scholarly journals Uncovering Redox Non-Innocent H-Bonding in Cu(I)-Diazene Complexes

2021 ◽  
Author(s):  
Evan Gardner ◽  
Sean C. Marguet ◽  
Caitlyn Cobb ◽  
Dominic Pham ◽  
Jeffery A. Bertke ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Dynamic Equilibrium ◽  
Cation Radical ◽  
High Energy ◽  
Dft Studies ◽  
Nmr Studies ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Potential Strategy

<div><p>The life-sustaining reduction of N<sub>2</sub> to NH<sub>3</sub> is thermoneutral yet kinetically challenged by high energy intermediates such as N<sub>2</sub>H<sub>2</sub>. Exploring intramolecular H-bonding as a potential strategy to stabilize diazene intermediates, we employ a series of [<sup>xHet</sup>TpCu]<sub>2</sub>(𝜇-N<sub>2</sub>H<sub>2</sub>) complexes that exhibit H-bonding between pendant aromatic N-heterocycles (<sup>X</sup>Het) such as pyridine and a bridging <i>trans</i>-N<sub>2</sub>H<sub>2</sub> ligand at copper(I) centers. X-ray crystallography and IR spectroscopy clearly reveal H-bonding in [<sup>pyMe</sup>TpCu]<sub>2</sub>(𝜇-N<sub>2</sub>H<sub>2</sub>) while low temperature <sup>1</sup>H NMR studies coupled with DFT analysis reveals a dynamic equilibrium between two closely related, symmetric H-bonded structural motifs. Importantly, the <sup>x</sup>Het pendant negligibly influences the electronic structure of <sup>xHet</sup>TpCu<sup>I</sup> centers in <sup>xHet</sup>TpCu(CNAr<sup>2,6-Me2</sup>) complexes that lack H-bonding as judged by nearly indistinguishable n(CN) frequencies (2113 - 2117 cm<sup>-1</sup>). Nonetheless, H-bonding in the corresponding [<sup>xHet</sup>TpCu]<sub>2</sub>(𝜇-N<sub>2</sub>H<sub>2</sub>) complexes results in marked changes in n(NN) (1398 - 1419 cm<sup>-1</sup>) revealed through rRaman studies. Due to the closely matched N-H BDE’s of N<sub>2</sub>H<sub>2</sub> and the neutral pyH<sup>0</sup> cation radical, the aromatic N-heterocylic pendants may encourage partial H-atom transfer (HAT) from N<sub>2</sub>H<sub>2</sub> to <sup>x</sup>Het through redox non-innocent H-bonding in [<sup>xHet</sup>TpCu]<sub>2</sub>(𝜇-N<sub>2</sub>H<sub>2</sub>). DFT studies reveal modest thermodynamic barriers for concerted transfer of both H-atoms of coordinated N<sub>2</sub>H<sub>2</sub> to the <sup>x</sup>Het pendants to generate tautomeric [<sup>xHetH</sup>TpCu]<sub>2</sub>(𝜇-N<sub>2</sub>) complexes, identifying concerted dual HAT as a thermodynamically favorable pathway for N<sub>2</sub> / N<sub>2</sub>H<sub>2</sub> interconversion.</p></div>

scholarly journals Uncovering Redox Non-Innocent H-Bonding in Cu(I)-Diazene Complexes

2021 ◽  
Author(s):  
Evan Gardner ◽  
Sean C. Marguet ◽  
Caitlyn Cobb ◽  
Dominic Pham ◽  
Jeffery A. Bertke ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Dynamic Equilibrium ◽  
Cation Radical ◽  
High Energy ◽  
Dft Studies ◽  
Nmr Studies ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Potential Strategy

