivatives, the highest contribution to surface contacts arises from contacts in which H atoms are involved.

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