TY - JOUR
T1 - Structures of Dineopentylbis(triethylphosphine)platinum(II) and Bis(triethylphosphine)-3,3-dimethylplatinacyclobutane
T2 - Reactant and Product in a Thermal Cyclometalation Reaction
AU - Ibers, James A.
AU - DiCosimo, Robert
AU - Whitesides, George M.
PY - 1982/1/1
Y1 - 1982/1/1
N2 - Thermal decomposition of dineopentylbis(triethylphosphine)platinum(II), 1, Pt(CH2C(CH3)3)2(P(C2H5)3)2, yields neopentane and bis(triethylphosphine)-3,3-dimethylplatinacyclobutane, 5, [formula omitted]. Compound 1 crystallizes with four molecules in space group (C2h6−C2/c of the monoclinic system in a cell at −158 °C of dimensions a = 8.776 (2) Å, b = 17.761 (3) Å, c = 17.669 (3) Å, and β = 109.62 (1)∘. The structure has been refined to an R index on F2 of 0.035 for 6877 observations and 115 variables. Compound 1 has crystallographically imposed C2 symmetry. Compound 5 crystallizes with four molecules in space group C2v9−Pn21a of the orthorhombic system in a cell at −158 °C of dimensions a = 15.947 (3) Å, b = 14.301 (2) Å, and c = 9.383 (2) Å. The structure has been refined to a R index on F2 of 0.032 for 3255 observations and 181 variables. Some average metrical parameters for 1 and 5 respectively are as follows: Pt-P, 2.322 (1), 2.285 (2) Å; Pt-C, 2.118 (2), 2.083 (3) Å; P-C, 1.839 (2), 1.827 (2) Å; C-C (ethyl), 1.525 (3), 1.521 (4) Å; P-Pt-P, 94.09 (3), 103.01 (9)∘; C-Pt-C, 85.5 (1), 67.3 (3)∘. In 1 the neopentyl group is of normal geometry with a C-C(terminal) distance of 1.529 (3) Å; in 5 the C-C distances of the metallacycle average 1.535 (6) Å and the β-C atom is 0.38 Å out of the plane through PPPtCC. A comparison of structures of 1 and 5 indicates that 1 is significantly sterically congested and suggests that relief of this congestion may be an important component of the thermodynamic driving force for the conversion of 1 to 5.
AB - Thermal decomposition of dineopentylbis(triethylphosphine)platinum(II), 1, Pt(CH2C(CH3)3)2(P(C2H5)3)2, yields neopentane and bis(triethylphosphine)-3,3-dimethylplatinacyclobutane, 5, [formula omitted]. Compound 1 crystallizes with four molecules in space group (C2h6−C2/c of the monoclinic system in a cell at −158 °C of dimensions a = 8.776 (2) Å, b = 17.761 (3) Å, c = 17.669 (3) Å, and β = 109.62 (1)∘. The structure has been refined to an R index on F2 of 0.035 for 6877 observations and 115 variables. Compound 1 has crystallographically imposed C2 symmetry. Compound 5 crystallizes with four molecules in space group C2v9−Pn21a of the orthorhombic system in a cell at −158 °C of dimensions a = 15.947 (3) Å, b = 14.301 (2) Å, and c = 9.383 (2) Å. The structure has been refined to a R index on F2 of 0.032 for 3255 observations and 181 variables. Some average metrical parameters for 1 and 5 respectively are as follows: Pt-P, 2.322 (1), 2.285 (2) Å; Pt-C, 2.118 (2), 2.083 (3) Å; P-C, 1.839 (2), 1.827 (2) Å; C-C (ethyl), 1.525 (3), 1.521 (4) Å; P-Pt-P, 94.09 (3), 103.01 (9)∘; C-Pt-C, 85.5 (1), 67.3 (3)∘. In 1 the neopentyl group is of normal geometry with a C-C(terminal) distance of 1.529 (3) Å; in 5 the C-C distances of the metallacycle average 1.535 (6) Å and the β-C atom is 0.38 Å out of the plane through PPPtCC. A comparison of structures of 1 and 5 indicates that 1 is significantly sterically congested and suggests that relief of this congestion may be an important component of the thermodynamic driving force for the conversion of 1 to 5.
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U2 - 10.1021/om00061a004
DO - 10.1021/om00061a004
M3 - Article
AN - SCOPUS:0002506792
SN - 0276-7333
VL - 1
SP - 13
EP - 20
JO - Organometallics
JF - Organometallics
IS - 1
ER -