Volume 37, Issue 5

1-Isopropyl-2,3-di-tert-butyl-1,2,3-azadiphosphirane (1) was synthesized by [2+1] cyclocondensation of Cl(t-Bu)P-P(t-Bu)Cl with (Me 3 Sn) 2 N(i-Pr) at 75 °C. 1 could be isolated in pure state by fractional distillation and is stable at room temperature under inert conditions. The temperature independent 31 P NMR spectrum indicates that the arrangement at the nitrogen atom is planar, probably due to dative π-bonds from nitrogen to the phosphorus atoms

The title compound was prepared by heating the hydrolysis products of AsPO 4 in a sealed tube. The crystal structure was determined and refined to R = 0.028 [P2 1 /n, a = 454.5(1), b = 1229.0(2), c = 972.8(3) pm, β = 100.13(2)°, Z = 4]. The structure, which is not isostructural with As 3 O 5 (0H), consists of infinite layers, containing pyramidal AS(III)O 3 and tetrahedral P(V)O 4 groups, and stabilised by hydrogen bonding of the form P-O-H­···O-P

The compound 1,2,3,4-tetra-tert-butyl-1,4-bis(trimethylsilyl)tetraphosphane, Me 3 Si-(t-BuP) 4 -SiMe 3 , C 22 H 54 P 4 Si 2 , crystallizes monoclinically in the space group P2 1 /n (No. 14) with a = 889.9 pm, b = 2292.8 pm, c = 1568.0 pm, β = 94.14° and Z = 4 formula units. The molecule forms a twisted Si-P 4 -Si-chain with two kinds of P-P-bonds. The atoms neighbouring the silicium atoms take part in bonds of length d̄(P-P) = 218.8 pm, whereas the central bond d̄(P-P) = 221.4 pm is much longer. A special feature of the structure is a short contact d̄(P-P) = 345.6 pm. Therefore, the inner region of the molecule has the shape of a nearly planar trapezium of the four phosphorus atoms. The periphery of the molecule is as expected. The average bond lengths are d̄(P-Si) = 228.5 pm, d̄(P-C) - 190.2 pm, d̄(Si-C) = 186.6 pm, d̄(C-C) = 151.8 pm and d̄(C-H) = 94 pm

The new compound [Pd(NH 3 ) 4 ]l 8 crystallizes monoclinically in the space group P2 1 /m with a = 959.0 pm, b = 835.4 pm, c = 1301.1 pm, β = 103.37° and Z = 2 formula units. The crystal structure has been solved by 'direct methods' and refined to R = 0.057 with 1357 observed reflections. The structure consists of quadratically coordinated cations [Pd(NH 3 ) 4 ] 2+ and planar, Z-shaped and completely ordered octaiodide anions I 8 2- . According to the sequence of interatomic distances d(I-I) = 295.0 pm, 289.9 pm, 336.2 pm, 279.1 pm, 327.0 pm, 339.3 pm, 273.8 pm the anions may be described as [I 3 - • I 2 • (I- • I 2 )]- The iodide-iodine sides (I- • I 2 ) are joined with the distance d(I---I) = 364.1 pm to a slightly bent triiodide chain being part of an octaiodide ribbon 1 ∞ [I 8 2- ]- Next contact spacings between neighboring anions start at d(I---I) = 403.7 pm

New nonstoichiometric cesium bromo aurates(I,III) Cs 1+x (AuBr 4 )(AuBr 2 , Br 3 ,Br) x have been synthesized, in which the almost equally shaped anions AuBr 3 - and Br 3 - can interchange themselves. The compounds crystallize in a disordered cubic perovskite structure with a = 547.5 pm or in a tetragonal superstructure with a 16-fold perovskite cell (a = 1553, c = 1099 pm). The investigations show that other bromoaurates as the previously reported "Cs 2 AgAuBr 6 " can contain perceptible amounts of Br 3 - ions also. The IR and 197 Au Mössbauer spectra of the new bromoaurates and of Cs 2 AuoBr 6 are discussed

The crystal structure of the intermetallic phase HgZn 3 was determined using X-ray single crystal and powder diffraction methods. The phase belongs to the orthorhombic system, most probable space group being Cmc2 1 , and appears to be isostructural with β'-Cu 3 Ti. Under standard preparative conditions a statistical distribution of both atomic species was observed

