The crystal structures of the low-temperature (space group C2/c, Pearson symbol mS144, a = 7.1379(4) Å, b = 12.3823(7) Å, с = 27.3904(9) Å, β = 94.308º, R I = 0.0765) and high-temperature (space group Fm-3m, Pearson symbol cF12, a = 5.859(1) Å, R1 = 0.0391) modifications of Cu 2 Se were determined by means of X-ray powder and single crystal diffraction. The basic features of the two modifications are similar. The Se atoms are stacked in a close-packed arrangement with the layers in the sequence ABC. The Cu atoms are distributed over all tetrahedral interstices. The positions of Cu are completely ordered in the lowtemperature modification, whereas they are disordered in the high-temperature modification.

The [Ni(Im)(2)(L-tyr)(2)]·4H(2)O (1) complex was obtained in crystalline form as a product of interaction of L-tyrosine sodium salt, imidazole, and NiSO(4). The X-ray structure was determined, and the spectral (IR, FIR, NIR-vis-UV, HF EPR) and magnetic properties were studied. The Ni(2+) ion is hexacoordinated by the N and O atoms from two L-tyrosine molecules and by two N atoms of imidazole, resulting in a slightly distorted octahedral [NiN(2)N(2)'O(2)] geometry with a tetragonality parameter T = 0.995. The bands observed in the electronic spectra were ascribed to the six spin-allowed electronic transitions (3)B(1g) → (3)E(g) and (3)B(2g), (3)B(1g) → (3)A(2g) and (3)E(g), and (3)B(1g) → (3)A(2g) and (3)E(g). The spin Hamiltonian parameters g, D, and E, which were determined from high-field HF EPR spectra, excellently reproduced the magnetic properties of the complex. Calculation of the zero-field splitting in the S = 1 state of nickel(II) using DFT and UHF was attempted. The biological activity of the complexes has been tested for antifungal and antibacterial effects against Aspergillus flavus, Fusarium solani, Penicillium verrucosu, Bacillus subtilis, Serratia marcescens, Pseudomonas fluorescens, and Escherichia coli.

the occasion of approaching her 70th birthday and a 15 year fruitful collaboration. ‡ Electronic supplementary information (ESI) available: Listing of all 104 fragments and 54 structures with geometry data extracted from CSD. Table containing energy of dimer (AB) and each monomer (A, B), basis-set superposition error [a.u.] and interaction energy [kcal mol −1 ]. See

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Crystal structures of two polymorphs of [H2m4na]Cl (1α,1β) and (H2m4na) 2 SnCl 6 •H 2 O (2), where 2m4na = 2methyl-4-nitroaniline are shown and comparison of these crystal structures with the bromide salt reported earlier is presented. In all the presented crystal structures, alternatively arranged cations and anions form chain and ring hydrogen-bonding patterns of weak unconventional N−H•••Cl hydrogen bonds. Interrelations among the elementary graph-set descriptors and descriptors of the hydrogen-bonding patterns are presented. Nonhydrogen bonding interactions between the nitro groups are also described using graph-set descriptors. Comparison of the experimental, also for deuterated 1α polymorph, and theoretical, for H2m4na + ion with B3LYP/6-31G(d,p), spectra showed good agreement among the frequencies due to very weak interactions existing in studied compounds. Detailed analysis of the spectra revealed that the interaction between adjacent −NO 2 groups in 1α is stronger than the other types involving the nitro group. The bands were assigned on the basis of theoretical calculations of vibrational frequencies for H2m4na + ion and PED analysis.

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