<div><p>The life-sustaining reduction of N<sub>2</sub> to NH<sub>3</sub> is thermoneutral yet kinetically challenged by high energy intermediates such as N<sub>2</sub>H<sub>2</sub>. Exploring intramolecular H-bonding as a potential strategy to stabilize diazene intermediates, we employ a series of [<sup>xHet</sup>TpCu]<sub>2</sub>(𝜇-N<sub>2</sub>H<sub>2</sub>) complexes that exhibit H-bonding between pendant aromatic N-heterocycles (<sup>X</sup>Het) such as pyridine and a bridging <i>trans</i>-N<sub>2</sub>H<sub>2</sub> ligand at copper(I) centers. X-ray crystallography and IR spectroscopy clearly reveal H-bonding in [<sup>pyMe</sup>TpCu]<sub>2</sub>(𝜇-N<sub>2</sub>H<sub>2</sub>) while low temperature <sup>1</sup>H NMR studies coupled with DFT analysis reveals a dynamic equilibrium between two closely related, symmetric H-bonded structural motifs. Importantly, the <sup>x</sup>Het pendant negligibly influences the electronic structure of <sup>xHet</sup>TpCu<sup>I</sup> centers in <sup>xHet</sup>TpCu(CNAr<sup>2,6-Me2</sup>) complexes that lack H-bonding as judged by nearly indistinguishable n(CN) frequencies (2113 - 2117 cm<sup>-1</sup>). Nonetheless, H-bonding in the corresponding [<sup>xHet</sup>TpCu]<sub>2</sub>(𝜇-N<sub>2</sub>H<sub>2</sub>) complexes results in marked changes in n(NN) (1398 - 1419 cm<sup>-1</sup>) revealed through rRaman studies. Due to the closely matched N-H BDE’s of N<sub>2</sub>H<sub>2</sub> and the neutral pyH<sup>0</sup> cation radical, the aromatic N-heterocylic pendants may encourage partial H-atom transfer (HAT) from N<sub>2</sub>H<sub>2</sub> to <sup>x</sup>Het through redox non-innocent H-bonding in [<sup>xHet</sup>TpCu]<sub>2</sub>(𝜇-N<sub>2</sub>H<sub>2</sub>). DFT studies reveal modest thermodynamic barriers for concerted transfer of both H-atoms of coordinated N<sub>2</sub>H<sub>2</sub> to the <sup>x</sup>Het pendants to generate tautomeric [<sup>xHetH</sup>TpCu]<sub>2</sub>(𝜇-N<sub>2</sub>) complexes, identifying concerted dual HAT as a thermodynamically favorable pathway for N<sub>2</sub> / N<sub>2</sub>H<sub>2</sub> interconversion.</p></div>

Solution multinuclear (31P,111Cd,77Se) magnetic resonance studies of cadmium complexes of heterocyclic aromatic thiones and the structure of [tetrakis(2(1H)-pyridinethione)cadmium] nitrate, [Cd(C5H5NS)4](NO3)2

2000 ◽  
Vol 78 (5) ◽  
pp. 590-597 ◽  
Author(s):  
Umarani Rajalingam ◽  
Philip AW Dean ◽  
Hilary A Jenkins
Keyword(s):  
Cadmium Nitrate ◽  
Cadmium Complexes ◽  
Nmr Studies ◽  
X Ray ◽  
X Ray Crystallography ◽  
Stoichiometric Reaction ◽  
Complex Salts ◽  
Reduced Temperature ◽  
Aromatic Heterocyclic ◽  
Phosphine Chalcogenides

The complex salts CdL4(O3SCF3)2 (L = 2(1H)-pyridinethione (Py2SH), 4(1H)-pyridinethione (Py4SH), or 2(1H)-quinolinethione (Q2SH)) have been synthesized by the stoichiometric reaction of Cd(O3SCF3)2 and the appropriate thione. Both ambient-temperature 13C and reduced-temperature 111Cd NMR of CdL4(O3SCF3)2 in solution are consistent with L being bound through sulfur. Reduced-temperature NMR (31P, 77Se, 111Cd, as appropriate) of mixtures of CdL4(O3SCF3)2 and Cd(EPCy3)4(O3SCF3)2 (E = Se, Cy = c-C6H11) and of Cd(EPCy3)4(O3SCF3)2 (E = S, Se) and L in solution provides evidence for various [CdLn(EPCy3)4-n]2+. Similarly, reduced-temperature metal NMR of [CdL4]2+ and [CdL'4]2+ (L, L' = Py2SH, Py4SH, Q2SH; L not equal L') in solution shows the formation of [CdLnL'4-n]2+. Thus it has been demonstrated that at reduced temperature [CdL4]2+ is intact in solution and exchange of L is slow on the timescale of the metal chemical shift differences. From the NMR studies of Cd(EPCy3)4(O3SCF3)2 (E = S, Se):L mixtures, the binding preferences are found to be L > EPCy3 in solution. Similarly, from the reduced temperature metal NMR spectra of mixtures where L and L' compete for Cd(II) in solution, the binding preferences are Py4SH > Py2SH > Q2SH. The structure of Cd(Py2SH)4(NO3)2 (4) has been determined by single crystal X-ray analysis. Colorless crystals of 4 are tetragonal, I4(1)/acd with 8 molecules per unit cell of dimensions a = 18.660(3), c = 15.215(3) Å. The structure is comprised of recognizable NO3- anions and [Cd(Py2SH)4]2+ cations. In the cations, which have S4 symmetry, the ligands are S-bound. A network of NH···O hydrogen bonds links the cations and anions.Key words: aromatic heterocyclic thiones, cadmium complexes, phosphine chalcogenides, 111Cd, 31P, 77Se NMR, X-ray crystallography.

