WO2007026831-A1  GIANNINI L. ET AL.: &apos;Organometallic Reactivity on a Calix[4]arene Oxo Surface. Synthesis and Rearrangement of Zr-C Functionalities Anchored to a Calix[4]arene Moiety&apos; JOURNAL OF THE AMERICAN CHEMICAL SOCIETY vol. 119, no. 39, 1997, pages 9198 - 9210, XP001199593;  GIANNINI L. ET AL.: 'Organometallic Reactivity on a Calix[4]arene Oxo Surface. Synthesis and Rearrangement of Zr-C Functionalities Anchored to a Calix[4]arene Moiety' JOURNAL OF THE AMERICAN CHEMICAL SOCIETY vol. 119, no. 39, 1997, pages 9198 - 9210;  GIANNINI L. ET AL.: 'Organometallic Reactivity on a Calix[4]arene Oxo Surface. Synthesis and Rearrangement of Zr-C Functionalities Anchored to a Calix[4]arene Moiety' JOURNAL OF THE AMERICAN CHEMICAL SOCIETY vol. 119, no. 39, 1997, pages 9198 - 9210, XP001199593;  MILIONE S. ET AL.: &apos;Cationic benzyl zirconium heteroscorpionates: synthesis and characterization of a novel ethylene polymerisation catalyst showing an unusual temperature dependent polymerisation mechanism&apos; CHEMICAL COMMUNICATIONS no. 10, 2003, pages 1176 - 1177, XP003009746;  MILIONE S. ET AL.: 'Cationic benzyl zirconium heteroscorpionates: synthesis and characterization of a novel ethylene polymerisation catalyst showing an unusual temperature dependent polymerisation mechanism' CHEMICAL COMMUNICATIONS no. 10, 2003, pages 1176 - 1177;  MILIONE S. ET AL.: 'Cationic benzyl zirconium heteroscorpionates: synthesis and characterization of a novel ethylene polymerisation catalyst showing an unusual temperature dependent polymerisation mechanism' CHEMICAL COMMUNICATIONS no. 10, 2003, pages 1176 - 1177, XP003009746;  TSUKAHARA T. ET AL.: &apos;Neutral and Cationic Zirconium Benzyl Complexes Containing Bidentate Pyridine-Alkoxide Ligands. Synthesis and Olefin Polymerization Chemistry of (pyCR2O)2Zr(CH2Ph) and (pyCR20)2Zr(CH2Ph)+ Complexes&apos; ORGANOMETALLICS vol. 16, no. 15, 1997, pages 3303 - 3313, XP002260137;  TSUKAHARA T. ET AL.: 'Neutral and Cationic Zirconium Benzyl Complexes Containing Bidentate Pyridine-Alkoxide Ligands. Synthesis and Olefin Polymerization Chemistry of (pyCR2O)2Zr(CH2Ph) and (pyCR20)2Zr(CH2Ph)+ Complexes' ORGANOMETALLICS vol. 16, no. 15, 1997, pages 3303 - 3313;  TSUKAHARA T. ET AL.: 'Neutral and Cationic Zirconium Benzyl Complexes Containing Bidentate Pyridine-Alkoxide Ligands. Synthesis and Olefin Polymerization Chemistry of (pyCR2O)2Zr(CH2Ph) and (pyCR20)2Zr(CH2Ph)+ Complexes' ORGANOMETALLICS vol. 16, no. 15, 1997, pages 3303 - 3313, XP002260137