Volume 31, Issue 5

The Na and NH 4 salts of the [VOF(C 2 O 4 )2] 3 --ion have been prepared. The crystal structure of the former has been determined from X-ray diffractometer data. The crystals are triclinic, space group P with Z = 2. The structure was solved by `direct methods' and refined to R 0.050 for 1749 reflections. In the anion, vanadium(IV) is octahedrally coordinated by a terminal oxygen atom, a fluorine atom in cis-position to the former, and two bidentate oxalate ligands. The terminal V—O-bond exhibits a strong ‘trans’ effect.

The crystal structure of [enH 2 ][VOF 4 (H 2 O)]2 has been determined from X-ray diffractometer data. Crystals are monoclinic, space group C2/c with Z = 4 in a unit cell of dimensions a = 16.576(13), b = 7.781(4), c = 10.338(8) Å, β = 120.0(1)°. The structure was refined by least-squares methods to R 0.053 for 1436 reflections. The structure contains monomeric [VOF 4 (H 2 O)]⁻-ions with the oxygen atoms in trans position. The bond distances are 1.577 Å (terminal oxygen) and 2.333 Å (H 2 O molecule), resp. The V–F distances vary between 1.769(2) and 1.858(2) Å for fluorine atoms involved in strong hydrogen bonds.

In the reaction of V 2 O 5 with aqueous or alcoholic solutions of tetraalkylammoniumhydroxide the orange decavanadates (NR 4 ) 3 H 3 V 10 O 28 , (NR 4 ) 4 H 2 V 10 O 28 , (NR 4 ) 5 HV 10 O 28 (NR 4 ) 6 V 10 O 28 and colourless metavanadates can be obtained. The tetrabutylammoniumsalt [N(C 4 H 9 ) 4 ] 3 HV 4 O 12 is the first known metavanadate with discrete polyanion. Its molecular weight was determined by vapor pressure osmometry in chloroform. The Raman spectrum is identical with the spectrum of a sodium metavanadate solution. The vibration spectra of the compounds are discussed and partial assignments were made.

FeNb 11 O 29 (m), FeNb 11 O 29 (o) and two mixed oxides with the composition limits FeNb 29 O 74 and TiNb 14 O 37 were prepared by chemical transport. The crystal structures of the compounds have been examined by two-dimensional high resolution electron-microscopy. They are composed of ‘blocks’ of (n × 3) corner shared octahedra and belong to a series of structure related compounds with the general formula Me 3n O 8n-3 . Crystallographic defects and the thermic behavior of the materials are discussed.

[Au(NH 3 ) 4 ](NO 3 ) 3 crystallizes in the orthorhombic space group Cmmm, α = 7.243, b = 13:805, c = 5.302 Å, Z = 2. The crystal structure is built up by NO 3 - anions and square planar [Au(NH 3 ) 4 ] 3+ cations with Au-N bond lengths of 2.02 A. The vibrational spectra of the compound are discussed.

The weak resonances at + 22 and + 49 ppm appearing in the 31 P NMR spectrum of melts or solutions of (PPh) 5 that have been attributed previously in the literature to “dimeric” and “monomeric phenylphosphorus” are caused by (PPh) 6 and (PPh)4, respectively. This was proved by comparison with the 31 P NMR parameters of related compounds and by 31 P NMR spectroscopic investigation of authentic samples of (PPh) 6 and (PPh) 4 , the latter of which was prepared in high yield from (Me 3 Si)PhP–PPh–PPh(SiMe 3 ) and PhPCl 2 . (PEt)4 and mixed-substituted phenyl-ethyl-cyclotetraphosphanes exhibit similar chemical shifts as (PPh)4, corresponding mixed-substituted cyclohexaphosphanes have similar chemical shifts as (PPh) 6 . Generally, cyclophosphanes establish an equilibrium between (PR) n -species of different ring-size. Probably, the ring-interconversion proceeds via a multi-center mechanism. No 31 P NMR spectroscopic evidence for the existence of free PPh or P 2 Ph 2 under the conditions described could be detected. On thermolysis of (PEt)4 the existence of (PEt) 3 was proved for the first time.

Coordination compounds of unusual color and stoichiometry PtCl 2 (CNR) 2 are identified by experimental evidence as ionic tetrakis(isonitrile)platinum(II)tetrachloroplatinates(II). The synthesis of several new complexes [Pt(CNR)4][PtCl 4 ] with varying R and of “mixed” compounds [Pt(CNR) 2 (CNR') 2 ][PtCl 4 ] is described. The influence of the isonitrile ligands in these complexes is discussed especially concerning the resulting solid state properties.

By means of calculated examples it is demonstrated that chemical equilibria can be discussed in a much simpler way by writing the equations in matrix notation. Our basic idea is to treat a problem as a linear one as far as possible and to formulate the nonlinear part as side condition. The rank R* of the stoichiometry matrix proves to be very useful as well for the derivation as for the application of the phase rule.