Supramoleküle aus Kronenethern und geminalen Sulfonen: Synthese von vier binären Komplexen und Kristallstruktur von (CH2CH2O)4·2H 2C(SO2C2H5)2/Supramolecules of Crown Ethers with Geminal Sulfones: Synthesis of Four Binary Complexes and Crystal Structure of (CH2CH2O )4·2H2C(SO2C2H5)2

1995 ◽  
Vol 50 (7) ◽  
pp. 1018-1024 ◽  
Author(s):  
Axel Michalides ◽  
Dagmar Henschel ◽  
Armand Blaschette ◽  
Peter G. Jones
Keyword(s):  
Monoclinic Space Group ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Binary Complexes ◽  
Cyclic Polyethers ◽  
Adjacent Unit ◽  
Methylene Group

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.

Configurational and conformational studies on condensation products of biogenic amines with 2,5-anhydro-D-mannose

1985 ◽  
Vol 63 (11) ◽  
pp. 2915-2921 ◽  
Author(s):  
Ian M. Piper ◽  
David B. MacLean ◽  
Romolo Faggiani ◽  
Colin J. L. Lock ◽  
Walter A. Szarek
Keyword(s):  
Hydrogen Bond ◽  
Intermolecular Hydrogen Bond ◽  
Direct Methods ◽  
Conformational Studies ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Twist Conformation ◽  
Cell Dimensions ◽  
Internal Hydrogen Bond

The products of a Pictet–Spengler condensation of tryptamine and of histamine with 2,5-anhydro-D-mannose have been studied by X-ray crystallography to establish their absolute configuration. 1(S)-(α-D-Arabinofuranosyl)-1,2,3,4-tetrahydro-β-carboline (1), C16H20N20O4, is monoclinic, P21 (No. 4), with cell dimensions a = 13.091(4), b = 5.365(1), c = 11.323(3) Å, β = 115.78(2)°, and Z = 2. 4-(α-D-Arabinofuranosyl)imidazo[4,5-c]-4,5,6,7-tetrahydropyridine (3), C11H17N3O4, is orthorhombic, P212121 (No. 19), with cell dimensions a = 8.118(2), b = 13.715(4), c = 10.963(3) Å, and Z = 4. The structures were determined by direct methods and refined to R1 = 0.0514, R2 = 0.0642 for 3210 reflections in the case of 1, and to R1 = 0.0312, R2 = 0.0335 for 1569 reflections in the case of 3. Bond lengths and angles within both molecules are normal and agree well with those observed in related structures. In 3 the base and sugar adopt a syn arrangement, which is maintained by an internal hydrogen bond between O(2′) and N(3). The sugar adopts a normal 2T3 twist conformation. The sugar has the opposite anti arrangement in the β-carboline 1 and the conformation of the sugar is unusual; it is close to an envelope conformation with O(4′) being the atom out of the plane. This conformation is caused by a strong intermolecular hydrogen bond from O(5′) in a symmetry-related molecule to O(4′). Both compounds are held together in the crystal by extensive hydrogen-bonding networks. The conformations of the compounds in solution have been investigated by 1H nmr spectroscopy, and the results obtained were compared with those obtained by X-ray crystallography for 1 and 3.

Synthesis and characterization of a linked, π-π stacked organotin compound of 2-mercapto-6-nitrobenzothiazolyl diphenyltin chloride with 2-ethoxyl-6-nitrobenzothiazole

2003 ◽  
Vol 81 (7) ◽  
pp. 825-831 ◽  
Author(s):  
Chunlin Ma ◽  
Qin Jiang ◽  
Rufen Zhang
Keyword(s):  
Title Compound ◽  
Organotin Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Stacking Interaction ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Π Stacking ◽  
Π Stacking Interaction ◽  
Molecular Components

The new organotin compound, Ph2Sn(Cl)[S(C7H3N2O2S)]·[(C7H3N2O2S)OEt], assembled by an intermolecular aromatic benzothiazole–benzothiazole π-π stacking interaction, has been synthesized by the reaction of diphenyltin dichloride with 2-mercapto-6-nitrobenzothiazole. The title compound was characterized by elemental, IR, 1H NMR, and X-ray crystallography analyses. Single-crystal X-ray diffraction data reveals that the title compound has two different molecular components. The component Ph2Sn(Cl)[S(C7H3N2O2S)] has a pentacoordinate tin, which further forms an infinite one-dimensional chain by intermolecular non-bonded Cl···S interactions, resulting in an intercalation lattice that holds (C7H3N2O2S)OEt molecules. The formation of the molecule (C7H3N2O2S)OEt as well as its intercalated mechanism has also been discussed.Key words: organotin, assemble, π-π stacking interaction, 2-mercapto-6-nitrobenzothiazole, non-bonded interaction, crystal structure.

scholarly journals Silylated gallium and indium chalcogenide ring systems as potential precursors to ME (E=O, S) materials

