Crystallographic identification of a novel 2,4,5-tri(N-methyl-4-pyridinium)-1,3-thiazole with a complex network of polyiodide/iodine counter ions and co-crystallized cyclododecasulfur (S12)

The crystals of an unprecedented 2,4,5-tri(N-methylpyridinium)-1,3-thiazole are monoclinic and belong to the space group P21/c as determined by single-crystal XRD. Crystal data for C21H21I13N4S5.98: monoclinic, a = 7.5627(5) Å, b = 30.6764(19) Å, c = 20.8848(15) Å, β = 91.632(6)°, V = 4843.2(6) Å3, Z = 4, T = 100.01(10) K, μ(Cu Kα) = 67.840 mm-1, Dcalc = 2.977 g/cm3, 17906 reflections measured (7.152° ≤ 2Θ ≤ 162.94°), 17906 unique (Rsigma = 0.0607) which were used in all calculations. The final R1 was 0.1366 (I > 2σ(I)) and wR2 was 0.3926 (all data). The crystal lattice contains 2,4,5-tri(N-methylpyridinium)-1,3-thiazole, molecular iodine and triiodide counterions which interact with one another to coordinatively form polyiodides, as well as a surprising co-crystallized neutral molecule of cyclododecasulfur (S12). Close monitoring of the synthetic procedure reveals chemical condensation and decomposition of the thioamide reagent to be the impetus for the formation of individual components of the crystal lattice. Analysis of the XRD, including a Hirshfeld surface analysis, shows that (a) the crystal lattice has a number of stabilizing Coulombic short contacts such as I∙∙∙I, I∙∙∙S, I∙∙∙C, and C∙∙∙S and non-classical C-H∙∙∙I and C-H∙∙∙S hydrogen bond interactions (b) the iodine/iodide network are major determinants in the stability of its crystal lattice despite the reduced occupancies of sulfur and (c) the Hirshfeld analysis in comparison with the conventional Mercury visualization program was able to simplify, identify and quantify complex atom-atom interactions such as H∙∙∙H and N∙∙∙I in its crystal lattice. Herein, it is reported, for the first time, the formation of co-crystallized, neutral cyclododecasulfur (S12) from thioamide as the sulfur source. S12 displays a consistent geometry and comparable average S-S distances, S-S-S angles and torsion angles with previously reported crystal structures of S12. The complex network facilitated by the formation of polyiodides via the interaction of symmetric and asymmetric triiodides and iodine has resulted in quite strong interactions that are less than the sums of the van der Waals radii of two connected atoms as well as an array of fascinating geometrical alignments such as T-shape, trigonal pyramidal and L-shape

Tricarbonyl[N,N′,N″-tris(2,6-diisopropylphenyl) guanidine]molybdenum(0)

Publisher's Version/PDFIn the title compound, [Mo(C37H53N3)(CO)3], the Mo atom to ring-centroid distance in the η6-coordinated tricarbonylmolybdenum group is 1.958 (1) Å. The three C≡O groups are pseudo-octahedrally disposed with C—Mo—C angles ranging from 80.7 (1) to 87.4 (1)°. The two uncoordinated 2,6- diisopropylphenyl-substituted benzene rings form dihedral angles of 75.96 (8) and 78.01 (9)° with the mean plane of the guanidine group. The coordinated benzene ring is in a slight sofa conformation with the N-substituted C atom and the bonded N atom dispaced by 0.090 (3) and 0.458 (4) Å, respectively, from the mean plane of the remaining ring atoms. In the crystal, despite there being two N—H donor groups, no conventional hydrogen bonds are present. This may be because of the steric effects of the bulky diisopropylphenyl groups

Bulky 2,6-disubstituted aryl siloxanes and a disilanamine

Open access article. Creative Commons license (CC BY) appliesThe crystal structures of 5-bromo-1,3-di-tert-butyl-2-[(tri­methyl­sil­yl)­oxy]benzene, C17H29BrOSi, (I), 1,3-di-tert-butyl-2-[(tri­methyl­sil­yl)­oxy]benzene, C17H30OSi, (II), and N-(2,6-diiso­propyl­phen­yl)-1,1,1-trimethyl-N-(tri­methyl­sil­yl)silanamine, C18H35NSi2, (III), are reported. Compound (I) crystallizes in space group P21/c with Z′ = 1, (II) in Pnma with Z′ = 0.5 and (III) in Cmcm with Z′ = 0.25. Consequently, the mol­ecules of (II) are constrained by m and those of (III) by m2m site symmetries. Despite this, both (I) and (II) are distorted towards mild boat conformations, as is typical of 2,6-di-tert-butyl-substituted phenyl compounds, reflecting the high local steric pressure of the flanking alkyl groups. Compound (III) by contrast is planar and symmetric, and this lack of distortion is compatible with the lower steric pressure of the flanking 2,6-diisopropyl substituents.Ye