The phosphino and (thio)phosphoryl formamides 1a, b, 2a-c, 3a, b, 4a, b which were partially unknown are synthesized by various methods, and their reactions with carbonylmetal halides of manganese and iron are described. The formation of the P,N- and S,N coordinate chelate complexes, (CO) 4 MnL (5 a, 8a), is limited to the N-phenyl derivatives la and 4a. With L = 2a, b, the unidentate P-coordination predominates. Thus, the carbonylmetal halide complexes cis-(CO) 4 Mn(X)L (6a, b: X = CI, 7a, b: X = Br) and η 5 -C 5 H 5 (CO)Fe(X)L (9a, b: X = I, 10a, b: X = Br) are obtained. Due to the low stability of the formamide complexes, their formation is always accompanied by isocyanate elimination as a side-reaction

Compounds of the sulfur(IV) diimines with elements of the main group IVb were prepared. Spectroscopic behaviour and the scope and limitations of preparing sulfurdiimines from amines and N 3 S 3 CI 3 are discussed

New hydride halide compounds MHX (M = Eu, Yb, Sm; X = Cl, Br, I) of divalent rare earths have been prepared by solid-state reactions. Lattice parameters and X-ray diffraction patterns are presented for these compounds. All compounds are isostructural with tetragonal PbFCl. Refined lattice parameters of alkaline earth hydride halides are given. The crystal chemistry of MHX and MFX is compared and the geometric variations in the structure of these compounds are interpreted on the basis of changes in covalency

The mixed chloro-bromo complexes [PtCl n Br 6-n ] 2- , n = 1-5, are separated by ion exchange chromatography on diethylaminoethylcellulose. The separation of corresponding stereoisomers for n = 2, 3, 4 is not possible. Due to the stronger trans-effect of Br compared with Cl, on treatment of [PtBrß]2- with Cl- in the presence of Br2 nearly pure cis-isomers, and by reaction of [PtClsBr]2- and cis-fPtC^Bro]2- with Br~/Br2 completely pure transisomers are formed. The stereoselectivity of the successive ligand exchange reactions is better than in corresponding series of Re, Os and Ir. The highly resolved vibrational spectra allow the distinction of the mixed ligand complexes as well as the estimation of purity of the isomers. All allowed stretching frequencies are observed and assigned according to point groups D 4h , C 4V , C 3V and C 2V . Especially in the ν(Pt-Br) region it is possible to distinguish bands arising either from symmetric Br-Pt-Br or asymmetric Cl-Pt-Br axes. The UV/VIS spectra exhibit systematic hypsochromic shifts on the successive exchange of Br-ligands by Cl. A critical discussion of the literature concerning chloro-bromo-platinates- (IV) shows the importance of effective separation processes for the isolation of pure mixed ligand complexes

Guanidiniumditellurate obtained from aqueous solution at room temperature forms triclinic crystals of space group P1̄ with lattice parameters a = 17.486(4) Å, b = 8.459(7) Å, c = 7.134(8) Å; a = 107.42(2)°, β = 83.95(2)° and y = 103.14(2)°. The unit cell contains two crystallographically independent anions with symmetry centers at 0, 0, 0 and 1/2, 0, 1/2. They consist of two octahedral TeO 4 (OH) 2 units which share two common oxygen atoms. The guanidinium ions are connected over an irregular network of bridging hydrogens and terminal oxygen atoms of the anions, in similar manner as ditellurate ions are joined by water molecules in aqueous solutions: the Raman spectrum of the guanidinium salt is nearly identical with the solution spectrum of a ditellurate, but exhibits pronounced differences regarding the spectrum of the solid potassium salt K 4 Te 2 O 6 (OH) 2 • 7 H 2 O

The central phosphorus atom of the anion 2 in piperidinium bis(diethoxyphosphinoyl)- phosphide acts as an electron donor towards one or two M(CO) 5 groups (M-Mo,W) forming the crystalline coordination compounds 4 and 5. The NMR and IR spectra as well as the X-ray diffraction data are presented

