This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division. We thank the University of North Carolina Wilmington for providing the seawater.

1. 합성 1,4- 벤젠 비스 (iminoguanidinium) 클로라이드 (BBIG-CL) <ol><li> 제자리 1,4- 벤젠 비스 (iminoguanidinium) 염화물 리간드 (BBIG-CL)의 합성 및 황산염과의 결정화에 <ol><li> 자기 교반 바가 장착 된 25 mL의 둥근 바닥 플라스크에 0.067 테레프탈 g 및 탈 이온수 10 ㎖에 aminoguanidinium 클로라이드의 0.5 M 수용액 2.2 mL를 추가. </li><li> 20 ℃에서 4 시간 동안 자기 적으로 교반 용액. 이 BBIG-CL의 약간 황색 용액을 얻을 것입니다. </li><li> 황산나트륨의 1 M 수용액 0.5ml를 추가. 이것은 결정 성 백색 고체로서 BBIG-SO (4)의 바로 침전 될 것이다. </li><li> BBIG-SO 4를 복구하여 고체를 진공 여과 필터. 순수한 황산 염을 얻기 위해 여과지에 물 5ml 분취 량으로 5 회 고체를 세척한다. </li><li> 결정 BBIG-SO의 위상 순도를 확인 <sub&gt; 4 분말 X 선 회절에 의해 얻어진 12. 도 1에 도시 된 패턴을 비교한다. </li></ol></li><li> 1,4- 벤젠 비스의 예 제자리 합성 (iminoguanidinium) 염화물 (11) <ol><li> 테레프탈 4 g 및 50 ml의 자기 교반 바가 장착 된 둥근 바닥 플라스크에 에탄올 20 ㎖에 aminoguanidinium 클로라이드 7.26 g을 추가한다. </li><li> 핫 플레이트를 사용하여 60 ° C에 대한 해결책을 가열하고, 2 시간 동안 자기 교반 막대로 저어. 20 ℃로 용액을 냉각시키고, 그 후, 3 시간 동안 앉아 필터 페이퍼 장착 흡인 여과기를 통해 진공 여과에 의해 고체를 수집하자. </li><li> 비등까지 핫 플레이트상에서 에탄올 및 열이 고체를 20 mL의 일시. 고체가이 시점에서 용액에 완전히 들어 가지 않을 경우 모든 고체가 용해 될 때까지 매번 비등 온도에 도달하는 용액을 허용 에탄올 작은 분취 량 (1 ㎖)에 추가한다. </li><li> 플라스크 실내 temperatu으로 냉각 할 수 있도록 허용다음 하룻밤 0 ° C의 냉동고에 배치 다시. 진공 여과법을 사용하여 흡인 여과기를 구비 한 필터 종이를 통해 여과하여 고체를 수집한다. </li><li> 1 H NMR 분광법 (13)에 의해 BBIG-CL의 정체성과 순도를 확인합니다. 도 2에 도시 된 스펙트럼과 비교한다. </li></ol></li></ol> 해수 2. 황산 분리 <ol><li> BBIG-SO 4로 황산염 결정 주 : 황산 제거 할 필요 BBIG-CL의 양은 해수 황산의 정확한 양에 의존한다. 그것은 황산의 99 % 제거에 황산 결과 BBIG-CL 상대의 1.5 당량을 사용하는 것으로 나타났습니다. BaCl 2 적정에 의해 측정 된이 프로토콜에 사용 된 해수는 30 mM의 황산의 농도를 갖는다. <ol><li> 부유 분진 및 생체 유기물을 제거하는 작은 기공 크기 0.22 μm의 주사기 필터 나 여과막과 해수 필터. </li><li> 30 확인이전 섹션에 기술 된 바와 같이 제조 된 탈 이온수 및 고체 BBIG-CL을 사용 BBIG-CL의 MM의 솔루션입니다. </li><li> 1 (v / v)의 비율 : 1.5의 해수에 BBIG-CL 솔루션을 추가합니다. </li><li> 황산 정량 (&gt; 99 %) 제거를 보장하기 위해 몇 시간 동안 교반한다. </li><li> 진공 여과법을 사용하여 흡인 여과기를 구비 한 필터 종이를 통해 여과하여 고체를 수집한다. 