2013 ◽  
Vol 11 (7) ◽  
pp. 1225-1238
Author(s):  
Iliana Medina-Ramírez ◽  
Cynthia Floyd ◽  
Joel Mague ◽  
Mark Fink
Keyword(s):  
Thermal Decomposition ◽  
Room Temperature ◽  
Membered Ring ◽  
Molecular Structures ◽  
Nmr Studies ◽  
X Ray ◽  
X Ray Crystallography ◽  
High Yields ◽  
Vt Nmr ◽  
State 1

AbstractThe reaction of R3M (M=Ga, In) with HESiR′3 (E=O, S; R′3=Ph3, iPr3, Et3, tBuMe2) leads to the formation of (Me2GaOSiPh3)2(1); (Me2GaOSitBuMe2)2(2); (Me2GaOSiEt3)2(3); (Me2InOSiPh3)2(4); (Me2InOSitBuMe2)2(5); (Me2InOSiEt3)2(6); (Me2GaSSiPh3)2(7); (Et2GaSSiPh3)2(8); (Me2GaSSiiPr3)2(9); (Et2GaSSiiPr3)2(10); (Me2InSSiPh3)3(11); (Me2InSSiiPr3)n(12), in high yields at room temperature. The compounds have been characterized by multinuclear NMR and in most cases by X-ray crystallography. The molecular structures of (1), (4), (7) and (8) have been determined. Compounds (3), (6) and (10) are liquids at room temperature. In the solid state, (1), (4), (7) and (9) are dimers with central core of the dimer being composed of a M2E2 four-membered ring. VT-NMR studies of (7) show facile redistribution between four- and six-membered rings in solution. The thermal decomposition of (1)–(12) was examined by TGA and range from 200 to 350°C. Bulk pyrolysis of (1) and (2) led to the formation of Ga2O3; (4) and (5) In metal; (7)–(10) GaS and (11)–(12) InS powders, respectively.

[Zn(phen)2(CX3COO)]+, X = H orCl; Influence of X on the Coordination Mode of the Carboxylate Group (phen = 1,10-Phenanthroline)

2005 ◽  
Vol 60 (10) ◽  
pp. 1049-1053 ◽  
Author(s):  
Zeanab Talaei ◽  
Ali Morsali ◽  
Ali R. Mahjoub
Keyword(s):  
Nmr Spectroscopy ◽  
Elemental Analysis ◽  
Coordination Mode ◽  
Bidentate Ligand ◽  
Carboxylate Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Coordinate Geometry ◽  
C Nmr

Two new ZnII(phen)2 complexes with trichloroacetate and acetate anions, [Zn(phen)2(CCl3COO)- (H2O)](ClO4) and [Zn(phen)2(CH3COO)](ClO4), have been synthesized and characterized by elemental analysis, IR, 1H NMR, 13C NMR spectroscopy. The single crystal X-ray data of these compounds show the Zn atoms to have six-coordinate geometry. From IR spectra and X-ray crystallography it is established that the coordination of the COO− group is different for trichloroacetate and acetate. The former acts as a monodentate whereas the latter acts as a bidentate ligand.

One-pot synthesis of 5-(8-ethoxycarbonyl-1-naphthyl)-10,15,20-triphenyl porphyrin (ENTPP) and spontaneous resolution upon crystallization

2011 ◽  
Vol 15 (03) ◽  
pp. 197-201 ◽  
Author(s):  
Juanxia Yang ◽  
Jiaxun Jiang ◽  
Weiguang Fang ◽  
Xiaoxu Kai ◽  
Chuanjiang Hu ◽  
...  
Keyword(s):  
Soret Band ◽  
Ester Group ◽  
Spontaneous Resolution ◽  
Cd Spectra ◽  
One Pot ◽  
Nmr Spectrum ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Entire Structure

5-(8-ethoxycarbonyl-1-naphthyl)-10,15,20-triphenyl porphyrin (ENTPP) has been synthesized in a one-pot reaction, and the corresponding chiral crystalline samples have been obtained by spontaneous resolution. 1 H NMR spectrum suggests it is mononaphthyl substituted species and an ethyl group is over the porphyrin plane. The structure has been further confirmed by X-ray crystallography. ENTPP·C6H14 (C57H50N4O2 ): monoclinic, P21, a = 10.707(2) Å, b = 12.203(2) Å, c = 17.858(4) Å, β = 103.06(3)°, V = 2272.8(8) Å3, Z = 2. The 8-position substituent, ester group, lies above the porphyrin plane and leads to the conformational chirality. The entire structure is built up with homochiral molecules, which leads to a chiral crystal through packing in P21 space group. Circular dichroism (CD) spectra have exhibited remarkable absorptions in the Soret band region, which further confirms the homochirality of the crystalline samples.

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