In gamma-irradiation of cytosine in aerated aqueous solution, two new radiolysis products were isolated and identified: 1-carbamoyl-5-hydroxyhydantoin and N-formylbiuret. This formation involves ring cleavage between C4 and C5 and belongs to the nondeamination pathway.

The sym. 1,2,3-trichloropropenylium ion is an intermediate on the reaction of 1,2,3,3-tetrachloro-l-propene with SbF 3 to 1,2-dichloro-3,3-difluoro-1-propene. This is shown by the fluorination of 1,2,3,3-tetrachloro-(1,3- 14 C)-1-propene, with unsym. distribution of 14 C, and studies with degradation products labelled with 14 C.

The synthesis of 5-diazo-5-[ 13 C]-homoadamantan-4-one (12) is achieved by ring expansion of adamantanone with 13 C-labelled diazomethane, conversion of the resulting 4-[ 13 C]-homoadamantan-4-one (10) to the hydroxymethylene compound (11), followed by deformylative diazo group transfer reaction. The photolysis of 12 with pyrex filtered UV-light in dioxane-water (10:1) yields adamantan-2-carboxylic acid containing all the label in the 2-position of the adamantane skeleton. The total absence of isotope scrambling excludes the intermediate formation of the polycyclic oxiren (16) (Scheme 3).

Heating 2-carboxyindole-3-acetic acid anhydride (1) with primary amines, the cyclic imides 1,2,3,4-tetrahydro-9 H-2-arylpyrido[3,4-b]indole-1,3-diones (2) were obtained. Compounds 2 coupled with diazonium salts to give 4-arylazo derivatives (3), condensed with aromatic aldehydes afforded 4-arylmethylene derivatives (4). Benzylation of 2 yielded the 4,4-dibenzyl derivative (6). 2 reacted also with p-nitrosodimethylaniline to yield the azomethine derivatives (7) which were hydrolysed by hydrochloric/acetic acid mixture to give the triketo compounds (8). The structure assigned to the condensation products have been supported by NMR and IR data.

The preparation of the title compounds from aldehyd-aniles and alkylnitroacetates in acetic anhydride is described. The nitrocinnamates, which in solution are mixtures of the E- and Z-isomers, are studied PMR-spectroscopically, using Eu(fod) 3 as a shift reagent. A simple method for the signal assignment is worked out, making it unnecessary to prepare pure diastereomers.

Dehydrogenation of N-hydroxy-Δ 3 -pyrroline with mercuric oxide leads via the cyclic conjugated 2 H-pyrrolenine-N-oxide to the tautomeric N-hydroxy-pyrrole, which has pronounced reactivity towards dienophiles. With N-phenyl-maleic-imide the endoconfigurated Diels-Alder-adduct is formed, whose stability is increased by acylation of the N-hydroxy group. The O-acylated Diels-Alder adducts can be prepared independantly from N-acyloxy-pyrroles and the corresponding dienophile.

The hydroxamic acids are useful chelating agents for inorganic and organic analysis. For their rational application the data on dissociation constants are desirable. In the present communication the thermodynamic dissociation constants of several hydroxamic acids have been determined at 25°C. The calculation method is described earlier 1 .

The structure of 6 esters of 7 β-hydroxy-3,4-didesoxy-8-epi-maytol has been elucidated.

Cyclic sulfur-nitrogen-halogen compounds constitute a traditional field of inorganic chemistry 1 - 10 . Established as long ago as the close of the previous century by DEMARCAY’S preparation of (NSCl) 3 -, S 4 N 3 Cl-, S 3 N 2 Cl 2 -, S 3 N 2 Cl-, S 3 N 2 Br-compounds 11 whose SN cyclic structures were only recognized much later - the study of halocyclothiazenes, as these species are now called, has gained considerable impetus during the past quarter of a century.

Following schemes 1-22 a survey, general and special synthesis, structural proofs, properties and reactions of isolated and spiral fivemembered ring systems (and derived compounds) from silicon, nitrogen and “hetero elements” B, Ge, Sn, P, As, Sb, S, Ti and Zr are given.

The reactions of hexachlorocyclotriphosphazatriene, N 3 P 3 Cl 6 , and to a lesser extent octachlorocyclotetraphosphazatetraene, N 4 P 4 Cl 8 , and other halogenocyclophosphazenes with primary, secondary, and tertiary amines, are described. The effect on the substitution pattern of variables such as the structure of the amine, nature of the reaction solvent, etc., are discussed in some detail. Attention is drawn to the importance of steric effects. Isomerisation reactions are referred to. The physical properties of aminocyclophosphazenes and aminohalogenocyclophosphazenes are discussed in some detail. These include basicity studies, 1 H and 31 P NMR and 35 Cl NQR studies, Faraday effect measurements, etc. Attempts are made to correlate the above properties with X-ray crystallographic studies and quantum chemical calculations. The distinction between ground state and perturbed state properties is emphasised. Synthesis, structure, and properties of phosphazenylcyclophosphazenes and related compounds are described and a novel conformational behaviour is discussed and rationalised.