물 5 mL를 분취하여 여과지에 5 회 고체를 세척한다. </li><li> 진공에서 분리 된 고체를 건조 수율을 결정하는 데 무게. </li></ol></li><li> 리간드 복구 <ol><li> 자기 교반 막대가 구비 된 20 ㎖ 섬광 바이알 중의 NaOH (10 %)의 2 ml의 용액에 BBIG-SO 4 53.1 mg의 추가. </li><li> 20 ° C에서 2 시간 동안 혼합물을 교반한다. 약간 노란색 침전물을 형성 할 것이다. </li><li> 진공 여과법을 사용하여 흡인 여과기를 구비 한 필터 종이를 통해 고체를 필터. 0.2 여과지상의 고체를 씻어ml의 물, 진공하에 건조. </li><li> 비스 (구아니딘) 유리 염기로서 정체성을 확인하는 NMR (13)에 의해 회수 된 고체의 특성을. 도 3에 도시 된 NMR 스펙트럼과 비교한다. </li></ol></li><li> 액체 섬광 계수를 β에 의한 해수에서 제거 황산의 양의 결정 주의 :이 기술은 일반적으로 대부분의 실험실에서 발생되는 것보다 위험 다른 클래스 포즈 방사성 동위 원소의 사용을 포함한다. 방사성 핵종을 처리 할 때 특수 방사선 보호 장비는 일반적으로 필요합니다. 따라서, 절차가주의 깊게 뒤에 있고 안전 책임자가 조언 및 지침에 대한 상담을하는 것이 필수적이다. <ol><li> (CI를 다음 식 (CPM 및 큐리을 사용하여 해수 용액 밀리리터 분 (CPM) 당 500 만 카운트,이 있는지 확인하기 위해 사용되는 황-35 동위 원소 (5 mCi의 / ㎖)의 스톡 용액의 부피를 계산 ) 측정 (F)의 두 단위또는 방사능) <img alt="식 (1)" src="/files/ftp_upload/54411/54411eq1.jpg" /> <img alt="식 (2)" src="/files/ftp_upload/54411/54411eq2.jpg" /> <img alt="식 (3)" src="/files/ftp_upload/54411/54411eq3.jpg" /></li><li> 35 S 방사성 황산나트륨 용액 5.0 mCi의 / ㎖ 용액 0.0112 mL로 해수 25 ㎖의 스파이크. </li><li> 탈 이온수 BBIG-CL의 0, 15, 30, 33, 45 및 60 mM의 용액을 제조하고 35 S-방사성 황산 동량이 용액 0.750 ㎖의 결합은 2 mL의 원심 분리 관으로 해수 아군. </li><li> 24 시간 동안 25 ± 0.2 ° C의 일정한 온도로 유지 인큐베이터 / 공기 창에 회전 휠 또는 소용돌이를 통해 혼합물을 저어. </li><li> 25 ° C에서 10 분 동안 1,500 XG에 용액을 원심 분리기. </li><li> 원심 분리 후, 주사기를 이용하여 각 용액의 1.2 ml의 제거 후 현탁 제거 0.22 μm의 주사기 필터를 통해 필터링<html> 침전물. 피펫 폴리 프로필렌 섬광 유리 병에 섬광 칵테일 20 ㎖에 이러한 솔루션의 각 1.0 ml의. 더 BBIG-CL (제어 용액)을 함유하지 않는 용액을 사전 섬광 칵테일을 첨가 탈 이온수로 10 배 희석한다. </li><li> 샘플 및 액체 섬광 계수기에서 섬광 칵테일을 함유하는 신틸레이션 바이알을 놓고 그 전에 어두운 적응 샘플을 허용 카운트에 1 시간 방치. 참고 : 이전에 샘플을 계산에 악기를 보정하고 각각의 샘플은 30 분 동안 계산 할 수 있습니다. 용액을 황산의 농도를 결정할 때 사용되는 배경 보정을 허용하기 위해서 단지 섬광 칵테일을 함유하는 바이알을 추가 개수. </li><li> 다음 식을 사용하여 제거 황산의 양을 결정 : <img alt="식 (4)" src="/files/ftp_upload/54411/54411eq4.jpg" /> 54411 / 54411eq5.jpg &quot;/&gt; <img alt="식 (6)" src="/files/ftp_upload/54411/54411eq6.jpg" /></li></ol></li></ol>

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The authors have nothing to disclose.

