{"title":"Transition-metal imido-boroxide complexes: a structural and spectroscopic investigation of the influence of boron","authors":"Sarah C. Cole, M. Coles, P. Hitchcock","doi":"10.1039/B207277G","DOIUrl":null,"url":null,"abstract":"The four coordinate compounds Mo(NR)2[OB(mes)2]2 (1, R = tBu; 2, R = Ar = 2,6-iPr2C6H3) have been obtained from the reaction of [(mes)2BOLi(Et2O)n]x with the corresponding Mo(NR)2Cl2(dme) starting material; for structural comparison, Mo(NtBu)2[OCH(mes)2]2 (3) was also synthesised. The related five-coordinate complexes Ti(NtBu)[OB(mes)2]2(py)2 (4) and Ti(NtBu)[OCH(mes)2]2(py)2 (5) were made using analogous procedures. X-Ray structural investigations of 1–5 were performed to assess the effect that the boron atom has on the metal–oxygen and metal–nitrogen(imido) bond lengths and angles. On average, both classes of compound displayed longer metal–oxygen bonds and shorter metal–nitrogen(imido) bonds for the boroxide derivatives. Spectroscopic investigation of the Δδ values for the tert-butylimido derivatives revealed that complexes incorporating the [OB(mes)2]− anion exhibit a reduction in the electron density at the imido nitrogen atom, in agreement with the observations from the solid state structures.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":"5 1","pages":"4168-4174"},"PeriodicalIF":0.0000,"publicationDate":"2002-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"13","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of The Chemical Society-dalton Transactions","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1039/B207277G","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 13
Abstract
The four coordinate compounds Mo(NR)2[OB(mes)2]2 (1, R = tBu; 2, R = Ar = 2,6-iPr2C6H3) have been obtained from the reaction of [(mes)2BOLi(Et2O)n]x with the corresponding Mo(NR)2Cl2(dme) starting material; for structural comparison, Mo(NtBu)2[OCH(mes)2]2 (3) was also synthesised. The related five-coordinate complexes Ti(NtBu)[OB(mes)2]2(py)2 (4) and Ti(NtBu)[OCH(mes)2]2(py)2 (5) were made using analogous procedures. X-Ray structural investigations of 1–5 were performed to assess the effect that the boron atom has on the metal–oxygen and metal–nitrogen(imido) bond lengths and angles. On average, both classes of compound displayed longer metal–oxygen bonds and shorter metal–nitrogen(imido) bonds for the boroxide derivatives. Spectroscopic investigation of the Δδ values for the tert-butylimido derivatives revealed that complexes incorporating the [OB(mes)2]− anion exhibit a reduction in the electron density at the imido nitrogen atom, in agreement with the observations from the solid state structures.
四个配位化合物Mo(NR)2[OB(mes)2]2 (1, R = tBu;2、R = Ar = 2,6- ipr2c6h3)由[(mes)2BOLi(Et2O)n]x与相应的Mo(NR)2Cl2(dme)原料反应得到;为了进行结构比较,还合成了Mo(NtBu)2[OCH(mes)2]2(3)。用类似的方法制备了相关的五坐标配合物Ti(NtBu)[OB(mes)2]2(py)2(4)和Ti(NtBu)[OCH(mes)2]2(py)2(5)。对1-5的x射线结构进行了研究,以评估硼原子对金属-氧和金属-氮(亚胺)键的长度和角度的影响。平均而言,这两类化合物的硼氧化物衍生物显示较长的金属-氧键和较短的金属-氮(亚胺)键。对叔丁基氨基甲酸酯衍生物Δδ值的光谱研究表明,含有[OB(mes)2]−阴离子的配合物在亚胺氮原子处表现出电子密度的降低,与固体结构的观察结果一致。