Volume 49, Issue 3

We have determined the crystal and molecular structure of trans-bis(acetonitrile)dichloroplatinum(II). Crystallographic data for trans-Pt(CH 3 CN) 2 Cl 2 : monoclinic, space group P2 1 /c, a = 5.0453(9), b = 6.9896(5), c = 11.962(1) Å , β = 101.40(1)°, V = 413.5 Å 3 , Z = 2 ,D x = 2.796 g cm -3 ,μ(CuKα) = 377.5 cm -1 , R = 0.0502, wR = 0.0529 for 43 variables and 807 reflections with F > 3σ(F). The Pt atom is in a planar configuration with N and Cl atoms in trans positions. The shortest distance between two Pt atoms corresponds to the length of the crystallographic a-axis (5.045 Å). Additionally, we present optical absorption data of the cis-and trans-isomer.

The title compounds have been prepared as black-blue crystals with metallic lustre by the reaction of CuCl 2 and CuCl, respectively, with Me 3 SiNPMe 3 in CH 2 Cl 2 suspensions. The complexes have been characterized by cyclic voltammetry and by crystal structure determinations. [Cu 6 Cl 6 (NPMe 3 ) 4 ]Cl[Me 3 SiNPMe 3 ] · CH 2 Cl 2 : Space group P2 1 2 1 2 1 , Z = 4, structure solution with 4407 unique observed reflections, R = 0.057. Lattice dimensions at -70 °C: a -1159.3(8), b = 2027.1(14), c = 2063.3(12) pm. The compound consists of cluster ions [Cu 6 Cl 6 (NPMe 3 ) 4 ] + , in which the copper atoms form a regular octahedron. Four planes of the octahedra are capped by μ 3 -nitrogen atoms of the (NPMe 3 ) - groups. Each of the Cu atoms is connected with a terminal chlorine atom . Another chloride ion serves for charge compensation; this ion occupies another Cu 3 plane of the octahedron. Without bonding interaction one Me 3 SiNPMe 3 molecule and one CH 2 Cl 2 molecule are included in the lattice. [Cu 6 Cl 6 (NPMe 3 ) 4 ][Cu(Me 3 SiNPMe 3 ) 2 ]Cl 2 : Space group Pna2 1 , Z = 4, structure solution with 5676 unique observed reflections, R = 0.071. Lattice dimensions at -70 °C: a = 3117.2(21), b = 1927.4(11), c = 1002.7(8) pm. The compound consists of cluster ions [Cu 6 Cl 6 (NPMe 3 ) 4 ] + , the complex ion [Cu(Me 3 SiNPMe 3 ) 2 ] + , and chloride ions. In the cation [Cu(Me 3 SiNPMe 3 ) 2 ] + the copper atom is linearly coordinated by the nitrogen atoms of the phosphaneimine molecules.

Reactions of di-silver-1,n-alkanedisulfonates 1a (n = 1) and 1b (n = 2) with Cl 2 SiR 1 R 2 lead to the monomerie 3,3-diorganyl-2,4-dioxa-1,5-dithia-1,1,5,5-tetraoxid-3-silacyclohexanes (for n = 1) 2a (R 1 = R 2 = Me), 3a (R 1 = Me and R 2 = Ph) and 4a (R 1 = R 2 = Ph) and -heptanes (for n = 2) 2b (R 1 = R 2 = Me), 3b (R 1 = Me and R 2 = Ph) and 4b (R 1 = R 2 = Ph). In the case of 2a-4a a competition reaction is observed leading to the dimerization products 5a (R 1 = Me and R 2 = Me), 6a (R 1 = Me and R 2 = Ph) and 7a (R 1 = Ph and R 2 = Ph). The six-membered ring-systems of 2a-4a are compared with related silanes. An X-ray structure analysis is per­formed for the 3,3-diphenyl-2,4-dioxa-1,5-dithia-1,1,5,5-tetraoxid-3-silacycloheptane (4b).

Redox reactions of cyclooctyne and 1,1-bis(diiodboryl)ethane lead to 4,5-cycloocta-2,3-dihydro-1,3-diiodo-2-methyl-1,3-diborole (1a), which is methylated with AlMe 3 to give 4,5-cycloocta-2,3-dihydro-1,2,3-trimethyl-1,3-diborole (1b). Complexation of 1b with the complex fragments (C 5 H 5 )Co, (C 8 H 12 )Ni, (C 5 H 5 )Ni, and (OC) 3 Co leads to the corresponding metal complexes 2b, 3b, 4b, and 5b. Their constitutions are derived from spectroscopic data and confirmed for 2b and 4b by X-ray structure analyses. 2b contains a C-H-B 3c/2e bond, its hydrogen atom could be located. [(C 8 H 12 )Ni(1b)] (3b) is the first example for a (C 8 H 12 )Ni complex having a C-H-B interaction.

