Zinc(II) and nickel(II) com­plexes of 3,5-di­methyl-1-(pyri­din-2-yl)-1H-pyrazole: relationship between fluorescence and crystal packing

The single-crystal structures of Zn^II and Ni^II com­plexes of 3,5-dimethyl-1-(pyri­din-2-yl)-1H-pyrazole are reported and their fluorescence properties are described.

Structural, spectroscopic and DFT theoretical studies of phospho­rescent CuIP₂S-containing cuprous com­plexes

In the two CuIP₂S-type cuprous com­plexes [CuI(TPP)₂(TU)] (I) and [CuI(TPP)₂(DHBIT)] (II), tri­phenyl­phosphane (TPP), thio­urea (TU) and 2,3-di­hydro­benzimidazole-2-thione (DHBIT) all exhibit a terminal coordination mode. TD-DFT calculations and wavefunction analysis demonstrate that the pale-blue–green phospho­rescence should be emitted from a metal-perturbed triplet TPP-centred (in I) or DHBIT-centred (in II) excited state.

Alkali metal salts of 4-hy­droxy­benzoic acid: a structural and educational study

Although 4-hy­droxy­benzoic acid (H₂hba) is a relatively simple organic mol­ecule, it displays remarkable coordinative flexibility in its reactions with alkali metal hydroxides, forming ionic networks containing the dianion (hba²⁻), the monoanion (Hhba⁻) or the neutral acid species (H₂hba). A common feature of the structures of the lattices is their layered arrangement: alternating hydro­philic layers made up of closely packed metal–oxygen polyhedra are separated by the hydro­phobic nonpolar com­ponents of the hy­droxy­benzoate linking units.

Crystal structure and optical properties of a two-sited Eu^III com­pound: an Eu^III ion coordinated by two [Eu^III(DOTA)]⁻ com­plexes (DOTA is 1,4,7,10-tetra­aza­cyclo­dodecane-1,4,7,10-tetra­acetate)

The crystal structure of a two-sited Eu^III com­pound solved from a nonmerohedral crystal is reported. The optical properties of the two different Eu^III centres were studied in three media.

Study of naphtho­pyran derivatives: structure and photochromic properties in solution and in polymer film

Single-crystal X-ray analysis of two naphtho­pyran derivatives revealed the structure–property relationships.

Mol­ecular structures of the penta­phenyl­cyclo­penta­dienyl iron com­plexes [(C₅Ph₅)Fe(CO)₂R] (R = Me, Ph, iPr and Bu)

The penta­phenyl­cyclo­penta­dienyl iron alkyl and aryl com­plexes [(C₅Ph₅)Fe(CO)₂R] (R = Me, Ph, iPr and Bu) were prepared and their crystal structures examined.

cis-Bis(L-DOPA-κ²N,O)copper(II) monohydrate: synthesis, crystal structure, and approaches to the analysis of pseudosymmetry

The cis isomer of bis­(L-DOPA-κ²N,O)copper(II) monohydrate, a singular example of a structurally characterized, homoleptic, crystalline metal L-DOPA complex, crystallizes in the space group P2₁, with Z′ = 2. The two independent mol­ecules are square planar and are inter­connected by an unusual linear hydrogen-bonded chain containing 12 independent hydrogen bonds. Pseudosymmetry along a 4₂ axis was analyzed using the MATCH procedure in the Crystals for Windows program.

Crystal structure and com­putational study of an oxo-bridged bis-titanium(III) com­plex

The structure of a new oxo-bridged bis-titanium(III) com­plex is described, along with com­putational modelling of its spin state.

Stabilization of an elusive tautomer by metal coordination

With reference to a [1,2,4]triazolo[3,2-c][1,2,4]triazole ligand, for which the 3H-tautomer has an energy only 1.4 kcal mol⁻¹ greater than the most stable 2H-tautomer, we show that metal com­plexation is a successful and reliable way for stabilizing the higher-energy elusive tautomer.

One- and two-dimensional Pb^II com­pounds resulting from reaction of PbBr₂ and Pb(SCN)₂ with pyrimidine-2-thione

The reaction products of pyrimidine-2-thione (HSpym) with Pb(SCN)₂ and PbBr₂ in N,N-di­methyl­formamide (DMF), with the formulae [Pb(Spym)(NCS)]_n, (I), {[Pb₂Br₃(Spym)(HSpym)]·DMF}_n, (IIa), and [Pb₂Br₃(Spym)(HSpym)]_n, (IIb), are two-, one- and three-dimensionally arranged in the solid state, respectively.

Synthesis, crystal structure determination, and spectroscopic analyses of 1-chloro-2-(2,6-diiso­propyl­phen­yl)-4,4-di­methyl-2-aza­spiro­[5.5]undecane-3,5-dione: an unyielding precursor to a cyclic (alk­yl)(amido)­carbene

The single-crystal X-ray structure of 1-chloro-2-(2,6-diiso­propyl­phen­yl)-4,4-dimethyl-2-aza­spiro­[5.5]undecane-3,5-dione, an unyielding precursor to a cyclic (alk­yl)(amido)­carbene, was compared to two structurally similar compounds that are known to undergo deprotonation to afford stable carbenes. Additionally, percent buried volume calculations were performed on the three compounds, which qu­anti­tatively revealed why deprotonation of the title dione did not occur.

Synthesis and characterization of the Anderson–Evans tungsto­anti­monate [Na₅(H₂O)₁₈{(HOCH₂)₂CHNH₃}₂][SbW₆O₂₄]

The isolation and characterization of the Anderson–Evans-type tungsto­anti­monate [Sb^VW^VI₆O₂₄]⁷⁻ with a T-shaped sodium–serinol com­plex, [Na₅(H₂O)₁₈{(HOCH₂)₂CHNH₃}₂]⁷⁺, as counter-cation is reported.

Structural investigations into a new polymorph of F₄TCNQ: towards enhanced semiconductor properties

A new polymorph of 2,3,5,6-tetra­fluoro-7,7,8,8-tetra­cyano­quinodi­methane (F₄TCNQ) has been characterized using single-crystal X-ray diffraction and is presented in com­parison with the previously reported structure of the com­pound.

Phase behaviour and crystal structures of 2′,3′-di­fluorinated p-terphenyl derivatives

A common feature of the conformation of three difluorine derivatives of p-terphenyls is the noncoplanar twisted arrangement of the three rings of the p-terphenyl moiety. Two-dimensional (2D) Hirshfeld fingerprint plots are consistent with H⋯H and C⋯H contacts in the crystal packing. The phase behaviour has been investigated by POM and DSC analysis. One of the com­pounds is mesogenic, with enanti­otropic nematic behaviour.