이 기법은 매우 강력하게 기입 절차에 많은 편차가 아니라 저항성이다. 따라야하지만 두 가지 중요한 단계가 있습니다. 우선, BBIG-CL 리간드 가능한 순수 할 필요가있다. 불순물만을 결정화하고, 생성 된 황산염의 용해도에 영향을 미치지 않을 것, 또한 어려운 용액으로부터 정량 황산 제거를 위해 필요한 양을 계산하게된다. 이 기술은 미묘한 변화에 매우 민감 할 수 있기 둘째, β 액체 섬광 카운?...

경쟁 수용액에서 친수성 oxoanions (예를 들어, 황산염, 크롬 산염, 인산염)의 선택적 분리 환경 개선에 관련성, 에너지 생산, 인간의 건강에 근본적인 도전을 나타냅니다. 1,2 황산을 특히 물에서 인해 추출하기 어려운 그 고유의 자기 저항은 수화 영역을 흘리다 덜 극성 환경으로 마이그레이션 할 수 있습니다. 3 수성 황산 추출을보다 효율적으로 만들기 일반적으로 합성 종종 독성 시약 및 용매를 포함, 정화 어렵고 지루한 복잡한 수용체를 필요로합니다. 4,5 선택적 결정화가 물에서 분리 황산염 할 수있는 간단하면서도 효과적인 대안을 제공합니다. 6-9 등 바 2 +, 납 2+, 또는 라 2+ 형태로 매우 불용성 황산 염과 같은 일부 금속 양이온, 황산 분리에서의 사용은 항상 실제 아니지만 그들의 높은 toxi에도시 때로는 낮은 선택도. 황산 침전제로 유기 리간드를 사용하는 유기 분자 특성 설계 구조적 다양성과 가공성을 활용합니다. 수성 황산 결정화를위한 이상적인 유기 리간드는 수용성 아직 상대적으로 짧은 시간에 그리고 경쟁 이온의 높은 농도의 존재 하에서 불용성 페이트 염 또는 복합체를 형성한다. 또한, 합성 및 재활용이 용이해야한다. 그러한 리간드, 1,4- 벤젠 비스 (iminoguanidinium) (BBIG) 자기 조립 개의 시판 전구체 테레프탈 및 aminoguanidinium 클로라이드 시츄 최근 수성 황산 분리에 매우 효과적인 것으로 밝혀졌다. 10 리간드 수용성 염화물 형태이며, 선택적으로 쉽게 간단한 여과에 의해 용액으로부터 제거 될 수있는 매우 불용성 염으로 황산 결정화된다. BBIG 리간드는 다음과 탈 양성자하여 복구 할 수 있습니다queous NaOH를 다른 분리 사이클에서 다시 수성 HCl과 염화 형태로 변환하고 재사용 할 수있는 중립 비스 iminoguanidine의 결정화. 물 황산을 제거하는이 리간드의 효능은 용액에 남아 황산 농도를 모니터링하는 음이온 미량의 정확한 측정을 할 수있는보다 진보 된 기술을 요구하는 더 이상 사소한 작업이되도록 크다. 이를 위해 β 액체 섬광 계수와 함께 방사성 35 S 황산 트레이서 기법은 일반적으로 액체 - 액체 추출 분리하여 이용하고, 최근 모니터링 황산 결정화 효과적인 것으로 입증 채용 하였다. (8) 이 프로토콜은 현장 상기 BBIG 리간드의 합성과 수용액에서 황산 염으로 결정화에서 하나의 냄비를 보여줍니다. 리간드 (11)의 전 현장 합성도 공동으로 제공됩니다사용할 준비가 될 때까지, 결정 형태로 저장 될 수 BBIG-CL 많은 양의 생산 nvenient 방법. 이전에 조제한 BBIG-CL 리간드를 이용하여 해수로부터 제거 황산염 다음 설명된다. 마지막으로, 35 S 표지 황산 해수 황산 농도를 측정 β 액체 섬광 계수의 사용을 입증한다. 이 프로토콜은 수성 음이온 분리를위한 선택적 결정화의 사용을 탐험에 크게 관심이있는 사람들에 대한 자습서를 제공하기위한 것입니다.

