Syntheses and Theoretical and Mechanistic Aspects of 1-Thia-2,4- and 1-Thia-3,4-diphosphole Formed from CS₂ and ^tBuCP and Crystal and Molecular Structure of the First 1-Thia-3,4-diphosphole Complex:  cis-[{PtCl₂(PEt₃)}₂(P₂SC₂^tBu₂)]

Abstract

The reaction of t BuCP with CS 2 (or its ylide type complexes such as R 3 PCS 2 (R ) Et, Ph, cyclohexyl), (C 5 H 10 N) 2 CCS 2 , or (C 4 H 8 NO) 2 CCS 2 ) gives a mixture of 3,5-di-tert-butyl-1-thia-2,4-diphosphole and 2,5-ditert-butyl-1-thia-3,4-diphosphole, which were characterized by NMR spectroscopy. The latter was also characterized by the single-crystal X-ray structure determination of its bis(platinum(II)) complex [(PtCl 2 PEt 3 ) 2 (µ-P 2 SC 2 t Bu 2 )]. This is the first structural characterization of a 1-thia-3,4-diphosphole ring. The mechanism of these reactions was explored by B3LYP/6-311+G** level quantum chemical calculations. The reaction pathway involves a phosphadithiolediylcarbene and its diphosphatetrathiafulvalene dimer as intermediates. Several other possible reaction pathways were ruled out.

Oxazol-2-ylidenes. A new class of stable carbenes?

“…27 The reaction of carbon disulfide with t-BuCP was also shown to proceed via the cycloaddition intermediate. 28 While for some 1,3-heterocumulenes the cycloreversion was investigated and the stability of nitrogen-containing rings was established, in that study 29 neither oxazol-2-ylidene (9) nor selenazol-2-ylidene (10) was considered. Changes in the carbenes' stability might trigger changes also in their catalytic activity.…”

Electronic Structure and Bonding in Neutral and Dianionic Boradiphospholes: R′BC2P2R2 (R=H, tBu, R′=H, Ph)

“…[13,14] Moreover, isoelectronic substitutions on 1,2,4-triphospholyl tBu 2 C 2 P 3 À (2) give the possibility of both neutral and anionic equivalents of Cp À , typified by anionic arsena-and stibolyl-heterodiphospholyl rings and neutral 1,2,4-thia-, selena-, and telluradiphospholes, shown here. [15][16][17][18] The cyclopentadienyl cation (Cp + ) also presents an interesting story. Initially Hoffmann and Stohrer [19a] suggested a nido-3 structure for Cp + (similar to B 5 H 9 ), which was further substantiated by Masamune et al [19b,c] who observed long-lived derivatives of square pyramidal Cp + .…”

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“…196 The use of 2,9-(Ph 2 P) 2 substituted phen and 6,6A-(Ph 2 P) substituted 2,2A-bipy (L) to make heteropolynuclear complexes (metallocryptands) by complexing the P atoms to two atoms of one metal and the N to one of another, already known for Au and Tl, has now been extended to Pd and Pt (M) with the synthesis of [M 2 TlL 3 ] + , in which the Tl is coordinated only by M and not by N atoms, with M-Tl bond lengths of about 280 pm. In this work the X-ray crystallography studies were supplemented by 31 P, 195 Pt and 205 Tl NMR spectroscopy. 197 Nanomolecular rings and cages are a very fast developing topic.…”

“…204 One product from the reaction of Bu t CP with CS 2 is the thiadiphosphole L 8 , which forms [(PtCl 2 PEt 3 ) 2 (m-L 8 )] with bridging through the P atoms. 205 There are prospects of new coordination chemistry with the synthesis of complexes of 2-Ph 2 PNHC 5 H 4 N (HL).…”