J. Am. Chem. SOC.1990, 112, 2011-2013 c59
A66
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A
A
w m V . k n g t h (m)
Figure 2. A, electronic absorption (A,, = 498 nm, c = 31 400 L mol-' cm-I); B, uncorrected emission [X(excitation) = 500 nm] spectra for [Au21r(CO)Cl(p-dpma),1 [PF,], in dichloromethane solution at 23 OC; C, uncorrected emission at 77 K.
spectral features can readily be accounted for by modifying the simple molecular orbital picture developed for the d8d10d8Ir*Aul-Ir* chain to this d'od8d10chain in which the predominant interactions involve the filled d,Z and empty pr orbitals that are directed along the Au-Ir-Au a x k 2 Preliminary results indicate that 3 reacts with a variety of other transition-metal ions including Agl, Pd", and Ir'. The structures and properties of the products are under investigation.
Acknowledgment. We thank the National Science Foundation (CHE-8941209 and CHE-8519557) for support, Johnson Matthey, Inc., for a loan of precious metal salts, and Professor H. Hope for experimental assistance. The diffraction and computing equipment used in this study were purchased under N S F Grant CHE-8802721 to the University of California, Davis.
Figure 1. Top: Cation of 3, [Ir(CO)(dpma)J+; bond distances (angstroms), lr-P(l), 2.367 (4); Ir-P(2), 2.400 (4); Ir-P(3), 2.358 (4); IrC ( I ) , 1.853 (4); Ir--As(l), 4.316 (2); Ir-As(Z), 4.384 (2); angles (degrees), P(l)-lr-P(4), 169.1 (I); P(2)-Ir-P(3), 108.1 (I); P(2)-Ir-C(l), 127.3 (4); P(3)-Ir
