4-Phenyl-diazenyl-2-[(R)-(1-phenyl-ethyl)imino-meth-yl]phenol.

The title chiral photochromic Schiff base compound, C(21)H(19)N(3)O, was synthesized from (R)-1-phenyl-ethyl-amine and the salicylaldehyde of an azobenzene derivative. The mol-ecule corresponds to the phenol-imine tautomer, the C=N and N-C bond distances being 1.279 (3) and 1.477 (3) Å, respectively. An intra-molecular O-H⋯N hydrogen bond occurs. The diazenyl group adopts a trans form with an N=N distance of 1.243 (3) Å.

A chiral photochromic Schiff base: (R)-4-meth-oxy-2-[(1-phenyl-ethyl)imino-meth-yl]phenol.

The title chiral photochromic Schiff base compound, C(16)H(17)NO(2), was synthesized from (R)-1-phenyl-ethyl-amine and 5-methoxy-salicylaldehyde. The mol-ecule of the title compound exists in the phenol-imine tautomeric form. The dihedral angle between the two aromatic rings is 62.61 (11)°. An intra-molecular O-H⋯N hydrogen bond with an O⋯N distance of 2.589 (2) Šis observed. The crystal packing is stabilized by C-H⋯π inter-actions involving the aromatic ring.

Diaqua-bis(2,4-dichloro-6-formyl-phenolato)zinc(II)-bis-(µ-2,4-dichloro-6-formyl-phenolato)bis-[aqua-(2,4-dichloro-6-formyl-phenolato)zinc(II)] (2/1).

The crystal of the title compound, [Zn(C(7)H(3)Cl(2)O(2))(2)(H(2)O)(2)](2)·[Zn(2)(C(7)H(3)Cl(2)O(2))(4)(H(2)O)(2)], consists of monomeric and dimeric Zn(II) complexes. Both complexes afford a six-coordinated coordination environment about the Zn atoms with cis-configuration ligands. The deprotonated hydr-oxy groups of the 3,5-dichloro-salicylaldehyde ligands bridge two metal cations, forming a centrosymmetric dimeric complex. Inter-molecular O-H⋯O hydrogen bonding occurs between the coordinated water mol-ecules and deprotonated hydr-oxy groups in the crystal structure.

Thiosemicarbazone derivatives of nickel and copper: the unprecedented coordination of furan ring in octahedral nickel(II) and of triphenylphosphine in three-coordinate copper(I) complexes.

The influence of substituents at the C(2) carbon of N(1)-substituted thiosemicarbazones, {C(4)H(3)X-C(2)(CH(3))=N(3)-N(2)H-C(1)(=S)N(1)HR(2)} (X = O, S) on the geometry of nickel(ii) complexes has been investigated. The presence of a methyl group at the C(2) position of 2-acetylfuran-N(1)-substituted thiosemicarbazones {(C(4)H(3)O)-C(2)(CH(3))=N(3)-N(2)H-C(1)(=S)N(1)HR(2), R(2) = CH(3), HaftscN-Me; C(2)H(5), HaftscN-Et; C(6)H(5), HaftscN-Ph} induces unusual coordination by the furan ring and yielded high spin octahedral nickel(II) complexes, [Ni(κ(3)-O, N(3), S-aftscN-R(2))(2)], CH(3)1, C(2)H(5)2, and 2[Ni((κ(3)-O, N(3), S-aftscN-Ph)(2)] 3 (µ(eff) = 2.98, 1; 2.96, 2; 2.92, 3). With 2-acetylthiophene-N(1)-substituted thiosemicarbazones, {(C(4)H(3)S)-C(2)(CH(3))=N(3)-N(2)H-C(1)(=S)N(1)HR(2), R(2) = CH(3), HattscN-Me; C(2)H(5), HattscN-Et; C(6)H(5), HattscN-Ph}, N(3), S chelated low spin trans square planar complexes, {[Ni(κ(3)-O, N(3), S-attscN-R(2))(2)], R(2) = CH(3), 4; C(2)H(5), 5; C(6)H(5), 6} with pendant thiophene rings have been obtained. The bigger sized sulfur atoms of the thiophene rings form short intramolecular contacts with the deprotonated hydrazinic nitrogen atoms (SN(2)) inhibiting its lability for possible coordination to nickel(II). Complexes have one independent molecule (1) or two independent molecules (2, 3) in their respective crystal lattices. The simultaneous presence of methyl groups at the C(2) and N(1) atoms of 2-acetylthiophene-N(1)-methylthiosemicarbazone (HattscN-Me) have facilitated the binding of triphenylphosphine in three-coordinate copper(i) halide complexes, [CuX(η(1)-S-HattscN-Me)(Ph(3)P)] (X, Br, 7; Cl, 8), which represent an unusual donor set of ligands, namely, triphenylphosphine, sulfur of a thio-ligand and a halide.