Crystals of the adduct Hg(SCN) 2 · 2HgCl 2 ·2C 6 H 12 N 4 were obtained from an aqueous solution containing 0.1 mol/l hexamethylenetetramine and 0.05 mol/l potassium thiocyanate and mercury(II) chloride. The compound crystallizes monoclinically; space group P2 1 /n, a = 767.3(4), b = 1854.7(7), c = 872.5(7) pm, and β = 101.48(5)°. The structure consists of a net­ work of chains -Cl-Hg-Cl-Hg- and -(Cl-Hg-) 2 NCS-Hg-SCN-(Hg-Cl) 2 -which share common Hg atoms and form distorted hexagonal and trigonal channels. The hexamethylenetetramine molecules lie in the hexagonal channels. They act as μ 3 bridging ligands, forming bonds to two Hg atoms in a given layer, and an additional bond to a Hg atom a neighbouring layer.

Crystals of the adducts Zn(SCN) 2 · (C 6 H 12 N 4 ) 2 (1), and {Zn(SCN) 2 · C 6 H 12 N 4 · 2H 2 O} n (2) were obtained by crystallization from aqueous solutions containing hexamethylenetetrami­ne, potassium thiocyanate and zinc nitrate or zinc sulfate, resp., under identical conditions, as two totally different products. 1 crystallizes orthorhombically, space group P nmm, Z = 2, a = 622.4(5), b = 1152.3(7), c = 1394.0(9) pm; 2 is monoclinic, space group C2/c, a = 984.4(3), b = 1217.0(5), c = 1257.4(6) pm, and β = 111.69(5)°. The crystal structure of 1 contains discrete molecules of the complex, in which the zinc ion is tetrahedrally coordinated by two NCS ligands, and two hexamethylenetetramine molecules, which act as monodentate ligands. In 2 however, the zinc ions are octahedrally coordinated. A “supramolecular” structure is form­ed: The hexamethylenetetramine molecules act as bridging bidentate ligands and connect [Zn(H 2 O) 2 (NCS) 2 ] units forming zig-zag chains. Adjacent chains are interconnected via hydrogen bonds. The formation of the two compounds with different coordination may be due to the fact, that the educts Zn(NO 3 ) 2 · 4H 2 O and ZnSO 4 · 7H 2 O contain Zn(H 2 O) 4 and Zn(H 2 O) 6 moieties, resp., and that these species are retained in solution.

The chloro ligands in [LRuCl 3 ] (1), the crystal structure of which has been determined, are readily substituted in aqueous solution by NCO - , NCS - , and N - 3 with formation of LRu III X 3 complexes. [LRu(N 3 ) 3 ] is very thermolabile and light sensitive and forms diamagnetic [LRu II (N 3 ) 2 (N 2 )]. The thiocyanate species probably contains N- and S-coordinated NCS-ligands: [LRu(N̲CS) 2 (S̲CN)]. The electrochemistry of the new complexes is reported.

A new and efficient synthetic route to di- and tri(silyl)methane is presented. Starting from bis- and tris(phenylsilyl)methane, bis- and tris(trifluoromethanesulfonatosilyl)methane can be obtained by Si-Ph cleavage with equivalent quantities of trifluoromethanesulfonic acid (triflic acid). Their reduction with lithium aluminium hydride yields di- and tri(silyl)methane. Substitution of the previously employed liquid anhydrous hydrogen bromide by triflic acid thus offers an experimentally more simple alternative with shorter reaction times and high selectivity.

