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We report the synthesis of molybdenum and tungsten bromo dicarbonyl complexes (POCOPtBu)MIIBr(CO)2(M = Mo or W; POCOPtBu = κ3-C6H3-1,3-[OP( tBu)2]2) supported by an anionic PCP pincer ligand, and the chromium complex (PNPtBu)Cr0(CO)3(PNPtBu = 2,6-bis(di- tert-butyl-phosphinomethyl)pyridine) bearing a neutral PNP pincer scaffold. The three group six complexes described in this study have been characterized by Liquid Injection Field Desorption Ionization Mass Spectrometry (LIFDI-MS), NMR, and IR spectroscopy. Single crystal X-ray diffraction studies show the MoIIand WIIcomplexes adopt a six-coordinate distorted trigonal prismatic geometry, whereas the Cr0complex exhibits a distorted octahedral geometry.
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Siloxyaluminate and Siloxygallate Complexes as Models for Framework and Partially Hydrolyzed Framework Sites in Zeolites and Zeotypes
Abstract Anionic molecular models for nonhydrolyzed and partially hydrolyzed aluminum and gallium framework sites on silica, M[OSi(OtBu)3]4−and HOM[OSi(OtBu)3]3−(where M=Al or Ga), were synthesized from anionic chlorides Li{M[OSi(OtBu)3]3Cl} in salt metathesis reactions. Sequestration of lithium cations with [12]crown‐4 afforded charge‐separated ion pairs composed of monomeric anions M[OSi(OtBu)3]4−with outer‐sphere [([12]crown‐4)2Li]+cations, and hydroxides {HOM[OSi(OtBu)3]3} with pendant [([12]crown‐4)Li]+cations. These molecular models were characterized by single‐crystal X‐ray diffraction, vibrational spectroscopy, mass spectrometry and NMR spectroscopy. Upon treatment of monomeric [([12]crown‐4)Li]{HOM[OSi(OtBu)3]3} complexes with benzyl alcohol, benzyloxide complexes were formed, modeling a possible pathway for the formation of active sites for Meerwin–Ponndorf–Verley (MPV) transfer hydrogenations with Al/Ga‐doped silica catalysts.
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- Award ID(s):
- 1955643
- PAR ID:
- 10237072
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- Volume:
- 27
- Issue:
- 1
- ISSN:
- 0947-6539
- Format(s):
- Medium: X Size: p. 307-315
- Size(s):
- p. 307-315
- Sponsoring Org:
- National Science Foundation
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