The reaction of Cp(CO) 2 Fe-SiHCl 2 with Co 2 (CO) 8 yields the heteronuclear complex Cp(CO) 2 Fe-SiCl 2 -Co(CO) 4 (1) and HCo(CO) 4 .1 is degradated by AgBF 4 to Cp(CO) 2 Fe-SiF 3 . PMe 3 transforms 1 to Cp(CO) 2 Fe-SiCl 2 -Co(CO) 3 PMe 3 (2). L n M-SiH 2 Me reacts with Co 2 (CO) 8 to give L n M-SiMe-Co 2 (CO) 7 [L n M = Cp(CO) 2 Fe (3a), Cp(CO) 2 PMe 3 W (3b)]. Starting with Cp(CO) 2 Fe-SiH 3 , μ 3 -Cp(CO) 2 Fe-SiCo 3 (CO) 9 (4), the second example of a μ 3 -metallosilylidine tricobalt cluster is obtained in high yield, which is cleaved by acetic acid to Cp(C0) 2 Fe-Si[OC(O)Me] 3 (5). The composition and structure of the silicon transition metal complexes 1-5 is proved by NMR, IR and mass spectroscopy. 29 Si NMR shifts are determined for the first time for a tri- and tetra-metalated silicon species

Room-temperature Mössbauer spectra are reported for μ3 -RP-bridged heterometallic iron clusters of the type μ3 -RP-(C 5 H 5 (CO) 2 Mn)Fe 2 (CO) 6 L n . The Mössbauer parameters of these clusters show that the structures are in agreement with the lattice constants of low-spin hetero manganese-iron clusters

Displacement of the CO ligand in CpV(NO) 2 CO (Cp = η 5 -cyclopentadienyl) by various Lewis bases (L) in solution leads to a series of (28) complexes CpV(NO) 2 L which were characterised by the 51 V NMR chemical shift, the 13 C and 1 H NMR chemical shifts of the cyclopentadienyl ring, and by the NO stretching frequencies of the two nitrosyl ligands. The chemical shift δ( 51 V) varies over the range of ca. -1300 and -500 ppm depending on the nature of L, whereas δ( 13 C) of the cyclopentadienyl ring varies only between 98 and 102 ppm. The shielding of the 51 V and 13 C nuclei decreases as the electronegativity of the ligand atom bound to the metal increases in the order P <S <N <O

Tetrasulfur tetraimide reacts with (THF)M(CO) 5 (M = Cr, W) to form isolable complexes of the type (S 4 N 4 H 4 )M(CO) 5 (1) and (S 4 N 4 H 4 )[M(CO) 5 ] 2 (2) respectively, 1 H NMR and X-ray investigations show the metal to be coordinated to sulfur atoms. In solution partially dissociation of M(CO) 5 moieties is observed leading to different equilibria. They are studied by 1 H NMR

The reaction of Re 2 (CO) 10 with LiSi(C 6 H 5 ) 3 and subsequent alkylation by (C 2 H 5 ) 3 OBF 4 yields not only (CO) 9 Re 2 C(OC 2 H 5 )Si(C 6 H 5 ) 3 but also Re 1 -ax,Re 2 -eq-[C(OC 2 H 5 )Si(C 6 H 5 ) 3 ] 2 (CO) 8 Re 2 (1). The analogous isomeric complexes Re 1 -ax-[C(OC 2 H 5 )C 6 H 4 CH 3 ]-Re 2 -eq-[C(OC 2 H 5 )Si(C 6 H 5 ) 3 ](CO) 8 Re 2 (2) and Re 1 -ax-[C(OC 2 H 5 )Si(C 6 H 5 ) 3 ]-Re 2 -eq-[C(OC 2 H 5 )C 6 H 4 CH 3 ](CO) 8 Re 2 (3) are obtained by treatment of eq- or ax-(CO) 9 Re 2 C(OC 2 H 5 )Si(C 6 H 5 ) 3 with LiC 6 H 4 CH 3 and subsequent alkylation by (C 2 H 5 ) 3 OBF 4 . Reaction conditions, and properties and spectroscopic data of the new compounds are reported

