Inorganic Chemistry Communications (v.4, #3)

Contents (iii-iv).

First examples of M–Se–P–N–N heterocycles by Matthew L. Clarke; Gemma L. Holliday; Alexandra M.Z. Slawin; J. Derek Woollins (115-118).
The synthesis, structure, and co-ordination chemistry of a novel ligand containing a Se–P–N–N backbone has been studied. Monodentate Se co-ordination and Se,N bidentate co-ordination has been observed.
Keywords: Selenium; Co-ordination chemistry; Platinum complexes;

Complexes of the type Cu(Im) n (sal)2 (1,2,3) (where Im = imidazole, and sal = salicylate ion) have been prepared from the reaction of Im with tetrakis (aspirinato) dicopper (II) and were crystallographically and spectroscopically characterized. The three imidazole complexes 1 (n=2), 2 (n=5) and 3 (n=6) co-crystallize and each complex is found in the unit cell. Crystals that contained 1, 2 and 3 have unit cell parameters of a=12.772(5), b=13.078(4) and c=18.199(7) Å, α=79.53(3), β=81.20(3) and γ=75.98(3)° and belong to the space group P l ̄ .In 1 the copper ion is coordinated in a trans arrangement by two imidazole nitrogen atoms and two carboxylate oxygen atoms from the salicylate ligands. The second carboxylate atoms form weak interactions with the copper ion. For complex 2 the copper ion is in a distorted square pyramidal environment of nitrogen atoms from five imidazole ligands. There are two salicylate counterions. Complex 3 exists as tetragonally distorted octahedral copper (II) cation with six coordinated imidazole ligands and two salicylate counterions.
Keywords: Copper (II); Salicylate; Imidazole; Crystal structure;

Reaction of [WI2(CO)3(NCMe)2] with two equivalents of HC2Ph in CH2Cl2 gives the crystallographically characterised complex [WI2(CO)(NCMe)(η2-HC2Ph)2] (1). Complex 1 is a single component catalyst for the polymerisation of phenylacetylene.
Keywords: Bis(phenylacetylene); Tungsten(II); Polyphenylacetylene; Crystal structure;

The tris(2-mercapto-1-phenylimidazolyl)hydroborato ligand, [TmPh], has been used to prepare [TmPh]ZnOH, the first structurally characterized terminal zinc hydroxide complex of a tridentate sulfur donor ligand; as such, [TmPh]ZnOH represents a good structural model for the zinc enzyme 5-aminolevulinate dehydratase (ALAD).

A molecular propeller with three quadruply-bonded blades by F. Albert Cotton; Lee M. Daniels; Chun Lin; Carlos A. Murillo (130-133).
Reaction of the trinegative tricarboxylate anion 1,3,5-tricarboxylatobenzene (the anion of trimesic acid) and Mo2(DAniF)3Cl2 (DAniF=N,N -di-p-anisylformamidinate) under reducing conditions produces the propeller-shaped hexanuclear complex [Mo2(DAniF)3]3(1,3,5-C6H3(CO2)3). Its structure has been established by X-ray crystallography; 1H NMR is also consistent with the presence of highly symmetrical species in solution. The three quadruply-bonded Mo–Mo distances are 2.082(4), 2.087(3), and 2.090(4) Å. This neutral complex is electrochemically active.
Keywords: Dimolybdenum quadruple bonds; Hexanuclear complex; Electrochemistry; Supramolecular chemistry; Trimesic acid.;

The synthesis and structure of nickel(II) and copper(II) complexes with N,N-dimethyl-N -(2,4-dichlorophenoxy)acetyl hydrazine by Victor F. Shulgin; Natalie S. Pevzner; Vera Y. Zub; Natalie G. Strizhakova; Yurii A. Maletin (134-137).
The first examples of nickel(II) and copper(II) complexes derived from unsymmetrical N,N-dimethylhydrazine have been obtained and studied using both spectroscopic and X-ray analyses. Square planar copper(II) coordination is slightly distorted with two trans dimethylamino and two trans imidole–oxygen donor groups. Any extra coordination due to other donor centers is hindered by methyl groups whose carbon atoms are located at a distance of 2.837–2.918 Å from the central ion.
Keywords: N,N-dimethylhydrazine derivatives; Copper(II) complex; Nickel(II) complex; Molecular structure;

