Nien-Tsu Chuang

A New Type of Asymmetric Tridentate Pyrrolyl-Linked Pincer Ligand and Its Aluminum Dihydride Complexes

The new pyrrolyl-linked pincer-type ligand, [C(4)H(2)NH(2-CH(2)NH(t)Bu)(5-CH(2)NMe(2))] (1), that has been employed conveniently in high yield by treatment of (2-t-butylaminomethyl)pyrrole with 1 equiv of formaldehyde and dimethylamine hydrochloride each in diethylether and its corresponding aluminum derivative, [C(4)H(2)N(2-CH(2)NH(t)Bu)(5-CH(2)NMe(2))]AlH(2) (2), that has been generated from Me(3)N.AlH(3) using diethylether as a solvent are described. Furthermore, reactions of 2 with 2 equiv of either 1,3-diphenylpropane-1,3-dione in diethylether or phenyl thioisocyanate in dichloromethane interestingly formed [C(4)H(2)N(2-CH(2)NH(t)Bu)(5-CH(2)NMe(2))]Al(PhCOCHCOPh)(2) (3) and [C(4)H(2)N(2-CH(2)NH(t)Bu)(5-CH(2)NMe(2))]Al(SCHNPh)(2) (4), respectively, following deprotonation or hydroalumination reaction kinetics under a dry nitrogen environment. All of the compounds have been subjected to the X-ray diffraction technique in the solid state as well as characterized by NMR spectra.

Bis{N′-[1-(2-pyrid­yl)ethyl­idene-κN]benzohydrazidato-κ2N′,O}nickel(II)

In the title complex, [Ni(C14H12N3O)2], the NiII atom lies at the centre of a distorted octahedron formed by two tridentate hydrazone ligands. Intermolecular hydrogen bonds of the type C—H⋯X (X = N, O) link the complexes into a two-dimensional network.

{N'-[1-(2-Pyrid-yl)ethyl-idene-κN]benzo-hydrazidato-κN',O}{N'-[1-(2-pyrid-yl)ethyl-idene-κN]benzohydrazide-κN',O}copper(II) trichloro-acetate.

In the title complex, [Cu(C14H13N3O)(C14H12N3O)](CCl3COO), the central Cu(II) ion exhibits a distorted octahedral geometry with the two ligands coordinating in an meridional format. The N4O2 ligand environment is defined by two benzoyl O atoms, two pyridyl N atoms and imino N atoms. As evidenced by the bond lengths, the two benzohydrazone ligands exist in distinctively different forms, one of them as a regular neutral ligand and the other as an anionic enolate arising from deprotonation. The much longer Cu—O bond and longer Cu—N bond lengths in the neutral benzohydrazone ligand imply weak ligation in comparison with the anionic enolate form. The acute angles of the five-membered rings cause a significant deviation from a regular octahedral geometry.

Dichlorido{2-[2-(dimethyl­ammonio)ethyl­imino­meth­yl]-6-methoxy­phenolato}zinc(II)

The structure of the title complex, [ZnCl2(C12H18N2O2)], contains a zwitterionic Schiff base ligand. The complex adopts a distorted tetrahedral coordination geometry around the metal centre with the Schiff base ligand coordinated in a bidentate fashion via the imine N and phenolate O atoms. In the crystal, intermolecular N—H⋯O and C—H⋯Cl hydrogen bonds link the molecules into chains parallel to the c-glide planes.

Bis[N'-(2-pyridylmethyl-ene-κN)benzo-hydrazide-κN']bis-(thio-cyanato-κN)cobalt(II).

In the title complex, [Co(NCS)2(C13H11N3O)2], the CoII centre adopts a distorted octahedral coordination geometry with two cis-bidentate Schiff base ligands and two cis thiocyanate ligands. The Schiff base ligand coordinates via the imine N and pyridine N atoms. The CoII atom lies on a crystallographic twofold rotational axis. Non-classical intermolecular C—H⋯O hydrogen bonds link the complex molecules into chains along [001].

Synthesis and Structural Aspects of Two Trinuclear Cyano-bridged Heterometallic Complexes with Monodentate Coordination of Perchlorate and Acetate Anions

Two new cyano-bridged trinuclear heterometallic complexes [Ca2(phen)4(ClO4)(H2O)3- Fe(CN)6]・H2O (1) and [Ca2 (phen)4(CH3COO)(H2O)3Fe(CN)6]・2H2O (2) (where phen = 1,10- phenanthroline) have been synthesized and characterized by single-crystal X-ray diffraction techniques, IR spectroscopy and thermogravimetric analysis. The structure of complex 1 features a central [Fe(CN)6]3− unit that links a monocation [Ca(phen)2(H2O)(ClO4)]+ and a dication [Ca(phen)2- (H2O)2]2+ via two trans cyanide bridges. Similarly, complex 2 also features a central [Fe(CN)6]3− unit that links a monocation [Ca(phen)2(H2O)(CH3COO)]+ and a dication [Ca(phen)2(H2O)2]2+ via two trans cyanide bridges. In 1 and 2, both Ca centers are seven-coordinated and achieve a pentagonal- bipyramidal geometry whereas the Fe center in both the complexes possesses a distorted octahedral geometry. Intra- and intermolecular hydrogen bonding networks are present in 1 and 2 that impart the overall molecular stability to both the systems. Graphical Abstract Synthesis and Structural Aspects of Two Trinuclear Cyano-bridged Heterometallic Complexes with Monodentate Coordination of Perchlorate and Acetate Anions

A dissymmetric, singly phenoxido-bridged Cu II dinuclear coordination compound: synthesis, characterisation, magnetic and computational study

A singly phenoxido-bridged dinuclear Cu∥ complex, [Cu2(L)2(SCN)2(H2O)], has been obtained from a Schiff-base ligand (2-[{[2-(dimethylamino)ethyl]imino}methyl]-6-methoxyphenol), generated by condensation of o-vanillin with N,N-dimethylethane-1,2-diamine. The Cu(II) complex has been fully characterised by analytical, spectroscopic, magnetic susceptibility and EPR measurements and DFT calculations, as well as single-crystal X-ray diffraction analysis. It consists of two geometrically distinct square-pyramidal and octahedral copper(II) centres, exhibiting N2O3 and N4O2 donor sets. In the dimeric unit, the copper atoms are connected by a μ2-phenolato oxygen atom, belonging to one bridging Schiff-base ligand. Variable-temperature magnetic susceptibility measurements indicate strong antiferromagnetic exchange interactions between the Cu(II) centres, with a 2J value of −89(1) cm−1.