Structure of 1,4-bis(diiodophenylstannyl)butane

The molecule of I₂PhSnCH₂CH₂CH₂CH₂SnPhI₂ (1) in the solid state, is centrosymmetric with the molecular center-of-symmetry coincident with a crystallographic center-of-symmetry. It crystallizes in the monoclinic space group,P2₁/c (Z=2), witha=13.495(1) Å,b=6.844(1) Å,c=14.732(1) Å, and β=116.12(2)^o. The compounds consist of essentially individual molecules, separated by I(2)---I(2ⁱ) and I(2)---I(2ⁱⁱ) distances [4.258(12) Å], close to the sum of the van der Waals radii. There are no interactions between the two diiodophenylstannyl moieties. The tin atoms have slightly distorted tetrahedral geometries, with the bond angles at tin varying from 103.40(3) [I(1)?Sn?I(2)] to 117.0(3)⁰ [C(1)?Sn?C(7)] and with Sn?I(1) and Sn?I(2) bond lengths of 2.6980(9) and 2.7106(10) Å, respectively.¹H-,¹³C- and¹¹⁹Sn-NMR spectra in CDCl₃ solution have also been obtained.     

A Doubly Interpenetrated Layer Structure: 4-Acetamidobenzaldehyde 4-Nitrophenylhydrazone

Abstract  

The title molecule, 4-acetamidobenzaldehyde 4-nitrophenylhydrazone, is essentially planar with the maximum deviations from the least-squares plane through the 22 non-hydrogen atoms being 0.176(1) ? (nitro-O) and −0.152(1) ? (amide-O). The dihedral angle between the benzene rings is 6.93(7)°. The conformation about the C=N bond is E. The presence of amide-H···O-nitro and hydrazine-H···O-amide hydrogen bonding leads to the formation of zigzag 2-D arrays with a pseudo three-connected brick-wall network when viewed normal to the plane of the layer. The layers are sustained by 38-membered {···OCNC₅N₂C₄NO···HNCO···HN₂C₅NH···ONC₄NH} synthons and the rather large voids defined by these are occupied by a centrosymmetrically related layer to result in the formation of a doubly interpenetrated network. These stack along the b direction being connected by C–H···O interactions. The compound crystallizes in the monoclinic space group P2₁/c with a = 10.8152(3) ?, b = 10.9469(2) ?, c = 12.9198(4) ?, β = 113.679(1)°, and Z = 4.     

Soft C—H⃛O hydrogen bonds in methyl 2,4‐di­nitro­benzene­sulfenate: sheets built from R22(10) and R66(42) rings

Molecules of the title compound, C₇H₆N₂O₅S, are linked into sheets containing R₂²(10) and R₆⁶(42) rings by C—H?O hydrogen bonds [C?O 3.405 (3) and 3.511 (2) Å; C—H?O 159 and 169°], in which both acceptors are in the same nitro group. Comparisons are made with the hydrogen bonding in other nitro­benzene­sulfenate esters.     

Five N′‐benzylidene‐N‐methylpyrazine‐2‐carbohydrazides

The compounds N′‐benzylidene‐N‐methylpyrazine‐2‐carbohydrazide, C₁₃H₁₂N₄O, (IIa), N′‐(2‐methoxybenzylidene)‐N‐methylpyrazine‐2‐carbohydrazide, C₁₄H₁₄N₄O₂, (IIb), N′‐(4‐cyanobenzylidene)‐N‐methylpyrazine‐2‐carbohydrazide dihydrate, C₁₄H₁₁N₅O·2H₂O, (IIc), N‐methyl‐N′‐(2‐nitrobenzylidene)pyrazine‐2‐carbohydrazide, C₁₃H₁₁N₅O₃, (IId), and N‐methyl‐N′‐(4‐nitrobenzylidene)pyrazine‐2‐carbohydrazide, C₁₃H₁₁N₅O₃, (IIe), have dihedral angles between the pyrazine rings and the benzene rings in the range 55–78°. These methylated pyrazine‐2‐carbohydrazides have supramolecular structures which are formed by weak C—H...O/N hydrogen bonds, with the exception of (IIc) which is hydrated. There are π–π stacking interactions in all five compounds. Three of these structures are compared with their nonmethylated counterparts, which have dihedral angles between the pyrazine rings and the benzene rings in the range 0–6°.     

A simple model for a two-stage chemical reaction with diffusion

We analyse the evolution of a two-stage chemical reaction betweentwo neighbouring plumes of reactants. Under the assumption thatthe plumes are approximately Gaussian we derive a system ofordinary differential equations for the total amount, the centroidand the variance of each reactant. We compare the solution ofthese equations with full numerical simulation of the reaction.Excellent agreement is obtained, with solution of the near-Gaussianmodel requiring considerably less computational effort thanthe full simulations. Of key importance is the yield of thereaction, and we discuss this feature in particular.     

(p‐Nitro­benzoato)­tri­phenyl­tin at 298 K

The structure at 298 K described here, [Sn(C₆H₅)₃(C₇H₄NO₄)], completely confirms the results at 173 K obtained previously [Weng, Das & Robinson (1990), Malays. J. Sci. 12 , 57]. In both structures, weak interaction between Sn and the carbonyl O atom of the benzoate group provides a distorted trigonal‐pyramidal environment at the Sn atom derived from its pseudo‐tetrahedral primary coordination in both mol­ecules of the asymmetric unit.