Michael J. Newlands

Binuclear copper(II) complexes of tetradentate (Ne) diazine ligands. Crystal structures of [μ-1,4-Bis(4,6-dimethyl-2-pyridylamino)phthalazine-N,μ-N3,μN3,N]-(μ-Dichloro)dichlorodicopper(II), [μ-3,6-Bis(2-pyridylthio)pyridazine-N,μ-N1,μ-N2,N] (μ-dichloro)dichlorodicopper(II) ethanol, and 3,6-Bis(2-pyridylthio)-pyridazine

Abstract The X-ray structures of two binuclear copper(II) chloride complexes of the tetradentate ligands 1,4- bis(4,6-dimethyl-2-pyridylamino)phthalazine (PAP46Me) and 3,6-bis(2-pyridylthio)pyridazine are reported. [Cu2(PAP46Me)Cl4] (1) and [Cu2(PTP)Cl4]· CH3CH2OH (2) contain triply bridged binuclear centres involving a diazine (NN) and two chlorobridges with copper-copper separations in the fange 3.19–3.25 A and distorted square pyramidal copper stereochemistry. The reduced room temperature magnetic moments indicate antiferromagnetically coupled binuclear copper(II) centres. Complex 1 forms green crystals with a= 15.795(3), b=10.661(3), c=16.155(4) A, β= 113.82(3)°, C2/c, Z = 4, Rf=0.031. Complex (2) forms green crystals with a=33.9022(8), b= 9.1626(5), c= 15.7885(5) A,β= 114.853(2)°, C2/c, Z=8, Rf=0.047. The structure of the ligand PTP is also reported and compared with that of 2.

Binuclear copper(II) complexes of some sexadentate phthalazine-hydrazone ligands with strong antiferromagnetic exchange

Abstract Sexadentate phthalazine-hydrazone ligands (N6), involving pyridine and N-methylimidazole as peripheral donor groups, form binuclear hydroxo-bridged copper(II) complexes which exhibit very strong antiferromagnetic exchange (−2J=885−1211 cm−1), which is propagated via a superexchange mechanism through the bridging diazine (NN) and hydroxide groups. When the hydroxide bridge in [Cu2(APHPH)(OH)(H2O)2](ClO4)2·H2O (APHP=1,4-dihydrazinophalazine-bis(2-pyridine) acetaldimine) (−2J=988 cm−1) is replaced by a pyrazolide bridge, a dramatic decrease in exchange is observed (−2J=521 cm−1) indicating the importance of hydroxide as a dominant superexchange bridge. The complexes are highly colored, exhibiting very intense visible absorptions (16 400–16 700 cm−1) associated with charge transfer transitions. The crystal and molecular structure of [Cu2(APHPH)(OH)(H2O)2](ClO4)2·H2O (VI) is reported. VI crystallized in the monoclinic system, space group P21/n, with a=8.0110(20), b=24.100(5), c=15.6750(20) A, β=100.240(20)° and four formula units per unit cell. Refinement by full-matrix least-squares gave final residuals of R=0.076 and Rw=0.038. This complex has a hydroxo-bridged suare-pyramidal structure with a CuCu separation of 3.296(2) A and a CuO(H)Cu angle of 117.8(3)°.

A binuclear copper(II) complex with a large unoccupied rigid cavity derived from a non-macrocyclic polyhydroimidazole

The ligand 1,2,4,5-tetrakis(4,5-dihydroimidazol-2-yl)benzene (btim) forms a bis-chelating binuclear square-pyramidal copper(II) complex (Cu–Cu 7.610 A) with a large, unoccupied cavity and two parallel, eclipsed benzene rings separated by 3.93 A.

The crystal structure of 2β,4β-cyclo-5α-androstane-3α, 17β-diol diacetate

Abstract An X-ray crystal structure determination was performed on 2β, 4β-cyclo-5α-and rostane-3α, 17β-diol diacetate. The parent diol, but not its 3β-epimer, had been shown to be an effective inhibitor of a 3β-hydroxysteroid dehydrogenase.