Oxysulfide chlorides, M 4 OS 4 Cl 2 , of the lanthanides (M = La - Nd) are obtained upon the oxidation of the metals with sulfur in the presence of MOCl (or M 2 O 3 ) and MCl 3 in appropriate molar ratios. Additional NaCl or an excess of MCl 3 serving as a flux provide even single crystalline material after reactions at 850 °C for seven days in sealed tantalum capsules. The crystal structure of M 4 OS 4 Cl 2 (hexagonal, P6 3 mc, no. 186, Z = 2; M = La: a = 933.19(3), c = 701.22(4) pm, c/a = 0.7514, R = RH = 0.020; M = Ce: a = 925.49(3), c = 694.13(3) pm, c/a = 0.7500; M = Pr: a = 919.72(4), c = 688.53(4) pm, c/a = 0.7486; M = Nd: a = 914.25(4), c = 683.12(4) pm, c/a = 0.7472, R = 0.022, R w = 0.019) contains isolated O 2- -centered (M 3+ ) 4 tetrahedra which are surrounded by twelve S 2- and six Cl - , capping vertices, edges, and faces of each tetrahedron and linking to other [OM 4 ] units. Basically, the structure is identical to that of Ba 4 OCl 6 if Ba 2+ is substituted by M 3+ and 2/3 of the CL - anions are replaced by S 2- to secure charge neutrality in M 4 OS 4 Cl 2 . Different models for the Cl - /S 2- replacement are presented on the basis of comparisons of the Madelung part of the lattice energy (MAPLE) with the MAPLE sum of the binaries (M 2 O 3 , M 2 S 3 , and MCl 3 ).

Gd(HSO 4 ) 3 is obtained on treatment of Gd 2 (SO 4 ) 3 in conc. H 2 SO 4 in closed vessels at 200 °C. The extremely moisture-sensitive crystals belong to the orthorhombic space group Pbca. Lattice constants are a = 12.080(8), b = 9.574(8), c = 16.513(8)Å and Z = 8. Gadolinium is coordinated by eight oxygen atoms of the hydrogensulfate ligands forming a distorted square antiprism. There are three different HSO 4 - anions within the structure. One of them is coordinated with two Gd atom s while two HSO 4 - anions bridge three Gd atoms. The Gd-O bond lengths vary in the range of 2.334(6)-2.423(5)Å .

Single crystals of KCuHo 2 Mo 4 O 16 have been prepared by recrystallisation from melts and investigated by X-ray diffractometer techniques. The compound crystallizes with monoclinic symmetry, space group C 2/c, a = 521.6(1), b = 1251.3(2), c = 1953.1(2) pm, β = 92.903(18)°, Z = 4. KCuHo 2 Mo 4 O 16 represents a new structure type characterized by HoO 8 and alternate CuO 6 /KO 10 polyhedra chains. The connection of these polyhedra chains to each other and by MoO 4 tetrahedra is described and the crystal structure discussed with respect to related compounds of the CuLnMo 2 O 8 and KLnMo 2 O 8 types.

Single crystals of KBaCuV 2 O 7 Cl have been prepared by a flux technique and investigated by X-ray analysis. The compound crystallizes with tetragonal symmetry, space group C 2 4v -P4 bm, a = 8.8581, c = 5.4711 Å, Z = 2. The crystal structure shows Cu 2+ within a one sided strongly distorted CuO 4 Cl 2 octahedron. The copper ion is shifted towards the nearer Cl - neighbour to form a CuO 4 Cl square pyramid. Two VO 4 tetrahedra are connected to give stretched V 2 O 7 double tetrahedra, and linked in planes via the oxygen corners of the CuO 4 Cl pyramids. The crystal structure and the structure of the complex BaO 8 Cl 2 polyhedron are discussed.

1,3,5-Trichlortriazinium hexachloroantimonate has been prepared by the reaction of CCl 2 = N-COCl with antimony pentachloride in boiling dichloromethane. The compound was characterized by IR spectroscopy and by a crystal structure determination. [HC 3 N 3 Cl 3 ]SbCl 6 crystallizes in the monoclinic space group P2 1 /n with four formula units per unit cell. 2503 observed unique reflections, R = 0.029. Lattice dimensions at 19 °C: a = 1314.1(1), b = 958.2(1), c = 1329.1(1) pm, β = 117.113(5)°). The compound forms ion pairs via a linear N-H ··· Cl bridge, thus distorting the SbCl 6 - ion from octahedral geometry. The C 3 N 3 skeleton of the [HC 3 N 3 Cl 3 ] + ion is nearly planar, but the hydrogen atom lies about 30 pm out of this plane.

The compounds [FeL 1 (MeOH)Cl] 2 (1), [FeL 2 Cl] 2 (2) and [FeL 3 Cl] 2 (3), with L 1 for N-2-hydroxy-4-chlorophenylsalicylaldimin, L 2 for N-2-hydroxyphenyl-3-hydroxy-2-naphthaldimin, and L 3 for N-2-hydroxy-4-chlorophenyl-3-hydroxy-2-naphthaldimin, have been synthesized. 1 crystallizes in the monoclinic system, space group P2 1 /c. The lattice parameters are a = 7.347(1), b = 21.390(1), c = 9.555(2) Å, β = 104.92(1)° with Z = 2. The crystal structures of 2 and 3 were reported previously. In all structures, two identical [FeL] fragments, related by an inversion center, are connected by two bridging oxygen atoms to form a binuclear unit in the supported condition. Magnetic susceptibility measurements in the range 4.2 < T < 286.5 K re­vealed the diiron (III) centers of 1, 2, and 3 to be weakly antiferromagnetically coupled with spin exchange coupling constants J 1 = -7.7(1) cm -1 , J 2 = -6.5(1) cm -1 , and J 3 = -10.9(1) cm -1 , respectively.

