Emerging supramolecular synthons: C-H···π(chelate) interactions in metal bis(1,1-dithiolates)

Crystal structures of transition and main group element 1,1-dithiolates are shown to be partially sustained by C-H···π(chelate) interactions. For the planar binary bisdithiocarbamates, C-H···π(MS(2)C) interactions lead to aggregation patterns ranging from a 0-D four molecule aggregate to a 3-D architecture but with the majority of structures featuring 1-D or 2-D supramolecular assemblies.     

Synthesis of 4-aryl(hetaryl)pyrazolo[1,5-a]pyrazines by palladium-catalyzed Suzuki–Miyaura cross coupling

Chemistry of Heterocyclic Compounds - 4-Bromopyrazolo[1,5-a]pyrazines react with aryl(hetaryl)boronic acids in the presence of catalytic amounts of Pd(dppf)Cl2·CH2Cl2 and an excess of Cs2CO3...     

Dampened circumrotation by CH···π interactions in hydrogen bonded [2]rotaxanes

Establishment of CH···π interactions between the aliphatic axis and the benzylic amide macrocycle of hydrogen-bonded [2]rotaxanes causes a measurable interference in the pirouetting submolecular motion of these interlocked molecules.     

The nature of the [TTF]˙+···[TTF]˙+ interactions in the [TTF]2(2+) dimers embedded in charged [3]catenanes: room-temperature multicenter long bonds

The properties of tetrathiafulvalene dimers ([TTF](2)(2+)) and the functionalized ring-shaped bispropargyl (BPP)-functionalized TTF dimers, [BPP-TTF](2)(2+), found at room temperature in charged [3]catenanes, were evaluated by M06L calculations. The results showed that their isolated [TTF](2)(2+) and [BPP-TTF](2)(2+) dimers are energetically unstable towards dissociation. When enclosed in the 4(+)-charged central cyclophane ring of charged [3]catenanes (CBPQT(4+)), [TTF](2)(2+) and [BPP-TTF](2)(2+) dimers are also energetically unstable with respect to leaving the CBPQT(4+) ring; since the barrier for the exiting process is only about 3 kcal mol(-1), that is, within the reach of thermal energies at room temperature (neutral [TTF](2)(0) dimers are stable within the CBPQT(4+) ring). However, the [BPP-TTF](2)(2+) dimers in charged [3]catenanes cannot exit, because this would imply breaking the covalent bonds of the BPP-TTF(+) macrocycle. Finally, it was shown that the [TTF](2)(2+), [BPP-TTF](2)(2+) dimers, and charged [3]catenanes are energetically stable in solution and in crystals of their salts, in the first case due to the interactions with the solvent, and in the second case mostly due to cation-anion interactions. In these environmental conditions at room temperature the TTF units of the [BPP-TTF](2)(2+) dimers make short contacts, thus allowing their SOMO orbitals to overlap: a room-temperature multicenter long bond is formed, similar to those previously found in other [TTF](2)(2+) salts and their solutions.     

C-H···π interactions in the CHBrF2···HCCH weakly bound dimer

The microwave spectra of four isotopologues of the CHBrF(2)···HCCH weakly bound dimer have been measured in the 6-18 GHz region using chirped-pulse and Balle-Flygare Fourier-transform microwave spectroscopy. Spectra of (13)CH(79)BrF(2) and (13)CH(81)BrF(2) monomers have also been measured, and spectroscopic constants are reported. Measurement of spectra for the (79)Br and (81)Br isotopologues of CHBrF(2) complexed with both (12)C(2)H(2) and (13)C(2)H(2) have allowed the determination of a structure with C(s) symmetry for this complex. CHBrF(2) interacts with the triple bond of acetylene via a C-H···π contact (R(H···π) = 2.670(8) ?) with the Br atom lying in the ab plane, located 3.293(40) ? from a hydrogen atom of the HCCH molecule. The structure of CHBrF(2)···HCCH has been compared with recently studied related acetylene complexes, including a comparison with (and further structural analysis of) the CHClF(2)···HCCH complex.     

Strong phenyl-perfluorophenyl π-π stacking and C-H?F-C hydrogen bonding interactions in the crystals of the corresponding aromatic aldimines

The X-ray diffraction analysis of two co-crystals, 1·2 (aldimines 1 and 2) and 3·4 (aldimines 3 and 4), reveals that there are strong phenyl-perfluorophenyl π-π stacking and intermolecular hydrogen bonding interactions. The new perfluoroaryl-aryl face-to-face interaction of the crystalline aldimines provides a design motif for a new class of self-assembling system.     

Highly selective ion probe for Al3+ based on Au(I)···Au(I) interactions in a bis-alkynyl calix[4]arene Au(I) isocyanide scaffold

A bis-alkynyl calix[4]arene Au(I) isocyanide complex has been synthesized and demonstrated to be a selective ion probe for Al(3+) based on Au(I)Au(I) interactions.     

