Metal π-complexes of cyclooctatetraenes. V. Synthesis and x-ray analysis of tetrameric dibenzo[a,e]cyclooctatetraenecopper(1) chloride, a new "step" configuration for the Cu 4Cl 4 ring

Tetrameric dibenzo[a,e]cyclooctatetraenecopper(I), 3 3 IUPAC name: cyclotetra-μ-chlorotetrakis[9-10:11-12-η-dibenzo[a,e]cyclooctenecopper(I)] [2]. [(C 16H 12)CuCl] 4, 1, has been synthesized and characterized by X-ray crystallography. Complex 1 crystallizes in space group P1 with a 9.287(7), b 10.818(7), c 13.234(5) Å, α 91.34(4), β 103.44(4), γ 95.20(5)°, V 1287(1) Å 3, and Z = 1. The structure has been refined to R F= 0.063 and R wF= 0.078 for 3286 observed Mo-K α data and 325 variables. The cyclic molecule, which has crystallographically imposed 1 symmetry, consists of an eight-membered ring of alternating Cu and Cl atoms in a "step" (or "chair") configuration, with an organic ligand π-bonded to each metal center via a pair of olefinic double bonds. The two symmetry-independent copper(I) atoms are in distorted trigonal pyramidal coordination, each being bound asymmetrically to chloride and olefin ligands at distances in the ranges 2.263(2)-2.278(2) and 2.099(5)-2.801(6) Å, respectively. © 1983.link_to_subscribed_fulltex

Synthesis and optical properties of poly(thienylacetylenes)

3-Ethynyl-4-(trimethylsilyl)thiophene (1a) and 3-ethynyl-4-bromothiophene (1b) selectively undergo acetylene polymerizations in the presence of the MoCl5- and WCl6-Ph3SiH catalysts to give soluble, high-molecular-weight poly(thienylacetylenes) (2) (M-w up to 602000) in high yields (up to 100\%). Light transmission spectra of THF solutions of 2 continuously red-shift with increasing concentration. The concentratochromism shows a logarithmic concentration dependence; that is, the optical transitions of 2 are predictably tunable by simply changing their concentrations

Synthesis and photophysical studies of chiral helical macrocyclic scaffolds via coordination-driven self-assembly of 1,8,9,16-tetraethynyltetraphenylene. Formation of monometallic platinum(II) and dimetallic platinum(II)-ruthenium(II) complexes

This paper is concerned with the synthesis and reactions of enantiopure 1,8,9,16-tetraethynyltetraphenylene (3). We obtained 3 in 34% yield through four steps starting from 1,8,9,16-tetrahydroxytetraphenylene (2a) via a functional group interconversion strategy. On the basis of this chiral "helical" building block, three rigid helical macrocycles 14, 15, and 22 were designed. Complexes 14 and 15 were constructed via coordination-driven self-assembly with platinum(II) complexes 8 and 9b, while 22 cannot be obtained successfully. Then macrocycle 28 was designed on the structural basis of 22 to which octyl chains were introduced, in the hope of improving the solubility of the complex. Macrocycle 28 was finally formed and was characterized by NMR spectroscopy, elemental analysis, and electrospray mass spectrometry. For the enantiopure 15 and 28, circular dichroism (CD) spectra also exhibited chiral properties. Complexes 27 and 28 both exhibited an intense emission band at 621 nm in acetonitrile at 298 K upon excitation at λ > 420 nm. © 2010 American Chemical Society.link_to_subscribed_fulltex

Thermotropic liquid crystals based on 1,8,9,16-tetrasubstituted tetraphenylenes and their structure-property relationship studies

Twelve 1,8,9,16-tetraalkoxytetraphenylenes were synthesized and characterized, five of which exhibiting thermotropic liquid crystal properties were examined by differential scanning calorimetry (DSC), polarizing-light optical microscopy (POM) and variable-temperature X-ray diffractometry (VTXRD). The structure-property relationship of each mesomorphic solid is discussed in the context of the racemic/non-racemic nature of the sample, different chain length of n-alkyl substituents, effect of chain lipophilicity and intermolecular interactions. © The Royal Society of Chemistry 2011.link_to_subscribed_fulltex