Stefan Jäger

Synthesis and Structural Studies of Pyridine‐2‐selenolates − Reactions with Electrophilic Phosphorus(III) Compounds and Related Complex Chemistry

The reaction intermediates in the synthesis of 2,2′-bis(pyridyl) diselenide (2,2′-Py2Se2) have been determined. The reaction of Na2Se2 with 2-BrC5H4N (2-BrPy) leads to a tautomeric mixture of pyridine-2-selenol (2-PySeH) and pyridine-2(1H)-selone (2-PyHSe), which have been investigated by spectroscopic means. Additionally, the crystal structure of the latter has been determined. Reductive cleavage of the Se−Se bond in 2,2′-Py2Se2 with KBsBu3H leads to K-2-SePy, which was trapped, either as [(18-crown-6)K]+[2-PySe]−, whose structure contains polymeric cation−anion chains, or as [Et4N]+[2-PySe]−. Reactions of K-2-SePy or [Et4N]+[2-PySe]− with Ph2PCl, tBu2PCl, or tBuPBr2 lead to the corresponding, extremely air-sensitive (pyridyl)selenophosphanes Ph2P-2-SePy, tBu2P-2-SePy, and tBuP(2-SePy)2. The latter was trapped as tBuP(O)(2-SePy)2, whose crystal structure has been determined. Metal complexes of these (pyridyl)selenophosphanes have been prepared starting from the phosphane and CuBr, AgBr, (tht)AuCl (tht = tetrahydrothiophene), or [(η6-C7H8)Mo(CO)3], in one-pot syntheses. All crystal structures of the resulting metallacycles [({(C5H4N-2-Se)tBu2P}-N,P)Cu(µ-Br)]2, [({(C5H4N-2-Se)tBu2P}-N,P)Ag(µ-Br)]2, [({(C5H4N-2-Se)tBu2P}-P)AuCl], and [({(C5H4N-2-Se)2tBuP}-N,N′,P)Mo(CO)3], were determined. Additionally, comprehensive spectroscopic investigations are presented.

Organometallic selenolates. Part 2. A new synthesis of dimeric (selenolato) tetracarbonylmanganese(I) complexes. Crystal structures of [Mn(CO)4SeR]2; R = CH2 Ph, C(O) Ph and CO2Me

Abstract Dimeric selenolato-carbonyl manganese(I) complexes [Mn(CO) 4 SeR] 2 (R = CH 2 Ph, C(O)Ph, CO 2 Ph, CO 2 Me) have been synthesised via reaction of elemental selenium with NaMn(CO) 5 and subsequent reaction with the corresponding organohalides in one-pot syntheses. They have been characterised by spectroscopic methods ( 1 H, 13 C, 77 Se) and the chemical shifts have been compared with the assumed reaction intermediate [Mn(CO) 4 Se] 2 Na 2 . Additionally, X-ray crystal structure analyses have been performed for [Mn(CO) 4 (SeR)] 2 (R = CH 2 Ph, C(O)Ph, CO 2 Me).

1,3,5-Triphosphorinane. Synthese und Struktur der Isomeren des 1,3,5-Triphenyl-1,3,5-triphosphorinans/ 1,3,5-Triphosphorinanes. Synthesis and Structure of the Isomers of 1,3,5-Triphenyl-1,3,5-triphosphorinane

The reaction of lithiated Ph(H)PCH2P(H)Ph with (ClCH2)2PPh yields 1,3,5-Triphenyl-1,3,5- triphosphorinane (1) as a mixture of two isomers. The isomers have been separated by column chromatography and characterized by NMR spectroscopy and single crystal X-ray diffraction as the eq-eq-eq (1a) and eq-eq-ax-isomers (1b). (1a) crystallizes with a = 1326.9(3) pm and c = 933.4(3) pm in the rhombohedral space group R3 and displays 3-fold symmetry, showing an eq-eq-eq conformation. (1b) crystallizes in the monoclinic space group P21/c with a = 984.09(12) pm, b = 1757.5(2) pm, c = 1083.13(12) pm, β = 93.329(2)° and displays an ax-eq-eq conformation.

Organoselenido Complexes of Tungsten

Organometallic tungsten selenido complexes of the type [cpW(CO)3]2Sem; m = 2 (1), 3 (2), 4 (3), can be easily synthesized via insertion of selenium into the alkali-metal tungsten bond of LiWcp(CO)3 in appropriate ratios and subsequent oxidation of the produced W-selenolates with O2/SiO2. In contrast, reactions of K2Se6 with [cpW(CO)3Cl] and 18-crown-6 in DMF lead to a mixture of [cpW(CO)3]2Se4 (3), the η1 Se-bonded selenocarbamato complex [cpW(CO)3SeC(O)NMe2] (4) and the ionic complex [(18-crown-6)K]+[cpW(Se4)2]− (5). The crystal structures of 3 and 4 together with their 77Se NMR data are presented.