2024/09/11 by Brenna K. Collins, John A. Gladysz · 1 citation
Chemistry · #Organometallic Complex Synthesis and Catalysis #Synthesis and Properties of Aromatic Compounds #Synthesis and characterization of novel inorganic/organometallic compounds
paper · doi:10.1002/chem.202402833
openalex publication_date 2024/09/11 · openalex created_date 2024/09/12 · openalex updated_date 2026/07/30
Abstract The overarching goal of this study is to effect the elimination of platinum from adducts with cis –C≡C−Pt−C≡C‐ linkages, thereby generating novel conjugated polyynes. Thus, the bis(hexatriynyl) complex trans ‐( p ‐tol 3 P) 2 Pt((C≡C) 3 H) 2 is treated with 1,3‐diphosphines R 2 C(CH 2 PPh 2 ) 2 to generate (R 2 C(CH 2 PPh 2 ) 2 ) 2 Pt((C≡C) 3 H) 2 ( 14 ; R= c , n ‐Bu; e , p ‐tolCH 2 ). These condense with the diiodide complexes R 2 C(CH 2 PPh 2 ) 2 PtI 2 ( 9 a , c ) in the presence of CuI (cat.) and excess HNEt 2 to give the title macrocycles [(R 2 C(CH 2 PPh 2 ) 2 )Pt(C≡C) 3 ] 4 ( 16 c , e ) as adducts of the byproduct [H 2 NEt 2 ] + I − (30–66 %). DOSY NMR experiments establish that this association is maintained in solution, but NaOAc removes the ammonium salt. The bis(triethylsilylpolyynyl) complexes ( n ‐Bu 2 C(CH 2 PPh 2 ) 2 )Pt((C≡C) n SiEt 3 ) 2 ( n =2, 3) are synthesized analogously to 14 c . They react with I 2 at rt to give mainly the diiodide complex 9 c and the coupling product Et 3 Si(C≡CC≡C) n SiEt 3 . The possibility of competing reactions giving IC≡C species is investigated. Analogous reactions of the Pt 4 C 24 macrocycle 16 c also give 9 c , but no sp 13 C NMR signals or mass spectrometric C x z + ions ( x =24–100) could be detected. It is proposed that some cyclo[24]carbon is generated, but then rapidly converts to other forms of elemental carbon. No cyclotetracosane (C 24 H 48 ) is detected when this sequence is carried out in the presence of PtO 2 and H 2 .