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  • Author: Wolfgang Milius x
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The crystal structures of CuTe2Br and CuTe2I have been refined on the basis of single crystal data. Both compounds crystallize monoclinically in space group P21/c. The structures are isotypic with that of CuTe2Cl. The lattice parameters of CuTe2Br are a = 834.5(8) pm, b = 492.8(4) pm, c = 1573.3(5) pm and β = 135.3(2)°. The unit cell dimensions of CuTe2I are a = 866.5(8) pm, b = 491.4(4) pm, c = 1649.6(3) pm and β = 135.1(2)°.

Abstract

The chlorinated titanium amides [(Cl3Si)2N]2TiCl2 (1) and (Cl3Si)2NTiCl3 have been syn­thesized selectively from hexachlorodisilazane lithium and TiCl4. The crystal structure of 1 was determined by single crystal X-ray methods at room temperature (P212121, a = 1232.4(2), b = 1265.5(2), c -1469.1(2) pm, Z = 4). The central titanium atom of 1 is bound to two nitrogen atoms and two Cl atoms and is weakly coordinated further by two Cl atoms of the trichlorosilyl groups.

A series of trinuclear carbonylmetal complexes of tri(1-cyclohepta-2,4,6-trienyl)phosphane, P(C7H7)3 (1), has been prepared by the reaction of P(SiMe3)3 with η7-tropylium halfsandwich salts, [(η7-C7H7)M(CO)3]BF4, (M = Cr, Mo, W). While phosphorus remains uncoordinated in the chromium complex P[(η6-C7H7)Cr(CO)3]3 (2a), the molybdenum and tungsten analogues, (M = Mo (2b), W (2c)), contain a coordinated phosphorus atom together with a η4-norcaradienyl substituent. Reaction of 2a with pentacarbonylmetal fragments, [M(CO)5], leads to trinuclear products, - (CO)4][(η-C7H7)M(CO)3]2 (M = Cr (5a), W (5c)), in which phosphorus is coordinated next to an η2-cycloheptatrienyl substituent. Several alkyl- and arylphosphanes containing [(η6-C7H7)Cr(CO)3] substituents (X), e. g. Ph2P(X) (6a), RP(X)2 (R = Me (7a), CH2Ph (8a), Ph (9a)) and (X)2P(R')P(X)2 (R' = methylene (10a) or ο-phenylene (11a)), have also been synthesized. The chromium complexes 6a - 11a contain an uncoordinated phosphorus center, but in contrast to 9a, the corresponding tungsten compound PhP (9c) has again a structure similar to 2c. The arsenic complexes, As[(η6-C7H7)M(CO)3]3 (M = Cr (12a), W (12c)) both contain an uncoordinated arsenic center, analogous to 2a. The molecular structures of all new complexes in solution at room temperature were deduced from a consistent set of 1H, 13C and 31P NMR data, and X-ray structure determinations were carried out for 2a and 5c.

2-Phenoxy-1,3,2-diazaphospha-[3]ferrocenophane and related derivatives (oxide, sulfide, selenide) were prepared, characterized in solution by multinuclear magnetic resonance methods (1D and 2D 1H, 13C, 15N and 31P NMR) and in the solid state by X-ray structural analysis. The conformation of the 2-phenoxy derivative differs from that of the 2-tert-butyl compound. For further comparison, 2-R- 2,3-dihydro-1H-1,3,2-diazaphospha-phenalene derivatives R = 'Bu, PhO were prepared and studied by the same NMR techniques. The molecular structure of a selenide was determined, and together with the NMR evidence, it was concluded that the conformation of these heterocycles is independent of the respective substituent at the phosphorus atom

The molecular structure of tri(2-thienyl)borane (1) was determined [monoclinic, space group P21/ c; a = 12.216(2), b = 7.765(2), c = 12.605(2) Å, β = 93.13(2)°]; two of the three thienyl groups are disordered, as is also indicated by the solid-state 13C CP/MAS NMR spectrum of 1. The 13C NMR spectra of 1 were measured at variable tem perature in solution and the barrier to rotation about the B-C bonds was found to be <35 kJ/mol. Thus, CB(pp)π interactions must be regarded as rather weak, in spite of suggestive δ11 B. δ13C data and structural parameters.