The thermolysis of Na[C 8 H 14 B(Et)OH] (2), prepared from 9-Et-9-BBN (1) and NaOH, leads at about 100 °C in the presence of NaHBEt 3 as catalyst to ethane and the solid NaOBC 8 H 14 (3), which crystallizes with one mole THF as the tetrameric heterocubane 4 in the triclinic space group P1̄. The lattice constants of 4 (at 120 K) are: a = 1127.7(2), b = 1179.5(2), c = 2055.9(4) pm; α = 87.06(2), β = 87.83(2), γ = 75.37(2)°. 4 contains a slightly distorted central Na 4 O 4 cube with C 8 H 14 B and THF substituents at the oxygen and the sodium atoms respectively. 3 can also be prepared by heating an equimolar mixture of Na[H 2 BC 8 H 14 ] (5) and Na[(HO) 2 BC 8 H 14 ] (6), or from (9H-9-BBN) 2 and NaOH and from 9-HO-9-BBN and NaH in THF.

The trans-dimer of (9-HS-9-BBN) 2 (1) 2 , obtained from H 2 S with (9H-9-BBN) 2 or with (9-BBN) 2 S, crystallizes in the monoclinic space group C2/m [lattice constants (at 120 K): a = 15.279(2), b = 15.909(3), c = 6.822(4) Å; β = 91.05(4)°] with a planar B 2 S 2 ring. The cis-dimer of (9-HSe-9-BBN) 2 (2) 2 , obtained from (9-BBN) 2 Se with aniline, crystallizes in the monoclinic space group P2 1 /n [lattice constants (at 225 K): a = 6.892(1), b= 20.623(3), c = 12.226(2) Å; β = 97.28°] with an folded B 2 Se 2 ring.

Hexacarbonyl-μ-η 5:5 -fulvalene-dimolybdenum (1) reacts photochemically with 1,3-cyclopentadiene (a), and 1,3-cyclohexadiene (b) to yield the corresponding tetracarbonyl-η 4 -1,3-cyclodiene-μ-η 5:5 -fulvalene-dimolybdenum complexes 4a, 4b. With a also mixed valent tricarbonyl-η 5 -cyclopentadienyl-μ-η 5:5 -fulvalene-hydrido-dimolybdenum (3) is formed. Hexacarbonyl-μ-η 5:5 -fulvalene-ditungsten (2) yields with a only tricarbonyl-η 5 -cyclopentadienyl-μ-η 5:5 -fulvalene-hydrido-ditungsten (5). The η 4 -1,3-cyclodiene ligands in 4a, 4b are u-oriented towards fulvalene. The complexes 4a, 4b show hindered inversions with energy barriers of ΔG # 273 = 59.9 ± 2 kJ/mol (4a) and ΔG # 293 , = 62.7 ± 2 kJ/mol (4b).

Reaction of 1,2-hydroxyketones 5 with (2,2-diethoxyvinylidene)triphenylphosphorane (2) or (2,2-diethoxyvinyl)triphenylphosphonium tetrafluoroborates 6 yields the 2,2-diethoxy- 2.5-dihydrofurans 9. Depending on the reaction conditions used, the orthoesters 9 can be hydrolized to give 2(5 H)furanones 10 and 2-ethoxyfurans 11, respectively. 4,5-Dimethyl- 5.6-dihydro-2-pyranone (20) and 8-methoxycoumarin (23) are prepared, starting from (2,2-diethoxyvinyl)triphenylphosphonium tetrafluoroborate (6 a) and 1-hydroxy-2-methyl- 3-butanone (16) or 2-hydroxy-3-methoxy-benzaldehyde (21). The 2-ethoxyfuranes 11 readily undergo Diels-Alder reactions with 2-chloracrylonitrile (24), maleic anhydride (26), N-phenyl-1,2,4-triazoline-3,5-dione (28) and dimethyl acetylenedicarboxylate (30) to give the corresponding Diels-Alder products 25, 27, 29 and 31, respectively. Contrary to 2-ethoxyfuran 11b , 11a reacts with two equivalents of acetylene 30, to yield barrelenone 34. The structure of 34 unequivocally is established by X-ray structure analysis.