The preparation and the properties of phosphorus sulfides and selenides are reviewed. The exact number of phosphorus sulfides and selenides has been determined from the phase diagram. Phosphorus does not react with tellurium. The ternary diagram P—S—Se shows no P—S—Se compounds. The domains of P—S and P—Se glasses has been also determined. IR and mass spectrometry show that phosphorus sulfides and selenides have a tetrahedral arrangement of P atoms close to that of white phosphorus.

Bromine reacts with tetrasulfur tetranitride S 4 N 4 in solution in different solvents to give thiodithiazyl dibromide S 3 N 2 B r2 . Iodine reacts under the same conditions with S 4 N 4 to give trithiazyl iodide (SN) 3 I. The addition of chlorine, bromine or iodine to a mixture of tetrasulfur tetranitride and white phosphorus leads to compounds with the general formula P 2 S 3 N 3 X n , with n = 1 or 3 depending on the nature of X.

Quantum mechanical calculations for a number of cyclophosphazenes reveal that transannular bonding and antibonding interactions contribute considerably to the stability and conformation of these PN ring systems. Charge distributions are only in agreement with the island theory; the latter is confirmed by Faraday effect measurements.

Two routes for the preparation of (CH 3 ) 2 SnS 2 N 2 are given, which are kinetically controlled reactions. The molecule (CH 3 ) 2 SnS 2 N 2 was characterized by X-ray analysis. It is an interesting starting material for the preparation of S 2 N 2 CO and S 3 N 2 O. The latter reacts with iminosulfur oxides and isocyanates under the formation of S 3 N 3 SO 2 F and S 3 N 3 SO 2 CF 3 . The structure of S 3 N 3 SO 2 F was established by X-ray analysis. The bonding properties are discussed. The cleavage of thin-nitrogen derivatives with S 3 N 2 Cl 2 yields also five membered sulfurnitrogen rings. The structure and properties of P 3 N 3 F 5 NS 3 N 2 and C 3 N 3 F 2 NS 3 N 2 are reported. Six, eight and ten membered rings are formed by the reactions of (CH 3 ) 3 Si–N = S = N–Si (CH 3 ) 3 with FSO 2 –N=S=O, these are S 4 N 4 O 2 and S 5 N 5 +S 3 N 3 O 4 , respectively. The cation S 5 N 5 + is a planar molecule, while the oxygen containing species are puckered. In S 4 N 4 O 2 the oxygens are attached to one sulfur atom, which has a tetrahedral configuration. The structure of the silicon containing cyclic and bicyclic rings (CH 3 ) 2 Si(NSN) 2 Si(CH 3 )2 and CH 3 Si(NSN) 3 SiCH 3 were determined.

Fluorides LiPbM III F 6 with M III = V, Cr, Fe and Ga were prepared. They crystallise hexagonally (ordered superstructure Li 2 ZrF 6 ). With M III = Al and Ti the compounds Pb 3 (AlF 6 )2 and Pb 3 (TiF 6 )2 are obtained.

The U 2 S 3 -type structure of Dy 2 Se 3 was confirmed and refined from single-crystal data.

The structures of 1-chloro-4,5-benziodoxalin-3-one (1) and 1,2-dichloro-4,5-benziodazalin-3-one (2) have been determined by x-ray crystallography. These are compared with those of some compounds related to the former, as well as with I 2 Cl 6 . The bond of iodine to its exocyclic substituent appears to be very sensitive to environmental changes, as are the endocyclic iodine-oxygen and carbon-oxygen bonds (both where applicable) in the heterocyclic ring. The shapes of the molecules and their possible interactions with donor functions on adjacent molecules are discussed.

The reaction of Ga(CH 3 ) 3 or Sb(CH 3 ) 5 with diacetamide leads to (CH 3 ) 2 GaO 2 C 2 (CH 3 ) 2 N or (CH 3 ) 4 SbO 2 C 2 (CH 3 ) 2 N. The behaviour, the 1 H NMR and vibrational data of these covalent and monomeric compounds with an chelated O 2 C 2 (CH 3 ) 2 N-ligand are discussed.

The carmine-red H 3 [Mn(CN) 5 NO] and the olive-green H 3 [Cr(CN) 5 NO] were prepared in crystalline form by the acid treatment of the corresponding potassium compounds, and the ammonium salts of these by neutralizing the solutions of the above acids.

Alkalistilbenolate does not react, as expected, with dichlorotetramethyldisilane (1) to a six-membered heterocyclic, but the SiSi linkage is nucleophilic attacked by the oxygen and a five-membered heterocycle with only one Si-atom is formed. On the other hand, 1,2-dihydroxybenzene reacts with 1 to the new six-membered heterocycle in good yield.