Volume 58, Issue 4

The reaction of [ t BuN=VCp(PMe 3 ) 2 ] (1) with S 8 , Se, Te or I 2 have been studied. Via this pathway dinuclear diamagnetic tert-butylimidovanadium(IV) complexes are formed: [(μ-E)(μ- N t Bu) 2 V 2 Cp 2 ] (E=S, Se, Te), [(μ-η 1 −E 2 )(μ-N t Bu) 2 V 2 Cp 2 ] {E=Se (3), Te}, [(μ-N t Bu) 2 V 2 Cp 2 I 2 ]. In addition the vanadium(V) complexes [ t BuN=VCp (S 5 )] (9a) and t BuN=VCpI 2 could be isolated. The synthesis of t BuN=VCpF 2 is also described. All compounds obtained have been characterized by spectroscopic methods (MS; 1 H, 13 C, 51 V NMR), 3 and 9b by single crystal X-ray diffraction analysis.

Ethyltrifluorosilane reacts with tert-butyllithium in a molar ratio 1:2 to give Et(CMe 3 ) 2 SiF (1), which forms the aminosilane, Et(CMe 3 ) 2 SiNH 2 (2) in the reaction with NaNH 2 . The lithium salt of 2 and (Me 3 C) 2 SiF 2 gives (Me 3 C) 2 SiF-NHSi(CMe 3 ) 2 Et (3). 3 reacts with BuLi to give the lithium salt, (Me 3 C) 2 SiF-NLi-Si(CMe 3 ) 2 Et (4). tert-Butyl-(di-tert-butylfluoro)-silylaminoalanes (Me 3 C) 2 SiF-NCMe 3 -AlR 2 , R = Me (5), Et (6) are formed in the reaction of (Me 3 C) 2 SiF-NLi CMe 3 (I) and ClAlR 2 . The lithium salt (Me 3 C) 2 SiF-NLi-Si(CMe 3 ) 2 Me (III) reacts with BF 3 under formation of the bis(silyl)aminodifluoroborane (Me 3 C) 2 SiF-N(BF 2 ) Si(CMe 3 ) 2 Me (7). In the reaction of I with F 3 SiPh rotamers of (Me 3 C) 2 SiF-NCMe 3 SiF 2 Ph (8) are obtained. Stannyl-silylamines are prepared in reactions of the lithium salts (Me 3 C) 2 SiF-NLiR, R = CMe 3 (I), SiF(CMe 3 ) 2 (II); Si(CMe 3 ) 2 Me (III) and the chlorostannanes ClSnMe 3 (9,10,11) and Cl 2 SnPh 2 (12), (Me 3 C) 2 SiF-NSnMe 3 -Si(CMe 3 ) 2 R (9: R = F, 10: R = Me), (Me 3 C) 2 SiF-NSnMe 3 CMe 3 (11), (Me 3 C) 2 SiF-NCMe 3 SnClPh 2 (12). The NMR spectra of 9 and 10 prove the existence of rotamers. The reaction of III with Me 3 SiOSO 2 CF 3 in n-hexane leads to the formation of the tris(silyl)amine 13, (Me 3 C)SiF-NSiMe 3 ) 2 Si(CMe 3 ) 2 Me. However, the analogous reaction of III and 4 with Me 3 SiOSO 2 CF 3 in thf leads to the formation of the stable iminosilanes 14 and 15, (Me 3 C) 2 Si==N- Si(CMe 3 )R, R = Me (14), Et (15) crystal structures of 7 and 12 are presented.

A new oxoborate β -CaB 4 O 7 has been synthesized under high-pressure/high-temperature conditions from calcium oxide and boron oxide with a Walker-type multianvil apparatus at 7.7 GPa and 1100 °C. Single crystal X-ray structure determination of β -CaB 4 O 7 revealed: Pmn2 1 , a = 1058.4(1), b = 436.9(1), c = 419.4(1) pm, Z = 2, R1 = 0.0305, wR2 = 0.0587 (all data). The compound is isotypic to the known oxoborates SrB 4 O 7 , PbB 4 O 7 , and EuB 4 O 7 exhibiting a network structure of linked BO4 tetrahedra. As a prominent feature of the tetrahedral network an oxygen atom is coordinated to three boron atoms. The relation of the crystal structure of the high-pressure phase β -CaB 4 O 7 to the normalpressure phase α-CaB 4 O 7 as well as the relation to the isotypic phases MB 4 O 7 (M = Sr, Pb, Eu) are discussed. The results of IR-spectroscopic investigations on β -CaB 4 O 7 are also presented.