Variations of the metal chemical shifts δ( 51 V), δ( 55 Mn) and δ( 93 Nb) with the paramagnetic deshielding contribution to the overall shielding are discussed in terms of influences imposed by the ligand field splitting, the nephelauxetic effect and the covalency of the metal-to-ligand bond. Complexes under investigation are isoelectronic and/or iso-structural series [M(CO) 6-n L n ] q (M = V, Nb: q = -1; M = Mn: q = + 1; n = 0-6), η 5 -C 5 H 5 M(CO) 4-n L n (M = V, Nb; n = 0-4) and η 5 -C 5 H 5 M(L') 2 L (M = V, L' = NO; M = Mn, L' = CO). L is a monodentate or l/n oligodentate phosphine. η varies with the point symmetry of the complex, and with ligand parameters of primarily electronic or steric origin. Generally, for weak to medium π-interaction, there is a decrease of shielding with decreasing π-acceptor power of the ligand, increasing ligand bulkiness, increasing ring strains in chelate structures and increasing degree of substitution. For strong π-interaction, the trends may be interconverted. PF 3 is shown to be a slightly weaker π-acceptor than CO. Selected results on nuclear-spin spin coupling constants, 13 C and 31 P shielding are also presented

The preparations of new compounds, containing the complex anions [Hg 2 l 5 ] - , [Hg 2 l 6 ] 2- and [Hg 3 I 8 ] 2- , are reported. Distorted iodine-bridged configurations are proposed for the complexes in the solid state, utilising analyses, X-ray powder patterns, molar conductance measurements and spectral (IR, UV) data

Singlet oxygen was generated by the photosensitization of erythrosine. The lifetime of singlet oxygen and the quenching rate constant for singlet oxygen by NaN 3 were measured by a thermal lensing method in MeOH-H 2 O mixed solvents. The reciprocal of the lifetime increased linearly with the increase of the H 2 O mole fraction. Semi-log plot of the quenching constant against the reciprocal of the solvent polarity exhibited a linear relation. The quenching of the singlet oxygen by NaN 3 may proceed through a partial charge-transfer intermediate. The activation energy for the quenching reaction of N 3 - + 1 O 2 →[N 3 · 1 O 2 - ] increased with the increase of the solvent polarity. The lifetime was also measured in MeOH-ethyleneglycol mixed solvents, and its relation with viscosity was obtained

Trichloro(purinium)zinc(II) (1) and dichloro-bis-(7-azaindole)zinc(II) (2) have been prepared from respectively 1:1 (in acid solution) and 2:1 aqueous solutions of the parent base and zinc(II) chloride. In the latter case the salt di-[7-azaindolium]zinc(II) tetrachloride (3) is isolated under acid conditions. The structures of 1-3 have been established by X-ray structural analyses. Zinc coordinates the purine nitrogen N(7) in 1 and N(3) of 7-azaindole in 2. N(l) is protonated in 1. The bond length distribution of the cations 3 suggests a significant contribution from a resonance form in which N(9) carries the positive charge

4,4-Diphenyl-4-sila-piperidines 3 a-d and their hydrochlorides 4 a-d could be synthesized by two different methods starting from diphenyldivinylsilane (Scheme 1). Some properties of these compounds are described. They are the silicon analogues of the well known neuropharmaca 10. Preliminary pharmacological investigations show that the sila-compounds 4a-c have interesting affects concerning to the content of neurotransmitter in the homogenate of rat brains and to the bonding to different receptors

3,5-Di-tert-butyl-o-benzoquinone (1) reacts with 3-methyl-2,4-diphenyl-l,3-oxazolium- 5-olat (2) to give a [π4 + π4] adduct (3). Under thermal conditions compound 3 rearranges to give 5 and 6. The structure of 5 has been clarified by X-ray crystallography

N-mono- and N-di-substituted 3-amino-indene-l-ones with free secondary amines yield no Mannich products, but the corresponding 2,2'-methylene biscompounds. C-Aminomethylation is possible with hydrochlorides of secondary amines, aminals or methylene iminium salts. With primary amines and two equivalents of formaldehyde indenopyrimidines are available

Organolithium compounds react with the bis- (η 3 -allyl)metal complexes of nickel, palladium and platinum by addition to give ionic 'ate complexes in which one allyl group has been converted into the η 1 -allyl form