Volume 228, Issue 11

Interaction of dicopper(I)-decaborate Cu 2 B 10 H 10 with tetraphenylphosphonium decaborate ((C 6 H 5 ) 4 P) 2 (B 10 H 10 ) afforded the title compound, Ph 4 P[Cu(B 10 H 10 )]. The compound has been characterized using elemental analysis, FTIR spectroscopy and X-ray crystallography. The asymmetric unit contains one-fourth of a CuI cation, one-fourth of a tetraphenylphosphonium cation and one-fourth of a decaborate dianion. The copper and phosphorus atoms are located on a four-fold rotation and a four-fold rotation-inversion axes, respectively. The dianion is disordered over four sites by a four-fold rotation axis and a glide plane. Decahydro-closo-decaborate dianion B 10 H 10 2- acts as a bridge ligand through equatorial vertices. Each Cu I centre coordinates two decaborate anions through 3c2e (CuHB) bonds to give a one-dimensional {[CuB 10 H 10 ] - }n chain. Although a number of compounds with the {Cat[CuB 10 H 10 ]} n composition (where Cat is any cation) and chain {[CuB 10 H 10 ] - } n anions are known, this coordination mode for borates has not been observed earlier. The ability of the decaborate dianion to act as a bridge ligand through various vertices and edges allows {[CuB 10 H 10 ] - } n anions to form a number of positional isomers. Relation between the coordination mode of closodecaborate, the nature of cation and spatial features of polymer chain {[CuB 10 H 10 ] - } n in the structures of {Cat[CuB 10 H 10 ]} n (where Cat = Cs + , Cu + , (CH 3 ) 2 NH 2 + , (C 2 H 5 ) 3 NH + or Ph 4 P + ) is discussed.

The oxidation state specific and universal sets of the bond valence parameters (r 0 ; b) have been determined for Mn +m -O (5 ≤ m ≤ 7) bonds. The oxidation state specific r0 and b values obtained for Mn +m -O (5 ≤ m ≤ 7) bonds by using the standard calculation scheme are b = 0.37 Å (constant) and r 0 = 1.780 Å , 1.804 Å and 1.818 Å for m = 5, 6 and 7, respectively. The universal bond valence parameters obtained for the above bonds in two different calculation schemes are r0 = 1.757 Å and b = 0.26 Å .

High quality nonstochiometric Tb- and Gdbased single crystals Tb 0.81 Ca 0.19 F 2.81 (TCF), Tb 0.76 Sr 0.24 F 2.76 (TSF), Gd 0.85 Ca 0.15 F 2.85 (GCF), Gd 0.83 Sr 0.17 F 2.83 (GSF) are analyzed in crystallographic detail by single-crystal X-ray diffraction measurements. TSF shows only main reflections, and its structure is refined to a disordered P6 3 /mmc structural model. Additional satellite reflections observed in GSF lead to an ordered twinned P3̅ c1 structural model. The other two crystals TCF and GCF cannot be assigned uniquely to any of these space groups. Instead, their structures are interpreted as the coexistence of both space groups in separate domains.

The crystal structure of 3-benzyloxybenzyldehyde (2) has been determined from laboratory X-ray powder diffraction data. The DFT optimized molecular geometry in 2 agrees closely with that obtained from the X-ray study. The crystal packing in 2 has been compared with that of 2-benzyloxybenzaldehyde (1) and 4-benzyloxybenzaldehyde (3), and the role of weak intermolecular interactions in building supramolecular assembly in solid state has been analyzed. The Hirshfeld surface analysis of 1-3 and a few related benzyloxybenzyldehydes retrieved from the Cambridge Structural Database indicates that the H . . . H, C . . . H and O . . . H contacts can account for about 95% of the Hirshfeld surface area in this class of compounds.

Using simple methods of synthesis without template agents, 6 new compounds of strontium and dicarboxylic acids have been obtained. The resulting salts are: {1} strontium glutarate pentahydrate, {2} strontium adipate, {3} strontium pimelate monohydrate, {4} strontium suberate, {5} strontium azelate and {6} strontium dodecanedioate hemihydrate. Similarly to the known barium compounds, starting from the salt of azelaic acid, strontium compounds with longer dicarboxylic acids form acidic salts. Metal centers have the coordination number C.N. = 8, and the coordination polyhedra are dodecahedra. Glutaric acid form layered material, whereas with use of longer acids 3D systems are formed. Acids such as dodecanedioic and azealic form systems in which Sr-O polyhedra do not share edges or vertices. Isolated SrO 8 polyhedra are joined by carboxylic groups of dicarboxylic acids. Strontium salts {2, 4, 5} are anhydrous, but {1} is pentahydrate, {3} is monohydrate, and {6} is hemihydrate. During thermal decomposition strontium salts of dicarboxylic acids decompose through an unknown intermediate product to strontium carbonate.

A 1 : 1 : 1 co-crystal solvate formed between 1,8-dihydroxy-2,4,5,7-tetranitro-9,10-anthraquinone, dibenzothiophene and toluene (1), and a 1 : 1 co-crystal formed between 1,8-dihydroxy-2,4,5,7-tetranitro-9,10-anthraquinone and 4,6-dimethyldibenzothiophene (2) have been fully characterised. The molecular structures of the new and known coformer 1,8-dihydroxy-2,4,5,7-tetranitro-9,10- anthraquinone exhibit similar global features but differences in the orientations of the nitro substituents are evident. Also, in 1, the central ring of 1,8-dihydroxy-2,4,5,7- tetranitro-9,10-anthraquinone adopts a flattened half-chair conformation. Each of the remaining coformers are planar consistent with literature precedents. A common feature of the supramolecular aggregation in the crystal structures is the formation of stacks comprising alternating 1,8-dihydroxy- 2,4,5,7-tetranitro-9,10-anthraquinone and dibenzothiophene (or 4,6-dimethyldibenzothiophene in 2) molecules connected by π-π interactions. In 1, the central ring of 1,8-dihydroxy-2,4,5,7-tetranitro-9,10-anthraquinone does not form π-π interactions but in 2, it does, reflecting the different conformations of these rings. The new results are consistent with literature precedents of related p-rich dibenzothiophene co-crystals and suggest that the robust π-π synthons formed between these π-rich and π-deficient molecules may prove to be a useful strategy in deep desulfurization applications.