Synthesis and X-ray and neutron structures of anti-[L[sub 2]Rh[sub 2](H)[sub 2]](PF[sub 6])[sub 2] (L = 1,4,7-trimethyl-1,4,7-triazacyclononane) and a related species containing a syn-[Rh[sub 2](H)[sub 2]([mu]-H)[sub 2]][sup 2+] core. Isolation of [L[sub 2]Fe[sub 2]([mu]-H)[sub 3]]BPh[sub 4]
- Ruhr-Universitaet, Bochum (Germany)
- Anorganisch-Chemisches Institut der Universitaet, Heidelberg (Germany)
- Univ. of Southern California, Los Angeles, CA (United States)
- Brookhaven National Lab., Upton, NY (United States)
The macrocyclic ligands 1,4,7-trimethyl-1,4,7-triazacyclononane (L) and 1,2-bis(4,7-dimethyl-1,4,7-triaza-1-cyclononyl)ethane (Me[sub 4]dtne) react with RhCl[sub 3][center dot]3H[sub 2]O in ethanol affording the neutral complexes LRhCl[sub 3] (1) and [(Me[sub 4]dtne)Rh[sub 2]Cl[sub 6]]2H[sub 2]O (2). Aqueous suspensions of 1 and 2 react with NaBH[sub 4] yielding upon addition of KPF[sub 6] red-brown crystals of air- and moisture-stable anti-[L[sub 2]Rh[sub 2](H)[sub 2]([mu]-H)[sub 2]](PF[sub 6])[sub 2] (3) and syn-[(Me[sub 4]dtne)Rh[sub 2](H)[sub 2]([mu]-H)[sub 2]](PF[sub 6])[sub 2] (4), respectively, LFeCl[sub 3] and Li[AH[sub 4]] were found to form red [L[sub 2]Fe[sub 2]([mu]-H)[sub 3]]BPh[sub 4] (5) in tetrahydrofuran. The structure of 3 has been determined by single-crystal X-ray (295 K) and neutron diffraction (20 K). Neutron data for 3: monoclinic space group P2[sub 1]/c, a = 8.155(1) [angstrom], b = 11.768(2) [angstrom], c = 15.611(2) [angstrom], [beta] = 92.156(8)[degrees], V = 1497.1(2) [angstrom][sup 3], Z = 2, D[sub calcd] = 1.869 g/cm[sup 3]. The [HRh([mu]-H)[sub 2]RhH][sup 2+] core contains a planar Rh[sub 2]([mu]-H)[sub 2] ring (Rh-H[sub b] = 1.754(2) [angstrom]; Rh...Rh = 2.595(2) [angstrom]); each rhodium center has a terminal hydride ligand in anti-position with respect to each other (Rh-H[sub t] = 1.536(2) [angstrom]). The terminal hydride exerts a pronounced structural trans influence on the Rh-N bond in trans position (Rh-N[sub trans] = 2.276(1) [angstrom] vs average Rh-N[sub cis] = 2.082(1) [angstrom]). In 4 the [HRh([mu]-H)[sub 2]RhH][sup 2+] core is syn configurated due to the steric requirements of the strapped macrocycle. The solution behavior of 3 and 4 has been studied by [sup 1]H NMR spectroscopy. 3 is a fluctional molecule, and in contrast, 4 is rigid at ambient temperature.
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 5078746
- Journal Information:
- Inorganic Chemistry; (United States), Vol. 32:20; ISSN 0020-1669
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
HYDRIDES
STRUCTURAL CHEMICAL ANALYSIS
RHODIUM COMPLEXES
CHEMICAL PREPARATION
LATTICE PARAMETERS
MOLECULAR STRUCTURE
MONOCLINIC LATTICES
NUCLEAR MAGNETIC RESONANCE
X-RAY DIFFRACTION
COHERENT SCATTERING
COMPLEXES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
HYDROGEN COMPOUNDS
MAGNETIC RESONANCE
RESONANCE
SCATTERING
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties