Unexpected Formation of a Weak Metal-Metal Bond: Synthesis, Electronic Properties, and Second-Order NLO Responses of Push-Pull Late-Early Heteronuclear Bimetallic Complexes with W(CO)3(1,10
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- 作者：Maddalena Pizzotti ; Renato Ugo ; Claudia Dragonetti ; Elisabetta Annoni ; Francesco Demartin ; and Patrizia Mussini
- 刊名：Organometallics
- 出版年：2003
- 出版时间：September 29, 2003
- 年：2003
- 卷：22
- 期：20
- 页码：4001 - 4011
- 全文大小：192K
- 年卷期：v.22,no.20(September 29, 2003)
- ISSN：1520-6041
文摘
In attempts to bridge the complex [W(CO)3(phen)(pyz)] (phen = 1,10-phenanthroline; pyz= pyrazine) to acceptor centers, either soft centers such as cis-M(CO)2Cl (M = Rh(I), Ir(I))and fac-M(CO)3Cl2 (M = Ru(II), Os(II)) or hard centers such as BF3, the pyrazine ligand islost, while the fragment W(CO)3(phen) behaves as a 
-donor base with the unexpectedformation of heteronuclear early-late bimetallic compounds with a weak metal-metal bond,as confirmed by the easy substitution of W(CO)3(phen) by soft ligands (PPh3, CO, pyridine).The X-ray structures of [(CO)3(phen)W-cis-Ir(CO)2Cl] and [(CO)3(phen)W-fac-Os(CO)3Cl2]confirm a single metal-metal bond with an halogen bridging asymmetrically the two metallicmoieties and with the tungsten atom achieving a distorted (6 + 1) octahedral coordination.All the heteronuclear bimetallic complexes investigated show in their electronic spectra anew solvatochromic absorption band at around 385-450 nm in addition to the MLCT(W
*phen) absorption band typical of [W(CO)3(phen)L] complexes (L = CO, pyz, CH3CN)and an increased, in comparison to [W(CO)4(phen)], negative nonlinear (NLO) second-orderemission working with the EFISH technique with an incident wavelength of 1.907 
m. Theincrease is due to an additional negative contribution of the new absorption band at around385-450 nm, as shown by a solvatochromic investigation.
-donor base with the unexpectedformation of heteronuclear early-late bimetallic compounds with a weak metal-metal bond,as confirmed by the easy substitution of W(CO)3(phen) by soft ligands (PPh3, CO, pyridine).The X-ray structures of [(CO)3(phen)W-cis-Ir(CO)2Cl] and [(CO)3(phen)W-fac-Os(CO)3Cl2]confirm a single metal-metal bond with an halogen bridging asymmetrically the two metallicmoieties and with the tungsten atom achieving a distorted (6 + 1) octahedral coordination.All the heteronuclear bimetallic complexes investigated show in their electronic spectra anew solvatochromic absorption band at around 385-450 nm in addition to the MLCT(W*phen) absorption band typical of [W(CO)3(phen)L] complexes (L = CO, pyz, CH3CN)and an increased, in comparison to [W(CO)4(phen)], negative nonlinear (NLO) second-orderemission working with the EFISH technique with an incident wavelength of 1.907 m. Theincrease is due to an additional negative contribution of the new absorption band at around385-450 nm, as shown by a solvatochromic investigation.