Three new bivalent opioid peptide analogues, 1,3-di-(tyrosyl-D-alanyl-glycyl-phenylalanylamido)-2-propanol, 1,4-di-(tyrosyl-D-alanyl-glycyl-phenylalanylamido)-(2R, 3S)-butanediol and 1,4-di-(tyrosyl-D-alanyl-glycyl-phenylalanylamido)-(2R,3R)-butanediol, were synthesized and tested in vitro for μ, δ and ϰ receptor affinities. They were found to have potent opioid receptor binding activity. The (2S,3S)-butanediol bridge configuration yielded selectivity and high potency for μ and ϰ receptors, while the (2R,3R)-butanediol bridge configuration yielded high potency and selectivity for δ receptors. It thus appears that changes in the length and configuration of the polyhydroxyl bridge in dimeric enkephalin analogues can produce a shift in receptor selectivity profiles and therefore suggest the possibility of developing more selective drugs.

The isobaric melting and boiling diagrams for the systems: dimethyldichlorosilane/pyridine and 2,2-dichloropropane/pyridine are reproduced. The existence of the incongruently melting addition compounds (CH 3 ) 2 SiCl 2 · (Pyridine) 2 and [(CH 3 ) 2 CCl 2 ] 3 · Pyridine could be proved. Some measurements of the molar volume of mixtures of pyridine and dimethyldichlorosilane, and pyridine and 2,2-dichloropropane are reported. For both systems the molar excess volume has been calculated as a function of the mole fractions.

A unique, general redox process for the preparation of secondary amides by the interaction, of aldehydes with nitriles in the presence of two equivalents of iodotrichlorosilane (ITCS) is described and possible pathways are discussed.

The crystal structure of AsF 5 · is reported. It crystallizes in the orthorhombic space group Pnma with a = 749.1(3) pm, b = 770.6(3) pm and c = 1630.0(5) pm, V = 960.9(6) · 10 6 pm 3 , Z = 4.

[{Cp(CO) 2 Fe} 2 SnCl 2 ] reacts with AgBF 4 to form [{Cp(CO) 2 Fe} 2 Sn(F)FBF 3 ] 1.1 crystallizes in two monoclinic modifications with a = 1018.2(4), b = 1321.1(5), c = 1364.8(5) pm, β = 104.96(4)° (1a), and a = 983.1(2), b = 1760.2(6), c = 1060.4(3) pm, β = 104.28(2)° (1b). 1a and 1b contain a nearly tetrahedrally coordinated tin atom which is bonded to two {Cp(CO) 2 Fe} fragments, a F atom and a BF 4 group.

N-M ethyl-2-dimethylaluminium pyrrolide, (CH 3 ) 2 Al -C 4 H 3 NCH 3 , crystallizes in the triclinic space group P1̄ with the lattice constants a = 700.5(1), b = 725.9(1), c = 886.8(1) pm, α = 67.69(1)°, β = 70.99(1)°, γ = 88.48(1)°, and Z = 2. This compound is isotypic with the gallium homologue [1], the shortest metal-ring contact between the two molecules of one unit cell decreases to 228.6 pm. N-dimethylgallium tetramethylpyrrolide has been synthesized from Li-N (CCH 3 ) 4 and (CH 3 ) 2 GaCl. This “π-associate” crystallizes in the monoclinic space group P2 1 /c with the lattice parameters a = 989.9(2), b = 1305.4(3), c = 878.3(2) pm, β - 112.73(1)° and 4 units per cell. Again two centrosymmetrically orientated molecules form a dimer by short (224.0 pm) intermolecular “Ga - πC ” contacts but the structure differs significant from the structure of the indium homologue [1].

[Na(12-crown-4) 2 ] 2 [Fe 4 Se 4 Cl 4 ] has been prepared by the reaction of FeCl 2 with Na 2 Se 4 in dimethylformamide solution in the presence of 12-crown-4 as dark red crystals, which were characterized by a crystal structure determination. Space group P1̄, Z = 2, 6295 observed unique reflections, R = 0.085. Lattice dimensions at 20 °C: a = 1397.3(3), b = 1501.8(4), c = 1570.1(4) pm, α = 85.86(2)°, β = 64.06(2)°, γ = 65.01(2)°. The structure consists of [Na(12-crown-4) 2 ] + cations and cuban-like anions [Fe 4 Se 4 Cl 4 ]2 + with Fe ··· Fe contacts o f 282.8(3) pm.