The C-Cl···π interactions inside supramolecular nanotubes of hexaethynylhexamethoxy[6]pericyclyne

Model complexes of hexaethynylhexamethoxy[6]pericyclyne (HM6P) molecules, with or without dichloromethane (DCM) guests, have been calculated at the M05-2X/6-311G(d,p) DFT level. Analysis of nonbonding interactions shows that the cohesion of the supramolecular tubular assemblies previously observed in the crystal state, relies mainly on C-H···O hydrogen bonds between axial ethynyl and equatorial methoxy substituents of stacked HM6P C(18) macrocycles in a cyclohexane-like chair conformation. The intrinsic binding energy of one HM6P molecule with two neighbors is calculated to be more than 40 kcal mol(-1). The inner channel of the stacks (of ca. 8 ? diameter) are suitable for hosting DCM molecules. Using the Atoms In Molecules (AIM) theory, the interaction between DCM molecules and surrounding triple bonds is analyzed in terms of σ-hole-directed C-Cl···π halogen bonds. A σ-hole-directed Cl···Cl interaction between two chlorine atoms of different DCM molecules is also evidenced.     

[Cu(phen)2·Cl]·Bsesa的晶体结构

对苯磺酰牛磺酸阴离子一维链构筑的三维配位聚合物[Cu(phen)2·Cl]·Bsesa(phen=o-phenanth-roline,BsesaH=2-Benzenesulfonylamino-ethanesulfonicacid)进行了元素分析、红外光谱、X射线衍射等表征。分析结果表明此配合物属单斜晶系,空间群为P21/c,晶胞参数为:a=0.9719(2)nm,b=2.5521(5)nm,c=1.2505(2)nm,β=93.407(5)°,V=3.096(1)nm3,Z=4,Dc=1.553g/cm3,μ=0.978mm-1,F(000)=1484。配合物中的金属铜离子与2个邻菲咯啉配位,还与一个Cl阴离子配位。苯磺酰牛磺酸阴离子通过N-H…O氢键形成一维螺旋链,配阳离子通过π-π堆积作用形成一维链,邻近的一维链再通过π-π堆积作用形成二维网,在二维网之间平衡插入由苯磺酰牛磺酸阴离子构筑一维螺旋链,邻近的螺旋链之间的距离为0.972(1)nm,螺旋链与二维网之间通过弱而丰富的C-H…O氢键形成三维网结构。     

Excitonic coupling interactions in the self-assembly of perylene-bridged bis(β-cyclodextrin)s and porphyrin

A supramolecular self-assembly has been constructed by perylene-bridged bis(β-cyclodextrin)s with water-soluble porphyrin through hydrophobic interactions, showing strong excitonic coupling interactions between perylene backbones and included porphyrins.     

Energetically important C-H···F-C pseudohydrogen bonding in water: evidence and application to rational design of oligonucleotides with high binding affinity

It is controversial whether organic fluorine can form energetically important hydrogen bonds in aqueous environments. We previously showed by NMR and molecular modeling that the unexpectedly high binding affinity of 2'F-ANA is largely due to a C-H···F-C pseudohydrogen bond at pyrimidine-purine steps. Comparisons of the melting of duplexes with identical sequence composition but a rearranged sequence confirm that energetically important fluorine-mediated pseudohydrogen bonding is in operation in these sequences. The effect is of particular importance when the H-bond donor (purine H8) is activated by the presence of fluorine at its own 2'-position. These results provide a rational method to increase the binding affinity of antisense oligonucleotides by placement of 2'F-ANA modifications at pyrimidine-purine steps.     

[Ni(cien)2]2[Mn(NCS)6]·H2O的合成、晶体结构

硫氰酸根的结构为N三C-S-,其两端的N原子和S原子分别有一对和三对孤对电子,因此,硫氰酸根可采用多种不同的配位模式与金属离子发生配位.硫氰酸根可作为单齿配体与一个金属离子配位,形成M-SCN或M-NCS的单核配合物,也可以作为桥联配体同时与两个、三个甚至四个金属离子配位形成多核配合物[1-3];另一方面,硫氰酸根是一个具有一定共轭性的偶极子,可传递磁相作用.因此,选择硫氰酸根作为桥联配体,将多个顺磁金属离子桥联形成一维、二维或三维结构的多核金属配合物分子,并研究它们的磁性已成为分子磁学的一个研究领域[4-6].本文仅报道标题配合物的合成与晶体结构.     

Novel C-H···C contacts involving 3,5-dimethylpyrazole ligands in a tetracoordinate Co(II) complex

A violet-blue cobalt(II) complex [Co(4-nbz)(2)(DMP)(2)] (1), where 4-nbz = 4-nitrobenzoate and DMP = 3,5-dimethylpyrazole, has been prepared at room temperature. Crystallographic studies on 1·0.5H(2)O reveal that the molecules of 1 are linked by a variety of non-covalent bonds including a novel type of C-H···C contact forming, with assistance from N-H···O, C-H···O and C-H···π interactions, an intricate 3-D supramolecular network. Theoretical calculations suggest that the observed C-H···C interactions are energetically quite significant.     