<table border="0" cellpadding="0" cellspacing="0" width="740">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Terephthalaldehyde</td>
			<td style="width:92px;">Sigma</td>
			<td style="width:119px;">T2207</td>
			<td style="width:313px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Aminoguanidinium Chloride</td>
			<td style="width:92px;">Sigma</td>
			<td style="width:119px;">#396494</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sodium Sulfate</td>
			<td style="width:92px;">Sigma</td>
			<td style="width:119px;">#239313</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Barium Chloride</td>
			<td style="width:92px;">Sigma</td>
			<td style="width:119px;">#342920</td>
			<td>Highly Toxic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ethanol</td>
			<td style="width:92px;">Any</td>
			<td style="width:119px;"></td>
			<td>Reagent Grade (190 proof)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sodium Hydroxide</td>
			<td style="width:92px;">EMD</td>
			<td style="width:119px;">SX0590-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Hydrochloric Acid</td>
			<td style="width:92px;">Sigma</td>
			<td style="width:119px;">#258148</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Filter Paper</td>
			<td style="width:92px;">Any</td>
			<td style="width:119px;">-</td>
			<td>Any qualitative or analytical filter paper will work</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Syringe Filter (0.22 um)</td>
			<td style="width:92px;">Any</td>
			<td style="width:119px;">-</td>
			<td>Nylon filter</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">35S Labeled Sulfate</td>
			<td style="width:92px;">Perkin Elmer</td>
			<td style="width:119px;">NEX041005MC</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Ultima Gold Scintillation Cocktail</td>
			<td style="width:92px;">Perkin Elmer</td>
			<td style="width:119px;">#6013329</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Polypropylene Vials&#160;</td>
			<td style="width:92px;">Any</td>
			<td style="width:119px;">-</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Disposable Syringe (2-3 mL)</td>
			<td style="width:92px;">Any</td>
			<td style="width:119px;">-</td>
			<td>Any disposable plastic syringe works</td>
		</tr>
	</tbody>
</table>

sulfate separation by selective crystallization with a bis-iminoguanidinium ligand

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, 1,4-benzene-bis(iminoguanidinium) (BBIG), is demonstrated. The ligand is synthesized as the chloride salt (BBIG-Cl) by in situ imine condensation of terephthalaldehyde with aminoguanidinium chloride in water, followed by crystallization as the sulfate salt (BBIG-SO4). Alternatively, BBIG-Cl is synthesized ex situ in larger scale from ethanol. The sulfate separation ability of the BBIG ligand is demonstrated by selective and quantitative crystallization of sulfate from seawater. The ligand can be recycled by neutralization of BBIG-SO4 with aqueous NaOH and crystallization of the neutral bis-iminoguanidine, which can be converted back into BBIG-Cl with aqueous HCl and reused in another separation cycle. Finally, 35S-labeled sulfate and &#946; liquid scintillation counting are employed for monitoring the sulfate concentration in solution. Overall, this protocol will instruct the user in the necessary skills to synthesize a ligand, employ it in the selective crystallization of sulfate from aqueous solutions, and quantify the separation efficiency.

BBIG-SO 4 (도 1)의 분말 X 선 회절 패턴은 결정화 된 고체의 ID 명백한 확인을 허용한다. 기준 한 대 얻어진 패턴을 비교할 때, 피크 강도가 피크 위치보다 중요하다. 기준에 표시된 모든 강한 피크가 얻어진 샘플에 존재해야한다. 기준 패턴 결석 샘플 강한 피크의 출현은 불순물의 존재를 나타낸다. 1 ...

Watch this Scientific Journal Video about Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand at JoVE.com

Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand

비스 (iminoguanidinium) 리간드와 황산의 선택적 분리에서의 이용 현장 수성 합성을위한 프로토콜은 제공됩니다.

비스 - iminoguanidinium의 리간드 선택적 결정화에 의한 황산염 분리

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, ...

sulfate-separation-selective-crystallization-with-bis

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8.3K 조회수.  Oak Ridge National Laboratory.  비스 (iminoguanidinium) 리간드와 황산의 선택적 분리에서의 이용 현장 수성 합성을위한 프로토콜은 제공됩니다. 