Reaction of freshly precipitated Mn(OH) 2−2x (CO 3 ) x · yH 2 O, adipic acid and phenanthroline in CH 3 OH/H 2 O afforded a new dinuclear Mn(II) complex, Mn 2 (phen) 2 (H 2 O) 2 (C 6 H 8 O 4 ) 2 1, aside the known [Mn(phen) 2 (H 2 O)(C 6 H 8 O 4 )]·7H 2 O 2. Single crystal X-ray analyses showed that complex 1 consists of the centrosymmetric dinuclear molecules resulting from two [Mn(phen)(H 2 O)] 2+ moities bridged by two twisted tridentate adipato ligands. The Mn atoms are each in severely distorted octahedral geometry defined by two N atoms of one phen ligand, three carboxyl O atoms of two adipato ligands and one H 2 O molecule with d(Mn-N) = 2.246 and 2.296 Å and d(Mn-O) = 2.066 - 2.339 Å . The complex molecules are assembled via π-π stacking interactions into 2D layers, which are held together by both strong O-H ··· O and weak C- H ··· O hydrogen bonds. The thermal behavior of 1 and 2 upon heating in argon stream is discussed.

Mn[Cu(L)(O 2 CMe) 2 ] · H 2 O (L = N,N’-bis(2-hydroxy-3-methoxybenzylidene)-1,3-diaminopropane) was synthesized and the crystal structure determined. (C 23 H 26 CuMnN 2 O 8 ).H 2 O, monoclinic, space group P2 1 /c, a = 12.017(3), b = 8.217(3), c = 24.786(4) Å , β = 92.10(2)°, V = 2446(1) Å 3 , Z = 4. The crystal structure consists of ordered dinuclear units with Cu II and Mn II ions bridged by two oxygen atoms of the Schiff base ligand. The Cu II coordination sphere is a slightly distorted square-plane formed by the N 2 O 2 donor set of the Schiff base ligands. The average Cu-O and Cu-N distances are 1.920(1) and 1.957(4) Å , respectively. The coordination around the Mn II ion is a distorted tetrahedron with the donor oxygen atoms of the Schiff base ligands and oxygen atoms of the acetate anions. The Cu ··· Mn separation is 3.327(4) Å . There is also one non-coordinating water molecule in the crystal structure. The χ and χT versus T plots, χ being the molar magnetic susceptibility per Cu II Mn II unit and T the temperature, has been measured in the 4.9 - 301 K temperature range. The values of the interaction parameters are J = −28.3 cm −1 , g Mn = 2.01, g Cu = 2.07. This indicates an intramolecular antiferromagnetic interaction between Cu II and Mn II ions.

High-pressure/high-temperature conditions of 8 GPa and 1000°C were used to synthesize the new rare earth oxoborates RE 4 B 6 O 15 (RE = Dy, Ho) in a Walker-type multianvil apparatus. The single crystal X-ray structure determination of Ho 4 B 6 O 15 revealed the following data: C2/c, a = 1164.1(1), b = 436.7(1), c = 1882.5(1) pm, β = 96.71(1)°, Z = 4, R1 = 0.0291, wR2 = 0.0505 (all data). The two isotypic compounds exhibit a new structure type built up from corrugated layers of BO 4 tetrahedra. In contrast to all known oxoborates the linking of the BO 4 tetrahedra is partially realized via common edges. Regarding the “fundamental building block”-concept, we introduce a new descriptor “” for edge-sharing BO 4 tetrahedra. Temperature-resolved in situ powder diffraction measurements and IR/Raman-spectroscopic investigations on Dy 4 B 6 O 15 are also reported.

