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Platinum Indolylphosphine Fluorido and Polyfluorido Complexes: An Interplay between Cyclometallation, Fluoride Migration, and Hydrogen Bonding
Author(s) -
Sander Stefan,
Müller Robert,
Ahrens Mike,
Kaupp Martin,
Braun Thomas
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202102451
Subject(s) - chemistry , ligand (biochemistry) , reactivity (psychology) , phosphine , intramolecular force , hydrogen bond , stereochemistry , medicinal chemistry , moiety , coordination sphere , platinum , crystal structure , crystallography , molecule , catalysis , organic chemistry , receptor , medicine , biochemistry , alternative medicine , pathology
The reaction of [PtCl 2 (COD)] (COD=1,5‐cyclooctadiene) with diisopropyl‐2‐(3‐methyl)indolylphosphine ( i Pr 2 P(C 9 H 8 N)) led to the formation of the platinum( ii ) chlorido complexes, cis ‐[PtCl 2 { i Pr 2 P(C 9 H 8 N)} 2 ] ( 1 ) and trans ‐[PtCl 2 { i Pr 2 P(C 9 H 8 N)} 2 ] ( 2 ). The cis ‐complex 1 reacted with NEt 3 yielding the complex cis ‐[PtCl{ κ 2 ‐( P , N )‐ i Pr 2 P (C 9 H 7 N )}{ i Pr 2 P(C 9 H 8 N)}] ( 3 ) bearing a cyclometalated κ 2 ‐( P , N )‐phosphine ligand, while the isomer 2 with a trans ‐configuration did not show any reactivity towards NEt 3 . Treatment of 1 or 3 with (CH 3 ) 4 NF (TMAF) resulted in the formation of the twofold cyclometalated complex cis ‐[Pt{ κ 2 ‐( P , N )‐ i Pr 2 P (C 9 H 7 N )} 2 ] ( 4 ). The molecular structures of the complexes 1–4 were determined by single‐crystal X‐ray diffraction. The fluorido complex cis ‐[PtF{ κ 2 ‐( P , N )‐ i Pr 2 P (C 9 H 7 N )}{ i Pr 2 P(C 9 H 8 N)}] ⋅ (HF) 4 ( 5 ⋅ (HF) 4 ) was formed when complex 4 was treated with different hydrogen fluoride sources. The Pt( ii ) fluorido complex 5 ⋅ (HF) 4 exhibits intramolecular hydrogen bonding in its outer coordination sphere between the fluorido ligand and the NH group of the 3‐methylindolyl moiety. In contrast to its chlorido analogue 3 , complex 5 ⋅ (HF) 4 reacted with CO or the ynamide 1‐(2‐phenylethynyl)‐2‐pyrrolidinone to yield the complexes trans ‐[Pt(CO){ κ 2 ‐( P , C )‐ i Pr 2 P (C 9 H 7 N C O)}{ i Pr 2 P(C 9 H 8 N)}][F(HF) 4 ] ( 7 ) and a complex, which we suggest to be cis ‐[Pt{ C =C(Ph)OCN(C 3 H 6 )}{ κ 2 ‐( P , N )‐ i Pr 2 P (C 9 H 7 N )}{ i Pr 2 P(C 9 H 8 N)}][F(HF) 4 ] ( 9 ), respectively. The structure of 9 was assigned on the basis of DFT calculations as well as NMR and IR data. Hydrogen bonding of HF and NH to fluoride was proven to be crucial for the existence of 7 and 9 .