비디오: Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand

Preparation and Characterization of SDF-1&#945;-Chitosan-Dextran Sulfate Nanoparticles

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under appropriate conditions. The glycan nanoparticles are useful carriers for protein factors, which facilitate the in vivo delivery of the proteins and sustain their retention in the targeted tissue. The glycan polyelectrolyte complexes are also ideal for protein delivery, as the incorporation is carried out in aqueous solution, which reduces the likelihood of inactivation of the proteins. Proteins with a heparin-binding site adhere to dextran sulfate readily, and are, in turn, stabilized by the binding. These particles are also less inflammatory and toxic when delivered in vivo. In the protocol described below, SDF-1&#945; (Stromal cell-derived factor-1&#945;), a stem cell homing factor, is first mixed and incubated with dextran sulfate. Chitosan is added to the mixture to form polyelectrolyte complexes, followed by zinc sulfate to stabilize the complexes with zinc bridges. The resultant SDF-1&#945;-DS-CS particles are measured for size (diameter) and surface charge (zeta potential). The amount of the incorporated SDF-1&#945; is determined, followed by measurements of its in vitro release rate and its chemotactic activity in a particle-bound form.

The objective of this protocol is to incorporate SDF-1&#945;, a stem cell homing factor, into dextran sulfate-chitosan nanoparticles. The resultant particles are measured for their size and zeta potential, as well as the content, activity, and in vitro release rate of SDF-1&#945; from the nanoparticles.

SDF-1α-키토산 덱스 트란 황산 나노 입자의 제조 및 특성

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under ...

연구

화학

Synthesis of Ligand-free CdS Nanoparticles within a Sulfur Copolymer Matrix

Aliphatic ligands are typically used during the synthesis of nanoparticles to help mediate their growth in addition to operating as high-temperature solvents. These coordinating ligands help solubilize and stabilize the nanoparticles while in solution, and can influence the resulting size and reactivity of the nanoparticles during their formation. Despite the ubiquity of using ligands during synthesis, the presence of aliphatic ligands on the nanoparticle surface can result in a number of problems during the end use of the nanoparticles, necessitating further ligand stripping or ligand exchange procedures. We have developed a way to synthesize cadmium sulfide (CdS) nanoparticles using a unique sulfur copolymer. This sulfur copolymer is primarily composed of elemental sulfur, which is a cheap and abundant material. The sulfur copolymer has the advantages of operating both as a high temperature solvent and as a sulfur source, which can react with a cadmium precursor during nanoparticle synthesis, resulting in the generation of ligand free CdS. During the reaction, only some of the copolymer is consumed to produce CdS, while the rest remains in the polymeric state, thereby producing a nanocomposite material. Once the reaction is finished, the copolymer stabilizes the nanoparticles within a solid polymeric matrix. The copolymer can then be removed before the nanoparticles are used, which produces nanoparticles that do not have organic coordinating ligands. This nascent synthesis technique presents a method to produce metal-sulfide nanoparticles for a wide variety of applications where the presence of organic ligands is not desired.

Herein we present a method to synthesize ligand-free cadmium sulfide (CdS) nanoparticles based on a unique sulfur copolymer. The sulfur copolymer operates as a high temperature solvent and a sulfur source during the nanoparticle synthesis and stabilizes the nanoparticles after the reaction.

황 합체 매트릭스 내의 자유 리간드의 CDS 나노 입자의 합성

Aliphatic ligands are typically used during the synthesis of nanoparticles to help mediate their growth in addition to operating as high-temperature ...

