Gyroscope‐Like Molecules Consisting of PdX2/PtX2 Rotators within Three‐Spoke Dibridgehead Diphosphine Stators: Syntheses, Substitution Reactions, Structures, and Dynamic Properties. Issue 16 (6th March 2014)

• Record Type: Journal Article
• Authors: Nawara‐Hultzsch, Agnieszka J.; Stollenz, Michael; Barbasiewicz, Michał; Szafert, Sławomir; Lis, Tadeusz; Hampel, Frank; Bhuvanesh, Nattamai; Gladysz, John A.
• Is Part Of: Chemistry. Volume 20:Issue 16(2014)
• Page Start: 4617
• Page End: 4637
• Publication Date: 2014-03-06
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201304419
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Threefold intramolecular ring‐closing metatheses of <italic>trans</italic>‐[MCl<sub>2</sub>(P{(CH<sub>2</sub>)<sub><italic>m</italic></sub>CHCH<sub>2</sub>}<sub>3</sub>)<sub>2</sub>] are effected with Grubbs' catalyst. Following hydrogenation catalyzed by [RhCl(PPh<sub>3</sub>)<sub>3</sub>], the title complexes <italic>trans</italic>‐[<overline>MCl<sub>2</sub>(P((CH<sub>2</sub>)<sub><italic>n</italic></sub>)<sub>3</sub>P</overline>)] (<italic>n</italic>=2<italic>m</italic>+2; M/<italic>n</italic>=Pt/14, <bold>4 c</bold>; Pt/16, <bold>4 d</bold>; Pt/18, <bold>4 e</bold>; Pd/14, <bold>5 c</bold>; Pd/18, <bold>5 e</bold>) and sometimes isomers partly derived from intraligand metathesis, <italic>trans</italic>‐[<overline>MCl<sub>2</sub>{P(CH<sub>2</sub>)<sub><italic>n</italic></sub>(CH<sub>2</sub>)<sub><italic>n</italic></sub>}P</overline>(CH<sub>2</sub>)<sub><italic>n</italic></sub>)] (<bold>4′c–e</bold>, <bold>5′e</bold>), are isolated. These react with LiBr, NaI, and KCN to give the corresponding MBr<sub>2</sub>, MI<sub>2</sub>, and M(CN)<sub>2</sub> species (58–99 %). <sup>13</sup>C NMR data show that the MX<sub>2</sub> moieties rapidly rotate within the diphosphine cage on the NMR timescale, even at −120 °C. The reaction of <bold>4 c</bold> and KSCN gives separable Pt(NCS)<sub>2</sub> and Pt(NCS)(SCN) adducts (<bold>13 c</bold>, 28 %; <bold>14 c</bold>, 20 %), and those of <bold>4 c</bold>, <bold>e</bold> and Ph<sub>2</sub>Zn give PtPh<sub>2</sub> species (<bold>15 c</bold>, 61 %; <bold>15 e</bold>, 90 %). <sup>13</sup>C NMR spectra of <bold>13 c</bold>–<bold>15 c</bold> show two sets of CH<sub>2</sub> signals (ca. 2:1 intensity ratios), indicating that MX<sub>2</sub> rotation is no longer rapid. Reactions of <bold>4 c</bold> or <bold>4′c</bold> and excess NaCCH afford the free diphosphines P{(CH<sub>2</sub>)<sub>14</sub>}<sub>3</sub>P (91 %) and (<overline>CH<sub>2</sub>)<sub>14</sub>P</overline>(CH<sub>2</sub>)<sub>14</sub><overline>P(C</overline>H<sub>2</sub>)<sub>14</sub> (90 %). The latter has been crystallographically characterized as a bis(BH<sub>3</sub>) adduct. The crystal structures of eight complexes with P(CH<sub>2</sub>)<sub>14</sub>P linkages (PtCl<sub>2</sub>, PtBr<sub>2</sub>, PtI<sub>2</sub>, Pt(NCS)<sub>2</sub>, PtPh<sub>2</sub>, PdCl<sub>2</sub>, PdBr<sub>2</sub>, PdI<sub>2</sub>) and <bold>15 e</bold> have been determined, and intramolecular distances analyzed with respect to MX<sub>2</sub> rotation. The conformations of the (CH<sub>2</sub>)<sub>14</sub> moieties and features of the crystal lattices are also discussed.</p> </abstract>