De-Liang Long

Non-linear optical absorption of [{Ni(mnt)2}2]2− and its unique counter ion, a disodium triple-decker dication [Na2(benzo-15-crown-5)3(H2O)2]2+

Abstract Reaction of NiCl 2 ·6H 2 O and Na 2 [mnt] (mnt=maleonitriledithiolate) in CH 3 OH at room temperature leads to Ni(II) dithiolato complex [Ni(mnt) 2 ] 2− . An oxidation process of [Ni(mnt) 2 ] 2− affords [{Ni(mnt) 2 } 2 ] 2− and yields solid crystalline product [Na 2 (benzo-15-crown-5) 3 (H 2 O) 2 ][{Ni(mnt) 2 } 2 ] ( 1 ) in the presence of benzo-15-crown-5. X-ray diffraction analyses revealed that in solid state the dianions of 1 pack as columns and the counter ions are discrete disodium triple-decker dications. A non-linear absorption coefficient β of 2.4 cm GW −1 was recorded at 1064 nm for 1 in acetonitrile solution with a concentration of 1.0×10 −4 mol l −1 .

SYNTHESES, CRYSTAL STRUCTURES AND ELECTRONIC SPECTRA OF MIXED-LIGAND ZINC(II) COMPLEXES WITH DIIMINES AND DITHIOLATES

Abstract Three zinc(II) complexes, [Zn(bipy)(dmit)]2 (1), [Zn(phen)(dmit)]2 (2) and Zn(py)(mnt) (3), where bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline, py = pyridine, H2dmit = 4,5-dimer-capto-1,3-dithiol-2-thione, mnt = maleonitriledithiolate, have been synthesized and their crystal structures determined. Complex 1 is monoclinic, space group P21/c, with a = 11.570(3), b = 9.137(3), c = 15.051(6)Å, β = 109.56(2)°, Z = 2 and was refined to R 1 = 0.039. Complex 2 is monoclinic, space group P21/n, with a = 9.363(2), b = 13.732(3), c = 12.767(3), β = 94.06(3)°, Z = 2 and was refined to R 1 = 0.038. Complex 3 is orthorhombic, space group P212121, with a = 8.621(3), b = 10.546(4), c = 16.848(2), Z = 4 and was refined to R 1 = 0.040. IR and electronic absorption spectra were investigated.

Preparation, structure and preliminary magnetic studies of tri- and tetra-nuclear cobalt–lanthanide carboxylate complexes

Carboxylate-bridged cobalt–lanthanide complexes [Co2Nd(O2CCMe3)6(C9H7N)2(NO3)] and [Co2Er2(O2CCMe3)8(C9H7N)2(NO3)2] have been prepared and structurally characterised by X-ray diffraction; both of them are found to be antiferromagnetically coupled.

CRYSTAL STRUCTURE AND PROPERTIES OF A COPPER(II) COMPLEX OF AN 18-MEMBERED MACROCYCLIC LIGAND WITH N,N' -DICARBOXYLIC ACID ARMS

Abstract CuL 5H2O (H2L = 1, 15-diaza-3, 4; 12, 13-dibenzo-5, 8, 11 -trioxacyclo-octadecane-N,N′-diacetic acid) crystallized from water. Its crystal structure was determined by X-ray diffraction analysis and refined in space group Pnma, a = 20.1784(11), b = 15.8745(9), c = 8.9266(5)A, V = 2859.4(3)A3, Z = 4, ⋋(MOKα) = 0.71073, RW . = 0.0294 for 1822 observed reflection [I > 2[sgrave](I)]. The copper atom is surrounded by two nitrogen atoms, two oxygen atoms from the carboxyl groups in the ligand and one oxygen atom from a coordinated water to form a distorted square pyramidal arrangement. The three ether oxygen atoms in the cycle have no contact with the copper ion. The stability constant for the 1 :1 complex of copper(II) and protonation constants for the ligand have been determined by potentiometric titration in water (I = 0.1, KNO3) at 25°C. Electronic spectra, conductivity measurements, thermal analysis, and the EPR of the complex are discussed in terms of the crystal structure.

Synthesis, crystal structure and non-linear optical properties of two new cluster compounds, [MoCu3OS3(PPh3)3{S2P(OBu)2}] and [MoAg3S4(PPh3)3{S2P(OBui)2}]

Two novel O,O′-dialkyl dithiophosphate-containing Group 11–Group 16 sulfido clusters, [MoCu3OS3(PPh3)3{S2P(OBu)2}]1 and [MoAg3S4(PPh3)3{S2P(OBui)2}]2, have been synthesised through reactions of [NEt4]2[MoOS3] with Cu[S2P(OBu)2] and [NEt4]2[MoS4] with Ag[S2P(OBui)2] respectively in dichloromethane and in the presence of PPh3. The clusters crystallise in orthorhombic and triclinic forms respectively. The X-ray crystallographic structure determinations show that both clusters have a partial open cubane-like structure. The dithiophosphate ligands adopt a triply bridging role, employing two sulfur atoms to co-ordinate to the three Group 11 metal (M) atoms: one sulfur atom binds to one M atom, the other to two other M atoms. The clusters are soluble in common organic solvents and exhibit both non-linear absorption and non-linear refraction (self defocusing). Cluster 2 also exhibits a sizeable optical limiting effect.