Application of the NOE experiment to the analysis of boron hydride derivatives:: confirming the assignments of the pseudocloso-complex [1,2-Ph2-3-{Cp*}-3,1,2-IrC2B9H9] (Cp* = η5-C5Me5) and the closo-compounds 1-Ph-1,2-C2B10H11 and 1-Ph-2-Me-1,2-C2B10H10

The NOE experiment is demonstrated here as a viable tool in the NMR analyses of substituted borane and heteroborane compounds. We demonstrate that the saturation of H-1 NMR signals assigned to a substituent ligand can give rise to enhancements of signals arising from B-H's within a borane cage. These enhancements, though small (ca. 1-2%), are clearly detectable and have been used to confirm assignments for the pseudocloso -complex [1,2-Ph-2-3-{Cp*}-3, 1,2-IrC2B9H9] (CP* = eta(5)- C5Me5), the mono-substituted closo-carbaborane 1-Ph-1,2-C2B10H11 and the di-substituted closo-carbaborane 1-Ph-2-Me-1,2-C5B10H10. We compare the results of applying three alternative experimental NOE procedures to these problems, namely phase sensitive 2D NOESY, 1D truncated driven NOE and 1D DPFGSE-NOE. The differences between the quality and relevance of these procedures to the study of borane and heteroborane derivatives are discussed. (C) 1999 Elsevier Science S.A. All rights reserved.