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Synthesis, Characterization, and Interconversion of the Rhenium Polyhydrides [ReH 3 (η 4 ‐NP 3 )] and [ReH 4 (η 4 ‐NP 3 )] + {NP 3 = tris[2‐(diphenylphosphanyl)ethyl]amine}
Author(s) -
Albinati Alberto,
Bakhmutov Vladimir I.,
Belkova Natalia V.,
Bianchini Claudio,
Rios Isaac de los,
Epstein Lina,
Gutsul Evgenii I.,
Marvelli Lorenza,
Peruzzini Maurizio,
Rossi Roberto,
Shubina Elena,
Vorontsov Evgeni V.,
Zanobini Fabrizio
Publication year - 2002
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200206)2002:6<1530::aid-ejic1530>3.0.co;2-e
Subject(s) - chemistry , rhenium , protonation , nuclear magnetic resonance spectroscopy , amine gas treating , hydrogen bond , medicinal chemistry , adduct , spectroscopy , proton nmr , crystallography , molecule , stereochemistry , inorganic chemistry , organic chemistry , ion , physics , quantum mechanics
The rhenium(III) dichloride complex [ReCl 2 (η 4 ‐NP 3 )]Cl ( 1 ) was prepared from [ReCl 3 (CH 3 CN)(PPh 3 ) 2 ] by treatment with the tripodal tetradentate ligand N(CH 2 CH 2 PPh 2 ) 3 (NP 3 ) in ethanol. The reaction of 1 with LiAlH 4 in THF gave the rhenium(III) trihydride [ReH 3 (η 4 ‐NP 3 )] ( 2 ), which was converted into the rhenium(V) tetrahydride [ReH 4 (η 4 ‐NP 3 )]BPh 4 ( 3 ) by protonation in CH 2 Cl 2 with HBF 4 ·OMe 2 , followed by a metathetical reaction with NaBPh 4 . The classical polyhydride nature of 2 and 3 , as well as the overall molecular structures in solution, were determined by NMR spectroscopy, 1 H NMR relaxation, and IR spectroscopy. The polyhydride complexes 2 and 3 are stereochemically nonrigid in solution, and the thermodynamic parameters associated with the fluxional processes were determined by variable‐temperature NMR studies. A single‐crystal X‐ray analysis of 3 has shown the complex cation [ReH 4 (η 4 ‐NP 3 )] + to be eight‐coordinated by the four donor atoms of NP 3 and by four terminal hydride ligands in a distorted dodecahedral geometry. An in situ IR study in CH 2 Cl 2 has shown that the protonation of 3 occurs regioselectively at the metal center with no formation of a dihydrogen complex. Kinetic hydrogen bond products of the formula [(η 4 ‐NP 3 )H 3 Re ··· HOR] (ROH = C 2 H 5 OH, CFH 2 CH 2 OH, CF 3 CH 2 OH) were intercepted by IR spectroscopy at low temperature. The thermodynamic parameters associated with the formation of the hydrogen bond adducts were determined by either IR spectroscopy applying the Iogansen equation or van’t Hoff plots of the formation constant vs. temperature.