文摘

Static solid-state ³⁵Cl (I = ³/b>2b>) NMR spectra of the organometallic compounds Cpb>2b>TiClb>2b>, CpTiClb>3b>, Cpb>2b>ZrClb>2b>, Cpb>2b>HfClb>2b>, Cp*b>2b>ZrClb>2b>, CpZrClb>3b>, Cp*ZrClb>3b>, Cpb>2b>ZrMeCl, (Cpb>2b>ZrCl)b>2b>μ-O, and Cpb>2b>ZrHCl (Schwartz’s reagent) have been acquired at 9.4 T with the quadrupolar Carr−Purcell Meiboom−Gill (QCPMG) sequence in a piecewise manner. Spectra of several samples have also been acquired at 21.1 T. The electric field gradient (EFG) tensor parameters, the quadrupolar coupling constant (Cb>Qb>) and quadrupolar asymmetry parameter (ηb>Qb>), are readily extracted from analytical simulations of the spectra. The ³⁵Cl EFG and chemical-shift tensor parameters are demonstrated to be sensitive probes of metallocene structure and allow for differentiation of monomeric and oligomeric structures. First-principles calculations of the ³⁵Cl EFG parameters successfully reproduce the experimental values and trends. The origin of the observed values of Cb>Qb>(³⁵Cl) are further examined with natural localized molecular orbital (NLMO) analyses. The combination of experimental and theoretical methods applied to the model compounds are employed to structurally characterize Schwartz’s reagent (Cpb>2b>ZrHCl), for which a crystal structure is unavailable. Aside from a few select examples of single-crystal NMR spectra, this is the first reported application of solid-state ³⁵Cl NMR spectroscopy to molecules with covalently bound chlorine atoms. It is anticipated that the methodology outlined herein will find application in the structural characterization of a wide variety of chlorine-containing transition-metal and main-group systems.