Hexacarbonyl diiron complexes of N-substituted sulfimides (SNR) have been obtained from the parent tetrahedrane, Fe2(CO)6(μ-SNH) (1), by deprotonation to give the anion Fe2(CO)6(μ-SN-) (2) and subsequent reaction with either trialkyloxonium or carbenium tetrafluoroborates. The new aza-diferra-thia-tetrahedranes, Fe2(CO)6(μ-SNR) (R = CH3 (3a), C2H5 (3b), CPh3 (3c), cyclo-C3Ph3 (3d), cyclo-C7H7 (3e), and cyclo-(C7H7)M (CO)3 with M = Cr (3f), Mo (3g), W (3h)) were characterized by their 1H and 13C NMR as well as their IR and MS spectra. The molecular structure of Fe2(CO)6[SN-cyclo-C7H7Mo(CO)3] (3g) has been determined by X-ray diffraction.

Abstract

N-Lithio-N-trimethylsilyl-9-amino-9-borabicyclo[3.3.1]nonane (2) was prepared from the reaction of N-trimethylsilyl-9-amino-9-borabicyclo-[3.3.1]nonane (1) with rert-butyl lithium; 2 crystallizes as a trim er with a planar N3Li3 ring. The nitrogen atoms are tetrahedrally coordinated, but should be treated as sp2 hybridised, because the BN double bond, typical of aminoboranes, is retained.

Complexes of the types R3Pb-Fe(CO)2Cp [R=Me (a). Et (1b), iPr (lc), iBu (Id)]. R2Pb[Fe(CO)2Cp]2 [R=Me (2a), Et (2b)], iPr2(Br)Pb-Fe(CO)2Cp (3c) and [R2PbFe(CO)4]2 [R=Me (4a), Et (4b). iPr (4c)], as well as the spiro-complexes Pb[Fe(CO)4PbR2]2 [R = Me (5a). Et (5b). iPr (5c)] and Pb[Fe(CO)4]4 (6) were studied by multinuclear magnetic resonance spectroscopy (1H. 13C, 207Pb NMR). For the first time, coupling constants 1J(207Pb57Fe) were determined, covering a range between 33.5 (6) and 117 Hz (4a). The magnitude of the geminal coupling constants ∣2J(207Pb207Pb) ∣ in the spiro-compounds 5 decreases from 1090.0 Hz (5a) to 377.0 Hz (5c). The signs of the coupling constants nJ(207Pb13C(R)) (n = 1, 2) and nJ(207Pb1H(R)) (n = 2, 3) were determined by various 2D NMR experiments. Among all known Pb(IV) compounds the lowest 207Pb nuclear magnetic shielding was found in Pb[Fe(CO)4]4 (6): δ207Pb +3586.6. According to the single crystal X-ray structure determination of 4b (orthorhombic; space group Pbca; a = 967.4, b = 1367.7, c = 1772.4 pm), the Pb2Fe2 ring is planar with bond angles FePbFe = 102.8° and PbFePb = 77.2°, and there is a relatively short transannular distance of 340.8 pm between the two lead atoms.

Various six-membered cyclic sulfur diimides (3a—f) were prepared by aminolysis of the bis(chloro-dimethylsilyl)sulfur diimide (2) using NH3 (a) and primary amines RNH2 [R = Me (b), Et (c), nPr (d), nBu (e), iPr (f)]. Except for R = H, non-cyclic intermediates, the Si-monoamino- (7) and Si,Si′-diamino derivatives of 2 (8), were detetected for all groups R, including R = tBu (g). The reaction between R2SiCl2 and the sulfur diimide anion K[(NSN)SiMe3] gave non-cyclic silanes (9,10) and the eight-membered rings of the type R2Si(NSN)2SiR2 [R = Me (4), tBu (5)] of which 5 was studied by X-ray analysis (monoclinic, space group P21/c; planar ring system) and solid-state 15N and 29Si CP/MAS NMR spectroscopy. The ten-membered ring system 6 was obtained from the reaction between 1,2-dichlorotetramethyldisilane and bis(trimethylstannyl)sulfur diimide. All compounds were studied by 1H,13C, 15N and 29Si NMR. The δ15N NMR data proved useful to distinguish between fluxional systems with fast E/Z—Z/E isomerization (non-cyclic compounds 8 and the ten-membered cycle 6). Hahn-Echo-extended (HEED) polarization transfer (INEPT) pulse sequences served to measure coupling constants 1J(29Si15Namine) for the compounds 3 and 8. This also proved that the magnitude of 1J(29Si15NNSN) must be small (&lt; 1 Hz). In the case of the compounds 3, the rather small magnitude of both 1J(29Si15Namine) and 1J(15N1H) (3a) indicated that the aminonitrogen atom adopts a pyramidal environment.