Preparation of Biopolymer Aerogels Using Green Solvents

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers (gelatin, agar, cellulose), only recently have biomasses been recognized as an abundant source of chemically diverse macromolecules for functional aerogel materials. Biopolymer aerogels (pectin, alginate, chitosan, cellulose, etc.) exhibit both specific inheritable functions of starting biopolymers and distinctive features of aerogels (80-99% porosity and specific surface up to 800 m2/g). This synergy of properties makes biopolymer aerogels promising candidates for a wide gamut of applications such as thermal insulation, tissue engineering and regenerative medicine, drug delivery systems, functional foods, catalysts, adsorbents and sensors. This work demonstrates the use of pressurized carbon dioxide (5 MPa) for the ionic cross linking of amidated pectin into hydrogels. Initially a biopolymer/salt dispersion is prepared in water. Under pressurized CO2 conditions, the pH of the biopolymer solution is lowered to 3 which releases the crosslinking cations from the salt to bind with the biopolymer yielding hydrogels. Solvent exchange to ethanol and further supercritical CO2 drying (10 - 12 MPa) yield aerogels. Obtained aerogels are ultra-porous with low density (as low as 0.02 g/cm3), high specific surface area (350 - 500 m2/g) and pore volume (3 - 7 cm3/g for pore sizes less than 150 nm).

A new way for the production of biopolymer-based aerogels by carbon dioxide (CO2) induced gelation is shown. The technique utilizes pressurized carbon dioxide (5 MPa) for the production of biopolymer hydrogels and supercritical CO2 (12 MPa) to convert gels into aerogels. The only solvents needed besides CO2 are water and ethanol.

녹색 용매를 사용하여 생체 고분자 에어로젤의 제조

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers ...

Capillary Electrophoresis to Monitor Peptide Grafting onto Chitosan Films in Real Time

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. Compared to other analytical separation techniques, such as chromatography, CE is cheap, robust and effectively requires no sample preparation (for a number of complex natural matrices or polymeric samples). CE is fast and can be used to follow the evolution of mixtures in real time (e.g., chemical reaction kinetics), as the signals observed for the separated compounds are directly proportional to their quantity in solution.
Here, the efficiency of CE is demonstrated for monitoring the covalent grafting of peptides onto chitosan films for subsequent biomedical applications. Chitosan&#39;s antimicrobial and biocompatible properties make it an attractive material for biomedical applications such as cell growth substrates. Covalently grafting the peptide RGDS (arginine - glycine - aspartic acid - serine) onto the surface of chitosan films aims at improving cell attachment. Historically, chromatography and amino acid analysis have been used to provide a direct measurement of the amount of grafted peptide. However, the fast separation and absence of sample preparation provided by CE enables equally accurate yet real-time monitoring of the peptide grafting process. CE is able to separate and quantify the different components of the reaction mixture: the (non-grafted) peptide and the chemical coupling agents. In this way the use of CE results in improved films for downstream applications.
The chitosan films were characterized through solid-state NMR (nuclear magnetic resonance) spectroscopy. This technique is more time-consuming and cannot be applied in real time, but yields a direct measurement of the peptide and thus validates the CE technique.

Free solution capillary electrophoresis is a fast, cheap and robust analytical method that enables the quantitative monitoring of chemical reactions in real time. Its utility for rapid, convenient and precise analysis is demonstrated here through analysis of covalent peptide grafting onto chitosan films for improved cell adhesion.

모세관 전기 영동은 실시간으로 키토산 필름에 펩타이드 접목을 모니터링하는

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. ...

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene

A reliable, intermediate scale preparation of 1,2,3,4,5-pentamethylcyclopentadiene (Cp*H) is presented, based on modifications of existing protocols that derive from initial 2-bromo-2-butene lithiation followed by acid mediated dienol cyclization. The revised synthesis and purification of the ligand avoids the use of mechanical stirring while still permitting access to significant quantities (39 g) of Cp*H in good yield (58%). The procedure offers other additional benefits, including a more controlled quench of excess lithium during the production of the intermediate heptadienols and a simplified isolation of Cp*H of sufficient purity for metallation with transition metals. The ligand was subsequently used to synthesize [Cp*MCl2]2 complexes of both iridium and ruthenium to demonstrate the utility of the Cp*H prepared and purified by our method. The procedure outlined herein affords substantial quantities of a ubiquitous ancillary ligand support used in organometallic chemistry while minimizing the need for specialized laboratory equipment, thus providing a simpler and more accessible entry point into the chemistry of 1,2,3,4,5-pentamethylcyclopentadiene.

Reliable, intermediate scale preparation of 1,2,3,4,5-pentamethylcyclopentadiene (Cp*H) is presented. The revised protocol for the synthesis and purification of the ligand minimizes the need for specialized laboratory equipment while simplifying reaction workups and product purification. Use of Cp*H in the synthesis of [Cp*MCl2]2 complexes (M = Ru, Ir) is also described.