A novel tetrauclear iron–oxo complex has been synthesized and characterized by X-ray single crystal structural analysis: [Fe4O2O2CC2H5)7(bipy)2]PF6·2H2O (bipy=2,2-bipyridine). The title complex crystallizes in the monoclinic system, space group C2/c, with lattice parameters a=27.859(2)  A ̊ , b=13.0629(10)  A ̊ , c=17.2698(14)  A ̊ , β=123.6080(10)°, V=5234.3(7)  A ̊ 3, Dc=1.559  Mg/m 3, Z=4, R1=0.0493. The molecular structure shows that there are two types of coordination environments for Fe(III) atoms. One is formed by two N atoms and four O atoms, another by six O atoms, all in distorted octahedron, which forms a “butterfly” core structure. The corresponding variable temperature susceptibility measurement shows that there exists an antiferromagnetic interaction in the complex.
Keywords: Crystal structure; Magnetic property; Tetranuclear iron complex; Propanoic acid;

Lantern-type Ru2(OAc)4Cl reacts with pySH with complete substitution of the acetate ligands and oxidation to give a bioctahedral dimer [Ru2(μ-pyS)3(pyS)2](CF3SO3) (1), (Ru–Ru 2.693 Å) – the first Ru(III) complex of 2-mercaptopyridine. One-electron oxidation and reduction states of the dimer are also electrochemically accessible. The similarity in the behaviour of 2-mercaptopyridine and dithiocarbamates as ligands to Ru(III) is also addressed.
Keywords: Ru complexes; 2-mercaptopyridine; Dinuclear complexes; Redox properties; Crystal structure;

Metal-substituted ketenes: first 13C and 31P CP/MAS NMR determinations by Luciano Pandolfo; Alessandro Sassi; Livio Zanotto (145-149).
Cross-polarization, combined with magic-angle spinning, has been employed to obtain high-resolution solid-state 13C and 31P NMR spectra of a series of solid, peculiar ketenes, also known as η 1-ketenyl derivatives, bearing as substituents a PPh3 moiety and a coordinatively unsaturated Pt(II) fragment. Solid-state NMR data found for trans-[PtCl2(η 2-C2H4){η 1-C(PPh3)CO}], trans-[PtCl2{η 1-C(PPh3)CO}2], Ph3PCCO, trans-[PtCl2(η 2-C2H4){η 1-CH(PPh3)COMe}], trans-[PtCl2{η 1-CH(PPh3)COMe}2] and Ph3PCHCOMe, are compared with NMR values obtained in solution. The general utility of the CP/MAS NMR technique in the study of unstable or insoluble complexes is discussed.
Keywords: CP/MAS NMR; Ketenes; Ylides; Ph3PCCO; Pt;

The X-ray structural characterization of a moisture stable imido ester with an E-configuration, obtained from the nickel(II)-mediated alcoholysis reaction of the nitrile group of a newly synthesized 6,7-dicyano-2,3-di(2-pyridyl) pyrazine compound (L), is reported.
Keywords: Crystal structure; Alcoholysis; Imido ester; E-configuration;

The oxidation states of the transition metals in the chemically prepared nickel and cobalt Prussian White analoga Na2M[Fe(CN)6] and K2M[Fe(CN)6] as well as in the Prussian Blue analoga KM[Fe(CN)6] (M = Ni, Co) are investigated by analyzing the K-edge XANES and EXAFS spectra of the transition metals excited with synchrotron radiation. These similar substances exhibit different behavior depending on the insertion of nickel or cobalt. Structural data as derived from the EXAFS measurements are given.
Keywords: Prussian Blue derivative complexes; EXAFS; XANES;

The photolysis of bis(benzene)chromium(I) in chloroform by Erin L. Orazem; Patrick E. Hoggard (157-159).
Irradiation of [Cr(C6H6)2]Cl in chloroform at 254 nm yields CrCl3. The reaction occurs primarily through the photodissociation of CHCl3, followed by attack by CCl3 radicals or HCl on the complex.
Keywords: Photolysis; Bis(benzene)chromium(I); Chloroform; Solvent-initiated;

The novel cationic gold porphyrin complex [(TPYRP)AuIII]+CH3COO with TPYRP = dianion of 5,10,15,20-tetrakis(1-pyrenyl)porphyrin was prepared and characterized by optical spectroscopy and high-resolution electrospray mass spectrometry. In addition to metalloporphyrin intraligand transitions, the compound shows charge transfer (CT) absorptions in the visible spectral region that are sensitive to variations of the solvent polarity. The photoreactivity of an intramolecular charge separated state of the photosensitizer populated by CT excitation was investigated in the presence of dioxygen and an excess of the purine nucleobase guanine. A photocatalytic oxidative degradation of guanine with a quantum yield of 0.03±0.01 and an initial turnover frequency of 66 per hour was observed upon irradiation with monochromatic visible light at 298 K. The potential of the cationic metallointercalator complex [(TPYRP)AuIII]+ to serve as a catalytic photonuclease for the sequence specific cleavage of DNA has been demonstrated.
Keywords: Porphyrins; Gold; Pyrene; Photocatalysis; DNA; Photonuclease activity;