The syntheses and structures of some main group complexes of the sterically hindered N,N'-bis(2,6-diisopropylphenyl)-4-toluamidinate ligand

The stoichiometric reaction of the bulky benzamidine N,N’-bis(2,6-diisopropylphenyl)-4-toluamidine (HDippAm) with the metal alkyls BunLi (1 : 1 in THF), Bu₂Mg (2 : 1 in THF) and Me₂Al (1 : 1 in Et₂O) is presented. This provides the mononuclear dihapto benzamidinate compounds [Li(DippAm)(THF)2] (1), [Mg(DippAm)₂] (2) and [Al(DippAm)Me₂] (3), respectively. Compound 3 was also obtained by salt elimination using dimethylaluminium chloride and 1. All three compounds exhibit sterically strained geometries that are maintained in solution at increased temperatures. Compound 3 displays exceptional thermal and aerobic stability, while 2 constitutes a rare example of non-porphyrin supported square planar magnesium.René T. Boeré, Marcus L. Cole and Peter C. Jun

An N,P-disubstituted-2-aminophosphaalkene and lithium and potassium complexes of the deprotonated "phosphaamidinate" anion

The reaction of DippPH2 (Dipp = 2,6-iPr2C6H3) with DippNC(p-CH3C6H4)Cl in refluxing xylenes affords DippPC(p-CH3C6H4)N(H)Dipp; deprotonation with alkali metal reagents produces unique lithium and potassium complexes with the ligand in a different geometry to that of the free phosphaamidine.René T. Boeré, Marcus L. Cole, Peter C. Junk, Jason D. Masuda and Gotthelf Wolmershäuse

A rigid anionic Janus bis(NHC) - new opportunities in NHC chemistry

Open access article. Creative Commons Attribution 3.0 Unported License (CC BY 3.0) appliesA phosphanido-type bridged bis(imidazolium) salt, readily prepared in two steps via reductive deselenization of a tricyclic 1,4-diphosphinine diselone, affords access to a novel anionic P-functional tricyclic bis(NHC) via deprotonation. The former also offers a P-functionalization/deprotonation sequence to access the first mixed P-substituted tricyclic bis(NHCs), as well as coordination of the phosphorus centers to rhodium(I) fragments.Ye

Janus bis(NHCs) tuned by heteroatom-bridge oxidation states

Open access article. Creative Commons Attribution 3.0 Unported License (CC BY 3.0) appliesSynthesis of the first tricyclic bis(carbenes) with facially opposed imidazole-2-ylidenes and two linking phosphorus centres in different oxidation states is presented using a modular, high-yield synthetic route. The formation of homo bimetallic coinage metal complexes provides a glimpse on their potential use.Ye

The first unpaired electron placed inside a C-3-symmetry P-chirogenic cluster

The Pd-3(dppm*)(3)(CO)(n+) enantiomers (n = 2 (2), 1 (3)) were prepared either from (R, R)-or (S, S)-P-chirogenic bis(phenyl-m-xylylphosphino) methane (dppm*; 1) and Pd(OAc) 2 in the presence of CF3CO2H, CO and water (n = 2), and then by reductive electrolysis (n = 1). The stable enantiomeric [Pd-3((S,S)-dppm*)(3)(CO)](+center dot) (3), is the first C-3-symmetry radical-cation M-M bonded cluster, therefore the odd electron is delocalized onto the Pd-3 frame within this symmetry. The novel chiral species have been characterized by circular dichroism (CD) of both enantiomers of the Pd-3(dppm*)(3)(CO)(2+) clusters (2) and by EPR spectroscopy for the Pd-3((S, S)-dppm*)(3)(CO)(+center dot) paramagnetic compounds (3, g = 2.041). Evidence for reduced symmetry with respect to the achiral cluster was also obvious from the hyperfine splittings of the EPR signal which display three different hyperfine coupling values: 3 A(31P) = 83.9 10(-4) cm(-1), 3 X A(P-31) = 69.7 10(-4) cm(-1), 3 A(Pd-105) = 12.5 10(-4) cm(-1). In the absence of an X-ray structure for the paramagnetic clusters, DFT computations were performed to address the geometry. The optimized geometry of the Pd-3((S, S)-dppm*)(3)(CO)(+center dot) radicals (3) exhibits three phosphorus atoms placed well above the Pd-3 plane, while the three others are located below the trimetallic frame within C-3-symmetry due to intramolecular steric hindrance. This makes them chemically different with respect to the carbonyl group and explains the experimental EPR spectrum well. Consequently this C-3-symmetry deformation also induces a change in the shape of the SOMO (semi-occupied molecular orbital) towards this same symmetry compared to the corresponding achiral C-3v species

Symmetric heteropolynuclear Ti(IV)/Cu(I) complexes exhibiting stepwise electrochemical reductions to Ti(III) species

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