가치있는 리간드에 액세스하면 전이 금속에 대한 지원 : 1,2,3,4,5-Pentamethylcyclopentadiene의 수정, 중간 규모 준비

A reliable, intermediate scale preparation of 1,2,3,4,5-pentamethylcyclopentadiene (Cp*H) is presented, based on modifications of existing protocols that ...

Syntheses, Crystallization, and Spectroscopic Characterization of 3,5-Lutidine N-Oxide Dehydrate

The synthesis of 3,5-lutidine N-oxide dehydrate, 1, was achieved in the synthesis route of 2-amino-pyridine-3,5-dicarboxylic acid. Ochiai first used the methodology for non-substituted pyridines in 1957 in a 12 h process, but no X-ray suitable crystals were obtained. The substituted ring used in the methodology presented here clearly influenced the addition of water molecules into the asymmetric unit, which confers a different nucleophilic strength in 1. The X-ray suitable crystal compound 1 was possible due to the stabilization of the negative charge in the oxygen by the presence of two water molecules where the hydrogen atoms donate positive charge into the ring; such water molecules serve well to construct a supramolecular interaction. The hydrated molecules may be possible for the alkaline system that is reached by adjusting the pH to 10. Importantly, the double methyl substituted ring and a reaction time of 5 h, makes it a more versatile method and with wider chemical applications for future ring insertions.

Syntheses, Crystallization, and Spectroscopic Characterization of 3,5-Lutidine N-Oxide Dehydrate

Herein, we report the synthesis and crystallization of 3,5-lutidine N-oxide dehydrate by a simple protocol that differs from the classical synthesis of pyridine N-oxide. This protocol utilizes different starting material and involves less reaction time to yield a new solvated supramolecular structure, which crystallizes under slow evaporation.

종합, 결정 화, 그리고 3, 5-Lutidine N의 분 광 특성-산화물 탈수

The synthesis of 3,5-lutidine N-oxide dehydrate, 1, was achieved in the synthesis route of 2-amino-pyridine-3,5-dicarboxylic acid. Ochiai first used the ...

Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and porous metal-dithiolene network in the highly ordered single crystalline state. Unlike the highly reactive free-standing thiols, which tend to decompose and complicate the crystallization of metal-thiolate open frameworks, the thioester reacts in situ to provide the thiol species, serving to mitigate the reaction between the mercaptan units and the metal centers, and to improve crystallization consequently. Specifically, the thioester was synthesized in a one-pot procedure: an aromatic bromide (hexabromotriphenylene) reacted with excess sodium thiomethoxide under vigorous conditions to first form the thioether intermediate product. The thioether was then demethylated by the excess thiomethoxide to provide the thiolate anion that was acylated to form the thioester product. The thioester was conveniently purified by standard column chromatography, and then used directly in the framework synthesis, wherein NaOH and ethylenediamine serve to revert in situ the thioester to the thiol linker for assembling the single-crystalline Pb(II)-dithiolene network. Compared with other methods for thiol synthesis (e.g., by cleaving alkyl thioether using sodium metal and liquid ammonia), the thioester synthesis here uses simple conditions and economical reagents. Moreover, the thioester product is stable and can be conveniently handled and stored. More importantly, in contrast to the generic difficulty in accessing crystalline metal-thiolate open frameworks, we demonstrate that using the thioester for in situ formation of the thiol linker greatly improves the crystallinity of the solid-state product. We intend to encourage broader research efforts on the technologically important metal-sulfur frameworks by disclosing the synthetic protocol for the thioester as well as the crystalline framework solid.

Here, we present a one-pot, transition-metal-free synthesis of thiols and thioesters from aromatic halides and sodium thiomethoxide, followed by the preparation of single crystals of a metal-dithiolene network using thiol species generated in situ from the more stable and tractable thioester.

반도체 Gyroidal 금속-황 프레임 워크의 결정 화에 대 한 Thiol 빌딩 블록의 합성

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and ...

