Formation and reactivity of (octaethyltetraazaporphyrinato)rhodium complexes

Journal Article · Wed Apr 27 00:00:00 EDT 1994 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00087a045· OSTI ID:7071470

Ni, Y; Fitzgerald, J P; Carroll, P; Wayland, B B ^[1]

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1. Univ. of Pennsylvania, Philadelphia, PA (United States) United States Naval Academy, Annapolis, MD (United States)

A series of (octaethyltetraazaporphyrinato)rhodium, (OETAP)Rh, complexes including (OETAP)Rh-I, (OETAP)Rh-CH[sub 3], and [(OETAP)Rh][sub 2] were prepared for comparison with the corresponding (octaethyltetraazaporphyrinato)rhodium, (OEP)Rh, derivatives. [(OETAP)Rh][sub 2] (1) reacts like [(OEP)Rh][sub 2] (2) with CH[sub 3]I, CH[sub 3]NC, (CH[sub 3]O)[sub 3]P, and CH[sub 2]=CH[sub 2] in forming (OETAP)Rh-CH[sub 3] and (OETAP)Rh-I, (OETAP)Rh(NC)(CH[sub 3]NC), (OETAP)Rh-P(O)(OCH[sub 3])[sub 2], and (OETAP)Rh-CH[sub 2]CH[sub 2]-Rh(OETAP), respectively, but reactions of 1 are invariably much slower than those of 2. [(OETAP)Rh][sub 2] fails to react with H[sub 2], CO, CH[sub 3]CHO, and CH[sub 3]C[sub 6]H[sub 5], which participate in prominent substrate reactions for 2. Reactivity and equilibrium studies indicate that a substantially larger Rh-Rh bond dissociation enthalpy for 1 compared with 2 is primarily responsible for the slower rates and reduced scope of substrate reactions for [(OETAP)Rh][sub 2]. Dissolution of 1 in pyridine results in formation of a persistent OETAP anion radical complex of Rh(III), (OETAP[sup [sm bullet][minus]])Rh[sup III](py)[sub 2], which contrasts with 2 where disproportionation produces the (OEP)Rh[sup I] anion and the (OEP)Rh[sup III](py)[sub 2]cation. (OETAP)Rh-CH[sub 3] (RhC[sub 33]H[sub 43]N[sub 8]) crystallizes in the monoclinic system, space group P2[sub 1]/c. The X-ray crystal and molecular structure determination for (OETAP)Rh-CH[sub 3] reveals a smaller hole size and corresponding shorter Rh-N distances for the (OETAP)Rh derivative but virtually identical Rh-CH[sub 3] bond distances in comparison with (OEP)Rh-CH[sub 3]. Differences in the structures and reactivities of (OETAP)Rh and (OEP)Rh complexes are discussed in terms of the smaller hole size, lower energy of the [pi]* orbitals, and the doming of the OETAP ligand.

• DOE Contract Number: FG02-86ER13615
• OSTI ID: 7071470
• Journal Information: Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 33:9; ISSN 0020-1669; ISSN INOCAJ
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CARBOXYLIC ACIDS
CHELATES
CHEMICAL REACTIONS
COHERENT SCATTERING
COMPLEXES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
EQUILIBRIUM
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
MOLECULAR STRUCTURE
MONOCLINIC LATTICES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PORPHYRINS
RADICALS
RHODIUM COMPLEXES
SCATTERING
TRANSITION ELEMENT COMPLEXES
X-RAY DIFFRACTION