Sulfurdiimides RN=S=NR react in donating solvents with two equivalents of lithiumalkyls to give the dimeric C,N-dilithium-methylenediimidosulfite solvent adducts [(Et 2 O)Li 2 {H 2 CS-(NSiMe 3 )(N t Bu)}] 2 (1) and [(thf)Li 2 {H 8 C 4 S(N t Bu) 2 }] 2 (2). Firstly, addition of a lithiumalkyl to sulfurdiimide gives the diimidosulfinates [RS(NR')2] - (1: R = Me, R′ = t Bu, SiMe 3 ; 2: R = nBu; R′ = t Bu) while in a second step the α-carbon atom in R is metalated with one equivalent of lithiumalkyl to give the asymmetric S-ylides. The reaction of 3-bromothiophene with one equivalent of nBuLi and one of sulfurdiimide t BuN=S=N t Bu resulted in the dilithium-3-thiophenylenediimidosulfite [(thf)Li2{(SC 4 H 2 )S(N t Bu) 2 }] 2 (3). It can be regarded as the first example of a dianionic S(IV)-β-ylide. This class of compounds can be rationalised as sulfite analogues, where two oxygen atoms are isoelectronically replaced by a NR group each and the remaining oxygen atom is replaced by a CR 2 group. The rich coordination chemistry of the triimidosulfites is extended by the introduction of a hard carbanionic centre.

The reaction of Cp*V(CO) 4 (1) with molecular oxygen in diluted pentane solution leads to a tetrameric dioxide, [Cp*V(O)(μ-O)] 4 (2), which is a precursor of the octanuclear aggregate Cp* 6 V 8 O 17 (3). The molecular structures of 1 and 2 have been determined by X-ray crystallography.

Treatment of 1-methylimidazol-2-yl lithium with Cp 2 Zr(Cl)CH 3 (6) gave the corresponding methyl(1-methyl-2-imidazolyl)zirconocene complex 7. Treatment of 7 with B(C 6 F 5 ) 3 (8) led to selective methyl abstraction. The resulting (imidazolyl)zirconocene cation 9 dimerized under the reaction conditions to yield the dinuclear imidazolyl bridged bis(zirconocene) dication complex 10 that was structurally characterized by X-ray diffraction and by DFT calculations.

The 1,1-dithiolates Ph 2 C═N-C(CO 2 Et)═CS 2 2− and Me 2 NC(CO 2 Et)═CS 2 2− from diphenylmethylene glycine ethylester or N,N-dimethylglycine ester and CS 2 react under basic conditions with chlorophosphine compounds of Pd(II), Pt(II) and gold(I) to give the complexes Ph 2 C═N-C(CO 2 Et)═CS 2 ML 2 , Me 2 N-C(CO 2 Et)═CS 2 ML 2 (M = Pd, Pt; L = PPh 3 , 2L = Ph 2 PCH 2 CH 2 PPh 2 ) and Ph 2 C═N-C(CO 2 Et)═CS 2 (AuPPh 3 ) 2 , and Me 2 N- C(CO 2 Et)═CS 2 (AuPPh 3 ) 2 . The structures of the palladium complex Ph 2 C═N-C(CO 2 Et)═CS 2 Pd(PPh 3 ) 2 and of diphenylmethylene- L-alanine ethylester were determined by X-ray diffraction. Besides this S,S-complex also the (less stable) S,O-isomer could be detected.

Reactions of chloro bridged complexes with R-3-(3-pyridyl)alanine afford the chelate complexes L n M[NH 2 CH(CO 2 )CH 2 C 5 H 4 NH + ]Cl − (L n M = Ph 3 P(Cl)Pd, (tol 3 P)(Cl)Pd, (Ph-pyridyl) 2 Ir, Cp٭(Cl)Rh, Cp٭(Cl)Ir, (p-Cymol)(Cl)Ru) with protonated pyridine substituents. An analogous Cp٭Rh complex with 3-(2-pyridyl)alaninate was also obtained. Addition of base (NaOMe) to these complexes gives dimeric and trimeric complexes with coordination of the pyridine N atom.

A reinvestigation of the acetone extract of the root of Salvia phlomoides (Labiatae) allowed the isolation of a new abietane diterpenoid whose structure (6,11-dihydroxy-12-methoxy-5,8,11,13-abietatetraen- 7-one) was established by exhaustive NMR spectroscopic studies and by partial synthesis from 14-deoxycoleon U, another abietane constituent of the same extract. The physical and spectroscopic data of the methoxyabietane isolated from S. phlomoides were identical to those reported for another diterpenoid previously found in Cryptomeria japonica (Taxodiaceae), to which the regioisomeric structure 6,12-dihydroxy-11-methoxy-5,8,11,13-abietatetraen-7-one had been erroneously attributed by other authors.

Herein we describe the synthesis of t-butyldimethylsilyl protected quinol (9), using an oxidation/ reduction sequence to create the desired orthogonality. The title compound acts as a synthetic equivalent for a quinone, required in the total synthesis of Elisabethin A. It contains a masked quinone and therefore is a suitable precursor for the quinone moiety of this diterpenoid.

A continuing study on the phytochemical constituents of Garcinia atroviridis Griff ex T. Anders (Guttiferae) has led to the isolation of a new prenylated hydroquinone from the roots of the plant. The compound has been elucidated to be 4-methylhydroatrovirinone, primarily by the use of gradient NMR and mass spectroscopy. The roots also yielded the known morelloflavone and its 7-O-β-D-glucopyranoside, fukugiside, together with 14-cis-docosenoic acid.

Two diorganotin(IV) complexes of general formula R 2 Sn[ 2 -OC 6 H 4 CH=NDN=C(O)Ph] (R = Ph, 1; R = Me, 2) have been synthesized from the corresponding diorganotin(IV) dichloride and the Schiff base derived from salicylaldehyde and benzoyl hydrazide. The two compounds have been characterized by elemental analysis, IR and NMR ( 1 H, 13 C, 15 N, 119 Sn) spectra, and their structures have been confirmed by single crystal X-ray structure analysis. Crystals of complex 1 re triclinic, space group P1̄ , a = 11.1631(5), b = 13.462(2), c = 16.511(1) Å , α = 106.193(9), β = 106.379(8), γ = 94.932(8)°, Z = 4, R 1 = 0.0461, wR 2 = 0.0939 for 13194 unique reflections. Crystals of 2 are monoclinic, space group P2 1 , a = 10.2073(5), b = 14.645(2), c = 10.411(3) Å, β = 92.572(9)°, Z = 4, R 1 = 0.0395, wR 2 = 0.0835 for 5050 unique reflections. The central tin atom of either complex adopts a distorted trigonal bipyramidal coordination with two ligand oxygen atoms in axial positions, the nitrogen atom of the ligand and two organic groups on tin occupying equatorial sites. The δ( 119 Sn) values for the complexes 1 and 2 are -329.2 and -150.3, respectively, thus indicating penta-coordinated tin centres.

Starting from a suitable protected (fluorocyclopropyl)methanol derivative a novel class of cyclopropanoid monofluorinated nucleoside analogues can be accessed very conveniently by a short sequence of steps.

The crystal structure of a new 1:1 complex of dimethyl carbonate and 2,4,6-tris(trifluoromethyl)-1,3,5-triazine is reported. A high tendency of sublimation was observed by differential thermal analysis (DTA) and thermogravimetry (TG). Donor-acceptor interactions between dimethyl carbonate and 2,4,6-tris(trifluoro-methyl)-1,3,5-triazine are assumed to be responsible for the complex formation.

The red title compound was synthesized by the metathesis reaction of [FeCl 2 (dppe)] (dppe = Ph 2 PCH 2 ) 2 PPh 2 ) and NaS-tBu in THF. The X-ray structure analysis revealed a dinuclear complex with two iron(II) centers coordinated in a distorted tetrahedral fashion by two bridging thiolates, one bridging dppe molecule and one terminal chloro ligand.