Separation of Aldehydes and Reactive Ketones from Mixtures Using a Bisulfite Extraction Protocol

The purification of organic compounds is an essential component of routine synthetic operations. The ability to remove contaminants into an aqueous layer by generating a charged structure provides an opportunity to use extraction as a simple purification technique. By combining the use of a miscible organic solvent with saturated sodium bisulfite, aldehydes and reactive ketones can be successfully transformed into charged bisulfite adducts that can then be separated from other organic components of a mixture by the introduction of an immiscible organic layer. Here, we describe a simple protocol for the removal of aldehydes, including sterically-hindered neopentyl aldehydes and some ketones, from chemical mixtures. Ketones can be separated if they are sterically unhindered cyclic or methyl ketones. For aliphatic aldehydes and ketones, dimethylformamide is used as the miscible solvent to improve removal rates. The bisulfite addition reaction can be reversed by basification of the aqueous layer, allowing for the re-isolation of the reactive carbonyl component of a mixture.

Here, we present a protocol to remove aldehydes and reactive ketones from mixtures by a liquid-liquid extraction protocol directly with saturated sodium bisulfite in a miscible solvent. This combined protocol is rapid and facile to perform. The aldehyde or ketone can be re-isolated by the basification of the aqueous layer.

알 데히드 류와 Ketones 반응 황산 추출 프로토콜을 사용 하 여 혼합물에서 분리

The purification of organic compounds is an essential component of routine synthetic operations. The ability to remove contaminants into an aqueous layer ...

Analyzing Protein Architectures and Protein-Ligand Complexes by Integrative Structural Mass Spectrometry

Proteins are an important class of biological macromolecules that play many key roles in cellular functions including gene expression, catalyzing metabolic reactions, DNA repair and replication. Therefore, a detailed understanding of these processes provides critical information on how cells function. Integrative structural MS methods offer structural and dynamical information on protein complex assembly, complex connectivity, subunit stoichiometry, protein oligomerization and ligand binding. Recent advances in integrative structural MS have allowed for the characterization of challenging biological systems including large DNA binding proteins and membrane proteins. This protocol describes how to integrate diverse MS data such as native MS and ion mobility-mass spectrometry (IM-MS) with molecular dynamics simulations to gain insights into a helicase-nuclease DNA repair protein complex. The resulting approach provides a framework for detailed studies of ligand binding to other protein complexes involved in important biological processes.

Mass spectrometry (MS) has emerged as an important tool for the investigation of structure and dynamics of macromolecular assemblies. Here, we integrate MS-based approaches to interrogate protein complex formation and ligand binding.

단백질 구조와 통합 구조 질량 분석, 단백질-리간드 단지 분석

Proteins are an important class of biological macromolecules that play many key roles in cellular functions including gene expression, catalyzing ...

Electrophoretic Crystallization of Ultrathin High-performance Metal-organic Framework Membranes

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and non-porous supports (polymer, ceramic, metal, carbon, and graphene). We developed a novel crystallization technique, which is termed the ENACT approach: the electrophoretic nuclei assembly for the crystallization of highly intergrown thin films (ENACT). This approach allows for a high density of heterogeneous nucleation of MOFs on a chosen substrate via the electrophoretic deposition (EPD) directly from the precursor sol. The growth of well-packed MOF nuclei leads to a highly intergrown polycrystalline MOF film. We show that this simple approach can be used for the synthesis of thin, intergrown zeolite imidazole framework (ZIF)-7 and ZIF-8 films. The resulting 500 nm-thick ZIF-8 membranes show a considerably high H2 permeance (8.3 x 10-6 mol m-2 s-1 Pa-1) and ideal gas selectivities (7.3 for H2/CO2, 15.5 for H2/N2, 16.2 for H2/CH4, and 2655 for H2/C3H8). An attractive performance for C3H6/C3H8 separation is also achieved (a C3H6 permeance of 9.9 x 10-8 mol m-2 s-1 Pa-1 and a C3H6/C3H8 ideal selectivity of 31.6 at 25 &#176;C). Overall, the ENACT process, owing to its simplicity, can be extended to synthesize intergrown thin films of a wide range of nanoporous crystalline materials.

A simple, reproducible, and versatile approach for the synthesis of intergrown, polycrystalline metal-organic framework membranes on a wide range of unmodified porous and non-porous supports is presented.

Ultrathin 높은 성능 금속-유기 프레임 워크 막의 전기 이동 화

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and ...