Characterization of C-H...π interactions in the structure of the CHClF(2)-HCCH weakly bound complex

The microwave spectra of four isotopologues of the CHClF(2)-HCCH dimer have been measured and used to determine the structure of the complex. An initial scan over the 7-18 GHz region using the chirped-pulse microwave spectrometer at the University of Virginia provided initial assignments of the (35)Cl and (37)Cl isotopologues, with two additional H(13)C(13)CH species assigned using the resonant cavity Balle-Flygare microwave spectrometer at Eastern Illinois University. For the most abundant isotopologue, the rotational constants and quadrupole coupling constants are: A = 3301.21(4) MHz, B = 1353.4268(19) MHz, C = 1153.7351(18) MHz, χ(aa) = 34.681(12) MHz, χ(bb) = -69.70(3) MHz, χ(cc) = 35.02(2) MHz and χ(ab) = -8.8(3) MHz, in good agreement with ab initio calculations at the MP2/6-311++G(2d,2p) level. The alignment of CHClF(2) with respect to acetylene reveals a C-Hπ interaction, with a secondary C-ClH-C interaction also present between the two monomers. The fitted distance between the CHClF(2) hydrogen atom and the center of the triple bond is 2.730(6) ?, the distance between the chlorine atom and the acetylenic hydrogen is 3.061(38) ?, and the C-Hπ angle is 148.2(6)°. In addition, the centrifugal distortion constants give an estimate of the binding energy for the weak interaction of about 4.9(5) kJ mol(-1), in reasonable agreement with several similar complexes.     

CRYSTAL STRUCTURE OF LANTHANUM (Ⅲ) COMPLEX WITH CRYPTAND [2,2,1]:H_2[2,2,1]·[La(NO)_3)_2·[2,2,1]]·La-(NO_3)_6·CH_3CN

<正> C34H69La2N13O34(Mr= 1418. 9) belongs to orthorhombic system, space group Pcab with a = 15. 513(3), b = 19. 463(5), c=38. 014(5)(?); Z = 8; V = 11477(4)(?)3; F(000) = 6000; μ=16.1cm-1(MoKa). The final R and Rw are 0. 045 and 0. 045, respectively. The molecule is Composed of one H2[2,2,1]2+, one [La(NO3)2[2,2, 1]]+, one La(NO3)63- and one solvent molecule CH3CN. The La3+ in [La-(NO3)2· [2,2,1]]+ is 11-coordinated by four oxygen atoms from two bidentate NO3- and seven heteroatoms from a [2,2,1] molecule; the La3+ ion in La (NO3)63- is coordinated to six bidentate NO3-. The La - O distances fall in the range of 2. 60-2. 70(?) and the La-N(cryp) mean distance is 2. 88(?).     

COMPLEX SALTS [Pd(NH3)4][Pd(NH3)3NO2] [CrOx3]·H2O AND [Pd(NH3)4][Pd(NH3)3NO2] [CoOx3]·H2O AND SOLID SOLUTIONS [Pd(NH3)4] [Pd(NH3)3NO2][CoOx3]x[RhOx3]1–x·H2O : PROMISING PRECURSORS FOR POROUS NANOALLOYS

Journal of Structural Chemistry - New complex salts [Pd(NH3)4][Pd(NH3)3NO2][CrOx3]·H2O I, [Pd(NH3)4][Pd(NH3)3NO2][CoOx3]·H2O II, and a series of solid solutions...     

Specific nonbonding interactions in the structure of (N2H5)2[Mo3S7I6]·1.5H2O

The crystal structure of (N₂H₅)₂[Mo₃S₇I₆]· 1.5H₂O is investigated;triclinic crystals, a-10.029(2), b = 10.258(3), c =14.152(2) å, a =109.21(2), Β =106.14(1), γ =98.97(2)?, V _cell =1270.6(5) å ³, space group P1, Z =2, d _calc =3.572 g/cm ³, CAD-4 diffractometer, λMoK_α, 2θ_max =50?, N _tot =4118, R(F) = 0.0554, wR(F²) = 0.1365 for 3057 F_hkl 4Σ(F). The cluster onions are united into centrosymmetric dimers with distances 3S_ax...I 3.324(5)-3.473(4) å. The dimers, in turn, form a three-dimensional framework with cations and solvate water molecules in the cavities due to additional contacts S_eq...I and S_ax...I 3.624(4)-3.785(4) å. The hydrogen bonds formed in the structure are N(N₂H₅)...O(H₂O) and N(N₂H₅)...I 2.78(4)-2.96(8), 3.64(3)-3.75(3) å. The nonbonding interactions completely determine the crystal structure.     

Syntheses and Crystal Structures of Two Ion Pair Complexes, [Ru(bpy)3]2[Fe(CN)6]I · 7H2O and [Ru(bpy)3]- [Fe(CN)5NO]CH3OH · H2O

Two ion pair complexes, [Ru(bpy)₃]₂[Fe(CN)₆]I [sdot] 7H₃O (1) and [Ru(bpy)₃][Fe(CN)₅NO](CH₃OH) [sdot] H₂O (2) (bpy = 2,2-bipyridine) have been synthesized and structurally characterized. X-Ray crystallographic structures of 1 and 2 both show Fe(III) and Ru(II) in distorted octahedral environments. In both complexes, H-bonding interactions between an uncoordinated water molecule and the nitrogen atom of a cyano group exist.